Onshore Pipelines The Road to Success Vol 1 by IPLOCA

Onshore Pipelines

THE ROAD TO SUCCESS

An IPLOCA document – 3rd edition September 2013

VOLUME ONE

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

IPLOCA OBJECTIVES Objective 1 To promote, foster and develop the science and practice of constructing onshore and offshore pipelines, and associated works. Objective 2 To make membership of the Association a reasonable assurance of the skill, integrity, performance, and good faith of its Members, and more generally to promote good faith and professional ethics in industry. Objective 3 To maintain the standards of the contracting business for onshore and offshore pipelines and associated works at the highest professional level. Objective 4 To promote safety and develop methods for the reduction and elimination of accidents and injuries to contractorâ&#x20AC;&#x2122;s employees in the industry, and all those engaged in, or affected by, operations and work. Objective 5 To promote protection of the environment and contribute to social, cultural and environmental development programs, both in Switzerland and worldwide. Objective 6 To promote good and co-operative relationships amongst membership of the Association as well as between contractors, owners, operators, statutory and other organisations and the general public. Objective 7 To encourage efficiency amongst the Members, Associate Members and their employees. Objective 8 To seek correction of injurious, discriminatory or unfair business methods practised by or against the industry contractors as a whole. Objective 9 To follow the established Codes of Conduct set out by the industry and others with respect to working within a free and competitive market, and in doing so, to promote competition in the interests of a market economy based on liberal principle, both in Switzerland and worldwide. Objective 10 To maintain and develop good relations with our Sister Associations as well as Associations allied to our industry and play a leading role in the World Federation of Pipeline Industry Associations.

Disclaimer

In the preparation of THE ROAD TO SUCCESS, every effort has been made to present current, correct and clearly expressed information. However, the information in the text is intended to offer general information only and has neither been conceived as nor drafted as information upon which any person, whether corporate or physical, is entitled to rely, notably in connection with legally binding commitments. Neither its authors nor the persons mentioned herein nor the companies mentioned herein nor IPLOCA accept any liability whatsoever in relation to the use of this publication in whatsoever manner, including the information contained or otherwise referred to herein, nor for any errors or omissions contained herein. Readers are directed to consult systematically with their professional advisors for advice concerning specific matters before making any decision or undertaking any action.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

Executive Summary â&#x20AC;&#x153;Onshore Pipelines: THE ROAD TO SUCCESSâ&#x20AC;? was produced under the patronage of IPLOCA to describe state-of-the-art project development and execution practices for onshore pipeline projects. It is the collaborative result from six different working groups with the goal of covering all stages in the development of a pipeline project.

Section 1

Introduction Pipeline issues and challenges.

Section 2

Development Phases of a Pipeline Project Section 2 describes the key points to be addressed during the FEL (Front End Loading) phases in order to properly prepare for the project execution phase. Much of FEL is done well before a project is sanctioned and begins construction to ensure a complete project assessment so as to fully understand the challenges and risks associated with a proposed pipeline project. During this period, project investors and their design contractors typically have due diligence obligation to themselves and their shareholders to achieve good FEL and therefore control the work process and make the key project decisions. A detailed review of the data requirements and activities during those phases is included.

Section 3

The Baseline of a Construction Contract The next steps take place at the point of project sanction, where construction soon begins. A baseline understanding of the project scope and its risks must be established when investors and contractors enter into mutual agreement underlying a construction contract. This section offers recommendations for establishing the baseline for the Project Execution phases with four chapters: the Scope of Works, the Programme, the Cost and the Contract.

Section 4

Dealing with Risks in Pipeline Projects After project sanction, irrespective of all the efforts to reduce challenges and risks through the FEL phases, there will inevitably be other challenges and risks that arise. These may represent disruptions and changes to the established project baseline, so any pipeline construction contract must document how these residual risks will be addressed and managed.

Section 5

Best Practices in Planning and Design Best practices are developed in this updated section for planning and design, with the process leading to the definition of the ROW and the information to be gathered during the different phases of a project. The routing and design of a pipeline requires a disciplined and organised sequence of actions to ensure that the most acceptable and optimised route avoiding as many hazards as possible has been selected and that the system has been designed under acceptable standards to satisfy fitness for purpose, environmental constraints and safety. The Minimum Data Requirements and Activities for the Five Typical Project Stages introduced in section 2 are defined in this chapter.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

Section 6

Earthworks The terrain, soil types, and geohazards traversed by the pipeline are key factors to consider in the design, construction, operation and maintenance of a pipeline project. Firstly, the terrain typically affects pipeline hydraulics, above ground stations and pipeline protection. Secondly, soil types will affect heat transfer, pipeline restraint, and constructability. Finally, geohazards often require special design and construction considerations. The Earthworks section offers guidelines on how to prepare the right of way (ROW) in different types of terrain, on the earthworks design, on the recommended measures to reduce the impact on the environment, and on the approach to health and safety.

Section 7

Crossings This new section, to be further developed, is initiated with a description and comparison of the different methods to execute major trenchless crossings.

Section 8

Logistics The risks associated with the logistics of pipe such as handling, transport, coating and storage begin this new section.

Section 9

Welding

Section 10 Non Destructive Testing The section starts with a review of the main concerns of the different stakeholders of the pipeline for completing the project. The second subject will be the role of codes and standards in the design and building of pipelines. Finally the issues involved with NDT at the various stages of the project are addressed: • • • •

The role of NDT in the FEL/FEED stages. Vendor inspection and NDT at the material suppliers Girth weld inspection during the construction stage NDT during the use of the pipeline; considerations during the construction stage for future maintenance

Section 11 Pipeline Protection Systems Most of the installed and currently planned onshore transmission pipelines around the world are steel pipelines and their integrity during all the manufacturing, handling, storage, installation and service life stages is an important aspect of any pipeline project. As the external corrosion and the mechanical impacts have been identified as the most common causes of pipe damage and failure in onshore pipelines, industry’s efforts have been focused on addressing these issues in order to avoid potential economic, environmental and human costs from pipeline failures. Therefore, this document reviews the passive external anti-corrosion systems as well as the active cathodic protection approach. However, onshore pipeline projects can have other specific requirements. Supplementary mechanical protection systems that protect the steel pipes and their coatings against damage from external impacts are reviewed, along with internal coating systems and thermal insulation. The floatability phenomenon has to be mitigated on onshore pipelines crossing wet environments, such as lakes, rivers, or swampy areas and the industry has developed specialized buoyancy control systems which are being presented here.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

Section 12 Pipelines and the Environment Section 13 Future Trends and Innovation The onshore pipeline industry involves collaborative efforts between multiple stakeholders, each of them having a key role to play at one stage or more during the project life cycle. Understanding the involvement of each of these players is a vital step towards enhancing the operations on the pipeline project in the areas of efficiency, quality, safety, and the environment. The GIS-based construction monitoring tool, the pipeline simulation tool, the Equipment Tracking System and the use of Google Earth in pipeline construction monitoring are presented as components of a well-rounded Integrated Pipeline Construction Management (IPCM) System.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

Table of Contents (Volume One) Page

Executive Summary

Preface

1. Introduction 2. Development Phases of a Pipeline Project 3. The Baseline of a Construction Contract 3.1 Defining the Scope of Work

3.2 Programming the Work

3.3 Contract Price Information to Facilitate Evaluation of Changes

3.4 Considerations in Developing the Conditions of Contract

Appendix 3.2.1: Recommendations for establishing Project Execution Plan Construction Phase

Appendix 3.2.2: A Primer to March Charts

Appendix 3.4.4: Contractual topics that have a particular importance for onshore pipeline projects

Appendix 3.4.5: Project Cost Estimate and Contingency

4. Dealing with Risks in Pipeline Projects 4.1 Analysis, Allocation and Mitigation of Risks during all Phases of a Pipeline Project 4.2 Management of Construction Risks on Pipeline Projects Appendix 4.2.1: Examples of evaluation of time and cost impacts of full stoppages or of slowdowns

1 19 25

5. Planning and Design 5.1 Right of Way & Constructability Guidelines

5.2 Minimum Data Requirements and Activities for the Five Typical Project Stages

Appendix 5.1.1: Pipeline Route Selection Process

Appendix 5.1.2: Google Earth in Pipeline Design and Route Selection

6. Earthworks 6.1 Typical ROW Cross Sections for Large Diameter Pipeline

6.2 Earthworks Design / Trenching

6.3 Environment

6.4 Health and Safety

Appendix 6.2.: Pipeline Trench Design

Appendix 6.3.: Environment Control Measures

Appendix 6.4.: Health and Safety Control Measures

6.5 Onshore Pipeline Survey Requirements by Project Phase (NEW)

6.6 Site Investigation Process (NEW)

107

6.7 Non-intrusive Survey Techniques (NEW)

111

6.8 Buoyancy Control (NEW)

126 7

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

7 Crossings 7.1 Trenchless Crossings

Glossary of Acronyms Bibliography Acknowledgements

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

Preface “Onshore Pipelines – THE ROAD TO SUCCESS” has been prepared and written under the patronage of IPLOCA, the International Pipeline and Offshore Contractors Association. IPLOCA is a non profit association with the key objective of fostering and developing the science and practice of constructing onshore and offshore pipelines and associated works. IPLOCA also promotes co-operative relationships between contractors, oil & gas investors & owners and other stakeholders in the pipeline industry and has established fruitful relations with some of the major oil & gas companies since its inception in 1966. This document relates to onshore pipeline projects only. Joint Development of “THE ROAD TO SUCCESS” In 2003 a joint project started on a concept of industrialising the laying of large-diameter pipelines for better, safer and faster installation. The land train concept was studied and a number of working groups were formed to identify the main bottlenecks and fields of potential improvements. The land train concept, which only addressed the pipeline construction aspects, was dropped in favour of a broader perspective that addresses all phases of the onshore pipeline project from early development through design, construction and commissioning. The joint work continued and all parties were very keen to develop the findings identified during the earlier phase; the result is summarised in the present document “Onshore Pipelines – THE ROAD TO SUCCESS” (herein after referred to as “THE ROAD TO SUCCESS” or “THE ROAD”). The list of those companies and persons having participated in this joint effort is included in the Acknowledgements section. It comprises persons coming from oil & gas investors & owners, design companies, construction contractors, suppliers and specialised subcontractors. This joint approach aims at producing a document that can be used by all stakeholders in the pipeline industry. To whom this document is addressed “THE ROAD TO SUCCESS” has been prepared to assist all stakeholders who participate in the development and construction of pipeline projects whether on a one-off or a regular basis, and in particular: - Investors/owners’ project managers, senior management and project engineers - Designers’ project managers, senior management and project engineers - Environmentalists who may be involved in pipeline projects - Construction contractors and subcontractors key construction personnel, Senior management and project engineers - Students and teachers in the pipeline industry It is IPLOCA’s sincere wish that THE ROAD TO SUCCESS will become a reference document for use in the training of people coming to the pipeline industry.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Preface

Objectives “THE ROAD TO SUCCESS” is prepared towards better identifying the key drivers in a pipeline project from development to commissioning. This knowledge should in turn • • •

Improve the preparation process of pipeline projects for mitigation of risks towards a more certain delivery date and budget Improve the relationship between investors/owners and construction contractors for the success of the projects Improve the competitiveness of the pipeline industry through sound engineering & construction practices and innovative solutions

“THE ROAD TO SUCCESS” is designed to focus on issues that concern specifically the onshore pipeline industry. General contracting issues are dealt with in existing publications some of which are listed in the Bibliography section. The intent is to provide the reader with the basic knowledge required to improve the delivery of a project, i.e. cost and schedule, whilst reducing the environmental footprint and achieving the desired safety objectives.

Collaboration with Research Entities As referred to in the First Edition, IPLOCA has moved forward by signing a Memorandum of Understanding with APIA (Australian Pipeline Industry Association), EPRG (European Pipeline Research Group) and PRCI (Pipeline Research Council International) to jointly develop research projects related to our industry. IPLOCA is proud of having served as a forum for such achievement and is committed to continue developing and promoting this document and our pipeline industry.

This Second Edition is published in ring binder format to allow for more practical and environmentally friendly updating of the book as the initiative progresses. The Second Edition is also available on DVD.

IPLOCA is proud of having served as a forum for such achievement and is committed to continue developing and promoting this document and our pipeline industry.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Preface

1. Introduction Pipelines and IPLOCA A pipeline is a facility through which liquids (crude oil and petroleum products), gases (natural gas, carbon dioxide, steam) or solids (slurries) are transported. Although other forms of transportation are available (tanker, road, rail), pipelines are the safest and most efficient means of transporting crude oil and natural gas from producing fields to refineries and processing plants, and of distributing petroleum products and natural gas to the consumer. Pipelines are the irreplaceable core of fluid product transportation across the world. They reach billions of consumers, directly into households and cars. Pipelines are selected as the main mode of transportation due to economics and safety. Road transportation costs escalate with distance, making road the most costly option. Rail is less dependent on distance, but still costly. Ship tankers are comparable to pipelines in terms of cost, but are limited by geography. Estimated percentages of volumes transported by each mode of transport are shown below.

Pipelines are not new. It is believed that pipelines were used from around 500 BC in China to transport gas. Since then the design and construction development of pipelines has continued, and in recent years pipeline contractors and investors from around the world have worked together within IPLOCA. IPLOCA was formed to share ideas, engage the industry and its stakeholders to facilitate business opportunities and promote the highest standards in the pipeline industry. With members in more than 40 countries, IPLOCA represents some 250 of the key players in the onshore and offshore pipeline construction industry worldwide.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Introduction

Pipeline Issues and Challenges International pipeline projects can be both challenging and rewarding. Challenges arise from the inherent interactions between the land, the pipeline route, the communities which live and work nearby and the further complexities of international languages, cultures, traditions, logistics, regulations, legal systems and business practices. The potential for catastrophe is always lurking close at hand to catch the na誰ve or complacent investor and contractor off-guard. However, when these challenges are successfully addressed, leaving a pipeline system with solid integrity and performance as well as satisfied investors, contractors and communities, projects can be very rewarding, both in financial terms as well as in the esteem accorded to all those involved. It is not always clear to investors or contractors how to overcome the challenges to reap the rewards. They begin the project journey together, often entering at different stages along the way, always with every intention of reaping the rewards, but all too frequently without an awareness of the challenges they face. When a challenge is encountered, temptation often overtakes the carefully-nurtured relationships and good intentions, leading either the investor or the contractor to expect, even demand, that the other part take some action on behalf of the project to remove a challenge, with little or no effort on their own part to address the very challenge they also face, being integrally involved in the very same project. Unexpected challenges usually lead to misaligned expectations that damage the project and the intended rewards for both parties. This dynamic has not been lost on the industry, especially the contracting experts within it. Contracting legal and commercial tools have developed to an ever-increasing sophistication, often attempting to commit one party or the other to bear the full consequences of any challenge the project might encounter, invoking the inevitable defensive reactions. Many explicit contract terms and conditions currently in use have been crafted in response to very specific known challenges. But not all challenges can be predicted in advance so, as new challenges become more widely understood within the industry, more and more terms and conditions are reactively developed to try to assign the challenge to one party or the other. Unfortunately, the projects which discover emerging challenges first, or are without benefit of prior experience, find themselves contractually ill-equipped to address the issues that arise. Prevailing contracting law and practice frequently falls back on obtuse and implied contractual obligations, leading to extended and often venomous disputes. The relationship and interactions between investor and contractor quickly become almost entirely focused on the dispute, leaving the project vulnerable to further challenges and disputes with the attendant loss of the rewards that enticed both parties to enter the journey to begin with. A downward spiral of failure easily and frequently results. The primary beneficiary is the litigation industry; everyone else loses. Various methods of conflict resolution or nearlitigation have been developed and are sometimes employed, but they all share the fundamental flaw of dealing with conflicts reactively.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Introduction

Key Principles There are three key principles that, if recognized and honoured, can prevent international pipeline projects from such a sad fate: 1. Projects are only successful when they establish, nurture and protect close working relationships between investors and contractors by jointly anticipating conflicts and preparing agreements and commercial terms that enable predictable, effective and amicable resolution. Unresolved project conflicts during project execution escalate and multiply rapidly as they damage the working relationships between investor and contractor and distract the attention of the project team from other challenges to come. 2. It is far better to proactively avoid and reduce project challenges than to assign their resolution, even amicably, to only one of the parties in a contract. Challenges add effort and cost, both of which inherently reduce the rewards for all the parties involved. The earlier in the project cycle the challenges are recognized and addressed, the more reward is preserved. Early data collection, design and planning during project development are essential in this respect. 3. A contract is nothing more than a document recording an agreement between two or more parties. It is essential to establish the mutual agreement before developing and executing the contract. Such an agreement for international pipeline projects must include, inter alia, how each party will address the mutually identified project challenges, both those known at the time and those as yet unknown. If an explicit and mutual agreement between the parties does not exist in the first instance, any attempt by any party to use a contract document to force an action later is unrealistic, counterproductive, abusive, unprofessional, manipulative, aggressive and rightfully interpreted as a prelude to (commercial) war.

THE ROAD TO SUCCESS It is with these key principles in mind that working groups, drawn from IPLOCA member companies and a select group of international oil companies, set out to create this guidance document called the THE ROAD TO SUCCESS. Our combined experience has led us to recognize why we have struggled on some projects before, why many projects have succeeded and what we need to do consistently to work together more effectively and succeed more often. It describes how to anticipate and avoid challenges before beginning construction, how to conduct construction work to minimize exposure to further challenges and, lastly, how to reach the mutual agreement necessary as the foundation for a successful contract, addressing both known and as yet unknown challenges. It is our firm belief that the approach outlined on THE ROAD TO SUCCESS will work anywhere in the world with any investor or contractor on any pipeline project under any form of contract compensation. THE ROAD TO SUCCESS is fairly simple in concept, but requires a degree of fair-minded and commercially mature behaviours if travellers are to complete the journey. The junctions on THE ROAD simply are: 1. Properly develop the project before beginning construction with, inter alia, adequate engineering performed by a multi-skilled team including construction and environmental input. 2. Establish a clear baseline for the project in the construction contracts, including the scope, the risks and the plans for responding to those risks. 3. Plan for all the risks involved with international business, but especially for those that are unique to pipeline projects but common within our industry. 4. Develop contract agreements, terms and conditions to predefine responses, responsibilities and commercial adjustments, ready to respond to unanticipated project challenges or events. 5. Implement best practices in Planning and Construction Techniques and evaluate merits of future trends and innovative solutions.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Introduction

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

Development Phases of a Pipeline Project

Pipeline projects are usually completed in five stages:

•

Three front-end loading (FEL) stages for business planning, facility planning and project planning

• •

Project execution stage Start-up and operations stage.

THE ROAD TO SUCCESS covers the three FEL phases and the project execution phase. The diagram below highlights a staged-gated project system and should be reviewed in conjunction with the minimum data requirements and activities for each FEL phase described in section 5.2. It is imperative that the foundations of any project are sound: front-end loading (particularly FEL 1 and FEL 2) forms a key part in providing the necessary framework and structure for a successful project.

Staged-Gated Project System

Front-End Loading FEL 1: Business Planning

FEL 2: Facility Planning

FEL 3: Project Planning

Project Execution

Start-up And Operations

Owner/Developer Engineer Construction Input Construction Contractor Operator

Active Participants Active participants through the lifecycle of the project have been highlighted above.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

2.1

Front-End Loading (FEL) Phases

Some of the key considerations that need to be defined during the three FEL phases include: Product availability Applicable codes and standards Product quality

Risk of natural hazards and human threats Pipeline route and its right of way corridor Topographic and geotechnical data Materials (linepipe, valves, tees, flanges, traps) Corrosion allowance

Design temperature

Stations (compressor, pump)

Design capacity

Above ground installations (valve stations, pigging stations, metering stations, off take stations) SCADA/telecoms

Pipe OD Pipe wall thickness

Maintenance and inspection requirements

Inspection requirements Pigging devices/integrity assessment Protection requirements (trench depth) Expansion mitigation

Corrosion coating, field joint coating Cathodic protection Insulation Operational philosophy (hydrates, waxing, asphaltenes)

Isolation valve spacing Crossings design Overpressure protection (surge protection, linepack)

Design life Design pressure

Leak detection Metering requirements

Inspection philosophy Schedule

Cost estimates Construction methodology • Camps • Clearing and grading • Material logistics • Ditching • Welding • Pipe bending • Field coating • Backfilling • Hydrotesting • Final grading Pipeline operations

2.1.1 Business Planning FEL 1 Before starting a project, the pipeline owner/investor (the body funding the project) must prove the economic viability and need for the project i.e. will the project produce the required revenues and profit? This phase captures the reasoning behind initiating the project and can take considerable time to prepare. FEL 1 includes:

• • • • • • • 2

Business case Strategic objectives Economic analysis Project expectations Market analysis Competitors review Environmental constraints

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

2.1.2 Facility Planning FEL 2 The purpose of FEL 2 facility planning (sometimes referred to as feasibility, preliminary, or pre-FEED), is to ensure the selection of an optimum solution and put some details behind the project. Here we can confirm the physical viability and anticipated cost of a project before any unnecessary time and energy is wasted. This stage of the plan can take from 2-6 months depending on project complexity. FEL 2 facility planning includes the review of:

• • • • • •

Environmental and social issues Routeing Pipeline dimensions (OD, WT, length) In-line facilities (pumps/compressor stations) Regulatory and governmental requirements Preliminary schedules

Led by the owner, developer or an appointed and experienced engineering contractor, these issues are performed by a joint team and should include a range of technical, engineering, environmental, social and legal specialists. The level of cost estimate at this point is typically +/-30%.

2.1.3 Project Planning FEL 3 Project planning or the FEED phase looks to develop the approved selected solution by narrowing the cost estimate to +/-15% and achieving a higher level of development schedule. At this point any project showstoppers would have been identified as part of the environmental and social impact assessment process and suitable mitigation measures agreed with the relevant stakeholders (as part of the project consent). It is only when consent has been granted that project sanction takes place and particularly since it is then possible to place material orders for long lead items (LLIs) at this stage so as to meet the development schedule. Project planning could take from 6-12 months depending on the complexity of project and the environment through which it is routed. If the pipeline has not managed to avoid sensitive environments, timescales for the FEL process can be extended by many months whilst detailed ecological or cultural studies are performed. In comparison with plant projects, the cost of FEL developments for a pipeline project are typically lower, except for possibly international cross-border pipelines or complex systems such as high temperature pipelines (design temperature > 70ºC), high pressure pipelines (design pressure > 200 bars), or fast track projects. However, whilst the cost of the development activity is lower, it is still significant and often underestimated. Pipeline project facility planning (FEL 2) for example can range from one third to three quarters of the activity associated with plant developments. However, the time taken can in certain circumstances be longer.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

2.2

Key points to address during FEL

For many project teams the development of a pipeline may be a once-in-a-career event so experience brought to the development may be limited. This often results in the required technology and development processes for pipelines being underestimated by the new developer with the design and plan far exceeding that expected, especially considering the management and approval processes which take time and effort to put into place. Directed by the inexperienced, a new development can be guided down the wrong path, which can lead to disappointing results, such as extended schedules, increased costs and an unfit-for-design installation. In order to limit disappointing results the following key points should be addressed:

•

Hire fully-qualified multi-skilled engineering resources with relevant experience

•

Design basis, operational and HSES philosophies are in place to fully define the safety, performance and operation requirements of the completed installation

•

Ensure adequate data is available for engineering (design conditions data, social and environmental data, geotechnical and topographical data)

•

Provision of pipeline technical designs to ensure clear and concise installation and that construction specifications and drawings can be produced

The key issues to be addressed will depend on the project type, size, length, location, terrain and whether it is inter-country. This will include a review of land-take, biodiversity, heritage, pollution control, agricultural disruption, traffic management, loss of remoteness, communicable diseases, employment and trade opportunities. Besides, no matter the type and size of the project, it is essential for investors/owners to develop their project execution planning from the early phases of the front-end loading. Too often this task is left to the construction contractor at the beginning of the project execution phase or during FEL 3 in case of EPC projects. Whilst the establishment of a very exhaustive and detailed project execution planning by the contractor is essential at that time (refer to section 3.2 and Appendix 3.2.1), the investors/owners should initiate it to control in a disciplined manner the progress of the project development. This should include contracting strategy; team participants and roles; integrated programmes with critical path activities and items; plans for health and safety; environment and quality; controls; costs and schedules. It is also important to remember that a pipeline project is a multi-discipline (joint team) effort involving pipeline engineers, metallurgy, process, control systems, electrical, piping, civil, mechanical as well as social, cultural and environmental specialists. Besides the pipeline design, other activities include SCADA and Telecoms, power supply, inline facilities such as valve stations, metering stations, scraper trap station design, rotating equipment selection and specifications. All the activities in FEL phases 1, 2 and 3 are key to attain a good foundation for the project. It will not help the schedule if a better development option has been found in FEL 3, because it will include retracing back to FEL 2. This is not an unusual occurrence resulting from a poor study/feasibility phase. A good study phase needs an open forum for ideas where all ideas are equally considered, however outlandish.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

All areas in business planning are key. It is important that an engineer with broad experience is involved in this phase, who could highlight key driver issues, such as environmental, social, pipe parameters (OD, length), in-line facilities and cost metrics. For the facility planning phase, there should be some joint environmental and construction expertise input, particularly in developing the construction schedules. Environmental restrictions can play a major part on the length of the schedule, or the number of construction spreads required to meet a particular schedule. This is also the phase when health and safety requirements to achieve the â&#x20AC;&#x153;zero accident and no harm to personsâ&#x20AC;? will be taken on board and further developed in the project planning phase to be fully in place for the construction and operation phases. For project planning, a whole range of issues and experts will need to be consulted, so as to address the potential key issues described above and also detailed in section 5.2.

The diagrams hereafter illustrate the fact that the front-end loading phases of the project are where the owners/investors have the most influence and impact on the project with the least cost and expenditures. Key decisions left to later in project lifecycle come with a penalty of high cost, with little influence to change the outcome.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

Fig. 1 â&#x20AC;&#x201C; Influence and expenditure profiles over time Fig. 1 indicates that at the early phases of the FEL process whilst expenditure is low, big decisions are made. â&#x20AC;&#x153;Where will the pipeline go? Will we build a pipeline or use ships?â&#x20AC;? The ability to influence the form of the project is high. It is thus essential at this stage that the investor and the engineer work closely and consider the value added outcomes of all potential solutions. For this to be effective, experience is essential. As the project moves to the next FEL stage the major project decisions have been made but critical parameters are yet to be fully addressed. The ability to influence the project is still high. It is therefore fundamental at this stage to gain more understanding of the route and of the system design. The system design will define the pressures, flows, pipe diameters and pump or compressor station requirements. However the main drive is to gain more knowledge of the route options and to remove uncertainty. Key factors for review are generally the pipeline profile, soil conditions and potential environmental and social constraints. As the expenditures are still low constraints such as unstable terrain or environmentallysensitive areas can be coped with by major re-routeing without disruption. The influence and expenditure graph shows how progression through the project phases results in a lower ability to influence the design. On a pipeline this is truer than with a plant development. The influence line drops off faster through FEL 3. However the expenditure on a pipeline even at this stage is low in comparison with plant developments. It is therefore essential to ensure experience and knowledge is used effectively at these early stages of the work. During FEL 3 it is likely that commitments will be made to authorities and land owners, the form of the project is almost fixed.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

Contingency Progression Per Project Phase

Fig. 2 The balance of contingency and estimated cost changes through the 5 project stages As with most standard estimating methods, the early stages of the project are called “screening estimates” or “conceptual estimates”. In these early stages of the project things remain undefined and a large contingency is required to cover the expected but unknown aspects of the design. In pipeline terms the knowledge of soils and land issues as well as an optimised system design has not been completed. The routeing is based on maps or images and the sizing based on norms and simplistic assessments. The project estimate “baseline” at this stage is therefore made up of the estimated price and an almost equal level of contingency. At this stage of the project this is not a real problem for the investor as he is looking to provide data that provides him with comparisons with other potential developments and to see if his expected returns can be realised. It should be realised that contingency is part of the estimate and is not discretionary or padding: it will be spent. Addition of arbitrary contingency to cover the estimate shortfalls is thus not a tenable solution. What remains a problem at the early stages of development is the project risk and how this will impact planning and quality or certainty of the baseline. Contingency should not be confused with design allowances or development or with management reserves (see Appendix 3.4.5 “Cost estimate of a pipeline project/contingencies”). As the project leaves FEL2 the feasibility has been tested the routeing information has been improved and the sizing of the system has been scoped and understood. The level of unknowns is lower and the contingency can be reduced. Throughout the stages of the project the knowledge and certainty improve until the developer is confident enough to sanction the full expenditure. It can be seen that if the work is performed well the out-turn cost or “baseline cost” of the project remains the same and contingency and unknowns are exchanged for certainty and knowledge. We are reducing project risk and becoming more confident of the baseline estimate.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 2

Fig. 3 Reduction of project risks during the FEL and execution phases Figure 3 illustrates that during the FEL phases the reduction of project risks is the most effective. It also shows how the total process of FEL and execution fits together. Of course even at project handover some operational residual risk still exists although if the process has been followed correctly this should be minimised.

Conclusion This section has stressed the importance of properly planning and executing the FEL 1, FEL 2 and FEL 3 phases towards safely executing a quality construction works within the optimum cost and schedule. It requires the early involvement of all experts under an integrated team during these phases covering the following topics:

• • • • • • • •

Safety Environment Construction Public relations Operations Pipeline design Socio-economic factors Security

Further information on the minimum data requirements and activities for each FEL phase is included in section 5.2. At a certain point of the FEL 3 a baseline will be established for the purpose of agreeing the construction contract. This is the subject of section 3.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 3

The Baseline of a Construction Contract

The recommendations below can be classified in four categories:

•

Detailed definition of the scope of works, of the physical conditions of the site, of the environment and of the socioeconomic and local constraints. This will define the baseline of the contract to be entered by the parties.

•

Establishment of a detailed project execution plan, including a fully resourced programme of the works described in the baseline to monitor progress and promptly assess the time impact of changes to the project or to its environment.

•

Recommended extent of the cost information to include in all the contracts may vary from just one of: • • • •

Cost plus Bill of quantities Activity schedule Lump sum

or a combination of the above, to enable a prompt evaluation of the cost impacts of: • Changes to the project or to the environment of the project • Mitigation measures elaborated to reduce the adverse consequences of the above changes

•

The conditions of contract

In this section and the following section 4, the owner/investor will be called the “client” being party to a contract entered into with the “contractor”, the other party.

3.1

Defining the Scope of Works

The scope of works also includes the physical conditions of the site, of the environment and of the socioeconomic and local constraints

3.1.1 Scope and Physical Conditions

•

Definition of the pipeline route/right of way… (see also section 5.1.1)

The pipeline route and its impact on the environment will need to be considered, justified and approved by regulators, the general public and land owners. Hence, consultation is a key part of routeing. Key environmental and regulatory steps are illustrated overleaf.

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The development of a pipeline route commences with the known start and end points, for example a gas field and a LNG terminal. Sometimes the integration of the terminal location with the route which a pipeline can take will also be a variable to consider. Once the end points are determined, the routeing becomes an iterative process starting with the consideration of a wide area of interest and several potential corridors. As major constraints and cost drivers are considered the investor/owner and the engineering team begin the process of refinement. The chosen corridor which emerges is progressively narrowed as the FEL process continues and as more data is available. At the end of FEL 3 the route is defined as the final right of way (ROW). Typically the route alignment steps are:

• • • • • • • •

Multiple 10 km wide corridors between the two end points of the pipeline 10 km-wide corridor of interest • Desktop routeing/satellite imagery 500 m-wide ‘preferred route corridor (large scale maps) Route using route maps with scale 1:50,000 100 m-wide ‘ specified corridor’ (more detailed maps) Large/scale routeing: detailed routeing using 1:5,000 to 1:10,000 maps 20 to 40 m-wide ‘construction corridor’ (detailed routeing/preliminary surveys) • Site reconnaissance; surveys; soils data; initial consultations with statutory authorities; preliminary alignment sheets 8 m-wide ‘permanent corridor’ (ROW) (final surveys)

Special attention is to be paid to ROW sections which may not be fully available at the commencement of the works due to land availability or environmental constraints. They should be clearly identified and become a programme constraint similar to sections where flooding or snow prevents access part of the year. Anticipation of such situations is more productive than facing the problems once the full spread(s) is in progress and suddenly stopped or disrupted.

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•

Other land areas beyond the linear construction corridor of the pipeline are required for: • Access routes to the right of way • Designated areas for camp sites • Waste disposal locations • Pipe storage area • Borrow pits • Benching (on side slope) • Additional working space adjacent to road, rail, water and special crossings (such as archaeological areas or environmental constraints) • Temporary nursery sites/translocation areas for storing turves, plant material or temporary removal of protected species • Compensation or accommodation works (agreed as part of the consent/easement) • Temporary airstrips and helipads • Temporary right of way for laying pipelines to water sources for the provision of water tests

These areas should be established and detailed as part of the FEL process.

• • • • •

• • •

Description of the geological assumptions together with an allowance for variations to be part of the baseline Seismic and volcanic constraint Crossing assumptions Other special physical constraints resulting from environmentally sensitive areas, archaeological surveys etc. Specific quality requirements for pipe and pipe protection such as: • Land pipe requirements (metallurgy for steel pipes etc.) • External mainline pipe coating, field joint coating and supplementary mechanical protection system (see section 11) Description of the extent of early works which are being carried out by others to provide, for instance, additional accesses to the site, drainage works, ROW clearance, crop removal and of their expected completion dates Description of additional site investigation or product testing (by whom) to conduct at the commencement of works and to include in the baseline Detailed description of the standards of reinstatement required

3.1.2 Health and Safety, Environment, Socioeconomic and Local Constraints The HSES requirements are essential aspects of a project development. Historically, whilst pipelines provide a very safe and environmentally friendly form of transportation, lost time incidents and other issues are still evident during construction. HSES costs time and money to implement effectively and must be planned for in depth from the outset of the development. Commercial pressures may develop to scale down costs at all levels of a project. Clients must prevent any scope or cost reduction in the field of HSES and define clearly from the onset the detailed requirements as described overleaf.

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The environment and the socio-economic and local constraints should be clearly defined in the contract documents and are generally contained in the social and environmental impact assessment. A summary of the commitments made as part of the pipeline routeing and FEL stages 1, 2 and 3 should be included in the scope of works as part of the construction contract and identified on the alignment sheets.

•

Detailed Health and Safety requirements in terms of organisation (detailed list of qualified personnel), provision of facilities (training schools, hospitals, infirmaries etc.), training requirements and expected targets to achieve plus allowance for additional resources to be part of the Baseline

•

Health provisions including working in contaminated land, dust inhalation, extremes of temperature and working time restrictions

•

Transmission of pests, diseases and alien species (plant material), particularly when working in intensive agricultural regions, or animal husbandry areas

•

Detailed environmental requirements (limitations on emissions, surface discharge, effluents, noise, waste selection and treatment; special treatment fauna and flora; special measures near living areas etc.) and allowance for potential additional requirements to be part of the baseline

•

Precise description of the weather assumptions to be part of the baseline together with the assumptions for flooding, snow and storms, all of which have a significant influence on the programme of works and on the way resources are mobilised

•

Detailed security measures envisaged in the context of the country where works will be carried out

•

Special attention to the socioeconomic environment including the extent of the required actions to be undertaken by all parties (i.e. public meetings, brochures, media publications, TV programmes etc.) in this respect should be well defined in a plan and part of the baseline with whatever allowance necessary to include. They should include inter alia the requirements of the laws of the country, of any special agreement made at government level or possibly of the financial institutions

•

Where applicable, description of the specific local constraints negotiated with the local governments or administrations: they may cover employment conditions of labour and staff, working hours, restrictions on employment of foreign labour and staff, procedures for permits and licences, custom procedures and restrictions, definition of the laws and regulations to apply to the project, accommodation works agreed with the local landowners or local administration organisations

•

Archaeology and protection of cultural sites of significance should be dealt with sensitively and in accordance with the consent conditions and local laws and customs

It is the responsibility of the client and its technical advisors (engineers, land agents and environmental advisors) to provide the contractor with a clear summary of the restrictions identified along the route of the pipeline and of the commitments which have been agreed during FEL phases 1, 2 and 3.

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3.2

Programming the work

The detailed project execution plan established for the construction phase (see Appendix 3.2.1 for detailed recommendations) of the works defined in the baseline will result in a fully resourced programme of works (manpower, plant, material, facilities) as defined below. A detailed March chart for all the linear activities combined with standard critical path method (CPM) programmes for fixed installations (such as pump/compressor stations or valve stations) should constitute this resourced programme. The March chart should incorporate all the details of the terrain (roads, railways, waterways, electrical power lines, underground utilities), expected ground conditions, anticipated weather in relation to the seasons and geography (mountains, low lands, arid zones, deserts, swamp areas), environmental constraints, local community constraints and political constraints as defined in the baseline. It is the recommended tool to assess correctly the complexities of a pipeline project, to evaluate the criticalities of the programme of works, to follow up progress and promptly assess the impacts of disruptions, changed conditions and stoppages as compared with the baseline (see Appendix 3.2.2 â&#x20AC;&#x201C; â&#x20AC;&#x153;A Primer to March Chartsâ&#x20AC;?). A typical sample is presented overleaf:

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 3

Extract from the March chart on the previous page:

In order to arrive at an acceptable construction programme, the following should be established in detail:

•

The minimum mobilisation time necessary for the contractor and the client (the engineering team where applicable) to assemble their teams, who will have to familiarise themselves with the project as a first step, then plan in detail and mobilise resources. Considering the pressure to get the project in operation as early as possible this preparation time can often be reduced to nearly nothing: this is certainly detrimental to achieving a proper “kick-off” to the project. Indeed the teams who tendered a contract on the contractor’s side and the teams who prepared and evaluated those tenders on the client’s side are not always the teams who will execute the project. Therefore a minimum preparation period varying from a few weeks to a few months, depending on the size and complexity of the project, in addition to the proposed construction programme, would certainly lead to a smoother development of the operations (unless that preparation period has been included in the tendering process as a step in the finalisation of the contract with the preferred tenderer)

•

The average rates of progress for the different activities I, II, III,…which are dependent on the terrain, the ground conditions, the weather at the considered period of the year, the environmental constraints, the local constraints and obviously the resources allocated

•

The minimum time lag between two activities, A0 (between activity I and II), B0, C0,… shown in the March chart extract above, should also be clearly established taking into consideration: • The contractor’s own constraints (learning curves, changing the teams of local labour when crossing different regions, maintenance of equipment, breakdowns) • The expected weather conditions at a given period of the year which may affect progress of one activity more than one of the following activities (e.g. rain at PK 100, good weather at PK 80) • The client’s constraints: the client may demand that allowances for minor stoppages should be incorporated (and priced) in the base programme (e.g. 2 days per month to cater for design considerations, local disturbances, shortage of some supplies etc.) or that there should be a limit to the distance of the various phases of the works

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With such a tool the most critical sequences of works will always be highlighted and the effects of changes or disruptions to the project on the programme of works can be promptly assessed. Any areas where the contractor considers the information is incomplete or alternative routeing/construction/mitigation measures should be considered should be clearly identified early in the construction programme to allow for consultation with the client, their advisors, local landowners and stakeholders.

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3.3

Contract Price Information to Facilitate Evaluation of Changes

Experience shows that the major cost impact of changes on projects is the additional cost of teams and resources related to the additional time they spend on site either working with full running costs or in standby with reduced running costs. Changes to the baseline/disruptions/stoppages have in general two consequences for a project:

• •

The duration of certain activities will be extended There might be a need for mobilising additional resources to mitigate an overall extension of project duration

In this section and in section 4 the word “cost” is understood from a client’s point of view: it means the price paid by the client to the contractor which includes the contractor’s direct and indirect costs, its overheads and profit. Therefore, in order to allow both client and contractor project management teams to promptly evaluate the cost impacts of changes and/or disruptions to a project, the contract price should include the breakdown of the weekly costs of the main working crews in operation (including energy, spare parts and consumables for the equipment and machines used as well as labour and staff costs including food, lodging and transport) and the weekly costs of the site overheads (offices, stores, yards etc.), as well as that of the management overheads, combined with a schedule of the costs of the same working crews in standby (when no energy and consumables for major equipment is used), and of the costs of potential mitigation measures (such as cost of moving different crews in relation with distance). All weekly costs would exclude the cost of incorporated materials since their cost impact is quantity-related instead of time-related. Examples of time-related costs (weekly costs) for a pipeline contract together with examples of evaluation of time and cost impacts of stoppages are attached in Appendix 4.2.1. In the case of cost plus type contracts, the actual costs plus fees are compared at given intervals to a bill of quantities or an activity schedule, which should include such time related cost information as described above. In the case of bill of quantities or activity schedule type contracts, these time-related costs should be incorporated as bill items or activity items in the pricing document. In the case of lump sum contracts, a breakdown of these time related costs should be in an appendix attached to the tender. This time related cost information, together with the fixed costs for mobilisation of teams, equipment and facilities (which generally form part of most contracts but should also be included in the lump sum tenders), are essential management tools to assess changes.

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3.4

Considerations in Developing the Conditions of Contract

Traditionally, contracts terms tend to be issued by clients, and market forces and/or financial institutions tend to drive in their favour. Too often risk allocation continues to be pushed from one party to another depending on prevailing environmental or market conditions, with little consideration to the loss of potential value and earnings incurred due to inattention to reducing the risk to begin with. However, as a general principle, the conditions of contract (general conditions and particular conditions) should not be overly favourable to one contracting party vis-Ă -vis the other(s). Indeed, experience shows that construction and operational risks are best allocated where they can most appropriately be managed and borne. A fair contract helps to significantly reduce the risks of conflicts, delays and disruptions when difficulties occur in the performance of a project by clearly identifying the agreed risk allocation and providing fair compensation for bearing them. Several (unsuccessful) attempts have been made in the past to develop standard balanced contract conditions, applicable to all types of major onshore pipeline projects. The failure of these attempts was largely due to the fact that national clients are bound to abide by the local contracting practices and global clients have, over the years, developed their own contract conditions which, they feel, can adapt to the varying context of their projects.

3.4.1 Pipeline Project Specifics Whatever the conditions of contract used, the recommendations above acknowledge the specificities of onshore pipeline projects as well as the uniqueness of their sites. Unlike the relatively small concentrated areas of other construction projects (such as terminals, pump/compressors stations etc.), onshore pipeline projects often extend over several hundred kilometres, crossing state and/or international boundaries. The likelihood, therefore, of encountering conditions different to those upon which the initial design and construction programme were predicated is higher than in other construction projects, hence the requirement for a good FEL as the likelihood of changes is inherent to pipeline projects. This requires that the parties analyse potential risks at an early stage (during the bid phase) and that the contractual baseline is set accordingly to ensure that anticipated risks are fairly allocated. Both parties can benefit from prudent front-end loading (see section 2).

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3.4.2 Clarifying Risk Responsibilities As demonstrated here, the baseline of a good pipeline construction contract must include a clear definition of inclusions and limitations for key risks. The scope of works provides the basis for an agreement between contractor and client. Under ideal circumstances this would be sufficient for an onshore pipeline contract. However, in reality, risk events, when they occur, lead to contractual disputes unless the contract addresses these issues. Contracts should therefore include terms which allow sufficient commercial flexibility to address these inevitable variances while still preserving the performance incentives inherent in the commercial terms for the baseline portion of the scope. This requires the recommended “spirit of trust and mutual co-operation between the parties” and the situation where lack of clear and concise scope and engineering definition leads one party to consider exploitation at the cost of the other should be avoided. The client may see under-priced lump sum bids as a benefit, whilst the contractor may see the opportunity for change and scope increase during the execution of the work. In actual fact the result is disputes, delays and additional costs seldom to any party’s benefit.

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Exemplary preferred conditions of contract have been achieved in international onshore pipeline projects. Clauses of general interest for all construction contracts such as exchange risk, country risk, indemnities, insurance, payment terms etc. are not further developed herein as they may be found in general contract literature. There are certain contractual topics that have a particular importance for onshore pipeline projects. The guidelines included in Appendix 3.4.4 address the following:

• • • • • • • •

The weather conditions/inclement weather The environment and archaeology The definition of (and access to) the site The programme (and adjustment thereto, including compensation) The relations with third parties (pipeline projects involve an unusually large number of third parties) The supply of materials The ground conditions The responsibility for design and constructability

3.4.3 Probability of Risk and Cost Outcome Many a contractor has fallen into a trap associated with risk pricing when clients insist in having the contractor to bear some of the risk impacts. The desire to achieve commercial advantage sometimes tempts a contractor to bid a lump sum contract based on a calculation of the estimated costs of inherent risks. The baseline cost estimate is normally based on the expected cost of the project. This cost includes the required contingency commensurate with the project definition at that stage of the work, where the contingency is added to the base estimate to a level that is equivalent to the 50/50 (or P50 – see graphic below). Onto this a bidder will add reserve that provides his company with the level of assurance that the execution of the work with all normal risks will achieve his goal of profitability. This level of bid is normally assessed at a level where the company can be 80-90% sure of the outcome or in general terms the P80 estimate (this process is described further in Appendix 3.4.5.) Whilst some bidders may be sufficiently confident in their ability to execute work to an estimated budget based on the 50/50 estimate, or with little-to-no reserve it does assume that the bidder has 100% definition of all risks and unknowns and that his price is complete. This is an unlikely condition and normally results in the bidder placing a high reliance on claims or changes to his advantage. Some project risks occur in a continuous and incremental fashion, so that the differing price points considered by different bidders will only vary from the actual cost outcome by degree, leaving the bidder a marginal profit or loss in the end. However, projects often have discrete risks which result in an “all or nothing” cost impact. While the probability of these risks is still variable, their cost outcome is not. Competitive pressures often tempt contractors to bid such risks at less than expected cost on the hope that the unconsumed contingency will become additional profit or can be recovered through claims. When the risk does arrive and is not sufficiently supported with funds, the expected profit is not only lost but profit is drawn from other aspects of the project to offset the risk cost impact. Contractors feel forced to recover their incurred risk costs from their clients, often creating an uneasy relationship with their clients. This inevitably leads to commercial stress and can work to unravel the contractual arrangements made between the parties.

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Cumulative Probability

The alternative advocated here is to be overt in the contract as to how much of the risk cost impact is included in the baseline and how the excess or residual risk will be addressed commercially. Clients are especially urged to avoid entering contracts where known risks have been aggressively priced at a point below the likely cost impact. The better answer is to have the client bear the risk and avoid the commercial inefficiency of potentially paying for the risk twice â&#x20AC;&#x201C; once in the baseline and again in a claim!

Cost Outcome Contracts need to contain an appropriate contractual and commercial mechanism to deal with (unanticipated) risks that eventuate during the course of the work â&#x20AC;&#x201C; despite partiesâ&#x20AC;&#x2122; best efforts to counter, factor in, or eliminate these risks. For risk not accounted for in the baseline, parties can agree, in advance, the form of compensation and the method of calculation of the adjustment. Therefore, the characteristics of onshore pipeline projects make it more important to attain a well defined allocation of risks between the parties. Furthermore, parties need to determine early on how they are going to deal with residual execution risk. This is fundamental to achieving optimum contractual co-operation between the parties and minimising conflicts surrounding eventual contract adjustments.

3.4.4 Conclusion The baseline of a construction contract needs to be clearly established including scope of work, the detailed execution plan with a resourced March chart programme for all linear activities combined to CPM programmes for all fixed installations, the cost elements and the conditions of contract. There may be circumstances when the baseline has not been sufficiently developed at time of going to tender and needs to be improved through early works to arrive at a better contract. Section 4 will review the main risks of pipeline construction contracts and propose mitigation measures which can be implemented at various stages of the development of the project.

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Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 3.2.1

Appendix 3.2.1 Recommendations for Establishing the Project Execution Plan Construction Phase 3.2.1.1.

Introduction

The project execution plan (PEP) is a substantial portion of a pipeline project development. In this document the selected contractor has to explain the way he plans to execute the project describing in detail the assumptions and all the considerations taken into account. A PEP is a tool that will help identify, during project development, all the strengths and weaknesses of the Plan which in the end will serve to define risk mitigation actions. Through this document, the clients get a very clear understanding of the extent of knowledge and evaluation done by the contractor, who shows his level of familiarity with all the characteristics of the project and the site.

3.2.1.2.

Project Background or Baseline

This is a description of the findings that determine the baseline which will serve as a basis to define the project execution strategy. In order to have a detailed baseline the PEP has to describe: • The applicable legislations of the country where the project is to be executed • The labour legislation and manpower availability • The evaluation made of suppliers and countries of origin for long lead items • The owner organisation for the project including evaluation of the financial capacity • The applicable and required technologies including others to be considered • The basic terms of contract and its deadlines • The project site including evaluation of historic weather conditions, registers and soil characteristics • The existing access facilities and transportation means in the area • The existing facilities to supply materials, tools and spare parts • The existing sources of food and available number of lodging facilities • The capacity of the existing fuel and grease facilities in the area • Customs import and export conditions for equipment and materials • Immigration conditions and language requirements to bring professionals and skilled HHRR • Health and safety requirements • Existing communication facilities

3.2.1.3.

Project Execution Organisation

In this section the contractor project management team will define the organisation chart that will be used to execute the project. It is very important to identify the name of the key personnel early on and make sure of their availability and commitment to remain in the project from the beginning of the project needs until the end of their assignment. Special attention should also be given to the organisation chart that the client intends to set up for project follow-up and their location in the area. This is essential to maintain good communication at all project levels.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 3.2.1

The organisation chart should also depict the interface with the headquarters and define the contractor’s representatives assigned to the project in case of joint ventures. Each of the following activities should be covered: a) Engineering: with clear definition of the group leaders, consultants and subcontractors. b) Main Supplies and Subcontract: special attention should be given to include the group which will execute the following activities: • • • • • • • • • •

Procurement of long lead items Lease or purchase of construction equipment Supplied materials Consumables Inspections at the supplier’s facilities Follow up and handling Import/export of all needed elements Customs clearance Transportation logistics Material management

c) Construction The construction organisation should define the structure - up to supervisory level - for all phases of the project. It should identify the number of crews being planned for all the different segments of the project (i.e. pump stations, pipeline, terminals, tank farms, SCADA etc.). e) Project Administration and Finance A list of the accountants, treasurers, human resources people and other related tasks required should be detailed in this area. f) Logistics This area includes camps, transports, supplies, fuel distribution, warehouses and communication systems amongst others. In many remote pipeline projects this is a very critical activity that should be very well planned and detailed g) Project Control This group is in charge of the cost reports and progress payment reports. Many projects also include progress control and planning in this group h) Equipment administration and maintenance The planned resources for line maintenance, repair shops, crew assistance etc. should be listed here based on the construction equipment to be used and the weather conditions.

i ) QA/QC A brief description of the quality assurance and control (QA/QC) programme and the resources to be deployed should be given in the section. j ) HSE A brief description of the HSE program and the resources to be deployed should be given in the section where the requirements of the environmental impact study and the environmental management plan should be taken into account.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 3.2.1

k) Technical Support This is an office set up to act as an interface between the engineering group and the construction people. It prepares work procedures to execute the activities in full compliance with the technical requirements, the HSE and QA/QC provisions of the contract. This group of people also produces sketches and detailed as-built surveys during construction. l) Contract Administration This group includes all needed resources to keep contractual communication with the client’s representatives, evaluate contract interferences, estimate scope changes m) Communications and systems A group of technicians to assist the systems needs of the project should be considered and detailed in the chart.

3.2.1.4.

Key Personnel:

The curriculum vitae of this group of people should be part of the PEP so as to provide a detailed qualification of the proposed leaders of the project execution.

3.2.1.5.

Indicative Content of the Project Execution Plan:

3.2.1.5.1 Engineering Execution Plan The engineering manager will define here his plans to: • • • • • • • •

Execute this task describing the subcontractors, consultants and advisors he is planning to use. Set up the software and hardware tools needed for his group. Identify the critical aspects and his plans to keep them under control. Interface with other actors of the project like suppliers, owner representatives, construction people and the community. Control the progress made in his area including the list of data sheets, drawings and specifications. Execute his activities under a CPM program depicting all the interfaces of his area with others. Assist the procurement group to place supply agreements for long lead items in full alignment with the warranty and design conditions of the contract. Test and commission all the facilities of the installation including HAZOP activities and design SCADA.

3.2.1.5.2

Procurement Execution Plan

The procurement manager defines here the methodology he plans to follow to supply the project with all materials and equipment. His plan should consider, • • • • • • • • •

Procurement of long lead items (defining also the warranty period) Lease or purchase of construction equipment Special tools and materials Supplied materials and spare parts Spare parts for construction equipment Consumables Inspections at the supplier’s facilities Follow up and handling Import/export of all required elements

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 3.2.1

• • • • • • •

Customs clearance Transportation logistics Temporary housing Food and lodging subcontracts Pipeyards and warehouses Material management system definition and set up Follow up information to be given to the client

3.2.1.5.3 Administration and Finance Plan Here the administration and finance manager defines how he plans to keep a register of all the costs and revenues of the project, the accounting system and the information that he will be able to produce. In joint ventures it is very important to also define the agreement that will govern the parties. The location of the bank accounts and advisors needed to carry out the activities in full compliance with the local law should be detailed as well. The financing lines, the cash flow and the insurance coverage for the project should be detailed in this paragraph. Type of guaranties to be issued for contract purposes should also be clearly defined to avoid last-minute inconveniences

3.2.1.5.4 Construction Execution Plan The construction manager describes here the most important aspects of the project and the construction techniques he is planning to put in place. A split of activities is recommended in order to better describe each crew scope and required resources with an indication of the production expected for each one. It is extremely important to issue a velocity chart, also called a March chart as described in section 3.2 and in Appendix 3.2.2. This chart allows the client to better understand the position planned for each crew at each moment with details of the expected progress. The access plans and transportation requirements should be considered for each portion of the project. The camps’ strategy and food preparation and distribution must be detailed including the subcontractors’ and owner’s representatives’ needs. For each crew, it is recommended to prepare: • List of personnel • List of equipment • Services and subcontracts needed • Scope of their work • List of challenges and plans to control them • Timing • Special methods or requirements • Procedures needed.

3.2.1.5.5

Health & Safety Plan

The health and safety manager for the project in coordination with the corporate HSE manager will adapt the corporate health and safety plan to the project needs and will describe his execution plan to induce all the HHRR involved in the project to a unified and leveled project plan. The target statistic figures for the project should be established here. Special attention has to be given to the existence of epidemics and generally to the health conditions of the site. The existence and location of first aid and hospital facilities should be carefully planned in order to give full coverage to all the project workers and also protect the community. It is very important to identify the number of H&S specialists that will act on each section of the project as well as the first aid facilities. Special attention should be given to all specific procedures needed, such as emergency evacuation, as described in the contract.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 3.2.1

3.2.1.5.6 Environmental Impact Plan The management plan to mitigate the environment impact of the project has to be described here by the environment manager in coordination with the corporate HSE manager. The environment impact study (EIS) for the project should be approved by the financial entities and/or the client before the project site construction activities get started. These entities have to make sure that the EIS has been duly discussed at all stages with the government and that the most important NGOs of the area have been consulted with so that everybody knows what is being planned in order to reduce the risk of last-minute disagreements and misunderstandings, detrimental to the project. The execution plan needs to define here all the mitigation plans to be used in the construction procedures to install the facilities and the restoration works, indicating also which are part of the contract and those other that should be instructed by the owner. This part of the PEP is essential in order to give clear definition of the scope of work and the construction methods that have been planned to execute the project. All last-minute requirements for environmental protection measures demand a lot of resources that may challenge the smooth execution of the project if not planned in advance.

3.2.1.5.7 Project Planning and Control Plan This is another substantial part of the PEP since it defines the way resources have been planned to get the progress of all phases of the project needed to reach the milestone dates. The project resourced programme should cover the entire project scope and also include sufficient detail to reflect the PEP. It is a document that ties together all elements of the PEP and provides the key basis to accurately evaluate the cost estimate. Additionally, all bill of quantities are shown here in order to give a clear idea of the amount of work that has been considered for each portion of the work. This information will be essential to provide the baseline to discuss impact of scope changes, interferences, weather restrictions and influence along with other disruptions like stoppages or suspensions of the project activities. The main tools to control the project execution are the March chart and CPM resourced programmes combined with the near-real-time project control system, as described in detail in section 13.1. This plan has to list all the information that will be produced to track the project progress and costs to be reported on a regular basis as required by the contract. Milestones should be defined in order to provide a tool that will help to track completion of certain activities that otherwise could be 99% complete and would remain there since the last 1% generally takes tremendous time and effort to get completed. This is essential to give some warning signs to the project team. Therefore, it is extremely important to chose project milestones that identify completion of key activities. One important element to control progress is the weighted “S” curve which is developed giving the percentage participation in the cost of the activity as estimated in the cost estimate to weight the percentage of physical progress.

3.2.1.5.8 Risk Analysis management plan. The project team should get together to list and evaluate all project risks identified during the project study. The entire life cycle and scope of the project including the social aspects should be analyzed to identify the potential risks of the project. These risks have to be classified as operational, financial, legal, contractual, climatic, community, inland security risks, etc. It is also important to identify which are associated with internal factors which could be under the project team’s control and those due to external factors that are out of the project team’s control. A probability level has to be given to each risk and also the gravity of it occurrence should also be valued in order to set up a matrix (probability/gravity) that will allow the project team to properly weight the risks in order to develop a mitigation plan for each risk.

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3.2.1.5.9 Quality Plan The QA/QC manager has to develop a quality plan for the PEP, based on the corporate quality Plan and the contractual conditions under the supervision of the corporate QA/QC manager. This plan has to identify the practices and the sequence of activities linked to the specific quality of the project. The plan has to define which processes are going to be controlled and also include the applicable procedures to be used as part of the quality plan. It very important to define the content and format of the information that will be included in the regular report to be issued by the QA/QC Manager to track the progress of the non-compliance reports (NCR) and the actions taken to fix these NCR, which otherwise could turn out to be an important barrier for project completion if not followed properly.

3.2.1.5.10 Community Relations Plan. Many pipeline projects face severe difficulties, delays and costs overruns due to disruptions created by the approach taken towards the communities. Many pipeline projects are executed in remote areas where the local people are unfamiliar with large machinery. When they are suddenly exposed to much new equipment and people in their territory, uneasiness and opposition to the newcomers may build up quickly. In order to prevent difficulties it is extremely important to develop a community relations plan in coordination with the local authorities, the client and the contractor. The client regularly takes this risky item in his hands but this plan has to be followed up and supported by the contractorâ&#x20AC;&#x2122;s own forces. Participation in all open meetings with the communities to explain the way the project will be executed is essential, as is the appointment of community relations team to keep a close contact with the local people. Both need to be clearly described in the PEP. The local regulations and common practices followed by other projects in the area are also extremely important to define the community relations plan. In this regard the PEP should also establish the rules for hiring local labour and the expectations regarding the involvement of local suppliers and subcontractors.

3.2.1.5.11 Systems The systems manager has to define the strategy to link all the project camps with the project offices and the headquarters, including also the ownerâ&#x20AC;&#x2122;s representative offices. He will also identify (in coordination with the leaders of each project activities) the type of software that will be used for engineering, material, procurement, accounting and control. The technical support will also be identified in order to give a clear understanding of the systems plan that is being considered to execute the project. It is extremely important to make sure that all systems to be used in the project will be able to interact with systems used by the client, the suppliers, the subcontractors and the consultants that are being part of the process. This seems to be simple but, if it is not well defined at the beginning it could trigger a lot of delays in the project execution. Should the operational organisation of the client (other than the construction organisation) require all the project build to be done in a certain software that has not been used to do all the engineering, the risk of errors and loss of information and data would be very high. Therefore, it is essential to analyze all the project scope, the contractual requirements and the full life cycle to define systems.

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Appendix 3.2.2 A Primer to March Charts Introduction Traditional scheduling software for the construction industry is dominated by Primavera, Microsoft Project, Power Project and others. All of these solutions provide opportunities to develop a series of activities that are logically connected in a sequence from project start to finish. While these tools are very powerful, they are better designed for the construction of buildings and other facilities (power generating stations, refineries, etc.) and are not adequate for the constructability issues and demands of building linear project such as pipelines, rail systems or roadways. A linear project is defined as a series of crews moving in sequence along a ROW (right-of-way) during construction. March charts (also known as Time-Distance charts) have been widely used in linear projects, particularly in Europe and the U.K. This methodology is newer to the Americas, but is rapidly gaining widespread acceptance. March charts are often hand drawn, prepared in Microsoft Excel or in a drawing program such as AutoCAD. Linear planning and scheduling software that automates development of the plan and progressing is relatively recent (approximately the last 15 years). Key advantages of March charts are that the schedule is connected to the ROW geography and any constructability issues that are important to the project. The intent of this “Primer to March Charts” is to provide an overview of how to interpret and use March charts with an emphasis on using a selection of the linear planning software tools that are currently available. A list of software is provided at the end of this appendix.

3.2.2.1 The Basics • Differences between Gantt and March charts Gantt charts are familiar to anyone who has planned and scheduled a project. The planner creates a series of activities based on the project execution plan and then logically connects these activities (Finish-Start, Start-Start, Finish-Finish and Start-Finish). Resources can be added to each activity schedule and resource loading can be easily displayed. In order to maintain crew sequencing in a pipeline project, the planner ensures that each activity is connected to its successor by a Start-Start and a Finish-Finish relationship. A typical Gantt chart for a pipeline job is shown in Fig. 1. Fig. 1 Traditional Gantt Chart

This Gantt charts clearly shows each activity with its start and end date. Any progress is shown on the Gantt chart as the percent completed for each task. The problem with a traditional Gantt chart is that reporting that a bending crew is 45 % complete is quite meaningless because these traditional tools assume that progress is from start to finish and no connection exists between progress and the geography of the ROW. The ability to include crew moves, permitting delays, environmental restrictions and other construction issues is simply not possible.

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A March chart on the other hand displays the same crews as a series of lines moving along the ROW. Each crew is logically connected to its successor with Start-Start and/or Finish-Finish relationships. Completed sections are easily identified with crew moves, crossings and environmental windows visible on the March chart. Using the same example, a March chart will clearly display which 45% of the ROW has been completed by the bending crew and how any moves or ROW access issues have impacted the progress. A typical March chart (Fig. 2) in its most basic form shows each crew represented by a different line type. Usually distance along the ROW is horizontal and increases from the left to the right. Time is typically represented vertically, increasing from bottom to top (although it can just as easily be shown increasing top to bottom). It should be noted that the orientation of the time and distance axes is a matter of personal preference and can easily be switched in the software. The advantage of March charts is immediately obvious as you can determine the location of each crew at any particular point in time. Any issues associated with crew productivity rates are also readily apparent. For example, the red arrow in Fig. 3 indicates that based on the productivity of each crew, the lower-in crew will overtake the ditching crew between KP 25+000 and 30+000, which was not obvious in the Gantt chart view (Fig. 1). Furthermore, in March charts the slope of the activity indicates the relative productivity rate for the crew. The steeper the slope, the slower the crew is moving (because more time is spent and less distance is completed).

Fig. 2 Simple March Chart

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Non-work periods such as scheduled days off or work stoppages appear as vertical segments on the crew line. A vertical line indicates that time is passing but the crew is not moving. Fig. 3 shows an example where the grade crew is moving slower (468 m/day) than the haul and string crew (600m/day) with each crew working a 6 day 10h shift rotation. The green bars across the March chart and the short vertical jumps in each crew indicate the day off each week. This March chart shows that grading has to start 18 days ahead of hauling and stringing in order to keep these crews from overlapping. The productivity rates that are displayed are calculated automatically by the March chart software based on duration and length of each task. For clarity and ease of explanation, all of the following examples in this guide will show only a few representative pipeline crews. Typically, each crew is assigned to a different layer of the March chart so that the planner can display one or many crews simultaneously, by activating the corresponding layers. Fig. 3 Productivity Rates and Slope

3.2.2.2 Constructability Issues With a basic understanding of these March chart elements, a March chart can be further enhanced to display any other critical element of your project. These can include the ROW profile, crossings, environmental restrictions and land acquisitions. Other elements such as vegetation type, soil type and rainfall data can also be included on the March chart. The amount and type of information shown on a March chart is determined by the project team.

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ROW Profile The ROW profile is important in developing the hydro-test plan and to determine productivity rate changes based on elevation (discussed later in the speed profiles section). Most profile data (LIDAR or survey) is available in a spreadsheet format and can be easily imported into a profile diagram using the import function of the march chart software to generate the ROW profile as seen below in Fig. 4. Fig. 4 Elevation Profile and Restricted ROW Access

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â&#x20AC;˘ Restricted ROW access Construction of pipelines may be hampered by periods when certain parts of the ROW are not accessible. This would include environmental windows for wildlife and rare plants, permitting issues or ROW acquisition delays. Restricted access periods are easily represented graphically on March charts by rectangular shapes as shown in Fig. 5. Once the impact of a restriction has been evaluated, it may be necessary to modify the work plan to avoid working in restricted areas. This can be done by splitting the crews so that work which is impacted by restricted areas will be completed at a later date once the restriction period is over. Fig. 5 illustrates a move for both the grade and string crew to avoid a restricted area. In this example, both crews skip the restricted area (a 1 day lag is included to allow for move) and continue to the end of the ROW at 30+000. Once this work is finished, and the environmental restriction has expired, both crews move back to the restricted area and complete it in a reverse lay. The red dashed lines indicate the logical links between each crew segment. Fig. 5 Restricted Access Showing Move Around

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â&#x20AC;˘ Crossings Once the environmental or land restrictions have been established on a March chart, the next step is to identify crossings. Crossing types can include foreign utilities, roads, rail or water and are important features to locate on March chart. The method of crossing will be dependent upon the type of crossing. Water crossings usually require an open cut (if permissible under the environmental guidelines) or will use a HDD (Horizontal Directional Drill). Most roads and rail crossings use some type of bore method while foreign utilities are exposed using a hydrovac. Each type of crossing can be colour-coded on the March chart for quick and easy identification. Fig. 6 shows a highway (at KP 1+793) shown in grey and a blue river crossing (KP 29+690) on the March chart. Fig. 6 Road and River Crossings

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â&#x20AC;˘ Stockpile locations and Valve Sites Virtually any information that is considered important can be inserted into the March chart. The following example (Fig. 7) shows the stockpile location (KP 26+102) and the supply zone for this pipe (KP 0+000 to KP 29+655). It is interesting to note that non-linear structured tasks (such as mainline block valves) can also be shown on a March chart. The two valves shown in Fig. 7 are represented by a series of rectangular shapes indicating different stages of installation from civil to mechanical to instrumentation and telemetry. Other non-linear features that can be added to a March chart would include hot bends (with delivery dates) and detailed HDD activities. Pump stations can also be represented as rectangular activities that can be progressed as well. In this regard, a March chart is able to represent both linear and non-linear components, providing an overview of the entire project. Fig. 7 Stockpile Sites and Valve Locations

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â&#x20AC;˘ Weather Risk Risk related to weather events such as precipitation levels or temperature, are easily evaluated by overlaying meteorological data on the March chart. In Fig. 8, the different shades of blue represent average monthly rainfall amounts. The heaviest rainfalls occur in the lower right of the March chart, represented by a darker blue. In this example, the planner has avoided working in this area during high rainfall thus reducing the risk of heavy rain impacting construction. Fig. 8 March chart showing monthly average rainfall data.

3.2.2.3 Other Features â&#x20AC;˘ Spend Profiles and resource histograms Spend profiles and resource histograms are simple to create once costs are added to the labour, equipment and materials used in the March chart. Fig. 9 illustrates an example where the weekly cost per crew and the total cumulative cost are presented in a histogram and table. It is also possible to display the resource histogram per week (month or day) to determine camp requirements. Spend profiles are a function of time and are therefore displayed parallel to the time axis of the March chart. It is also possible to create a spend profile parallel to the distance axis showing the cost per section of the pipeline. Any changes to the March chart (such as crew moves) automatically create a change to the spend profile.

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Fig. 9 Weekly Spend Profile (per crew with weekly and cumulative totals)

â&#x20AC;˘ Applying work and speed Profiles to crews Most estimates, schedules and March charts assume a consistent productivity (or work) rate for each pipeline crew along the ROW. This productivity factor is then applied for the entire length of the spread to determine the duration of each crew. Applying a constant productivity rate to a crew does not account for changes in profile, soil, terrain (muskeg versus mineral soil conditions) or vegetation types. For example, a logging crew that has a productivity rate of 2000 m/day would require 15 days to complete a 30 km ROW. While this provides a rough estimate it doesnâ&#x20AC;&#x2122;t account for productivity rates based on changes in vegetation types or whether there is logging required in certain areas (for example an old burn area that does not have salvageable timber). The following examples shown in Fig. 10 and Fig. 11, illustrate the difference when a vegetation classification system is used to define the productivity rates for logging and clearing crews in a Northern pipeline spread. In this example the vegetation data and productivity rates for both crews in a particular location were imported directly into the March chart from an Excel data file supplied by a survey.

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Fig. 10 Logging and Clearing Crews with constant productivity

In Fig. 10, we can see that both crews have very similar productivity rates with a duration of 25 and 26 days respectively for the logging and clearing crews. The vegetation index in this example defines the amount of work (area in Ha) and work rate for each vegetation type along the ROW. Once this data is known and available in a spreadsheet format, it is easy to apply this index to each crew as shown in Fig. 11. The first noticeable change is that the crews are not consistently progressing along the ROW. Each crew line now reflects a different productivity rate with each change in vegetation type. More importantly we can see that the duration for each crew has changed significantly. Specifically, logging has decreased from 25 days to 16 days while the duration for clearing has increased from 26 days to 40 days!

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Fig. 11 Logging and Clearing optimized by vegetation index

This approach could easily be used in any other geographic location where a known variable impacts on the work rate of crews along a ROW. The ability to define productivity in terms of the ROW conditions will enable the creation of a more accurate project plan and spend profile when compared to simply applying an uniform rate to each crew. Progress can now be applied against the adjusted crew profiles. Applying a speed profile to a crew, based on known changes in productivity, creates a more accurate picture of how the crew is moving along the pipeline ROW as seen in Fig. 12.

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Fig. 12 Crew Speed profile

3.2.2.4 Progressing March Charts Progressing crews on a March chart requires the start KP, end KP and the date range for each progress period (based on the inspector field reports) to be applied. The exception to using linear meters for progress would be to count the number of welds, usually back end welds, or the number of UPI items, such as bag weights. Fig. 13 shows progress for both the grade and the haul & string crews. Progressing is simple in the example software shows, selecting a crew by clicking on it, then entering the start and end date for the progress period and the start and end KP.

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Fig. 13 Progressing Crews in March Charts

The March chart software calculates the physical percent completed based upon the amount of work completed, divided by the total length of the pipeline. In this example, grading is 61% and haul & stringing is 40% complete. It should be noted that the progress is for the segment starts at KP 0+000 and ends at restricted access area, it does not include the other two segments for each of these crews. â&#x20AC;˘ Progress bar charts Progress can also be indicated in a bar chart format where the progress of each crew is represented by a shaded bar chart. As progress is applied to a crew the bar chart view is automatically updated to reflect this progress. In Fig. 14, the direction of build is from KP 162+000) to KP 112+000. In this example, the clearing, pioneering and grade crews have completed the entire length of the spread. Haul and string are between 40% and 50% complete and the automatic welding crew has just started.

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Fig. 14 Crew Progress Bar Chart

Conclusion The intent of this guide is to provide a comparison of traditional scheduling tools to March charts and to provide an overview of the how to interpret these charts. This overview described how to interpret march charts in the simplest form and then increased the complexity by adding constructability issues such as environmental restrictions and risks such as weather. The ability to represent non-linear activities (valves and pump stations) on a March chart makes this a very powerful solution that enables one to view the entire project on one March chart. Also described was the ability to apply speed and work profiles to connect the productivity rates to soil, timber or any other factor that will have an impact. Progress during project execution is dependent on the input of the crew inspector daily report. Typically the start and end KP for each crew is recorded daily for progressing the March chart. UPI items and welding may also be tracked as the number installed or completed. It should be apparent that March charts are well suited for pipeline construction projects. We have seen that March charts connect the schedule to the geography and risks of a project in a manner that is not simply possible using traditional scheduling methods. Hopefully, this guide has helped provide readers with an understanding and appreciation of March charts and the potential that is possible.

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Appendix 3.4.4 Contractual Topics that have a Particular Importance for Onshore Pipeline Projects Weather The contract should identify the baseline weather conditions that the contractor can expect to encounter along the route. This is usually obtained from publically available sources. The contractor should be required to allow sufficient time and resources to deal with the anticipated weather conditions. The contract may require the contractor to allow for slightly worse conditions than those anticipated by the weather data. The contract should also require the contractor to monitor actual weather conditions at identified locations along the pipeline route. Should the weather conditions be worse than those indicated in the contract then the contract should provide a mechanism for identifying and valuing the effect on programme and resources. The contract should then identify how and to what extent financial compensation and time extensions should be established.

Environment/Archaeology Prior to the commencement of pipeline construction, environmental and archaeological surveys from publicly-available sources will have been carried out as part of the FEL. This information will have identified a series of constraints that should be included within the contract documentation and which the contractor should allow for dealing with within the contract price. During the course of construction unanticipated environmental/archaeological issues are bound to arise. The contract should clearly identify responsibility for dealing with and mitigating the effect of these issues and a mechanism for valuing the effect on programme and resources.

Site and Access The site and access to it needs clear definition within the contract. The easement width available to the contractor for overland pipeline construction should be clearly stated-particularly if this varies throughout the route as a result of constraints. Additional land take required at each crossing should also be clearly identified together with land associated with valve stations/AGIs etc. It is usual practice for the client to obtain all permissions associated with securing pipeline route and installations. Pipeline construction contracts should also clarify who is providing land for pipe dumps, construction yards, mobilization/demobilization yards, parking areas along the spread, office compounds, and accommodation compounds. The document should indicate the location and area of each piece of land to be provided by the client and the general characteristics of the land i.e. is it virgin ground? Is it built on? Have any soils investigations been done? Are there services available? How long is it available for etc. It should be clearly stated in the contract if the contractor is to provide these facilities. As part of FEL the client should have determined suitable access routes to the site which should be identified in the environmental impact study. These can vary from negotiating with the highway authorities which roads can be used for heavy/light traffic to constructing major temporary roads and bridges to access the easement. Responsibility for obtaining permissions to construct off-easement accesses should be clearly set out in the contract. It is recommended to have the same party dealing with ROW easements and accesses at the same time. The contract should also state when each portion of land is available to be used by the contractor, whether for pipeline construction, support facilities or off-easement accesses.

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Programme The contract should contain the programme of works for the completion of the pipeline including the activities and milestone dates agreed by the contractor and the client. For pipeline construction this is generally in the form of a fully resourced March chart supplemented by CPM of special sections and crossings. These clearly identify the anticipated resources. The impact of any changes, stoppage or slow-down of production can be monitored via the contract programme and measures put in place to mitigate the effect of delays. The contract will contain provisions as to the financial responsibility for specific types of stoppage/delay (for example it is usually the client’s responsibility to pay for delays caused by lack of access and the contractor would bear his own costs if the delays were due to inadequate resourcing). Once the delay has been monitored and mitigation measures put in place the consequences in terms of resourcing can be valued at a predetermined set of rates and allowances.

Third Parties Pipelines by their very nature pass through diverse geographical and political areas and touch on many people’s lives and environmentally sensitive areas along the way. Many of these people will have an interest in and impact upon pipeline construction. They may include: • Farmers • Land owners • Local inhabitants • Local businesses • Local authorities/municipalities • Police • Army • Insurgents • Protestors • Port/railway/highway authorities • Other utilities • Customs authorities • Environmental agencies • Environmental pressure groups (NGOs) • State/national governments • Planning authorities The responsibility for dealing with third parties, although best served by a joint client/contractor’s approach, should be under the leadership of the client since it has to be initiated at a very early stage of FEL. It is extremely important to appoint people who understand the culture and the social aspects of the project’s environment. These people should preferably remain throughout the duration of the FEL phases and the construction of the project in order to maintain communication and commitments with the third parties. Many projects have encountered major problems when lacking a well-planned thirdparty programme. When appointed the contractor should jointly participate in this programme in order to provide a unified response to all the third-party issues and the contract should be clear how time and cost impact of any third-party action should be addressed.

Materials Where materials are to be supplied by the client the quantity and specification of the material should be included within the contract document. The delivery date(s) should also be included together with the location of the handover. The contractor usually has the duty to physically inspect the material to identify any obvious damage. Responsibility for any latent defect would remain with the client. Any change in the delivery date or the handover location is usually the client’s responsibility; they should carry the financial impact.

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Ground Conditions Please also refer to section 6 Earthworks As in most civil engineering contracts understanding the nature of the ground and what the contractor is required to construct in/on it is fundamental to the success of the project. During the FEL ground condition surveys/boreholes will have been taken along the proposed route with particular attention being paid to crossings. This information will have been used to select the optimum route. Particular attention will have been paid to crossings. The extent of survey information available can be extremely sparse and this creates huge risks for the project. This data will have been made available to the contractor during the tender/negotiation process and should form part of the contract. The contractor will have used this information to determine resource levels and construction methods for both the trench and the crossings. If there is insufficient reliable data available the client may be advised to instruct the contractor to base his tender assessment on a set of assumptions. If during the construction process it is found that the actual ground conditions are at variance to those indicated in the surveys/boreholes or with the set of assumptions and that those differences have caused either stoppage/delay or increased resource levels then the responsibility for financial consequences should be addressed in the contract. The contractor should normally be expected to accommodate minor changes in ground conditions but anything that affects production beyond a minor amount should generally be borne by the client.

Design The contact should clearly state who is responsible for which elements of the design. When the client is responsible for the design then any delay in issuing design information which causes additional costs should be the clientâ&#x20AC;&#x2122;s responsibility. It is recommended that the client always remains responsible for the accuracy and correctness of the information and data supplied at the time of tender or at any time thereafter. When the contractor is expected to endorse certain elements of the FEED, sufficient time (to be agreed) should be allowed to either identify errors or omissions or to request changes. Fit-for-purpose clauses should be qualified as being in accordance with the contract with a clear definition of the purpose.

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Appendix 3.4.5 Project Cost Estimate and Contingency 3.4.5.1 The Development of a Project Estimate An estimate is developed by considering the scope of a given project and estimating the quantities of material and resources needed to successfully complete the project within a given schedule. Any estimate carries risk. The allocation of allowances, escalation and contingency within an estimate and the assignment of an accuracy range to that estimate is a means by which a bidder endeavours to identify and manage the risks associated with any estimate. • Allowances Allowances cover incremental resources (for example, hours and money) included in estimates to cover expected but undefined requirements for individual accounts or sub-accounts. They cover design allowance for engineered equipment, bulk material take-off allowance, overbuy allowances, unrecoverable shipping damage allowance, provisional allowances for poorly defined items and freight allowance (equipment and materials). There are two main types of allowances, assumed (based on the bidders’ perception of the project requirements) and validated or historical (based on the bidders’ estimating database). • Escalation Escalation is a provision in actual or estimated costs for an increase in the costs of equipment, material, and labour from a set point in time and is due to a continuing price change over time until the completion of the project. Escalation does not cover hyper-escalation, that is escalation which is outside what is expected from published indices, Hyper-escalation should be covered by contingency and allocated based on the perceived risk. • Contingency A bidder will typically include three main types of contingency in an estimate, estimate contingency, event contingency and management Reserve. Estimate contingency is defined as a special monetary provision in the project budget to cover uncertainties or unforeseeable elements of time/cost in the estimate associated with the normal execution of a project, for example, labour rates and design development. Estimate contingency is calculated using a risk model with input from a knowledgeable team. Event contingency is defined as a monetary provision in the project budget to cover the costs associated with the occurrence of one or more specific risks, for example incurring liquidated damages or impacts from severe weather or hyper-escalation. Management reserve is a further contingency included based on the bidder’s management perception of the overall likelihood of the project cost and associated risks.

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3.4.5.2 What Contingency is not meant to cover Contingency is not meant to replace the development of an accurate estimate commensurate with the stage of the project and the associated definition at that stage. It is not meant to cover project scope change for example a change in pipeline throughput or terminal storage volume. It does not cover for design allowance which should form part of the normal project estimate basis. Contingency does not cover for management reserve or profit. These areas will also be discussed.

3.4.5.3 Development of Allowances, Escalation and Contingency • Pipeline Materials Most of the material qualities can be relatively easily quantified following the FEL process, the number and size of valves will be set, the location and specification of pig-traps will be defined. The associated allowances will be set based on historical data and escalation will be set based on the appropriate published indices. These do not cover the full estimate risks. The supply price that is the price at the time of purchase from the supplier is still likely to be subject to change as this often cannot be fixed until some months after the bid has been made to the developer. The risks associated with this will need to be assessed and appropriate contingency allocated. • Other Materials Other materials are likely to be subject to more significant quantity variations. For example, the allowances for weight coating will cover some repair and damage and additional usage as part of the overbuy allowance. However, contingency may also be included in the estimate to allow for potential local rerouting which might be required to solve problem and undefined ground issues. • Construction Labour The construction manpower estimate has many more variables. It starts with an assessment of the volume of work to perform, how many welds, how much ditch to dig etc. Following assessing the volume of work the construction schedule is developed to meet the requirements of the bid, as described in the March chart section of the “The Road”. Resourcing by activity is then developed to achieve the required speed of production. In generating the construction estimate many assumptions will have to be made for example how easy the soil is to dig, how much of the soil can be reused in the ditch, whether the ditch stand up without batter or stepping, and how well the ROW will stand up to multiple heavy traffic movements. All of these will be captured in the estimate basis. An assumption is made of construction labour productivity and equipment availability rate. The weather in the construction season is reviewed and the impact on progress evaluated. Many more risks are also inherent in this estimate. (A review of the risk register will demonstrate the issues confronting the bidder.)

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All elements of the buildup of the construction labour in the estimate will be reviewed and appropriate allowances, escalation and contingency included and defined in the bidder’s estimate basis. The determination of these figures can be complicated since, for example, the productivity/quality of the construction labour will not just influence the number of hours and therefore the number of people required to execute a project, it will also influence the loss and damage of materials due to poor installation or handling. • General As the various areas of the estimate are developed the variability and risk in each is different. However the bidder’s estimate cannot assume that all the potential problems associated with the construction will occur on the same job, his bid price would not be competitive. Similarly it would be unwise to assume that no mishaps will occur either. A Monte Carlo analysis, or similar statistical analyses, will determine the overall level of contingency that will be required to bid a project at a level of risk that is acceptable to the bidder.

3.4.5.4 What is the Estimate Range? The range of an estimate is defined as the difference between the lowest and highest probable values of the estimate. In single-point estimating, the estimator assigns a single cost value to the estimate. But picking a single point is equivalent to stating the project WILL cost this much and clearly does not take into account that this is an estimate with surrounding uncertainty. The single point tends to be the most likely cost in the estimator’s view, the probability of achieving this cost is not fully evaluated. Three-point estimating allows for uncertainty around the estimated cost. To help establish the most likely value of the estimate many approaches can be used. One such approach is a risk based assessment using Monte Carlo techniques. It is normal to represent each area of the estimate as a triangular distribution.

In the example above 20 individual costs could be found for the cost of a commodity . However the estimator can idealize the cost by knowing just three points as follows

minimum = $2,000 likely = $5,000 maximum = $11,000

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Using a simulation and allowing the cost to vary between the high and low values in a random way described by the shape of the triangular distribution results in a total project cost distribution as shown in the diagram below. In this example the most likely cost (mean) or the 50/50 estimate P50 is $74.5 million. This contrasts with the base case estimate of $70.9 which was found by adding only the most likely figures together.

The above graphic represents the output of a real estimate the distribution is slightly squewed. For the purposes of the ongoing discussion this distribution will be represented by a smooth normal distribution as follows. Normal Distribution

Median, mode, and mean are aligned

In a normal distribution without skew the mean, median and mode are aligned and have the same value, all equal the 50/50 or P50 probability.

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A good estimate from a developer’s perspective should have equal probability of overrun and under-run (i.e., a 50% probability). This is a risk neutral approach, the assumption being that some projects will overrun while others will under-run and, in the long run, they will balance out. The more conservative, risk-averse attitude used by companies that need to ensure each project returns a profit to their company (true for contracting organisations) normally specifies a probability of 80% or higher that the project will not overrun. This is a safer route but by specifying a high probability the required contingency (or contingency and management reserve) will increase and with it the project cost to the developer. This results in a sub-optimal use of funds. Large contingencies on projects in the developer organisation’s project portfolio will sequester monies that could otherwise be put to productive use (e.g., funding additional projects, beefing up R&D, investing in product improvement, new equipment). This is a key reason why reduction of risk to the bidder by the provision of a good FEL and by equitable allocation of risk, as discussed in “The Road “, is beneficial to the developer. The excessive contingency is removed and the funds remain with the developer for his use. Contingency added to the bid by a bidder, due to poor project scope definition, becomes part of his bid and is lost to the developer. Contingency is released or consumed by the project team as each of the risks is passed. It must be noted that the contingency which is determined in the development of the estimate is total required contingency. It does not reflect what is sometimes called "management reserve", a discretionary amount which is added to the estimate for possible scope changes or unknown future events which cannot be anticipated by the project team. Addition of this reserve increases in proportion to the lack of project definition and to the history the bidder has of the way in which the client manages change. At the final management review of the estimate past project metrics are commonly used to gauge the result and to provide a reality check. Some special risks also impact the assessment of the final project contingency. These include commercial terms of contract, for example, liquidated damages. Whilst these can play a part in a contract with well-developed conditions and FEL they are often applied without full consideration of the impact on schedule and, as such, when the bidder performs his risk analysis they are found to result in significant risk and a high probability of occurrence. In such cases the bidder adds the risk-based impact of these items to his final estimate expecting that they will be paid in full or in part. The developer has just unwittingly increased his cost for the project development.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 3.4.5

3.4.5.5 Estimate Accuracy What does a stated estimate accuracy of 15% mean? Any discussion of accuracy must be related to a specified confidence interval. In the next figure the median/mean/mode cost is $200 million. The 80% confidence interval in this example (i.e., the confidence that the actual cost will fall within this range 80 times out of 100) corresponds to costs between $170 and $230 million. The difference between $200 million and $170 or $230 million is $30 million, which is 15% of $200 million. Hence in this example the estimate of $200 million has a + or - 15% accuracy with 80 % confidence.

3.4.5.6 How do we set Contingency? Contingency is only meant to cover the project development as it has been described in the scope and basis of design, which at the current state of project definition cannot be accurately quantified, but which history and experience show will be necessary to achieve the given project scope. There is a tendency for those not involved or unfamiliar with estimate development to view contingency as evidence that the estimator is inflating or "sand-bagging" the estimate to improve the chance of bringing in a successful project i.e. one that achieves its budgetary goals. In an effort to reduce the projected cost of a project, clients and those unfamiliar with the process often try to limit contingency to a fixed percentage of the base estimate or in some cases delete it entirely. However, contingency forms an important and integral part of the estimate; it is not potential profit and as we will discuss later should be expected to be spent in the development of the project.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Dealing with Risks in Pipeline Projects

4.1

Analysis, Allocation and Mitigation of Risks during all Phases of a Pipeline Project

After project sanction, irrespective of all the efforts to reduce challenges and risks through the FEL phases, there will always be previously unknown challenges and risk events that arise. Risk events specific to pipeline construction projects retained in this section relate to events which lead to slowdowns, hindrances and stoppages (all being called “stoppages” in this document) affecting some part(s) or the whole of the construction activities. The table in the following pages lists those residual risks events which are likely to be encountered during the construction phase of a project.

•

Column 1 classifies the risks events in nine categories • Weather (Category A) • Archaeological and Man Made Artefacts (B) • Geological (C) • Flora and Fauna (D) • Social and Security (E) • Materials (F) • Engineering (G) • Permit Conditions (H) • ROW Remediation (I)

•

Columns 2 & 3 describe the risk event considered

•

Column 4 indicates at which FEL period the risk event should start to be considered

•

Columns 5 & 6 define who should be the risk owner

•

Column 7 defines the extent of the baseline reference and the extent of the risk mitigation (if any) to include in the baseline.

•

Columns 8 & 9 describe the respective duties and responsibilities of the contractor and of the client for each risk event

Weather

Category

Isolated cases of inclement weather FEL 3 X conditions such as storms/hurricane/typhoons, ROW flooding, snow event, temperature extremes, temperature and humidity extreme combined conditions, air quality (e.g. ozone, sandstorm, smog, blizzard whiteout, fog), rockfalls and snow slides.

Special weather constraints/weather FEL 2 X windows at crossings such as periods of flooding of a river, significant commercial fisheries imposing periods without construction activities etc.

Item

Consideration of risk at FEL phase N째

Inclement weather conditions creating FEL 2 X weather windows to be included in the programme of the works: those conditions may concern the rainy seasons/the monsoon, the periods when the land is flooded, when the snow constantly covers the land, the periods of permafrost, the periods when rock falls or snow slides are likely to occur, known periods of limitations (partial or total) to construction resulting from extreme temperatures or from temperature and humidity combined conditions or from uninterrupted humidity or light rain etc.

Contractor

Description of events

Risk Events Table

Weather constraints and weather windows at crossings to be part of the baseline.

Climatic data should be readily available. Define in contract the expected time loss for those events during certain months of the year and the conservative preventing measures to implement as baseline.

Make explicit and mutually agree the weather allowance in the baseline. Agree the criteria for defining a weather window including the consequenses of the said weather on accessibility, trafficability and environmental impact (i.e. land too wet which could be damaged badly in case of traffic although the cause the rain or the snow - has ended for some time etc). Plan the works around the predefined weather windows.

Mitigation defined at FEL 3

Mitigation measures

Baseline constraints to be included in the programme of construction of crossings.

Bear cost of preventing measures and include time loss in baseline programme.

All weather impacts and their consequences falling within the baseline weather allowance, said allowance being explicitly defined by the contract.

Normal baseline mitigation by contractor

Bear the cost of additional constraints in excess of baseline.

Bear cost of additional preventing measures and/or time loss in excess of baseline.

Bear the cost of any weather impacts above and beyond the baseline weather allowance as explicitly defined by the contract.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Client

Archaeological and Man Made Artefacts Weather

Category

Impact on cultural heritage (graves etc).

Unexploded ordinance, contaminated soil (prior human impact).

Perceived threat to antiquities.

Uncharted or unexpected archaeological find, unexpected mine workings, landfill.

Description of events

Item

Risk Events Table Consideration of risk at FEL phase N째 Contractor

FEL 3

FEL 3 X

FEL 3

Client

X Conduct field surveys and clearing activities prior to field mobilization. Develop response procedures to protect personnel and equipment.

X Conduct field surveys prior to field mobilization and avoid burial locations. Develop response procedures to protect the site.

Develop good relations with the local communities. Solicit their mitigations and implement them. Develop and conduct a community relations program.

X Conduct field surveys prior to field mobilization. Develop response procedures to protect the site.

Mitigation defined at FEL 3

Mitigation measures

Report all finds.

Develop good relations with the local communities. Solicit their mitigations and implement them. Develop and conduct a community relations program. Bear all costs for avoidance.

Report all finds.

Normal baseline mitigation by Contractor

Conduct surveys prior to work. Bear the cost for work. slowdown/relocation if required.

Intervene where relations deteriorate to threaten client reputation.

Conduct surveys prior to work. Bear the cost for work. slowdown/relocation if required.

Excess mitigation by Client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Geological

Category

Item

Geology at crossings.

Swallow holes, ground liquefaction, mud volcanoes, crusted unstable soil (subkha), karst.

Ground conditions differing from the ground conditions (hard rock, hard ground, soft ground, sandy area, etc) derived from field surveys conducted prior to field mobilization (including geophysical and subsoil work).

Description of events

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3

FEL 2

FEL 2 X

Client

X Conduct field surveys prior to field mobilization, including geophysical and subsoil work.

X Carry out detailed ground investigation at crossing including trial holes and boreholes and if possible carry out investigations below river beds. Ensure depth of investigation is below required construction depth. Consider seasonal variations of water table. Provide the design and set the baseline.

X Conduct field surveys prior to field mobilization, including geophysical and subsoil work in accessible areas; then define the baseline assumption of the various ground conditions to be encountered. At the start of work as soon as all sections of the ROW are available trial holes to be carried out to check initial assumptions.

Mitigation defined at FEL 3

Mitigation measures

Include a baseline allowance for minor deviation of geology from that expected and define that allowance explicitly in the contract.

Contractor to allow for competent performance based on conditions indicated in baseline ground information.

In addition to the baseline include an allowance for deviations from the expected geology and define that allowance explicitly in the contract. As a guideline the limit of those deviations would be: a change of the execution process; a change of equipment required; a variation of soil nature beyond an initially defined band.

Normal baseline mitigation by Contractor

Conduct surveys prior to work. Bear the cost for work slowdown/relocation if required.

Bear the cost for work slowdown/relocation or change of execution process or additional equipment required should unexpected geology beyond the deviations defined in the contract causing construction difficulty be identified at commencement or during construction phase.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Geological

Category

Side slope slows work rate.

Erosion.

Landslides/Rock streams.

Description of events

Item

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3 X

Client

Conduct field surveys prior to field mobilization to understand ROW constraints.

X Conduct field surveys prior to field mobilization, including geophysical and subsoil work. Implement erosion control techniques during construction/reinstatement.

X Conduct field surveys prior to field mobilization, including geophysical and subsoil work. Instigate landslide monitoring and mapping programmes.

Mitigation defined at FEL 3

Mitigation measures

Bear all costs.

Include a baseline allowance for erosion mitigation and define that allowance explicitly in the contract.

Include a baseline allowance for landslide mitigation and define that allowance explicitly in the contract.

Normal baseline mitigation by contractor

Conduct surveys prior to work.

Conduct surveys prior to work. Bear the cost in case additional mitigation in excess of the baseline allowance is required.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Geological

Category

Swamps.

Backfill and padding material/borrow pits and royalties.

Soil disposal (excess/surplus soil, native soil not required).

Item

Description of events

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3 X

Client

X Baseline to indicate the expected extent of materials to be disposed and identify the possible disposal grounds along the pipeline route as well as the licence requirements.

X Baseline to indicate the expected extent of possible reuse of excavated materials and identify borrow pit possibilities along the pipeline route as well as protection measures to the pipeline, if required, in rocky areas.

X Development of measures for working under those difficult conditions, taking into account seasonal work implementation, use of specialised machinery, plank roads construction, gravel & geotextile, work slowdown in those sections etc.

Mitigation defined at FEL 3

Mitigation measures

Adhere to baseline data with allowance for minor deviations to be defined in the contract.

Normal baseline mitigation by contractor

Bear the cost in case of work slowdown/ work front relocation, due to deviations beyond those defined in the contract.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Flora and Fauna

Category

Spread of animal and plant diseases.

Planned mandatory exclusion periods/animal habitats etc.

Introduction of invasive species.

Unexpected listed species or wildlife along pipeline route.

Description of events

Item

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3 X

Client

Identify exclusion zones and time periods before contract execution. Schedule work in the base plan to avoid them.

Identify potential diseases and ensure suitable wheel cleaning and mitigation measures are implemented.

Define species risk. Develop and adhere to control procedures and include them in tender requirements.

X Conduct field surveys prior to field mobilization. Develop response procedures to protect the wildlife.

Mitigation defined at FEL 3

Mitigation measures

Bear all costs. Adhere to control periods defined in contract.

Bear all costs for mitigation measures.

Bear all costs. Adhere to control procedures defined in contract.

Report all finds.

Normal baseline mitigation by contractor

Conduct surveys prior to work. Identify exclusion zones and time periods in the contract.

Conduct surveys prior to work. Define disease risk. Develop control procedures and include them in contract requirements.

Conduct surveys prior to work. Define species risk. Develop control procedures and include them in contract requirements.

Conduct surveys prior to work. Bear the cost for work slowdown/ relocation if required.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Flora and Fauna

Category

Unanticipated mandatory exclusion periods.

Habitat fragmentation.

g FEL 2 X

FEL 3 X

Hunting/ poaching pressure.

Item

Consideration of risk at FEL phase N째

Discovery of dangerous transient FEL 3 X species on ROW, site storage areas or worker camps.

Contractor

Description of events

Risk Events Table

Client

X Identify exclusion zones and time periods before contract execution. Schedule work in the base plan to avoid them. Identify the risk drivers of these exclusions and make some probabilistic time allowance for variations from the base plan (similar to weather allowance).

Ensure flight paths and species access across the spread are identified and kept open, minimise vegetation clearance or provide temporary secure crossing of ROW.

Ensure workforce are instructed hunting is unacceptable. Provide security to prevent unauthorised access via new access routes.

Ensure that fences/gates are properly maintained. Warn workforce if danger is known.

Mitigation defined at FEL 3

Mitigation measures

Identify the risk drivers of exclusions and provide a base time allowance for variations from the base plan. Explicitly define the allowance in the contract.

Bear all costs. Adhere to control procedures defined in contract.

Normal baseline mitigation by contractor

Conduct surveys prior to work. Bear the cost for work slowdown/ relocation in excess of the baseline allowance.

Conduct surveys prior to work. Define risk to species. Develop control procedures and include them in contract requirements.

Conduct surveys prior to work. Define risk by species. Develop control procedures and include them in contract requirements.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Social and Security

Category

Disease spread amongst the workforce.

Workforce substance abuse.

Unreasonable landowner behaviour causing disruption to schedule.

Unexpected protest groups along the route or a portion of the pipeline route crosses an area where security of the personnel involved in the construction may not be correctly ensured.

Description of events

Item

Risk Events Table

Contractor

Consideration of risk at FEL phase NÂ°

FEL 3 X

Client

Develop and enforce zero tolerance policies and procedures. Develop workforce testing programs and certification requirements for vehicle and machinery operators.

Maintain and appropriate health education program. Provide workforce monitoring. Discourage working sick. Quarantine where necessary. Coordinate with local community health officials. Maintain hygiene of common facilities.

X Develop good relations with the Local Communities. Solicit their mitigations and implement them prior to construction.

X Contractor to develop good relations with the local communities including villagersâ&#x20AC;&#x2122; representatives, local councils, government departments, affected landowners (all called local communities below). Provide for security patrols. Establish liaison with local law enforcement.

Mitigation defined at FEL 3

Mitigation measures

Bear all costs for avoidance.

Define the engagement of the contractor in local relations which should be measurable and included in the baseline. Include as well any allowance for lost time to be included in the baseline programme.

Normal baseline mitigation by contractor

Intervene to give support for avoidance actions.

Bear cost of excess stoppages.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Social and Security

Category

Population criminal act.

Workforce criminal act.

ROW and access roads sometimes provide access to areas previously inaccessible. They may then be used by others for their convenience.

Access to the ROW is available but access to the main supply points of the country (harbour, local main stores etc) or access to pipeyards/site stores or camps or access to borrow pits needed to supply suitable backfill materials are temporarily unavailable due to external reasons (e.g. national strike, national shortage of certain materials, intervention by action groups, other security reasons etc)

Certain portions of the site are not available as scheduled in the baseline programme due to preliminary works done by others not completed.

Item

Description of events

Risk Events Table

Contractor

Client

Bear all costs for avoidance and obtain support from local communities.

Report events.

Normal baseline mitigation by contractor

X Insert the time needed for preliminary Bear cost of baseline works in the baseline programme with agreed allowances. with agreed allowances.

X Provide security measures as may be Bear all costs of the defined in the baseline (e.g. security baseline allowance. guards/lighting...)

Bear cost to excess to baseline.

Bear cost of excess to baseline allowance.

Intervene to resolve matter with the local communities.

Excess mitigation by client

Contractual impact

X Provide security measures as may be Bear all costs of the defined in the baseline (e.g. security baseline allowance. guards/lighting...)

Maintain relationships with workforce. Define behavioural standards for the workforce. Provide a security/policing resource.

X Maintain relationships with local communities and law enforcement. Define behavioural standards for the workforce.

Mitigation defined at FEL 3

Mitigation measures

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Consideration of risk at FEL phase N째

Social and Security

Category

Contaminants.

Personnel protection against wild animals.

Transport/ infrastructure pressures.

Terrorism.

Impacts of project on local communities and their economy.

Description of events

Item

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3 X

Client

Permits should define actions and measures to take to investigate risks such as entomological, epizootic, radioactive or chemical issues and define the surveys required for the areas previously inaccessible. Those would define the baseline.

X Ensure that appropriate traffic assessments have been carried out prior to works and any mitigation measures agreed with local governing body.

Ecological surveys, areas revelation of wild animals habitation. Development of measures for personnel protection against wild animals.

X Pipeline guarding, work with local communities, selection of pipeline construction technology.

X Develop good relationship with local communities. Ensure that workforce understand codes of behaviour to be adhered too. Highlight the community and economic benefits rather than the negativities associated with the project.

Mitigation defined at FEL 3

Mitigation measures

Excess mitigation by client

Bear cost of baseline actions and measures.

Provide a Traffic Management Plan based on those traffic assessments as well as traffic monitoring and controls to be included in the baseline.

Bear all costs for protection and avoidance actions.

Report events.

Bear cost of excess to baseline resources and time.

Intervene to give support for avoidance actions.

Intervene to resolve matter with the local authorities.

Bear cost of excess to Joint actions by Contractor and Client with baseline resources and time. the Local Communities. Define allowances in terms of resources and time to provide in the baseline.

Normal baseline mitigation by contractor

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Social and Security

Category

War in region/hostilities.

Equipment failure/unsuitable equipment.

Workforce labour unrest/disruptions/strike.

Item

Description of events

Risk Events Table Consideration of risk at FEL phase N째

FEL 3

Contractor

Client

X Fully understand geo-political risks. Put evacuation plans in place. Work abandonment plans. Payments during hostilities.

Ensure contractor understands that the suitability of equipment is its full responsibility and that contractor has adequate maintenance capacity.

Develop good relations with the workforce and any representatives. Monitor external agents acting to influence the workforce. Develop and conduct an active labour relations program. Provide for security patrols. Establish liaison with local law enforcement. Develop a labour law compliance verification system and where applicable establish a site labour agreement.

Mitigation defined at FEL 3

Mitigation measures

Contractor and client to jointly prepare plans. Report events.

Bear cost of schedule impact in case of failure or unsuitability of equipment.

Bear all costs for avoidance.

Normal baseline mitigation by contractor

Contractor and client to jointly prepare plans. Report events. To be dealt with under employer's risks/force majeure.

Intervene to give support for avoidance actions.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Materials

Category

An event elsewhere affecting material supply/non-delivery of materials to be procured by contractor.

FEL 3

Consideration of risk at FEL phase N째

Client decides that further in-situ FEL 3 testing for new materials to be used in the project (e.g. new field joint coating material).

An event elsewhere affecting material supply/non-delivery of materials supplied by client.

Aggregate sourcing.

Description of events

Item

Risk Events Table

Contractor

Client

X Materials and testing procedures to be defined in the baseline.

As part of the quality assurance contractor to establish a procurement plan defining follow up procedures and controls with special emphasis on long lead items.

X A clear plan for the delivery of materials supplied by the client, with special attention to long lead items should form part of the baseline.

X Establish sources of aggregate prior to work commencement to ensure demand/quality can be met as part of the baseline.

Mitigation defined at FEL 3

Mitigation measures

Bear cost of baseline allowance.

Bear cost of delays or deal with the matter under employer's risks/force majeure.

Baseline programme to be based on such delivery plan.

Bear cost of baseline allowance.

Normal baseline mitigation by contractor

Bear cost of excess to baseline.

Assist in the follow up and controls of long lead items.

Bear cost and time impact of any delay to delivery plan.

Bear cost (if any) of any change of sourcing required.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Engineering

Category

Unplanned route diversion or the client decides to proceed with some changes to the scope of the works.

Change of crossing method/change of design.

Breakdown of crossing equipment (HDD or micro tunnelling machine) leading to the abandonment of the crossing attempt.

Crossing equipment becomes blocked due to tunnel collapse or ground squeeze.

Damage to third party pipeline/facilities resulting in spill/ damage to buried services.

Item

Description of events

Risk Events Table Consideration of risk at FEL phase N째

Contractor

FEL 3 X

FEL 3

Client

Normal baseline mitigation by contractor

Maintain spill response procedures and Initiate response actions equipment. Conduct spill response drills. and bear cost. Observe and report spill near misses. Train workforce in spill prevention. Identify all third parties in baseline survey. Engage third party in risk management. Ensure third party representative is on site when crossing their services.

X Early review of geology has governed Contractor to operate equipment within the the choice of crossing method and recommended mechanical equipment. limitations.

Bear repair cost as well as cost and time impact of resetting new equipment for a new crossing.

Bear cost and time of Contractor to establish impact due to change. detailed construction methodology of the baseline together with a breakdown of construction costs/unit rates.

The baseline crossing method defines Bear cost of breakdown, of time impact and of the crossing equipment to be used. resetting equipment for a new crossing.

X An early review of construction techniques should be carried out to determine feasibility of each crossing to ensure that the crossing can be safely built in the available time and that sufficient land/access is available. The crossing method derived from this early review to be included in the baseline.

Bear cost of excess above baseline.

Excess mitigation by client

Contractual impact

X Pipeline route and scope of the works Plan for the baseline with any minor deviation are defined in the baseline. specifically spelled out in the baseline.

Mitigation defined at FEL 3

Mitigation measures

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Engineering

Category

Unexpected earthquake fault crossing.

Off-spec water discharging into adjacent water ways.

Unidentified buried services.

Discovery of informal tips/fly-tipped waste.

Waste management on ROW and office sites.

Description of events

Item

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3

FEL 3 X

Normal baseline mitigation by contractor

Client

Baseline to include information of final survey before construction.

Include a baseline allowance for minor deviation of geology from that expected and define that allowance explicitly in the contract.

X Conduct field surveys prior to field mobilization, including geophysical and subsoil work.

Bear cost of these measures as part of the baseline.

Report all finds.

X Ensure that all buried services and their details are known (owner, size, service, depth, date of installation, design life, abandonment method).

Build catchment basin to impound water. Sample and test runoff daily and during rain events.Ensure engineering has designs for this at all likely locations prior to construction.

X Ensure appropriate mitigation measures are in place if necessary to avoid contamination/harm to workforce etc.

Conduct surveys prior to work. Bear the cost for work slowdown/ relocation if required.

Bear cost of excess above baseline.

If site conditions are such that additional measures are needed, bear cost of those additional measures.

Conduct field surveys prior to work. Bear the cost for work slowdown/relocation if required.

Control compliance with plan.

Excess mitigation by client

Contractual impact

Contractor to establish detailed Ensure compliance with waste management plan for all waste plan. produced by the project as part of the baseline.

Mitigation defined at FEL 3

Mitigation measures

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Permit Conditions

Category

Ground contamination due to chemical spillage.

Discharge of off-spec hydrotest water. FEL 3 X

FEL 3 X

Operations outside of permitted conditions such as: - Weather conditions not allowing work to proceed - Mud and ROW conditions preventing work from proceeding - Uncontrolled run-off spoiling the environment

Item

FEL 3 X

Consideration of risk at FEL phase N째

Failure to provide adequate protection, such as: - Providing sub-standard protection - Failure to maintain adequate protection - Sabotage or storm event damaging protection

Contractor

Description of events

Risk Events Table

Bear cost of compliance and remedials.

Normal baseline mitigation by contractor

Bear cost of compliance and remedials.

Prior to contract execution, define Bear cost of compliance discharge specification and treatment and remedials. options for off-spec water and gain approval for both supply and disposal of hydrotest water.

Maintain spill response procedures and equipment. Conduct spill response drills. Observe and report spill near misses. Train workforce in spill prevention.

Establish adequate controls.

Excess mitigation by client

Contractual impact

Understand the performance Bear cost of compliance standards for permit conditions and and remedials. define operational limitations. Identify a compliance officer to enforce them. Have adequate field engineers to provide suitable designs.

Understand the performance standards for permit conditions and design the ROW protections accordingly. Establish daily patrols, inspections and a correction crew. Suspend local operations as required until protections are restored.

Mitigation defined at FEL 3

Mitigation measures

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Client

Permit Conditions

Category

Any restriction on working hours at special points or specific crossings.

Late or slow issue of necessary permits.

Introduction of new permit conditions during construction.

Description of events

Item

Risk Events Table Consideration of risk at FEL phase N째 Contractor

FEL 3 X

FEL 3

Client

Any restrictions on working hours should be identified within the baseline tender.

X Understand the permitting process and cycle time risks before beginning work. Schedule work areas to adapt to higher risk permits. Incorporate likely risk areas into schedule and possibly instruct contractor to to provide costs for partial or full move rounds.

X Carefully review permit conditions and expectations and contingencies with relevant authorities before beginning work. In case of late changes a joint client/ contractor team to react swiftly.

Mitigation defined at FEL 3

Mitigation measures

Contractor should programme and price for complying with identified restrictions.

The baseline should include a clear permitting plan.

Report events. Apply for new permits and proceed to a joint risk mitigation exercise.

Normal baseline mitigation by contractor

Bear costs of delays in case plan is changed.

Bear costs resulting from new permit conditions.

Excess mitigation by client

Contractual impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

ROW Remediation

Category

Inadequate revegetation/bioreinstatement or difficulties of remediation.

Inadequate erosion protection cutback at river crossings and erosion protection at steep slopes.

Inadequate scour protection at river crossings.

Item

Description of events

Risk Events Table

Contractor

Consideration of risk at FEL phase N째

FEL 3 X

Bear cost of compliance and remedials.

Normal baseline mitigation by contractor

Establish adequate controls.

Excess mitigation by client

Contractual impact

Ensure adequate reinstatement Bear cost of compliance measures have been imposed i.e. and remedials. correct seed mix ratios/use of geojute/effective top soil storage to avoid loss/erosion.

Understand the performance standards for permit conditions and define operational limitations. Establish daily patrols, inspections and correction crew. Include designs in engineering.

Mitigation defined at FEL 3

Mitigation measures

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Client

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

4.2. Management of Construction Risks on Pipeline Projects Proposed guidelines are given in this section to deal with specific risk events associated with the construction of on shore pipelines which generally result in stoppages, slowdowns and hindrances (all three called “stoppages” below) to the progress of the works. It is understood that good design and works preparation at FEL phases can significantly reduce the occurrence and/or extent of stoppages at the construction stage. However, due to the very nature of pipeline construction numerous residual causes may trigger all types of stoppages. Below is the list of the most common causes of stoppages, followed by guidelines to assess:

• • •

Their impact on progress The possible mitigation measures The cost impacts of stoppages and the cost of mitigation measures

4.2.1 List of the most common causes The list of events which may lead to stoppages are developed in section 4 above under nine categories. Typical examples are highlighted below.

4.2.1.1 Weather and climate (Category A) The weather during certain periods of the construction may be worse than the limits defined in the baseline and taken into account in the construction programme.

4.2.1.2 Archaeology and other unforeseen events (Category B) Events affecting or stopping the progress of the works.

4.2.1.3 Geology/Ground conditions (Category C) When there is a significant change as compared with the baseline with a larger extent of ground conditions requiring specific equipment for excavation and/or backfill and/or reinstatement (e.g. quality and/or extent of the rock, presence of large boulders/cobbles, swamp areas etc.).

4.2.1.4 Fauna and Flora (Category D) Discovery of unexpected species or protected wildlife along the pipeline route.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

4.2.1.5 Access to the site, Social and Security matters (Category E) The access to certain portions of the site – the pipeline route or certain working areas – may not be available or may be restricted in some ways. There are many reasons which could create such a situation and the most common are listed below:

• • • •

Some land acquisition along the pipeline route might not be finalised or land owners may request to revisit the conditions of transfer of ownership Intervention by an action group using the publicity and/or the negative impact on the project schedule to promote their cause and/or obtain that the authorities consider their demands Security reasons: a portion of the pipeline crosses an area where security of the personnel involved in the construction may not be correctly ensured Access to the pipeline route is available to the construction team but, for instance: • access to the main supply points in the country (e.g. access to and from the harbour or airport or local supply stores) • access to the site pipe yards and/or to the main stores • access to the borrow pits (when excavated material, even treated, are not suitable for backfill)

are temporarily unavailable due to external reasons or interferences (e.g. national strike or national shortage of certain materials or consumables, intervention by action group, security reasons)

• •

Preliminary works or adjacent works done by others interfering with the pipeline route or with main access points to the ROW or to some of the main installations are not completed in an area at the time when work on the pipeline should proceed Seasonal restrictions including breeding periods for protected species, climatic conditions (flooding, rainy seasons, snowfall etc.)

4.2.1.6 Material supply (Category F)

• •

Late delivery of materials supplied by others (ordered directly by the client) and/or quality of such material (e.g. main valves) The client and the designer decide further in-situ testing for new material to be used on the project (e.g. new field joint coating)

4.2.1.7 Engineering, changes of scope/variation orders (Category G)

• •

There is a need to change the design of a certain portion of the work (e.g. unexpected ground conditions, seismic fault or unstable ground in a zone where access was not fully available for investigations at an earlier stage) Similarly the client decides to proceed with some changes to the scope of the works as a result of the above or for some other reason (e.g. new material/component to be used, procurement time impact, larger excavation required for a seismic fault and special backfill material to be used, procurement time impact)

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

4.2.1.8 Permits or Licences (Category H)

• • • •

Delays in the issuance by the authorities of permit for the works or permit to access some restricted areas (e.g. military zones, border zones etc.) or licences to use certain products (e.g. explosives) Delays in agreeing method statements for construction in sensitive areas (e.g. river crossings, designated sites) Restrictions due to transmittable diseases Consent for waste disposal facilities, water abstraction and discharge, camps and/or borrow pits have not been issued

4.2.2 Assessment of their impact on progress, possible mitigation measures and resulting cost impact

4.2.2.1 Impact and Management of Stoppages The impact of the above events on progress can only be correctly assessed if a detailed programme of works with precise assumptions has been understood and agreed by all parties at the onset (refer to section 3.2 “Establishment of a Detailed Resourced Programme” above). It is also essential that “Early Warning Procedures” be in place so that any party identifying an event with potential impact on progress can promptly organise early warning meetings to jointly establish the responses to the consequences of those events. Then the management of stoppages can follow the sequences below:

4.2.2.1.1

Stoppage affecting one activity

The significant stoppage (meaning greater than the allowance made in the base programme) of one activity does not affect other activities. This may be the case if: a) the activity affected is well ahead of the base programme b) the following later scheduled activities are significantly behind the base programme c) a combination of a) and b) – in other words the actual time lag A1 or B1 etc. is greater than the minimum agreed time lag A0 or B0 etc. In the above three situations, the overall programme is not affected and unless further significant stoppages are expected, there is no immediate need to mitigate the delay of the affected activity. In terms of cost impact, only the cost of the crew (people, equipment and consumables with the crew environment, transport, lodging and management) from the affected activity over the stoppage period is to be considered.

4.2.2.1.2

Stoppage affecting several but not all activities

The significant stoppage of one activity affects some but not all the subsequent activities. For instance the stoppage of activity I impacts on II and III but not on IV and on the others. As in 2.1.1 above, the overall programme is not affected and unless further significant stoppages are expected, there is no immediate need to mitigate the delay of the affected activities. In terms of cost impact, only the costs of the crews from the affected activities (I, II and III) over the stoppage period are to be considered.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

4.2.2.1.3

Stoppage affecting all activities

The significant stoppage of one activity does affect all the subsequent activities. This is often the case at the start of works when the stoppage of the ROW or the stringing, for instance, prevents the start of the activities which follow. It is also the case when all activities (whether progressing as per base programme or not) follow each other at intervals close to the agreed minimum time lag A0, B0, C0,.. Here in the absence of mitigation measures (such as strengthening certain crews to subsequently accelerate the works or jumping over the problem zone, (refer to paragraph 2.2) all subsequent activities will be delayed and there may be a risk for the completion date of the project. In terms of cost impact, the cost of the first crew affected as well as the cost of all following crews over the stoppage period should be considered but the effect of the stoppage may also induce the extra cost of an extension of the completion time of the project. Examples of evaluation of time and cost impacts of full stoppages or of slowdowns to certain activities intervening at various stages of the construction process are included in Appendix 4.2.1.1.

4.2.2.1.4

The special case of repeated stoppages

When repeated stoppages occur they may affect productivity of the working crews who have not had sufficient time to get over repeated remobilisation phases and learning curves. The evaluation of this loss of productivity is not simple. However should longer periods in the past without stoppages and better productivity exist, they should become the reference to estimate the impact of repeated stoppages during subsequent periods. In the absence of such reference a joint critical analysis of actual progress as compared with the planned progress is the only solution.

4.2.2.1.5

The special case of repeated changes to the works

This includes repeated re-routeing, changes of depth, changes of types of protection or backfilling material, when they occur close to the time when works were planned to be performed may also have a disruptive effect to the progress and to the productivity. They should be avoided as far as possible. The evaluation of the impact of those repeated changes is also complex and the same recommendations as in 4.2.2.1.4 should apply.

4.2.2.2 Mitigation Measures and Cost Impact When significant stoppage events occur, the different mitigation measures could consist of:

â&#x20AC;˘

Jumping over the affected zone: if possible (existence of adequate alternative roads or tracks to the ROW) solution prevailing when the duration of the stoppage is likely to last for much longer than the time needed to move equipment and personnel of a given crew. However the logistics of such a move need to have been prepared (or at least identified) in advance to obtain the full benefit (availability of sufficient transport equipment such as low beds for heavy equipment, availability of lodging for personnel, camps, availability of storage and materials etc.) Revised sequence of work (restarting work in another location initially planned to be done at a later stage) when, for instance a stoppage may prevent completion in an area where the weather is forecast to change soon (snow, heavy rain etc.) making jumping impossible. Logistical problems similar to those associated with jumping should be addressed

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

• • •

Strengthening some of the crews (for instance if more hard rock is encountered, this might need additional specific equipment or more requirements for imported backfill material requiring more dumpers for transport of appropriate material) Mobilisation of additional equipment and personnel to implement an overall acceleration Mobilisation of a full new spread

Similarly in the last three examples the logistics of such operations are fundamental to the successful implementation of the measures. It is therefore recommended to start some of the planning at the onset of the project:

• •

Make provisions in the tender such as the main infrastructure of the camps to be built in advance of their actual need in the base programme, provision of alternative access roads/tracks if feasible, provision of additional low beds for transfers of heavy equipment Prepare and mobilise the same at the start of the project and initiate the early identification of availability of specific equipment and additional acceleration equipment as soon as the early signs of delays materialise

The cost impact of certain mitigation measures could be significant. The more costly those measures become, the more difficult it is, for the project management, to make the required prompt decisions. In this respect, and under those circumstances, a sponsor group is needed to provide the required support to the project management. This sponsor group should associate senior executives from both the client’s and the contractor’s side, with no direct role in the management of the contract but who will closely monitor the development of the project.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 4

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 4.2.1

Appendix 4.2.1 Examples of Evaluation of Time and Cost Impacts of Full Stoppages or of Slowdowns 4.2.1.1.

Examples of evaluation of the time impact of stoppages â&#x20AC;&#x201C; full stoppages or slowdowns

For the purpose of this exercise we consider an extract of a project March chart ranging over a length of 60 km and over a period of 100 days as shown below. Extract of the Baseline Construction Programme

The six activities shown above follow each other with the minimum time lags a0 to e0 between activities, described in section 3.2. It means that should two activities follow each other with this minimum time lag in the actual construction progress, in the absence of any mitigation measures, any stoppage or slowdown of the preceding activity will sooner or later have an equal effect on the following activities. Different scenarios are presented below with the assumption that no mitigation measure is implemented.

4.2.1.1.1

Event stopping completely one or more activity

4.2.1.1.1.1

If during the actual construction in that area, all activities progress with the minimum time lag between them, a stoppage of D days of one activity will sooner or later induce the same delay of D days for all the subsequent activities as shown on the simplified diagram 1.a. below. Note that the delay D may not occur exactly at km 20 for all the subsequent activities but it will definitely happen at some stage for all of them.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 4.2.1

1.a. – Progress of all activities with the minimum time lag between activities

All activities will be delayed by the same delay “D” even if the event having caused the delay disappears before all activities have gone through.

4.2.1.1.1.2 Diagrams 1.b. and 1.c show the effect of stoppages if during the actual construction some activities are ahead of the following activities by more than the minimum time lag a0 to e0. These diagrams assume that the ROW and the stringing activities are ahead of the following activities by b0 + ∆. - If ∆ < D : the delay impact on the following activities will be (D - ∆) - If ∆ ≥ D : there will be no impact on the following activities 1.b. – With ∆ < D

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 4.2.1

1.c. – With ∆ > D

4.2.1.1.2

Event slowing down one or more activities

4.2.1.1.2.1

As described in section 1.1.1 above if all activities progress with the minimum time lag between them, a slowdown lasting D days for one activity, will result in a delay of D1 = D (1-P1/P0) as shown in diagram 2.b. below, where P0 and P1 represent the activity progress before and during the slowdown respectively. As shown on diagram 2.a, this will sooner or later induce a delay D1 for all subsequent activities, though this will not necessarily occur between km 20 and 30. 2.a. – Progress of all activities with the minimum time lag between activities

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 4.2.1

2.b. – Comparison with full stoppages

P0 = progress of the activity before stoppage/slow down P1 = progress of the activity during slow down D1 = D (1-P1/P0)

4.2.1.1.2.2

Should a similar slowdown occur in the situations illustrated by diagrams 1.b. and 1.c., whereby some activities are ahead of the following activities by more than the minimum time lag, i.e. b + ∆, then: - If ∆ < D1 : the delay impact on the following activities will be (D1-∆) - If ∆ ≥ D1 : there will be no delay to the following activities

4.2.1.1.3

Activities running slower or faster than planned

This is the most common situation in many phases of the projects. Actual progress Pa (expressed in km/day) is slower than the planned progress P0 (refer to diagram 3.a.) b) Actual progress Pb is faster than the planned progress P0 (refer to diagram 3.b.) a)

Delay impact for the case a) is

D1 = D (1 – P1/Pa)

Delay impact for the case b) is

D2 = D (1 – P1/Pb)

Since Pa < Pb

D1 < D2

Therefore the March chart helps to quantify the obvious: a slowdown leading to the same progress rate during the period of slowdown D affects more severely activities progressing faster than programmed than activities progressing slower.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 4.2.1

3.a. â&#x20AC;&#x201C; Progress of the activity slower than programmed

Pa = progress before slowdown but slower than the planned progress P0 P1 = progress of the activity during slow down

3.b. â&#x20AC;&#x201C; Progress of the activity faster than programmed

Pb = progress before slowdown but faster than the planned progress P0 P1 = progress of the activity during slow down

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 4.2.1

The previous evaluations of delays do not imply that compensation is due. This will depend on the causes of stoppages/slowdowns and on how the agreement between the parties intend to deal with activities running slower or faster than planned, which is the most common situation in real life.

4.2.1.2.

Evaluation of the cost impact of Stoppages

Assuming that compensation is due as per the agreement between the parties, there are a number of methods in contract literature to evaluate costs. However experience show that in the case of lump sum contracts one cannot easily find the mechanisms to promptly assess costs of delays D (stoppages) or D1 (slowdowns) calculated in chapter 1 above. Hence the suggestion in section 3.3 of THE ROAD TO SUCCESS (Volume one) to break down the lump sum contract price highlighting the time-related weekly costs of the main working crews in operation (here onwards, “weekly” costs would also mean “weekly or daily” costs). In parallel the standby weekly costs of the same crews should be indicated. The breakdown should also cover the weekly costs of the various site installations and of the site management. It would however exclude costs of incorporated materials which are quantity-related and not time-related. Those would represent some 10 to 15 items of weekly costs for the crews of each spread as well as for the weekly costs of the installations and of the site management and any other type of agreed overheads. That would not exceed 50 items of time-related weekly costs for a major project with two spreads. As an example the weekly costs of one of the crews shown on the diagrams of chapter 1, when in operation, would comprise: • The all-in cost of all the personnel of the crew plus the cost of food, lodging and PPE as well as the cost of transport to and from the site (the weekly cost of the camp management and of the security should be included in the camp weekly costs as part of the installation’s time-related costs). • The cost of construction plant and equipment comprising depreciation and/or hiring costs, maintenance costs (spare parts and consumables), the consumable tools (chains, bucket teeth etc.)and the fuel and lubricants The weekly cost of the same crew in stand-by would comprise the same items except that there would be, among other items: • a significant reduction of fuel and lubricant consumption for the construction plant • a reduction of the maintenance costs • a reduction of the personnel transport costs

When delays of the type D or D1 have been assessed, the application of the appropriate time-related weekly costs of all the crews affected would promptly allow the evaluation of the overall cost impact.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 5

Planning and Design

This section develops the guidelines for planning and design of a pipeline project in order to provide the right data at the right time in a project lifecycle to increase communication between all stakeholders, reduce project uncertainties, and plan for success. The objective is to prepare functional specifications and recommended guidelines to improve planning and design processes, simulation and control of the construction activities, and communications during all phases of an onshore pipeline project. The deliverables are to contribute improvements in safety, reduction of risks and uncertainties, better integrity management of the asset and efficient project execution. Current industry observations and findings reflect the following:

•

The pipeline route has a major influence on the success or failure of pipeline projects

•

Insufficient information along with disjointed or misaligned activities during the planning and design phases results in uncertainties, risks, and potential delays – it is very difficult to recover from a poor design or plan during construction

•

Data collection and data management standards are applied inconsistently across the industry and from project to project

•

Communication and data flow between all stakeholders is fragmented and complex

To address some of the issues related to the above stated observations the following activities were identified:

• •

ROW and constructability study & guidelines Minimum data requirements and activities for the five project stages

The deliverables for these activities are addressed in detail in sections 5.1 and 5.2.

5.1

Right of Way Constructability Guidelines

Constructability issues play a key part in the pipeline right of way (ROW) route selection. Selecting a route without considering constructability early in the selection process may lead to additional cost and schedule impacts in the latter phases of the project. It is not uncommon for the most cost effective route to be chosen during the early project phases only to find later on that the original cost savings have been offset by increased construction costs, leading to much higher overall higher project costs. In order to gain an appreciation of ROW constructability issues in the pipeline industry, the key consequential constructability issues that may arise during the route selection phase are discussed below. Reference is also made to Appendix 5.1.1, which discusses the pipeline route selection process.

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5.1.1 Constructability Issues ROW constructability issues can be broadly classified in the following eight categories:

Constructability Issues

General Description

Access

This covers access to the ROW from existing roads including the requirement to construct access roads from existing roads as well as access along the ROW i.e., the ease or difficulty of travel along the ROW and the frequency of access points to the ROW. Access to the pipeline and associated above ground installations (AGIs) is not only required during construction, but will be required all year round (365 days) for pipeline maintenance and emergency repairs.

Non-contiguous ROW

Also known as “skips”, this issue addresses sections of the ROW for which permission to work is pending, forcing the contractor to move around the section, disrupting continuous lineal progress and requiring a return of equipment and labor to complete the ROW at a later date.

Working Space

This includes satisfactory minimum width requirements, boundary restrictions, e.g. the need to remain within the strict confines of the ROW, constricted working space due to permit requirements, existing structures or parallel existing pipelines. Working space requirements will need to be of sufficient width, length and height to allow the use of equipment with sizes up to the maximum expected footprint.

Restoration

This covers the requirements to restore the ROW after construction to a near pre-construction state including dealing with landowners to settle damage claims.

Environmental Mitigation

This includes the considerations necessary to meet environmental permit requirements both during construction—special construction techniques to minimize damage to sensitive areas, flora and fauna—as well as for postconstruction mitigation requirements—strict restoration requirements: revegetation, construction of retaining walls, etc.

Permits

This includes the impacts resulting from permit compliance requirements and the issues associated with permits that must be obtained by the contractor.

Terrain

This covers the ROW preparation challenges posed by the physical conditions to be encountered e.g., hills, mountains, desert, wetlands. Typically it also includes aspects such as topsoil segregation requirements and road, rail and river crossings.

Community Relations

This includes issues more typically encountered on an international project in a developing country, such as local content requirements, community assistance programs during construction e.g., building a road to a village, and nominated local subcontractors which the contractor must utilize during construction.

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Industry experience to date generally considers that terrain is the top constructability issue, followed by access and working space. In developed countries, working space is a key issue, whereas in other countries access is often important due to remote terrains. Depending upon the region of the world where the project is built, community relations are sometimes also a priority. The issues can be ranked by order of importance as follows. Relative importance of various activities:

5.1.2 Overview of Constructability Issues The simple proposition to move hydrocarbons through a pipe from point A to B is quickly complicated by recognizing that the ROW element affects all the project stakeholders: owners, landowners/users, environmentalists, agencies, regulators, engineers, contractors and operators. Developing countries may present more flexibility for pipeline ROW options due to their less developed permitting and environmental guidelines, but these countries are fast adopting the approach of the developed countries, particularly regarding environmental issues. In developed countries, environmental concerns tend to dominate other route selection issues. Because of the predominant nature of environmental concerns, existing pipeline corridors or other existing linear corridors (such as roads or electrical lines) are preferred when a project looks to route a new line. A new scar on the landscape will likely add time and cost to the project from both an environmental and permitting perspective. The owner and engineer orient the pipeline route to comply with environmental and cultural limitations, permit restrictions, landowner/land-use constraints, and engineering and construction considerations. Within the boundaries of the available corridor and along with the regulatory confinements, attention is given to terrain, soil type and access to the ROW for construction and operation.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 5

The contractor has to manage multiple difficulties including limited access to the ROW during construction, and constrictions and restrictions to the working space. While these obstacles can be daunting, time consuming and costly, construction is a one-time event in the life cycle of a pipeline system. The multiple and sometimes conflicting variables which determine pipeline route selection may combine to make constructability issues appear to be a secondary consideration which could lead to an expensive and time-consuming mistake. In general, a pipeline route should be optimized to minimize the impact to habitations, environment and other valued land areas while at the same time be as short and as constructible as possible. Shorter pipelines (not withstanding those through inhabited areas and severe terrain) are typically less expensive to install and operate, offer less maintenance needs, expose less land (and often less of the public) to pipeline operations, are safer, have less impact on future development, and provide more efficient hydraulics. Choosing a pipeline route that meets these criteria can be a challenging balancing act between the desires of the landowners, the permitting authorities, and the pipeline owners whose functional and financial needs are the driving force behind the project. This process often includes a number of iterations of route selection, evaluation, negotiation, refinement before the final route is selected. Routeing preferences move toward terrains that are flat, open (unoccupied and unforested), dry, and have stable soils and away from terrains that are occupied, hilly to mountainous, heavily eroded, wet, contain unstable soils, and have numerous crossings (natural or manmade watercourses, roads etc.). An optimal route can be found by prioritizing and weighing all the different features and terrains encountered in combination with conscientious, good faith negotiations with the landowners and the permitting authorities and never losing sight of the ownerâ&#x20AC;&#x2122;s goals and needs for the pipelineâ&#x20AC;&#x2122;s functionality, cost, and safety. Appendix 5.1.2 discusses how to use Google Earth to aid in pipeline design and route selection.

5.1.2.1 Access Once a route has been selected, access to the route must be obtained first for engineering assessment and surveying, for construction, and then permanent access for operations and maintenance. Construction access is important as it involves the transport of heavy equipment and material to the ROW. Permanent access for operations and maintenance is by far the most important as this will be required all year round (365 days) for any potential emergency inspections and repairs. Access may be via public or private means. Public roads and highways are used to get material and equipment into the general vicinity of (if not directly to) the area on the ROW where they are needed. Otherwise, the contractor must rely on either access directly down the ROW or by private access, negotiated with landowners, to get his equipment and material to the ROW. Contractors rely heavily on access down the ROW, but this is frequently interrupted by the presence of natural features such as marshes and soft ground, streams, and ravines. Long driving distances are often involved in circumventing these features by public roads. In such cases, private access is often required, by means of a private road or temporary board or gravel road (built by the contractor) on private property. Temporary access roads are most often removed after construction and pre-existing private roads used must typically be left in as good or better condition than found.

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5.1.2.2 Non-contiguous ROW A non-contiguous ROW is primarily a planning and permitting issue, and is often encountered where landowner negotiations for the ROW have been prolonged or face litigation or where permitting issues have not been fully resolved in a given area at the time construction is scheduled to begin. Unresolved access to the ROW can force a contractor to reload, move, and unload his equipment repeatedly and also complicates the logistics of moving material to the ROW. Similarly, missing ROW sections can interfere with the efficient hydrostatic testing of the pipeline once installed and can force the contractor to return to the area once the ROW is obtained. This interference with the normal pipeline construction and testing process lowers construction efficiency, raises costs, and extends the construction schedule thus delaying the pipeline in-service time. As a result, every effort should be made to minimise noncontiguous ROW issues prior to start of construction.

5.1.2.3 Working Space Working space constitutes the area in which the construction equipment will operate while installing the pipeline and associated facilities. For the pipeline itself, this is a combination of the ROW and the temporary workspace outside the ROW, which is negotiated with land owners, for use on a temporary basis during construction only. This temporary workspace is often located parallel to and on both sides of the pipeline ROW. The full, running construction corridor (ROW and temporary workspace) is typically broken into three, parallel strips. First, there is the pipe trench located in the central portion of the corridor (and within the ROW), second, the spoil side workspace where the trench spoil is placed, and third, the working side (opposite the spoil side of the trench) where the pipe is strung and welded together, the side booms operate, and typically a travel or passing lane is provided outside the pipe and side booms. The width of the temporary workspace is largely dependent on the size of the pipe, the size of the equipment to handle it (side booms etc.), the depth of the trench, and the degree to which soil segregation is required. Typically, additional temporary workspace is provided at road, stream and other crossings where more or special construction equipment is required, crossing pipe sections (drag sections) must be fabricated, and additional requirements for spoil storage must be made. These additional temporary workspace requirements are essentially standard for road and stream crossings, but can be much larger and more complex for special construction areas such as at horizontal directional drilled (HDD) crossings. The proper allowance of workspace on a pipeline project creates an efficient construction environment where high levels of safety and productivity can be achieved and maintained, construction schedules are reduced, costs are mitigated, and a better industry reputation maintained altogether. On the other hand, inadequate workspace creates an inefficient and unsafe work environment where equipment and personnel must work too closely together, equipment is restricted in its ability to move and pivot, material storage and fabrications must be done at remote locations then transported to site, spoil must be transferred to multiple locations, access and passing lanes are nonexistent or restricted, and project schedules are prolonged, safety and quality is sacrificed, and costs increased etc. In general, adequate work space is a key component of a successful pipeline project. However, the availability of space is dependent on the terrain being crossed. Construction at the peaks of mountainous terrain will have limited working space, meaning that construction traffic will require more control moving up and down the right of way compared to a flat right of way. This will affect construction rates, and hence overall schedules.

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5.1.2.4 Restoration Restoration is the return of the temporary construction workspace and the pipeline ROW to a condition similar prior to the pipeline’s construction. Restoration plans are generally negotiated with the land owners, environmental engineers, and permitting authorities prior to construction commencement. Plans are drawn up according to the agreements with all involved. Typically the restoration of ROW and workspace involves the return of appropriate plant life to these areas and updating ground drainage to work as before. In some cases it will also involve the replacement of road and parking lot surfaces etc., or the stabilization of stream and river banks at crossings. In the latter cases, care should be taken to prevent settlement or erosion of those surfaces in the years following construction. Regarding plant life restoration, the workspace may be typically allowed to either return to its natural state on its own or be replanted with plant life, including trees, similar to those in the surrounding area. Typically the ROW itself is not replanted with trees or heavy brush as it must be passable by maintenance and emergency vehicles, and be able to be monitored by crews on foot or by plane. There are exceptions to this such as along navigable and scenic rivers where tree screens are often required by the permitting authorities. However, any trees or heavy brush planted near pipelines must have shallow roots so as not to interfere with the pipeline and its coating. At a minimum, the disturbed ground is typically graded then seed, lime, mulch, fertilizer etc. is spread to provide a temporary stabilization to the soil surface to mitigate erosion (in accordance with the approved plans). At times, the soil must be broken or aerated to some degree if it has been compacted too severely by construction equipment. Farmers will often take care of the restoration of their own cropland in accordance with their own plans with expectations of compensation for their effort. In some cases the restoration effort may extend over several years until a given percentage (specified in the permit) of the disturbed land has been restored. Complicated restoration efforts (as might be required in national parks) are often subcontracted out by the owner or prime contractor.

5.1.2.5 Environmental Mitigation As an example, a large-diameter pipeline 100 miles long may traverse various terrain types and cross through or near many farms, parks, forests, and/or prairies; and dozens of streams and/or rivers. Such a pipeline can potentially disturb over 1200 acres of land and leave in its path a prominent scar across the countryside. In an effort to mitigate the negative impact of a pipeline project on the environment it is important to first assess the types of environments through which the pipeline is proposed to pass. Second, to develop a plan by which the impact of the pipeline’s construction and operation in those environments is mitigated. This environmental mitigation plan for a pipeline project is prepared in cooperation with the land owners and the permitting authorities. Optimized routeing of the pipeline is the first and most important tool by which environmental impact is mitigated. By that means alone, very important or sensitive land areas have the best opportunity to minimize or eliminate negative environmental impact. Additional mitigation measures include:

• • • • • • •

Boring or HDD under or passed areas of concern Reduced ROW and/or workspace width Bridging over areas of concern Increasing the depth of cover or insulating the pipe (where surface heating or cooling is a concern) Rearranging mainline valves out of areas of concern Sharing ROW with adjacent utilities Using existing bridges

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 5

• •

Installing interconnections with existing pipelines (where extra capacity is available) rather than building a new pipeline Using skid mounted equipment prefabricated elsewhere

Further ways may also exist to reduce or eliminate the impact of pipeline construction and operation to the environment. As for land that is impacted by the pipeline, a plan must be developed in cooperation with the landowners and permitting authorities, to restore the disturbed environment to its preconstruction state as much and as soon as possible.

5.1.2.6 Permits Any and all pipelines that are to leave the property of the pipeline owner and cross either public land or private land, not owned by the pipeline owner, must be approved by the appropriate public authorities. It is the duty of the public authorities to ensure that all laws of the land are obeyed, that the rights of private property owners are respected, and that there is an overriding public good provided by the pipeline project. The approval of the project, by the public authorities, is generally provided in the form of a permit, signed by the appropriate public representative and officially issued. This permit, often issued with stipulations, is the means by which the pipeline is approved to be designed, constructed and operated. Different countries have differing regulatory and permit requirements. Such permits can typically be broken into three types. These are typically federal, state, and local. Generally speaking, if a pipeline is classified as having common carrier status (carrying the products of more than one company) then the owner company is given the right of eminent domain, which in effect allows the pipeline owner company to condemn property owners in court to obtain (at fair market value) the access, ROW, and/or workspace needed to construct and operate their pipeline. Typical reasons that permits are issued include the following:

• • • •

•

To confirm that a pipeline project is in the best public interest and that a fair increase in commodity or tariff rates may be made, by the owner company, to offset the projects costs To confirm that property owners, on whose property the pipeline is to be located, are not unduly burdened by it To confirm that the environmental impact is acceptable and that appropriate mitigation and restoration will be conducted To confirm that the route and workspace has been searched for prehistoric and historic sites in the vicinity of the project and that either the project’s impact to any such sites is nil or acceptable and that appropriate restoration will be performed (as required) To confirm that the route and workspace has been searched for endangered species and habitat in the vicinity of the project and that either the project’s impact to any such sites is nil or acceptable and that appropriate restoration will be performed (as required) To confirm the acceptance of road, railroad, stream and other crossings

Numerous additional types of permits might also be required. These permits can take from a few days to prepare a simple drawing and obtain a local road crossing permit to over a year to apply and obtain a federal permit for a large multi-state project.

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5.1.2.7 Terrain This is the most important construction issue. In weighing the construction, material, and operational costs and needs of a cross country pipeline, there will sometimes be decisions made during the routeing process to traverse a shorter distance through a more difficult terrain rather than take a longer distance through a more favorable terrain (and vice-versa). Generally, shorter pipelines make for lower construction, material, and operational costs. However, in some cases, it may be preferable to take a longer route around an area, such as a dense city or a mountain range, rather than take the shorter and more direct route through it. Complications can increase substantially in mountainous and other regions affecting safety and extending the construction schedule resulting in increased costs. In addition, product transportation and operation costs can significantly increase though mountainous regions (for liquid lines). In such cases, for example, the increase in costs for a mountainous route, over the life of the pipeline, could outweigh those for a longer route around a mountain range. These are issues that must be worked out in the overall process of optimizing the pipelines function and lifetime cost (construction, material, and operations). Nevertheless, difficult terrains are often part of a chosen pipeline route, and must be dealt with by the construction contractor. Such terrains might include mountains, marshes, permafrost, urban areas, unstable soils (moving sand dunes etc.), rugged areas with much erosion and exposed rock, areas with poor access etc. In all these cases, careful planning of the workspace, access, material storage yards, construction equipment to be used, pipeline installation methods, and construction schedule (winter, summer etc.) in consideration of the terrain will make vast improvements in the safety and productivity of the construction phase of the project.

5.1.2.8 Community Relations Presenting a proposed pipeline project in a positive way to the communities it affects, and maintaining a good and positive relationship with affected communities is key to minimizing many of the problems that can often hamper the permitting, construction, operation, and maintenance of a pipeline. Project administrators should notify communities early on about the plans for a proposed pipeline project by contacting community administrators, posting newspaper notices, and conducting public meetings. Open public meetings provide an opportunity for local officials, landowners, business leaders, and other affected parties to receive information about the pipeline(s) location(s), construction schedule, and key project contacts. These meetings can also provide a means of providing information about the benefits of a pipeline project (economic stimulus, jobs etc.), allow community members to have their questions answered and concerns addressed, rectify misunderstandings that frequently alarm people unnecessarily about pipeline projects, and avert negative media attention. Likewise, these meetings allow for dialogue with property owners and community. Overall, good relationships between pipeline owner companies and communities are invaluable toward improved routeing and facility location options, ROW and workspace negotiations, assistance from the local contractors and workforce, and opportunities for the use of community infrastructure and facilities among other things.

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5.2

Minimum Data Requirements and Activities for the Five Typical Project Stages

The diagram below shows the typical project cycle time and the project phases in relation with the Construction Contract duration. It is also important to bear in mind that a pipeline project is a multi-discipline effort involving coordination between pipeline engineers, metallurgy, process, control systems, electrical, piping, civil and mechanical works as well as social, cultural and environmental specialists.

5.2.1 FEL 1 Business Planning Business planning is of utmost importance as it sets the foundation stone for the project, ie why the project is required, that project expenditure is necessary, and the purpose of the project. Defining the purpose of the project is key, as the purpose of the project phases following this phase FEL 1 will be to provide the optimum solution to comply with the project purpose / statement of requirements (SOR). It basically sets the ground rules / constraints around which the design will be performed. The key activities normally involve the following:

• • • • • • • •

Business Case Strategic Objectives Economic Analysis Project Expectations Market Analysis Competitors Review/Competing projects Environmental Constraints Desk Top Routing Study to identify a Regional Corridor (typically 15 – 25 km wide

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Cost estimates (+/- 50%) and schedules are key drivers in the business planning phase and are determined by a multidiscipline effort. Major cost / schedule input items such as pipeline size determination and pump or compressor requirements are determined by pipeline and process/mechanical engineers. SCADA / telecoms, pipeline security, environmental issues, terrain, and regulations are also considered by a multidiscipline effort inclusive of electrical and instrumentation, piping, civil, environmental, social and safety engineers. For business planning of long distance pipelines crossing country borders, both legal and commercial inputs are also required to advise on international / cross border conditions, tariffs, and international negotiations. As stated above, a pipeline projects is a multi-discipline effort. A composite team of pipeline, process, controls, piping, civil, environmental, social and safety engineers is required. For business planning of long distance pipelines crossing country borders, both legal and commercial inputs are also required to advise on international / cross border conditions and tariffs, international negotiations. The costing analysis will need to offset revenue costs against:

• • •

Material and construction (pipe, valves, SCADA, rotating equipment, fiscal metering) OPEX (fuel usage, security, maintenance and inspection, CO2 offset) Tariffs (domestic and international)

A high level pipeline schedule showing the start and end date to commissioning the line is important. Key overview activities include:

• • • • •

EIA (Environmental Impact Studies) Regulatory permits and approvals Design Long lead items (pumps, compressors, linepipe, SCADA / telecoms) Construction

The minimum data requirements for business planning are typically:

•

Existing infrastructure information o Land use (agriculture, woodland, wetland, open water, residential, commercial) o Designated areas (existing or planned parks, public areas, developments) o Rights-of-way (roads, railroads, utility corridors to be crossed or paralleled) o Identify physical obstacles (swamps, mountains, lakes, and rivers) on maps o Identify geotechnical constraints including Seismic activity, karst areas, landslides, o Energy grid (alternative energy sources, competitor pipelines, existing company lines) o Origin and termination points of pipeline identified o Potential customers (taps) and potential partners (tie-ins) along route identified o Demographics, area growth potential o Need for new pipeline (U.S. proof of “convenience and necessity”)

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•

Political situations o Unrest and extremism o Regulatory atmosphere and pending legislation o Future tariffs, energy tax credits, infrastructure inducements Expectations o Customers o Partners o Regulatory approval provisions o Landowners Market information o Long term availability of oil or gas supply for pipeline o Long term demand by customers o Open season offering to gauge potential pipeline customers o Oil and gas price projections Financing o Lending environment o Cost of borrowing o Potential investors and partners Competitor data o Public information o Consultant information o Other in-house projects pending Key environmental constraints o Water bodies o Protected species o Archaeological sites o Air quality and noise o Hazardous waste areas Field Investigation o Regional pipeline corridor pinch points identified o Discussion with local agencies and business groups o Right-of-way research at courthouse o Assess landowner resistance o Estimate land cost

The key deliverables from the business planning phase are typically:

• • • • • • • • • •

Business case justification document Project statement of requirements Framework / Scope / Project Objectives Regulatory plan Decision Review Packages Cost Estimate – (+/- 50%, or order of magnitude OOM) Schedule Timeline Project Execution Plan Project Risk Assessment (commercial / technical / environmental) At least one feasible corridor identified

It is important that the above deliverables have been thoroughly studied, as any changes later on could introduce flaws for the whole philosophy leading to the effort having to be re-done. This would result in redundant work, and consequential impacts on cost and schedule.

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A Regulatory Plan is also of paramount importance to plan the submission of the key approval documents during the alternative selection phase. It is also needed to ensure that the schedule takes into account public consultation meetings, local area / local jurisdiction approvals and governmental approvals. Project Teams shall begin to organize their data collection around a Geographical Information System (GIS) structure to facilitate the management of this data throughout the life cycle of the project. Any problems in these areas can jeopardize the project viability.

5.2.2 FEL 2 Alternative Selection The alternative selection phase is where the pipeline system design is further progressed to confirm viability and to review and select the optimum solution. This phase improve accuracy of the cost estimate and to the schedule. The cost estimate for this phase is expected to achieve a +/-30% accuracy. The schedule for this phase of a project will become more detailed by adding more activities and confirming durations for more specific selections The selection phase will utilize the project statement of requirements (SOR), framework, scope, and project objectives to develop viable options meeting the project requirements. These options will be driven by safety, environmental and social constraints and cost, and can include: • Routing options • Pipeline configurations (single line / multiple lines) • Pipeline diameter vs design pressure options • Pipeline diameter vs number of pump / compression stations • Locations of stations It is important that all the viable options are considered in detail and that there is agreement on the optimum solution selected. It is important that solution selection criteria is prepared, is agreed, and is robust enough to ensure that the correct criteria is used for the selection analysis. The key requirements need to be prioritized in a list as appropriate. It is not uncommon that a number of selection phase studies are done to ensure that the correct solution for further engineering development is selected. In some cases, design competitions are held with this intention. The key engineering activities involved during this phase are generally:

• • • • • • • •

Establish Regulatory / Permitting requirements / schedule More detailed Route selection to identify alternative routes (100 to 500 meter wide) within the Regional Corridor (15 to 25 km wide)Generally performed on a desk top basis. Perform Hydraulic Study to ascertain pipeline sizes and station locations of alternative routes Determine pipeline operating / batching philosophy Preliminary SCADA / telecommunications design Class Location and Main Line Valve study Determination of road, RR, water body crossing methods Detailed Field reconnaissance of route alternatives and aboveground facilities locations

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•

• • •

By end of FEL 2, alternatives are trimmed to one primary route, and perhaps one or two alternatives, on the basis of cost, constructability and project SOR for purpose of environmental assessment and permitting to carry forward into the FEL 3 Stage. (Certain regulatory frameworks may dictate the number of alternatives required to carry forward for permitting/certification). Preparation of preliminary route maps HSE Plan Involvement of critical equipment / material providers (long lead items, coatings, etc)

Minimum data requirements for the FEL 2 Alternative Selection phase:

• • • • • • • • • •

FEL 1 Business Planning Report Project Statement of Requirements Applicable regulations and codes Pipeline owner / operator Design Specifications Satellite imagery and/or aerial photography and elevation data Identification of wetlands; i.e. geologic maps Preliminary survey of aboveground facilities Other data required for the work is collected as required Continued development and enhancement of the GIS system Environmental impact assessment

The key deliverable is a study report generally comprised of the following:

•

• •

• • • • • •

• •

Pipeline Route o Routing plan drawing o Route Maps o Number of and Station locations (valve, pigging, pump, compression, metering) o Terrain (topographical / geotechnical) description o Crossings Process description Pipeline system parameters: o Design code o Outside diameter o Wall thickness / material grade o Length o Pressure / Temperature profile o Corrosion protection (CP, coatings, etc.) SCADA / telecoms requirements AGI’s / Station layouts / plot plans (valve, pigging, pump, compression, metering) Plant layouts (equipment upstream and downstream of the pipeline system) Pipeline delivery and/or supply tie-in locations Preliminary Equipment list / MTO’s Regulatory o Permitting and regulatory plans o Authorizations and approvals plan o Crossings approval plan Construction methodology HSE o Safety Plan o Preliminary Environmental Impact Assessment o Environmental constraints (plant, pipeline and stations) o Health Plan

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• •

o Community Awareness Plan o Public Relations Plan o Environmental Risk Register Cost estimate Schedule

Topographical and geotechnical surveys should be scoped, specified and awarded at the start of Alternative Selection to enable critical areas to be evaluated with the results to be used during the selection process It is recommended that an Environmental Impact Assessment (EIA) report be commissioned after this phase using the pipeline route maps and station location / layouts as the basis. The purpose of this will be to highlight any major issues preventing project realization before committing to any further funding.

5.2.3 FEL 3 Project Definition The project definition phase is where the engineering of pipeline system is enhanced to a level providing a +/-15% estimate, and the schedule activities are now shown to a more detailed level. Key processes for this phase include:

• • • • • • • • • • • •

Project Management Contracts Plan Regulatory Material Selection Hydraulic Study Detailed Route Selection of primary route is narrowed down to a fixed 50m to 100m wide right of way (ROW) Detailed Engineering of pipeline and associated facilities ROW design completed and drawings finalized Alignment sheets are completed and marked for construction Procurement Plan Construction Plan HSE Plan

Minimum data requirements for this phase include:

• • • • • • •

Alternative Selection Phase report Field surveys with full access to route Detailed Topographical and Geotechnical Surveys Environmental Assessment Inputs from specialists (eg river / flood plain crossings) Regulations and codes Pipeline owner / operator Design Specifications

In this phase the route is finalized, the GIS system (geographic information system) and PODS database should be fully implemented, and constructability and construction planning becomes a key issue together with engineering.

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The Pipeline Open Data Standard (PODS) is one industry standard for pipeline data storage and interchange. The PODS Data Model provides the structure to associate pipeline data records, such as inspection results, with each specific pipe segment and geographic location. These data records may include (partial list): centerline location, pipeline materials and coatings, MAOP, valves and pipeline components, cathodic protection facilities and inspection results, hydrotesting, operating conditions, physical inspection results, leak detection surveys, repairs, foreign line crossings, inline inspection (ILI) results, close-interval survey results, pump and compression equipment specifications, geographic boundaries, external records, risk analysis methods and results, regulatory reports, and pipeline and ROW maintenance activities, among others. The PODS Data Model is used by many pipeline operators to manage pipeline, integrity, inspection, regulatory compliance, and operational data in a Geographic Information System (GIS). The early implementation of a PODS Data Model integrated with GIS during the project phase enables the project to record pertinent information obtained during the project execution in a standardized format and provides a more seamless transition of the handover to operations at the completion of the project. During the course of project definition, when the route maps have been better defined, a constructability session with engineers and construction contractors present should be conducted to ensure that the design has not introduced expensive and time consuming stipulations. Construction contractors maybe able to advise of more cost effective and less time consuming options regards pipeline and stations layouts. The Output of FEL 3 typically includes, but is not limited to, the following â&#x20AC;˘ Management o Design Basis o Economic Evaluation of Alternatives o Decision Review Packages o Org Charts o Risk Register o Staffing Plan o Cost Estimate - Class 3 o Detailed Project Schedule o Project Execution Plan o Freeze/Commit To Design o Scope Of Works o Construction Plan o March Charts o HSE Plan o Environmental Impact Assessment o Community Awareness Plan o Public Relations Plan o Environmental Risk Register â&#x20AC;˘ Procurement o Contractor Pre-Qualification/Selection o Contract Enquiry Packages o Contractor Technical Bid Evaluations o Contract Awards o Vendor Pre-Qualification/Selection o Material Enquiry Packages o Material Technical Bid Evaluations o Material Award Packages o Vendor Print Reviews o Procurement Support (typically long lead items)

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â&#x20AC;˘

o Line Pipe o Corrosion Coatings o Pig Launchers/Receivers o Material Logistics Plan Detailed Design o Permitting And Regulatory Plans o Authorizations And Approvals Plan o Crossings Approval Plan o Materials And Corrosion o System MAOP o Flow Assurance o Surge Analysis o Station Spacing/Location o Number Of Stations o Metering Philosophy o Horsepower Requirement/Station o Facility Specs (Pump/Compressors, Metering, Traps, Etc.) o Transient Analysis Results o MTO/Long Lead Items o Design Report o System Sketch o MTO Plan o Crossings List o Populate GIS o Environmental Compliance Engineering o Equipment Engineering o Project Data Sheets o Material Selection o Survey Specifications o Cathodic Protection Design o Equipment Specifications o Material Specifications o SCADA Philosophy o Operating Philosophy o Construction Specifications o Control Philosophy o Pre-Commissioning/Commissioning o Specifications o Mechanical Design Analyses and Calculations: o Wall Thickness o Operational Stress Analysis o Upheaval Buckling Analysis o Bend Analysis o Expansion/Anchoring Analysis o Anchor Flange Calculations o Line Erosion Analysis o Buoyancy o Road Crossing o Rail Crossing o River Crossing o Blasting o Earthquake o CP Plan

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o Typical Drawings: o Pipeline Right-Of-Way Detail o Bored Road Crossing o Minor Water Crossing o Open Cut Road Crossing o Trench & Backfill Details o Pipe Crossing Through Wet Areas o Bored Crossing Trench Detail o Railway Crossing Bored (Single) o Railway Crossing Bored (Dual) o Pipeline Concrete Coating o Pipeline Marker Sign o Pipeline Pig Launcher Arrangement o Pipeline Pig Receiver Arrangement o Valve Station Location Drawing o Pipeline Main Line Valve – Vented General Arrangement o Anchor Block Detail o Sketches o Plot Plans o Layouts o Tie-Ins o Detailed Drawings: o Plot Plans o Alignment Sheets o Valve Stations Health Plan o Scraper Station General Arrangement o Pipeline Main Line Valve o Cross-Sectional Crossing Drawings (Plan And Profile) Showing Pipeline In Relation To All Existing Facilities In addition to the pipeline design itself, the other elements of the design include the upstream and downstream facilities, pipeline safety and control, SCADA / telecoms, metering, station design, access roads / infrastructure, buildings etc. Pipeline design will include diameter and wall thickness confirmation and operability stress analysis, and will include anchoring analysis. Depending on the schedule, and market conditions it is not uncommon, to place some materials orders during this phase for long lead items (LLI’s) such as linepipe, rotating equipment, and SCADA. Specific engineering actions to define these long lead materials are then performed. Materials can be novated at a later stage to the contractor. HSEIA (Health Safety and Environmental Impact Studies) activities such as QRA, HAZOP / SIL, HAZID, SIMOPS, will be conducted. The findings from these studies will be included in the design. QRA (Quantitative Risk Assessment) is a risk assessment activity, part of an integrity management program, to understand the nature and location of risks along the pipeline and at the AGI’s / Stations. QRA (Quantitative Risk Analysis) is often used to qualify the probabilistic risk approach in which not only the consequence of an adverse event is calculated but also the likelihood is quantified. SIL (Safety Integrity Level) study is a measure of Probability to Fail on Demand (PFD) of any Safety Instrumented System (SIS) installed on the pipeline (eg surge protection equipment). SIL is a statistical representation of the integrity of the SIS when a process demand occurs. A demand occurs whenever

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the process reaches the trip condition and causes the SIS to take action. In simpler terms, SIL is a measurement of performance required for a Safety Instrumented System (SIS). Four SILs are defined, with SIL4 being the most dependable and SIL1 being the least. A SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management. Hazard and operability studies are a methodology for identifying and dealing with potential problems in industrial processes, particularly those which would create a hazardous situation or a severe impairment of the process. It is commonly known as HAZOP. It is sometimes also called Hazard and Operability Analysis. It is said to be the most widely used method of hazard analysis in the process industries, notably the chemical, petrochemical and nuclear industries. HAZOPs are conducted by a team of people that are knowledgeable in the process, the team is led by a trained facilitator that uses a list of guide words to lead the discussions. SIMOPS (SIMultaneous OPerationS) is defined as performing two or more operations concurrently. When installing a pipeline next t existing operating pipelines, a SIMOPs plan is required to ensure that the operation and safety of the existing pipeline is not compromised. A typical design chart is shown overleaf.

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Typical Design Chart

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5.2.4

Project Execution

The project execution phase at this stage of the project development by Client is mainly characterised by material procurement activities, construction planning and logistics. The engineering is completed to enable specification of all materials required. The main drivers for the project execution phase are characterised by: • Project Management • Contracts Plan • Regulatory • Material Selection The key engineering activities involved during this phase are generally: • Support to permitting, land acquisition, field survey, and construction activities • Construction centerline staked and 25-50 m permanent ROW and temporary workspaces marked, down to 8 m wide permanent ROW corridor) • Engineering Plan • Provide support to any minor re-routes that might be required to adjust to field conditions. • As-built survey data collected, Quality assurance, and incorporated into the project database. • Prepare all Project data for handover to Operations • Hydraulic/Flow Assurance confirmation • Detailed Routing (Minimum 22 m wide construction corridor • Procurement Plan support • Construction Plan support • HSE Plan support Input: • Output from Project Definition, FEL 2 and FEL 3 • Regulatory approvals • Permit approvals • Crossing approvals The key engineering activities will be to finalise the Scada and Telecoms design, the stations design, and prepare construction specifications. A multi-discipline engineering team will complete the design. Construction drawings are prepared for the crossings, and any special pipeline sections at route pinchpoints. Details on the drawings need to sufficiently clear to enable the construction site team to understand the requirements and to build to these requirements. Ambiguous information will result is site queries and loss of construction. Ambiguous information can also lead to misinterpretation of instructions leading to construction not consistent with the design philosophy. This is one of reasons to involve construction group in the design phase to ensure that handover from office engineering to site team is clear and concise. Construction engineering activities will include developing the material storage and logistic plans, construction spreads, hydrotest water supply and disposal plans, hydrotest plans. The supply and environmentally safe disposal of hydrotest water can sometimes be a key issue on remote location pipelines, particularly in hot countries. The project deliverables are not just pipeline engineering, but across the whole board from process, piping, controls to civil works and environment for access roads, infrastructure for maintenance and inspection to security fencing at the AGI’s and stations.

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Operating and commissioning manuals will need to be prepared in readiness for the pipeline start-up. The operating manuals will need to be clear and concise instructions on how to operate the system (start up, shutdown and for safely how long, turndown, turn-up rates, re-start, and pigging requirements and frequencies). There will also need to be manuals for the plant, AGI’s / stations, and for the SCADA / telecoms. A typical alignment sheet is shown below which shows the pipeline plan and topographical profile as well as data such as:

• • • • • • • • • • • • •

Pipe outside diameter Pipe wall thickness Pipe material Design factor / class location Coating Burial depth / soil cover depth, including special locations to mitigate against buckling (if required) Intersection Points (IP’s) locations where pipeline changes direction Chainage (KP) kilometre point Location of horizontal and vertical bends Water table Existing services Crossing location Any other project specific salient features

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5.2.5 Start-up and Operations The start-up and operations is the last phase where the pipeline is commissioned and formally handed over to the operating company. This is the true test that the installed system will meet the design conditions originally stipulated. The performance testing will involve introducing hydrocarbon into the pipeline, and ensuring that all the associated systems are working properly. Personnel from the Operating company will be heavily involved in the development of the commissioning plans and the introduction of hydrocarbons into the pipeline. The project team will ready all pertinent information obtained during the project for handover to the Operating company. The information will include all data necessary to provide the physical description of the pipeline and associated facilities as well as to document the integrity of the pipeline and construction related activities. As a minimum this would comprise the following: • Design basis • As-built survey information • Alignment sheets • Crossing drawings • Material specifications • Vendor documents (for material and equipment) • Line pipe material certificates • Hydrotest data • Construction records (weld sheets, joint coating sheets) • Inspection records (NDT, etc.) • GIS/PODS database Implementing GIS and PODS at the FEL 3 Definition phase will enable a cradle to grave information system that can be updated across the design and operating life span of the pipeline. It can also be used to generate alignment sheets and detailed drawings during design, track materials during the procurement and construction phase, record as-built survey information and to record maintenance and inspection history during the operational phase. The benefits of using GIS and PODS is that the project and as-built data can be stored with the GIS and PODS database system with the pertinent information tagged spatially to their exact locations. The data residing in the GIS and PODS database should have undergone a quality assurance process by the project team prior to handover to operations.

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Minimum data requirements, key activities and outputs for this phase and required for handover to operations are: • Execution phase documents • Operating and Commissioning Manuals • Summary Data Book • Design Basis Data Book • Design Calculations • Quality Plans And Manuals • Special Procedures • Cost Summaries • Manufacturing Data Book • Tender Specifications • Equipment And Material Specifications • Purchase Orders • As-Built Vendor Drawings • Material And Testing Certificates • Vendor Inspection Reports • Special Manufacturing And Fabrication • Procedures • Heat Treatment Certificates • Special Procedures • Fabrication Data Book • Pipeline Installation Data Book • Contracts • Job Hazard Analyses • Monthly Progress Reports • Non-Destructive Testing Summary And • Radiographs • Weld Procedures And Qualification Certificates • Pipeline Facilities Installation Book • Field Sketches, Survey Notes and Red-Line Mark-Up Data Book

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• • • • • • • • • •

Construction Inspection Reports As-Built Drawings As-Built Survey Data - Electronic Copy Cathodic Protection Survey Data Book Video Survey Data Book Pressure Testing Data Book Hydrotest Reports Pre-Commissioning Data Book Commissioning Reports Populated GIS and PODS database

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 5.1.1

Appendix 5.1.1 Pipeline Route Selection Process

Table Of Contents Page

5.1.1

Route Selection Process General Basis for Engineering Primary Selection Factors Corridor Selection in Project Key Stages Routing Activities within Project Phases 5.1.1.5.1 Route Corridor options [FEL 1, Appraise] 5.1.1.5.2 Route selection [FEL 2, Select] 5.1.1.5.3 Route investigation and consultation [FEL 3, Define , FEED] 5.1.1.5.4 Design and approval of final route [Project Execution phase, detailed design] 5.1.1.6 Key Routing Principles and Influencing Factors 5.1.1.7 Public safety, content of the pipeline, operating conditions and location class 5.1.1.8 Pipeline Above Ground Installations (AGIs) 5.1.1.9 Environmental and Regulatory Steps 5.1.1.10 Terrain, subterranean conditions, geotechnical and hydrographical conditions 5.1.1.11 Geohazards 5.1.1.11.1 Types of Geo-hazards 5.1.1.11.2 Geotechnical Investigations 5.1.1.11.3 Geo-Hazard Pipeline Routing 5.1.1.12 Selection Criteria 5.1.1.13 Existing and future land use 5.1.1.14 Permanent access 5.1.1.15 Transport facilities and utility services 5.1.1.16 Construction , hydrotesting, operation and maintenance 5.1.1.17 Security 5.1.1.18 Risk/Threat Assessment 5.1.1.19 Data Collection and Management 5.1.1.20 Graphical Information System 5.1.1.20.1 General 5.1.1.20.2 GIS Routing Optimization Methodology 5.1.1.20.3 Identification of Factors Affecting the Route 5.1.1.20.4 GIS Data and Data Sources 5.1.1.20.5 GIS Data Processing and Analysis 5.1.1.20.6 GIS Suitability Map Generation 5.1.1.21 Light Detection and Ranging - LiDAR

5.1.1.1 5.1.1.2 5.1.1.3 5.1.1.4 5.1.1.5

26 26 26 26 27 30 30 30 30 30 32 33 33 33 35 36 36 37 38 39 42 43 43 43 44 44 44 46 46 47 47 48 48 48 49

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5.1.1 Route Selection Process 5.1.1.1

General

The route selection process described below is a typical approach of routing a pipeline between the known start and end points and any intermediate offtake points. A description covering all potential eventualities would be impossible since no one pipeline routing selection process is similar to any other because of differences in location, land use, terrain, infrastructure, local permits and regulations, environment, and archeology. Furthermore, each route selection phase will depend on the project schedule. Each terrain will have its own issues. It is entirely conceivable to complete and approve the final route in the project planning (FEED, define) phase, whilst other projects may not do so until the project execution (detailed design) phase. Pipelines are routed to connect between a start point, intermediate take off points and an end point. The final route selected must be: • • • •

Safe Environmentally acceptable Economical Practical

No one routing process can be applied for all pipelines. This is because different factors, such as product to be transported, pipeline size, pipeline material, location, land use, crossings required, land ownership, terrain, infrastructure, local permits and regulations, environmental and archeology, have to be considered for different pipelines. Such factors will be key to defining when the route will be finalized and approved. For some projects the route can be finalized and approved in the project planning (FEED, define) phase, whilst other projects may not do so until the project execution (detailed design) phase.

5.1.1.2

Basis for Engineering

A pipeline route is a pivotal piece of information upon which the pipeline engineering depends. The route will define the pipeline size, terrain, soils, and engineering analysis requirements. Engineering assessment based upon an agreed alignment selection criteria is an important part of a linear project. To be able to reach the best construction line and optimize its components, the phases namely — corridor, route, alignment, and construction line selection — should be studied in the given order.

5.1.1.3

Primary Selection Factors

The detailed pipeline route selection is preceded by defining a broad area of search between the two fixed start and end points. That is, possible pipeline corridors. The route can then be filtered with consideration of public safety, pipeline integrity, environmental impact, consequences of escape of fluid, and based on social, economic, technical environmental grounds, constructability, land ownership, access, regulatory requirements and cost. Economic, technical, environmental and safety considerations should be the primary factors governing the choice of pipeline routes. The shortest route might not be the most suitable, and physical obstacles, environmental constraints and other factors, such as locations of intermediate offtake points to end users along the pipeline route should be considered. Offtake points may dictate mainline routing so as to minimise the need or impact of the offtake lines or spurs. Many route constraints will have technical solutions (e.g. routing through flood plains), and each will have an associated cost.

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5.1.1.4

Corridor Selection in Project Key Stages

Pipeline routing is an iterative process, which starts with a wide ‘corridor of interest’ and then narrows down to a more defined route at each design stage as more data is acquired, to a final ‘right of way’ (ROW). Initially, a number of alternative corridors with widths up to 10 km wide are reviewed. Typically the route alignment steps can be described as shown below (Fig. 1 and Table 1). Each project will have its own specific corridor-narrowing process depending on project size and location. Pipeline corridors should initially be selected to avoid key constraints. The route can then be further refined through an iterative process, involving consultation with stakeholders and landowners and a review of the EIA criteria, to avoid additional identified constraints. The ultimate aim is to achieve an economically and environmentally-feasible route for construction. Fig. 1 – Narrowing Down Of Pipeline Corridor During Project Stages

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Table 1 - Narrowing Down Of Pipeline Corridor During Project Stages: Key Descriptions STAGE

FRONT END LOADING FEL 1 BUSINESS PLANNING (APPRAISE)

FEL 2 FACILITY PLANNING (SELECT)

FEL 3 PROJECT PLANNING (DEFINE)

PROJECT EXECUTION (EXECUTE)

START UP AND OPERATIONS (OPERATE)

Cost Estimate Accuracy

Order of Magnitude

+/-30%

+/-15%

+/-5%

Complete

Process

Appraisal

Feasibility

Selection/ definition

Approvals/ execute/ construction

Operation

Activity

Desktop Route Route corridor Corridor options selection, and identification of alternative route alignment options

Route selection, route investigation and consultation, site survey, negotiations

Detailed alignment, Maintain easement approval of final route/construction line, finalise negotiation, acquire land

Corridor Width

500 m – 1 km 10 km-20 km wide corridor of wide preferred route corridor interest (large scale maps)

100 m – 200 m wide specified corridor (more detailed maps)

20 m – 36 m wide construction corridor

Imagery

Maps of either 1:25,000 or 1:50,000 scale can be used depending on complexity of the terrain.

Plans for Map sheets of 1:2,500 scale can landowner agreements should be used. normally be based Alignment sheets on 1:2,500 scale, can be prepared or smaller. Aerial from maps or photographs with a resolution aerial imagery of 1:2,500 scale. of 250 mm or better, overlaid with coordinates Special crossings should be at scales of detailed : scale 1:10,000 can typically between also be 1:250 and 1:25 produced and depending on the used complexity of the crossing. Maps of either 1:10,000 or 1:25,000 scale can be used.

8m wide easement ‘permanent corridor’ for ongoing inspection, and required maintenance As-built plans (to the same scale as the original plans) should be issued to all original recipients on completion of the work. These plans should include all details of any site alterations or deviations

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Table 1 - Narrowing Down Of Pipeline Corridor During Project Stages: Key Descriptions (cont.) STAGE

FRONT END LOADING FEL 3 PROJECT PLANNING (DEFINE)

FEL 1 BUSINESS PLANNING (APPRAISE)

FEL 2 FACILITY PLANNING (SELECT)

Imagery

Maps of either 1:25,000 or 1:50,000 scale can be used depending on complexity of the terrain.

Maps of either 1:10,000 or 1:25,000 scale can be used.

Output

Preliminary routing plans

Detailed routing : Route using route maps with 1:5,000 to scale 1:50,000 1:10,000 maps

PROJECT EXECUTION (EXECUTE)

Land acquisition/ 1:100,000 route wayleave Field maps reconnaissance drawings plans Final field survey plans Alignment sheets strip plans

START UP AND OPERATIONS (OPERATE)

As-built plans (to the same scale as the original plans) should be issued to all original recipients on completion of the work. These plans should include all details of any site alterations or deviations

Finalised alignment As-built plans sheets Plans for landowner agreements/ permits/approvals etc Land purchase Detailed crossing drawings

Crossing drawings

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5.1.1.5

Routing Activities within Project Phases

5.1.1.5.1

Route Corridor options [FEL 1, Appraise]

This phase involves the initial desk-top studies to identify route corridor options taking into account known key environmental and cultural sensitivities. It is to develop key pipeline routing information from available topographical and geological maps, aerial photography and/or satellite imagery, and the literature available in the public domain, such as town planning data. The information is used to identify corridor options, key routing constraints visible from the maps and publications, and key engineering data such as length and profile for use in costing and scheduling.

5.1.1.5.2

Route selection [FEL 2, Select]

A corridor should be selected by performing a key issues study, whilst ensuring as far as possible that the corridor selected is suitable and is not likely to create significant problems at a later stage. The desk study and visual appraisal, making use of all information available within the public domain, should precede the adoption of a provisional route within the selected route corridor. Information regarding geological, archaeological and environmental features should, in the first instance, be obtained from published sources to establish the route prior to discussions with the relevant institutions. The geographic limits within which pipeline route selection is to take place should be defined by identification of the starting point of the pipeline and any intermediate fixed points. These points should be marked on suitably scaled plans covering the area. The route of interest should then be straddled across these points so that key issues and constraints affecting the selection of the route can be plotted and assessed. The width of the corridor will depend upon the nature of the terrain traversed, current and likely future population and degree of complexity expected with regard to environmental, constructability and archaeological aspects. Where practicable, this corridor should be selected to avoid urban areas, major road, rail and water crossings and environmentally sensitive areas. Existing and planned constraints to route selection occurring within the area of interest should be identified to assist the selection of route options. The constraints identified should take into account the complexity of terrain and information gathered. Key constraints and obstructions should be avoided as much as possible A preferred route should then be selected, taking into account all the technical, environmental and safety-related factors that might be significant during installation and operation of the pipeline system. The selection should follow a comparative study. Consideration should be given to setting up and using a geographical information system (GIS), as described below, to record and manage the data collected, at this phase of the project. Delaying such a decision to a later phase will require extensive data catch-up.

5.1.1.5.3

Route investigation and consultation [FEL 3, Define, FEED]

This stage involves gathering more detailed information, highlighting and mapping constraints within the route corridor so as to assist in the selection of a preferred final route. This allows the project to proceed onto the next stage of negotiations. All the constraints and potential planning problems that could affect the pipeline (e.g. timing or method of construction) should now be addressed and recorded. A traffic management plan should be produced. A QRA, risk or threat assessment exercise allows for the comparison of pipeline routing alternatives based on the likelihood of occurrence of hazardous event and the associated consequences of the events along each route.

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A detailed investigation of the route and the environment in which the pipeline is to be constructed should be made. Topographical, geotechnical, and soil resistivity field surveys should be carried out, comprising a pipeline engineer, geotechnical engineers, environmental scientists, archaeologists, anthropologists, with appropriate approvals from landowners. Access roads, construction camps, facility sites, cathodic protection sites and main line valve sites should also be surveyed during this stage. The data collected is also fed into the design and engineering of the pipeline. Refinements to the pipeline corridor and locations for above-ground facilities should be made while in the field to avoid environmentally and culturally sensitive areas. The appropriate authorities and any third parties should be contacted to obtain details of any known or expected development or encroachment along the route, the location of underground obstructions, pipelines, services and structures and all other pertinent data. Consultations should be held as early as possible during route finalisation with the planning and statutory authorities (including local planning authorities, and government safety departments) and any other appropriate organisations, landowners, third parties, etc. Reviews of the preferred route should be carried out in the field. These should initially be based on the desktop study. Accompanied by the relevant landowner/occupier and the land agent, the proposed route should be examined in more detail, in particular those areas that might have been difficult to determine from maps and public rights of way during desk studies. Consideration should be given to negotiations for use of access roads for construction or maintenance purposes. Land and environmental surveys should be made that cover sufficient width and depth around the provisional route and have sufficient accuracy to identify all features that could adversely influence installation and operation of the pipeline. This should be accompanied by further detailed consultation with all affected third parties. Third-party activities along the pipeline route and related safety aspects should be investigated. Stakeholder, local jurisdiction and national government approval should be obtained in accordance with statutory requirements. A complete set of data relevant to design, construction and the safe and reliable operation of the pipeline should be compiled from records, maps and physical surveys. The selected route should be recorded on alignment sheets of an appropriate scale. The coordinates of all significant points, such as target points, crossings points, bend starting and end points, should be indicated. Contour lines should be recorded at intervals sufficient for design purposes, particularly with regard to the installation and operational phases, and consideration should be given to the need for a vertical profile of the route.

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5.1.1.5.4

Design and approval of final route [Project Execution phase, detailed design]

This is the final phase to define the best line and its components. Local planning authority and statutory approvals, and landowner/tenant agreements, should now be finalized. The route of the pipeline should be identified by a locating system such as markers placed along the route. Valve locations, AGI locations, river crossings, and geo-hazardous area crossings should be investigated in detail, and readied for construction The physical building and commissioning of the pipeline should now be able to commence in accordance with the design criteria

5.1.1.6

Key Routing Principles and Influencing Factors

The key principles to take into account when performing route selection are : a) Safety of the public and personnel - the route must provide a safe and secure environment for the pipeline during construction and over its operational life and ideally be routed away from populated areas b) Economic – the route should meet the project’s economic objectives, without compromising safety and environment and minimizing local economy impact on communities that the pipeline passes through, and have the smallest footprint feasible (ideally the shortest distance between pipeline start and end points). c) Land ownership related factors e.g. the number of landowners, anticipated ease and cost to obtain/purchase consents d) Easement width e) Contents of the pipeline and operating conditions, e.g. consideration of leakage of a high vapour pressure liquids. f) Environmental impact – the route must have a minimum negative impact on the environment and minimum land use g) Terrain and subterranean conditions, including geotechnical, hydrographical, and meteorological conditions. This includes ground stability, including other land uses which may create instability (e.g. mine subsidence, land development/excavation) h) Cultural heritage sites i) Existing and future land plan usage. This can be determined by research of public records and consultation with land planning agencies which should identify: • third-party activities • agricultural practice • existing facilities and services • future developments j) Existing and planned transport facilities and buried/above ground utility services k) Construction, testing, operation and maintenance - the pipeline must be installable along the route l) Permanent access – the pipeline must ideally be accessible for inspection and maintenance all year round over its operational life m) Security – The pipeline system should be routed to minimise security concerns, particularly due to trespass and sabotage, during both construction and operation. n) Other hazards o) Follow existing linear disturbances where possible (roads). Use of existing linear routes (e.g. roads or power-lines) may avoid or reduce impact to sensitive areas. Although using routes occupied by other infrastructure may affect safety and corrosion potential from for example electrical interference.

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5.1.1.7

Public safety, content of the pipeline, operating conditions and location class

The main operating conditions in pipelines that can affect route selection are: • • • •

The internal fluid Operational envelope Location Pipeline material, diameter and thickness

Various codes categorise fluid as to their hazard potential, and the most hazardous flammable and toxic fluid should, where practicable, avoid built-up areas or areas with frequent human activity. Consideration should be given to routing that minimises the possibility of external damage in these areas. The pipeline route should be an appropriate distance from buildings in accordance with the codes being used. Codes also use a system of area or location classification based on population densities or number of buildings. Design factors are stipulated relevant to the classification levels. Pipeline material, diameter and content, affect the probability of failure and associated consequences: • • • •

Pipe fracture Maximum rate of release of contents Change of state of the fluid under atmospheric conditions Total volume that can escape under emergency conditions

The consequential impact of the above should be considered in the routing process, and ensuing QRA and risk and pipeline threat assessments .

5.1.1.8

Pipeline Above Ground Installations (AGIs)

Similar to the pipeline route, the location of above ground installations (AGIs) installed on the pipeline in-line must also be selected with care and attention. The selection of these locations involve consideration and balancing of a number of factors, including pipeline hydraulics, safety and environmental risk, site conditions, site access, existing power infrastructure, proximity to residences/population.

5.1.1.9

Environmental and Regulatory Steps

The pipeline route, and its impact on the environment, will need to be considered, justified and approved by regulators, the general public and land owners. Hence, consultation is a key part of routing. Key environmental and regulatory steps are illustrated below.

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Detailed assessments should be undertaken to ascertain the impact of the pipeline on environmentally sensitive areas. When selecting the route and in-line station locations, care should be taken to identify and minimise any possible effects on typically the following : c) Ramsar sites (These are wetlands of international importance, designated under the Ramsar Convention) b) Sites of special scientific interest (SSSIs) c) National parks and country parks d) Nature reserves e) Flora and fauna f) Forests/tree preservation orders g) Heritage sites/coasts h) Special areas of conservation i) Special protection areas j) Areas of outstanding natural beauty (AONBs) k) Ancient monuments, archaeological and ornamental sites l) Natural resources, such as catchment areas and forests m) Mineral resources n) Indigenous population sites o) Groundwater protection areas The following should be attained, as far as practicable: 1) Location of AGIs (valve stations, metering stations, scraper trap stations) are such so as not to be a noise nuisance to the local population, particularly during relief operations, valve operation, blow-offs 2) Avoid contamination of ground water and watercourses 3) Minimise the volume of traffic 4) Minimise the number of trees to be removed An environmental noise survey should be carried out where pipeline construction and permanent facilities may give rise to noise complaints before the pipeline route is established, so that prior noise assessment can be made and the route or the construction method changed if necessary to minimise disruption. Relevant planning and approval authorities should be contacted at an early stage to determine the requirements and the extent/coverage of an environmental impact assessment (EIA), required for a pipeline and its associated above-ground installations. If required, an EIA should cover the effect of pipeline works on local amenities and take recognition of future developments. Regulatory requirements will normally dictate that an Environmental Impact Statement (EIS) is prepared. The EIS will normally address: • • • • • • • • • • •

Flora Specially protected (threatened) fauna Surface water and groundwater Soil and geology erosion Rehabilitation Construction pollution issues Risk and hazards Culture and heritage Archaeology Ecology (terrestrial and marine) Landscape and visual impact

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• • • • • • • • • • • •

Land use and agriculture Hydrology Hydrogeology Traffic/access Noise/vibration Air quality Site stability Site contamination Lighting Tourism and leisure Socio-economic factors Safety

The output from the EIS should be used within the route selection process against the criteria outlined below.

5.1.1.10 Terrain, subterranean conditions, geotechnical and hydrographical conditions The geography of the terrain traversed can generally be divided into surface topography and subterranean geology. Both natural and man-made geographical features can be considered under these two headings. The principal geographical features which are likely to be encountered and should be taken into account include: Surface Crops, livestock, woodlands Natural beauty, archaeological, Ornamental rivers, mountains

Water catchment areas, forestry

Population, communications, services Contouring, soil or rock type, water, soil corrosivity Designated areas, protected habitats, flora and fauna

Subterranean Earthquake zone Geological features Infill land and waste disposal sites, including those contaminated by disease, radioactivity or chemicals The proximity of past, present and future mineral extractions, including uncharted workings, pipelines and underground services Areas of geological instability, including faults, fissuring and earthquake zones Existing or potential areas of land slippage, subsidence and differential settlement Tunnels Ground water hydrology, including flood plains

Adverse geotechnical, hydrographic, and meteorological conditions should be identified and mitigating measures defined. Authorities, geological institutions and mining experts should be consulted on general geological conditions, slippage areas, tunnelling and other possible adverse ground conditions. Where there is a possibility that any of these conditions might arise during the lifetime of a pipeline, monitoring of the conditions should be incorporated in the regular inspection and maintenance procedures adopted. This can include measurement of local ground movements, fluctuation in water table levels and indicative changes in pipeline stresses. Each terrain, such as desert, mountain, forest, arctic, will have its own routing consideration requirements and constraints.

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5.1.1.11 Geohazards A geo-hazard is identified as a geological, hydro-geological or geomorphological event or process that poses an immediate or potential risk that may lead to damage or uncontrolled risk. The type, nature, magnitude, extent and rate of geological processes and hazards directly influence pipeline route selection. Therefore, the process of early-stage terrain evaluation and the identification and assessment of geo-hazards and ground conditions are important as they can lead to extensive cost and time savings in the design and construction of a pipeline. The process enables the routing of the pipeline through the most suitable terrain, problem areas are identified, serious geo-hazards are avoided, where possible, and risks are minimised and mitigated. In addition, terrain evaluation is undertaken so that the need for expensive remedial measures or site restoration works is limited or prevented and the operability of the pipeline is safeguarded through a proper appreciation of the terrain conditions. By minimizing the risk of damage to the pipeline the risk to the human safety is reduced. Terrain evaluation along the pipeline corridor can be achieved using a variety of low-cost techniques and include satellite imagery and aerial photography interpretation, surface mapping and various other remote sensing techniques (i.e. LiDAR surveys â&#x20AC;&#x201C; see below). This data can be incorporated, together with historical data on seismic events, geological features, meteorological processes and hydrological data, within a geographic information system (GIS â&#x20AC;&#x201C; see below) and detailed terrain and hazard models developed. Terrain evaluation supports the anticipation, identification and assessment of the physical hazards and constraints within and outside of the pipeline corridor. It is essential that features outside the corridor be evaluated, as hazardous events outside of the corridor may be triggered by construction activity within the corridor and the resultant event may impact upon the pipeline. The risks associated with geo-hazards or the likelihood of an event occurring and its consequences can be qualitatively and quantitatively assessed using a scoring system or by a quantitative risk assessment (QRA). Safety of the pipeline is paramount in the routing selection. The extreme effect of a geological hazard on the pipeline is a rupture and it is this event that terrain evaluation and risk analysis and seeks to avoid by improving the decision-making progress used in selecting the most appropriate route for the pipeline.

5.1.1.11.1 Types of Geo-hazards Geo-hazards are widespread phenomena that are influenced by geological and environmental conditions and which involve both long-term and short-term processes. They range in size, magnitude and effect. Many geo-hazards are naturally occurring features and processes but there are also many geo-hazards that are caused by anthropogenic processes and these too need to be taken into account during the pipeline routing exercise. See table 2 for some examples of geo-hazards.

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Table 2 – Types of Geo-Hazards

5.1.1.11.2 Geotechnical Investigations Geotechnical investigations and site-specific surveys aim to undercover the ‘good’ ground in which to install the pipeline. The definition of ‘good’ ground can be considered to be ground with low gradients that is devoid of landslides, cliffs, hard ground, rock outcrops, aggressive soils, difficult river crossings, deep gullies, scour, meta-stable materials and spanning. Conventional geotechnical site surveys used for civil engineering projects are not always appropriate for major pipelines that may span hundreds or even thousands of kilometers. The terrain may vary significantly along the narrow pipeline corridor and this variance needs to be identified so that potential and existing geo-hazards are avoided. Pipeline corridor selection, route definition and refinement procedures will seek to ensure that the majority of the pipeline is installed in ground that, as far as is possible, avoids locations of identified and/or predicted geo-hazards. Focused geotechnical investigations are required where unavoidable hazards are identified so that appropriate geotechnical mitigation strategies may be planned. Predicting the probability of a hazardous event occurring is a science that draws on a number of approaches to derive an informed probability estimate. In particular, historical records of the frequency of the particular event, an understanding of the events and the causes of the events, expert judgement and probability stability analysis is used. However, the estimates are by no means a guarantee of the occurrence or non-occurrence of a particular event. For this reason the estimates are termed “fit for purpose” and support the need for an extensive risk assessment in the pipeline routing process.

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5.1.1.11.3 Geo-Hazard Pipeline Routing As far as is possible all geo-hazards should be avoided by a pipeline route. This is rarely possible, therefore the following guidelines are applicable with respect to geo-hazards (to be avoided where practical): Table 3 – Pipeline Geohazards Geo-Hazard

Description

Routing Mitigation

Landslides

• Avoid if possible Ground displacement and movement of a mass of rock, earth or debris down • Minimise sidelong routing across the landslide, route parallel along the axis a slope of ground movement

Gullying, soil erosion & fluvial erosion

Removal of soils by water, wind or ice action or by down-slope scree

• Avoid areas of active erosion if possible • Minimise sidelong routing parallel to erosion area, cross at 90°

Mobile sand dunes

Fragile desert habitat that maybe damaged or blown away by wind.

• Avoid if possible • Minimise crossing length

Earthquakes & fault lines

• Avoid if possible A fracture in the continuity of a rock • Special design considerations (e.g. formation caused by a shifting or finite element analysis) will be required dislodging of the earth's crust, in which if un-avoidable adjacent surfaces are displaced relative to one another and parallel to the plane • Special/engineered backfill techniques likely to prevent pipe of fracture. damage during an earthquake (such designs are common in areas like Japan) • Special trench design (deepening)

Volcanoes

The vent and the conical mountain left by the overflow of erupted lava, rock and ash.

Soft soils

Soils that may not be able to support a • Methods to cross soft soils include support anchors screwed into hard pipeline (swamp, peat, bog) soil below the soft soil; support mattresses under the pipeline to reduce bearing pressure; neutral buoyancy to ensure that pipe neither sinks or floats after installation. It may also be possible to remove weak soil and replace with engineered backfill.

• Avoid • Avoid existing flow canals

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Table 3 – Pipeline Geohazards (cont.) Geo-Hazard

Description

Routing Mitigation • Avoid if possible • Methods to design for and cross underground cavities are possible. These include pumping concrete into the underground mines (subject to size and volume), the whole mine need not be filled in, but sufficient to limit settlement; use thicker wall pipe acceptable for estimated settlements.

Underground cavities

Areas of coal mining, caves, caverns, subsidence areas

River channel migration

• Feasible to estimate and design for River banks erosion leading to river river meander and river bed erosion. meander, and river bed erosion leading This will generally include sufficient to bed channels of varying depth burial in river bed, and sufficient deeper burial extent from river banks. • River bank erosion prevention methods can also be used. • Minimise crossing length

Aggressive soils

Contaminated soils

• Avoidance will depend on type of contamination, and if disturbed the safety impact on local population and works: environmental impact; and disposal issues. • Minimise crossing length

5.1.1.12 Selection Criteria Selection criteria should be developed following local codes and standards, national regulatory and local regulation requirements and detailed consultation with, and input from, the local community. Typical pipeline codes and standards include: • ASME B31.8 – Gas Transmission And Distribution Piping Systems (US/International Standard) • ASME B31.4 – Pipeline Transportation Systems For Liquid Hydrocarbon Pipelines (US/International Standard) • CSA Z662 – Oil And Gas Pipeline Systems (Canadian Standards Association) • NEN 3650 – Requirements For Pipeline Systems (Dutch Standard) • AS 2885.1 – Pipelines—Gas And Liquid Petroleum Part 1: Design And Construction (Australian Standard) • SNiP 2.05.06-85* Trunk Pipelines (Russia, Developed By Vniist) • VSN 51-3-85 Design Of Steel Field Pipelines (Russia, Developed By Vniigaz) • Bs En 1594 - Gas Supply Systems _ Pipelines For Maximum Operating Pressure Over 16bar Functional Requirements • IGE-TD/1 Edition 4 - Recommendation On Transmission And Distribution Practice – Steel Pipelines For High Pressure Gas Transmission, May 2001 • BSI PD 8010 - Code Of Practice For Pipelines • ISO 13623/En 14161 - Petroleum And Natural Gas Industries — Pipeline Transportation Systems

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Each country will have their own regulatory, permitting, and safety requirements and local constraints and environmental issues meeting the indigenous population and local environment for routing pipelines. The routing engineer should be fully conversant with the local requirements, as any lack of understanding could alienate populations or authorities the route passes, meaning that approvals and permits will require extensive and detailed and protracted negotiations leading to schedule delays, and may even be denied. Local issues should be clearly understood before any routes are selected and before any external discussions take place. It is not uncommon that a permit rejection of just a small section of the route through a local region can hold up the whole pipeline routing and construction. Corridor, route, alignment and construction line selection phases have vital importance in linear engineering structure projects such as pipelines. Each possible route should be assessed at every stage with against selection criteria. Large-scale geo-hazardous areas have to be avoided during the first two phases. Technical assessment of the alternatives at each stage is crucial. Assessment at every phase provides significant contribution in terms of timing, environment, safety, and cost. As evidenced in several international projects, precaution is much better than remedial work. Failing to apply adequate route assessment criteria, and the basic phases to select the best construction line, can lead to increased costs, sometimes up to 500%. In some cases, it is possible to have environmental destruction beyond the acceptable limits, e.g. pipeline located through farm fields and major active faults. Table 4 below lists possible selection criteria. Such criteria should be ordered, reviewed for relevance, ranked and then applied within routing evaluation. These criteria are also in line with best practice for infrastructural and pipeline projects.

Table 4 - Key Route Selection Criteria Community Criteria

Environmental Criteria

Technical Criteria/Project Requirements

Minimise impacts on people

Minimise impacts on wildlife and their habitat

Minimise pipeline length. Shorter routes may offer significant economic, environmental, social and logistical benefits.

Minimise community disturbance and land use conflicts.

Avoid impacts on archaeology/cultural heritage

Minimise major terrain constraints unduly steep or rugged mountain ranges, extensive areas of rock, large number of major river crossings, etc each tend to increase the difficulty and cost of construction and influence the scale of potential environmental impact.

Minimise disturbance to third-party infrastructure.

Minimise visual impacts

Minimise construction costs and difficulty - the route should consider all construction aspects and impacts.

Minimise proximity to dwellings/public centres.

Avoid protected areas and areas of high ecological value.

Minimise areas where construction is difficult, such as steep slopes, unstable surficial materials, and high water tables.

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Community Criteria

Environmental Criteria

Technical Criteria/Project Requirements

Minimise impact on planning/land use.

Minimise disturbance to sensitive or unstable landforms.

Minimise areas of geohazards (fault crossing, fault zone)

Minimise impacts on mining, agricultural, urban and infrastructure areas.

Minimise disturbance to riparian areas (watercourse crossings).

Avoids rocky ground and unstable soils, thereby minimising the risk of subsequent soil erosion from rain and wind leading to pipe exposure.

Account for public opinion and safety

Areas of conservation significance. Minor deviations may avoid impact on regional ecosystems.

Avoid severe physical constraints such as granite outcrops, erosion gullies and very steep slopes (both longitudinal and transversal)

Avoid of residences and other sensitive land uses; maintain a safe separation distance from all residences

Minimise environmental disturbance

Avoid landmines

Avoidance of potential native title and heritage conflicts

Minimise clearing in forested/woodland Minimise topographic changes (avoid highly constrained topography, e.g. areas high elevation/steep terrain)

Avoid crossing property

Minimise overall project footprint

Avoid crossing agricultural land

Minimise excavations Minimise landscape impacts by avoiding crossings of ridges and mesas (elevated area of land with a flat top and sides that are usually steep cliffs)

Avoid crossing forested land

Avoidance of remnant vegetation, nature reserves and other environmentally sensitive features

Minimise crossings (road, rail, river, pipeline, buried services, power cables, overhead cables). Consider trenchless technology.

Minimise impacts on native vegetation

Minimise areas subject to liquefaction (any extracted groundwater will need careful disposal)

Avoid World Heritage/RAMSAR

Minimise areas in landslide

Avoid coal mining/subsidence areas/underground features such as caves, caverns

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Community Criteria

Environmental Criteria

Technical Criteria/Project Requirements

Avoid protected areas

Minimise crossing floodplains

Avoid contaminated land (any extracted groundwater/soils will need careful disposal)

Avoid running parallel with high-voltage lines wherever possible and provide sufficient clearance for possible maintenance

Minimise project footprint In parcels of meadow and agricultural land, follow boundaries as much as possible; cross watercourses as seldom as possible; disturb drainage systems as little as possible; cause as little crop damage as possible

5.1.1.13 Existing and future land use The possibility of future development works should be taken into account to minimise the need for diversions or alternative works at a later date. Information on future developments should be obtained from local authorities that the route traverses through. Existing areas of development should be avoided as far as possible. Where this is unavoidable, the safe distance of pipelines to buildings and structures should be related to design parameters for the particular fluid transported as stated in the appropriate codes, which categorise fluid as to their hazard potential, and the most hazardous flammable and toxic fluid should, where practicable, avoid built-up areas or areas with frequent human activity. Permanent above-ground equipment, located on or adjacent to the line of pipelines, should be sited with the agreement of the landowners and occupiers concerned to minimise future obstruction, noise, vibration, interference, and security. Pipelines containing substances that could cause contamination of underground water supplies, rivers, streams should, where possible, avoid crossing exposed aquifers or land immediately upstream of waterwork intakes or reservoirs. Where avoidance is not possible, statutory water suppliers and private groundwater extractors can require additional precautions to be taken. This is particularly important in countries where the local population relies on ground water extraction as the sole source water for daily use in drinking and cooking. Water authorities should be consulted about all watercourse crossings, particularly in relation to future widening and deepening. The larger watercourses are classed as â&#x20AC;&#x153;main riversâ&#x20AC;? and are likely to be directly controlled by water authorities; lesser watercourses draining low-level areas might come within the control of local authorities, landowners, and farmers. In other cases owners and occupiers should be consulted. The jurisdiction of water authorities includes river embankments, sea and tidal defences and secondary works to reduce the spread of floodwater. Where pipelines cross or are laid adjacent to any such embankments, the relevant water authority should be consulted.

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Pipelines should be located to produce minimum disturbance to established agricultural practice. Any potential third-party activities along the route should be identified and should be evaluated in consultation with these parties. A control zone should be established to control all third-party activities in order to safeguard and secure the pipeline against external interference as well as to protect the safety of the parties involved. The probability of third-party interference to the pipeline will decrease as the depth of cover is increased. Pipeline protection analysis will need to consider the cost of protection against the threats posed, safety and reputation.

5.1.1.14 Permanent access The selected pipeline route should permit year-round 24-hr unhindered and adequate access to the pipeline, and associated above-ground installations, from the public highways for the equipment and materials necessary to carry out planned inspections, maintenance and emergency repairs. This may require the building of new roads, and ongoing maintenance of access tracks. Permanent access requirements should be taken into account at the time pipeline routing is being negotiated with landowners and occupiers. Access rights may also have to be negotiated with parties other than those through whose land pipelines will be laid. Access facilities should be determined by the frequency of use, the testing and repair equipment likely to be required, and the anticipated urgency of repairs.

5.1.1.15 Transport facilities and utility services Particular regard should be given to the layout and levels of existing transport facilities and utility services, and enquiries made regarding their foreseeable development. Local authorities that the pipeline passes through can impose special conditions for pipeline routes. All relevant authorities should be approached in good time, requesting details of their facilities and services. Ideally pipelines should be routed to minimise disruption to existing facilities and services. The number and lengths of crossings under or over transport facilities should be minimised, and the recommendations of the relevant transport authorities should be taken into account.

5.1.1.16 Construction, hydrotesting, operation and maintenance The route should permit the necessary access and working width for the construction, testing, operation and maintenance (including any replacement) of the pipeline. The availability of utilities necessary for construction, operation and maintenance should be analysed. Areas will be required to store materials, and set up construction camps, all requiring highly-demanding area re-instatement to the original found condition when the work finishes. All these will affect local populations and environments, and unless adequately thought out and thoroughly planned could lead to local area route rejection, and jeopardize the whole project. For remote locations issues such as material logistics, material storage, labour camps and associated environmental issues (sewage, drainage) need careful consideration and detailed planning. Availability and suitability of water for hydrostatic test purposes and its subsequent discharge will need early consideration. Trucking water in and out will be expensive. Water authorities may not allow water to be used from nearby rivers, nor its disposal back into streams due to internal pipe debris and chemicals that may have been used to treat the water prior to hydrotesting.

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5.1.1.17 Security The pipeline system should be routed to minimise security concerns, particularly due to trespass and sabotage, during both construction and operation. Typical issues that should be taken into account include : • • • • •

Construction site access restriction (pipeline and facilities) Personnel and equipment security during construction Associated pipeline facilities during operation access restriction Sabotage to buried operating pipeline, and associated above-ground pipework and facilities Mitigation to reduce likelihood of interference from third-party activity

5.1.1.18 Risk/Threat Assessment A QRA, risk or threat assessment exercise allows for identifying the likelihood of occurrence of hazardous event and the associated consequences of the events along the route. A risk assessment considers: • The hazard – what can go wrong? • The probability of the hazardous event • The consequences of the event • The relative importance of the event • The mitigating activities that are required to manage the risk Risk assessment methods are by no means guaranteed to provide a reliable estimate of the probability of hazardous event occurring but they do provide estimates that guide the route selection process and allow a pipeline route to be declared “fit for purpose”. Risk evaluation and risk management are an essential input into the route selection process as they provide judgments on the significance of the identified risks and they help to determine the most appropriate course for the pipeline at a risk level that is deemed to be as low as is reasonably practical (the ALARP principle).

5.1.1.19 Data Collection and Management Table 5 below summarises typical key data required for each route selection phase. Table 5 – Typical Data Requirements FRONT END LOADING FEL 1 BUSINESS PLANNING (APPRAISE) Maps Satellite imagery Air photos High quality digital imagery of the terrain

FEL 2 FACILITY PLANNING (SELECT) Initial reconnaissance survey Key constraints identified from initial consultations

FEL 3 PROJECT PLANNING (DEFINE)

PROJECT EXECUTION (EXECUTE)

Site surveys

Final site surveys

• Topographic • Geotechnical (soil type and composition) • CP/resistivity survey

Helicopter surveys

START UP AND OPERATIONS (OPERATE)

Final constructed route shown on asbuilt drawings and on GIS.

LiDAR Ongoing land based ROW/ easement surveys

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FRONT END LOADING FEL 1 BUSINESS PLANNING (APPRAISE) Information available in the public domain

FEL 2 FACILITY PLANNING (SELECT)

FEL 3 PROJECT PLANNING (DEFINE)

Set up GIS to collate and document available data

• Land survey (land heights and location of existing infrastructure) • Environmental surveys for flora and fauna

PROJECT EXECUTION (EXECUTE)

START UP AND OPERATIONS (OPERATE)

LiDAR surveys Helicopter surveys

EIS – Environmental impact statement GIS to collect/collate/sort field data. Slope threshold, slope criteria, cut and fill operations Constraint mapping Ongoing reconnaissance surveys Helicopter surveys LiDAR Information available from existing adjacent pipeline systems

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5.1.1.20 Graphical Information System 5.1.1.20.1 General Geographic Information Systems (GIS) are scientific and technological tools that enable the integration of data from different sources into a centralised database from which the data is modelled and analysed based on its spatial component. GIS-based tools and processes have been extensively used to address the challenges of optimizing pipeline route selection and route networks based on the collection, processing and analysis of spatial data such as topography, vegetation, soil type, land use, geology and landslide areas. Traditional manual pipeline routing uses available paper maps, drawings, aerial photographs, surveys and engineer experience. GIS techniques combine all of these sources of data in a convenient computer-based information system. The key to the GIS is that it has advantages in terms of speed of data processing and analytical capability. Fig. 2 is a simplified representation of how data is combined and processed in a GIS to produce models and required outputs. Data, such as well locations, surface topography, land use activities, soil conditions and infrastructure features, are combined based on their spatial component. This enables the engineer to test real-world scenarios within the spatial models. Fig. 2: Process To Optimize Pipeline Routes

GIS represents an innovative approach to pipeline routing that is both systematic and effective. Optimizing a pipeline route is essentially an optimization between costs of the material and the costs of the construction. Natural and man-made terrain obstructions cause spatial variations in construction cost due to changing features like types of soils, intervals of slope. GIS allows the engineer to use dynamic spatial models to aid in selecting an optimized pipeline route. The GIS software and data enables the processing of a large amount of location-based information to find a least cost path (LCP) between two locations by taking into account natural and manmade obstructions and features.

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5.1.1.20.2 GIS Routing Optimization Methodology The GIS approach to pipeline routing optimization is based on relative rankings and weights assigned to project specific factors that may affect the potential route. The result of this process is a least cost path (LCP) which represents that most economic path between the origin and the destination points of the pipeline. Fig. 3 is a representation of the methodology flow used to determine the LCP Fig. 3: Pipeline Optimization Methodology

5.1.1.20.3 Identification of Factors Affecting the Route As mentioned in the previous section on selection criteria the identification of project-specific factors that may constrain or impact on the pipeline is an important step and a vital input to the GIS. Several factors such as geo-hazards, social issues and construction costs impact on the route and need to be taken into account. At this stage a set of rules are determined that will be used in the routing exercise. Input from experienced engineers is required to ensure that the appropriate features are identified and the correct rules established. The accuracy of the subsequent analysis is dependent on the factors being correctly identified as the analysis is only as good as the inputted data. Examples of some factors and rules include: Factor/Feature Roads Railway lines Rivers Urban areas Terrain/topography

Rule • • • • • • • •

Avoid road crossings Proximity to roads is important Avoid railway line crossings Avoid river crossings Avoid built up/populated areas Avoid future development areas Avoid steep slopes Use flat terrain where possible

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Factor/Feature Environmental areas Wetlands Water bodies Surface geology

Rule • • • • •

Avoid highly-sensitive areas Avoid wetland crossings Avoid water bodies Avoid surface/sub-surface rock Stable soils are important

5.1.1.20.4 GIS Data and Data Sources Satellite imagery, maps, aerial photography, existing GIS data, LiDAR surveys and traditional geotechnical and topographical surveys are all sources of data that should be gathered and incorporated into the project GIS. The maps, satellite imagery and remote sensed data are scanned and geo-referenced and are then used to derive spatial features such as roads, rivers, urban areas and geological boundaries which form the GIS data to be used in the routing process.

5.1.1.20.5 GIS Data Processing and Analysis Once the data has been captured it needs to be processed and converted into raster data. The raster data is used to calculate the feature distance cost for each feature – the weighted cost as one moves away from a feature. For example rivers are given a high cost and the further you move away from the river the lower the feature distance cost becomes. The significance of the effect of a single feature on the pipeline route varies for each feature. For example, it is more important to avoid a deep valley crossing than it is to avoid a road crossing. The analytical hierarchy process (AHP) is one of the structured methods that can be employed to quantitatively rank each of the identified factors. Each factor is assigned a cost value which is benchmarked with typical constructions costs. The input from experienced engineers is vital when it comes to ranking and assigning weights to each layer.

5.1.1.20.6 GIS Suitability Map Generation After the feature layers have been ranked the data layers are combined together into one single layer based on the numerical value factor derived from the weighting process. The resultant layer is referred to as the suitability layer and this layer forms the basis for the GIS analytical work. The suitability map is used to create cost maps which related to relative construction costs. The highest costs are in steep mountainous terrain, urban areas, roads and large bodies of water. Moderate costs are associated with wetlands, forests and high slope areas. The lowest costs are to be found in areas of relatively flat bare ground, agricultural land or less dense native vegetation. See Fig. 4 for an example of a cost map.

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Fig. 4: Discrete Cost Map

The least cost path is the product of the GIS analysis and represents the path of least resistance from the origin of the pipeline along a surface to the destination point. The strength of the GIS is that re-routes can quickly be incorporated into the system and the implications of the reroutes or alternative routes can be quickly assessed. The combination of the data layers allows the engineer to test multiple pipeline network design and selection scenarios easily and efficiently. The GIS automatically calculates the lengths of new pipelines or pipeline networks. This allows for rapid total cost calculations and the running of multiple ‘what if’ scenarios to see the effect of changes to the pipeline design. A GIS can produce a number of outputs quickly and efficiently in relation to pipeline routing: • • • • • •

Survey request area delimination drawings Land allocation/permitting drawings Pipeline routing drawings Alignment sheets (see Fig. 5) Tabular outputs (i.e. MTOs) Pipeline coordinates

5.1.1.21 Light Detection and Ranging - LiDAR LiDAR (Light Detection and Ranging) can measure the height of the ground surface and other features during an airborne survey. It can provide models of the land surface at meter and sub-meter resolution, depending on ground cover conditions, e.g. in forested and woodland areas.

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The system comprises a scanning and ranging laser to produce topographic maps. Implementation involves flight planning, data acquisition, and the generation of digital terrain models. The basic components are a laser scanner, a global positioning system (GPS), and an inertial navigation system. The laser scanner is mounted within an aircraft and emits infrared laser beams at a high frequency. The scanner records the difference in time between the emission of the laser signal and the reception of the reflection. A mirror that is mounted in front of the laser rotates and causes the laser pulses to sweep at an angle, back and forth along a line. The position and orientation of the aircraft is determined using GPS. GPS systems are located in the aircraft and at several ground stations within the survey area. The round trip travel time of the laser signals from the aircraft to the ground are measured and recorded, along with the position and orientation of the aircraft at the time of the transmission of each pulse. After the flight, the data from the aircraft to the ground are combined with the aircraft position at the time of each measurement and the three dimensional XYZ coordinates of each ground point are computed and combined. Post-flight processing integration of the data points produces a horizontal position and vertical elevation for each laser signal. Each data point can be identified by type, i.e. ground, vegetation, building, power line or other object. Once correlated, it is simple to manipulate data, remove layers of data points and create digital terrain models (DTM) for GIS.

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5.1.2 Google Earth in Pipeline Design and Route Selection Introduction Google Earth is a virtual globe, map and geographical information program. It maps the Earth by the superimposition of images obtained from satellite imagery, aerial photography and GIS 3D globe. Google Earth is client-based software that is installed on individual PCs and also can be viewed using web browsers through a Google Earth plug-in. It is available in two versions: 1) Free license that uses public satellite photos and maps from Google servers 2) Licensed Google Earth Professional that can be used by advanced users and also can be connected to local licensed Google Earth servers with private satellite images and maps. Google Earth is widely used by different industries to design, monitor and maintain earthwork and construction projects. Municipalities and governments, for example, use Google Earth to design and track the installation of water pipelines, cities and urban design, roads construction, earthworks etc. Google Earth can be used in pipeline projects for initial pipeline routing, and to conduct preliminary hydraulic profiles at desktop level. It can also be used for pipeline construction monitoring â&#x20AC;&#x201C; see section 13.4. As an initial pipeline routing tool, Google Earth enables plan and profile data to be extracted to begin pipeline engineering design activities. Google Earth contains relatively up-to-date satellite imagery, allowing the reasonably confident routing of pipelines during the design stage, and reducing the time and effort spent in studying the landscape and elevation changes along pipelines. Several route options can be evaluated in a relatively short time, allowing the economics of each option to be analyzed. The satellite imagery is updated on a regular basis but the ability to display older satellite data enables detailed analysis to be conducted on the legacy of land use or terrain changes (for example river meander or changes in the built environment) where the pipeline route is being planned. The ability to easily add facilities data such as plot plans into the system helps confirm that the most suitable location has been chosen. The following sections will focus on the use of Google Earth during initial pipeline routing.

Pipeline Routing Routing The pipeline routing exercise starts with the client-identified start and end points of the proposed pipeline. These points are identified within Google Earth and the desktop routing process begins using the network tool from the drop-down menus. Nodes are added to the network at each change of direction until the start and end points are joined. Typically, several route options would be identified during the routing process, due to various factors such as topography, vegetation, habitation, environmental constraints, crossings of roads, rivers & railways etc. Each option would receive an economic evaluation to select the best solution. All of these features are identified from the satellite imagery and coverage can be located accurately (depending on the imagery scale). Once the initial route has been established this can then be published with ease via e-mail to the design team and client and transferred into the project geodatabase to be read by the GIS software. Google Earth Pro can also read shape file data created within the GIS, enabling the route to be adjusted according to the geodatabase data. Typically the Google Earth KML file extension is used to transfer the data.

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Keyhole markup language (KML) will be used to represent the pipeline route in Google Earth. KML is an XML notation, developed for use with Google Earth, for expressing geographic annotation and visualization within Internet-based, two-dimensional maps and three-dimensional Earth browsers. An example KML file is shown in the KML module section. KML data are often distributed as zipped (compressed) KMZ files. The contents of a KMZ file are a single root KML document (notionally "doc.kml") and optionally any overlays, images, icons, and COLLADA 3D models referenced in the KML, including network-linked KML files. Plan and profile output example

Profile The profile of the route can be displayed in Google Earth by using the menu functions associated with the network tool. By right clicking on the route itself a menu appears, and the profile is displayed when the â&#x20AC;&#x2DC;display profileâ&#x20AC;&#x2122; option is chosen. The elevation datum is based on the World Geodetic System (1984) (WGS84) projection parameters, the system used by most GPS systems worldwide. The hydraulics analysis software can then use this profile to start the preliminary analysis of the pipeline, and if required, the route can be changed to give a smoother profile dependent upon the behaviour of the inventory being transported. If the project intends to adopt a project-specific projection then the elevation values can be replaced, however the shape of the profile remains constant i.e. the differential in height between highs and lows remains the same.

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Route Optimisation The initial route is refined through an iterative process of route optimising where the aim is to deliver a pipeline route that has the shortest length possible and where environmental issues, construction complexities and excessive profile changes have been mimimised wherever possible. Using a combination of GIS-based tools and Google Earth imagery the routing engineer is able to address the challenges of optimising pipeline route selections. The approach is based on the concept of least cost path (LCP), where the choosen route represent the route that will â&#x20AC;&#x153;costâ&#x20AC;? the least relative to the cost to transverse an area based on discrete cost maps. These cost maps consider factors such as environmental constraints, geology, geomorphology, terrain topography, construction and socioeconomic and political conditions. The aim is to determine areas that are to be avoided and areas that are more favourable for pipeline activities. Discrete cost map example

After the discrete cost maps are determined, the initial route is modified so as to provide the optimum route through the area. In conjunction with this the route is further analysed to determine if the chosen route transverses any side slopes. Freely available digital elevation data are used in the GIS to create a digital elevation model (DEM) for the area through which the pipeline is routed. From this DEM, gradient slope models are produced and used to identify any potential side slope areas along the pipeline route, see example overleaf.

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Side slope avoidance example

Once the route has been refined the optimised route and slope analysis can be published to Google Earth and shown as KML features (the route) and images (the slope analysis).

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Flythroughs A flythrough along the proposed pipeline route is a very useful feature of Google Earth as the client and design team can obtain an immediate appreciation of the terrain the pipeline is passing through. Various attributes salient to the pipeline route can be displayed during the flythrough. The flythrough is started via the tools menu or the play tour button in the left hand side console, and can be saved as a KML file for exporting into other applications. Example of a flythrough in Google Earth

GIS interface An important functionality of Google Earth is the ability to seamlessly transfer data into and out of the project GIS. Typically, the Google Earth Pro version of the software enables more functionality than the free version. GIS data, as shapefiles, are easily displayed in Google Earth, enabling the display of environmental and constraint data. This can be saved as a KMZ file and then distributed to the client and design team for further analysis and comment. Benefits: Google Earth allows the pipeline routing to be carried out with a high degree of confidence, the Google Earth elevation data also enabling the initial hydraulic analysis to be carried out. As a desktop-based application the need for field surveyscan be delayed until the front end engineering design (FEED) stage. The campaigns to collect additional survey data can also be refined to those specific areas identified during the desktop routing exercise. Time is also saved during the initial stages of a pipeline project by the ability to seamlessly transfer the data into project GIS geodatabases and publish the routing and elevation data to the client and design team. The work done in this section used the free Google Earth client and Google Earth Web browser plugin. For advanced usage with proprietary satellite photos the Google Earth Enterprise server (which requires licensing) can be used.

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Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

Earthworks

The terrain, soil types, and geohazards traversed by the pipeline are key factors to consider in the design, the construction and the operation and maintenance of a pipeline project. First, the terrain typically affects pipeline hydraulics, above ground stations, and pipeline protection. Second, soils types will affect heat transfer, pipeline restraint, and constructability. Finally, geohazards often require special design and construction considerations. This earthworks section offers guidelines on how to prepare the ROW in different types of terrains, on the earthworks design, on the measures recommended to reduce the impact on the environment, and finally on the approach to health and safety. Section 6.1 describes the typical cross sections of the ROW in 10 different types of terrains with a table indicating the recommended dimensions for constructability. Indeed earthworks include preparing the right of way, digging the trench, ensuring trench side stability, soil handling and storage, backfill and excess spoil disposal, and finally reinstatement. Therefore the ROW configuration must allow smooth development of all those operations. Section 6.2 deals with the earthworks design and in particular the pipeline trench design. The recommendations to reduce impact of the earthworks operations on the environment are detailed in section 6.3. Finally statistics have shown that pipeline trenches and earthworks operations are a major source of fatalities in the pipeline industry. Therefore, health and safety is paramount, and all pipeline construction method statements and procedures must be developed around safety. This is the subject of section 6.4.

6.1

Typical ROW Cross-Sections for Large-Diameter Pipelines

The following drawings show typical ROW cross-sections for large-diameter pipelines in 10 different types of terrain.

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Cross Section n째1

Base case

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Cross Section n째2

Rock ROW

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Cross Section n째3

Sand dunes area

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Cross Section n째4

Wetland with dry construction

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Cross Section n째5

Shabka

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Cross Section n째6

Side slope

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Cross Section n째7

Wetland with underwater construction

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Cross Section n째8

Arctic conditions

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Cross Section n째9

Environmentally sensitive areas

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Cross Section n째10

Ridge

1: Base case

15 6

2.4

N-A

1.5

1.5 2

0.9

0.3

N-A

(all distances in meters)

Angle (trench top) (degree)

Traffic lane

Recommended ROW

Depth (trench) (42” pipe)

Angle (slope) (degree)

Material area

Material area 1

Material area 2

Snow + ice road

Trench top

Cover (Indicative - check code)

Working area

Top soil

Backfill

Economic ROW (material area)

Economic ROW (working area)

EW 17.5

12.5

N-A

0.1

15.5

0.8

1.5

N-A

11.5

N-A

2.1

N-A

2: Rock ROW

≥1

N-A

3.2

3: Sand dunes area

16.5

18.5

≥1

0.3

0.9

2.5

1.5

N-A

16.5

N-A

2.4

N-A

≥1

N-A

13.5

1.1

1.5

2.5

N-A

2.3

4: Wetland 5: Sabkha with dry construction

15.5

19.5

N-A

0.3

0.9

1.5

N-A

≥15

2.4

6: Side slope

6 40 2.4 40 N-A 14 16 N-A N-A 1 34 3 3 2 2 0.9 16 0.3 N-A 20 20

N-A 40 2.4 40 N-A 15 17 N-A N-A N-A 40 2 1 2 10 1.2 10 N-A ≥1 25 15

N-A

0.3

N-A

0.9

1.5

N-A

2.4

N-A

0.3

N-A

0.9

1.5

N-A

≥30

N-A

2.4

N-A

7: Wetland 8: Arctic 9: Environ- 10: Ridge with conditions mentally underwater sensitive construction areas 30 N-A 15 15

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6.1.2 Table of the dimensions shown on the cross sections

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6.2

Earthworks Design/Trenching 6.2.1 Introduction Trenching is the favoured pipeline installation method. In spite of its apparent simplicity, thorough analysis is required at the design stage of the numerous interrelated factors. This chapter provides an insight to the factors, issues and solutions for trenching which may be present and required to achieve a successful, design code and legally compliant pipeline trenching solution.

6.2.2 Why Are Pipelines Buried? 6.2.2.1 General Pipelines are buried for a number of reasons. These include: • To avoid the pipeline becoming a barrier to people, animals and vehicles • To minimise visual impact • To reduced the risks to the pipeline from third-party interference. This can be either voluntary (e.g. hot-tapping, vandalism, terrorism) or involuntary (e.g. vehicle, machine or tool impact) • To improve protection of the over-ground environment from a catastrophic pipeline failure such as an explosion, a high-pressure leak, or a toxic release • To use the soil as a part of the pipeline design. E.g. soil cover can provide restraint, and favour or hinder heat transfer • Cost – in most cases burial will result in a lower overall capital and maintenance cost These reasons, together with the pipe characteristics, the soil type, and the nature of the carried product, are considered in the trench and the backfilling requirements. They are discussed in more detail below.

6.2.2.2 Community access The most obvious reason for burying a pipeline is to make its presence virtually invisible to the above-ground community. In populated areas, the need for roads and access ways make the burial of pipelines a necessity. Moreover, pipelines often cross privately-owned land and it would not be acceptable to effectively divide properties into two or more parcels. Even in areas devoid of activity, it is often advisable to bury pipelines to allow hiking, hunting, off-road driving but also to preserve natural landscapes.

6.2.2.3 Wildlife Direct loss of habitat Pipeline construction results in changes in the habitat value of the land. Habitat discontinuities in forested landscapes and may also serve as conduits facilitating the spread of undesirable plants and animals (Seabrook and Dettmann, 1996; Parendes and Jones, 2000), thus creating a loss of habitat for indigenous species. Habitat fragmentation Pipelines dissect continuous habitat patches resulting in smaller patch sizes and higher edgeto-interior ratios. The loss of interior habitat is of concern for edge-sensitive species and smaller overall patch sizes may result in the loss of area-sensitive wildlife. Reduced access to vital habitats As barriers to wildlife movement, pipelines reduce access to vital habitats for a variety of wildlife species. Wide-ranging mammal species can lose access to important habitats when movements are restricted by pipelines. Critical habitats required by wildlife species can be separated on either side of a pipeline, jeopardizing local populations (Fig. 1).

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Disruption of social structure Decreased animal movement can undermine processes that help maintain regional populations over time. Barriers to movement can block the exchange of individuals among populations, eliminating gene flow and disrupting the ability of “source” populations to support declining populations nearby. Barriers to dispersing individuals also eliminate opportunities to re-colonize vacant habitat after local extinction events. Population fragmentation and isolation Pipelines create barriers to movement that subdivide animal populations. Local population extinctions may occur due to stochastic genetic and demographic events, environmental variability and natural catastrophes. Population extinction is more likely to occur in smaller populations, such as those produced by habitat fragmentation. Disruption of processes that maintain regional populations The dispersal of individuals between populations has been shown to be important for the maintenance of genetic viability within local populations, and for maintaining local and regional populations in the face of population extinctions. Fig. 1 – Wildlife and pipelines

6.2.2.4 Third-party risk The industry categorises “third-party” incidents as incidents caused by persons not involved with operating or maintaining the pipeline – farmers, homeowners, construction crews and excavators – i.e. people who in the course of their normal activities may cause pipeline damage. The root causes of third-party damage of pipelines are complex, random, and difficult to forecast and control. Third-party damage is the most common cause of incidents to pipelines, which can cause a hole or a complete rupture of the pipeline. Fig. 2 shows the third-party risk relative to other risks.

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Fig. 2 – Incidents by cause and size of leak (after Porter et al. 2004). Source: European gas pipeline incident data group (EGIG)

In most situations, the ground directly over a buried pipeline will be used in the same way as adjoining land. This means that third-party interference (whether intentional or not) can be encountered especially in rural areas where people are more likely to perform earthworks without first getting clearance from the local administration who would know about pipeline presence. In general, mechanical damage occurs after the pipeline is in service due to activities in the pipeline right-of-way. Such damage may occur slowly (e.g. from rocks) or quickly (e.g. excavation equipment). Activities associated with mechanical damage occurrences typically include:

• • • •

Drainage and agricultural activity Infrastructure construction (buildings, road-making, excavation, drilling, fencing, horizontal drilling and trenching) Exposure to projectiles: rocks, shrapnel, bullets (exposed pipelines) Unauthorized hot tapping and grinding

The risk of external interference can be mitigated by the following:

• • • •

•

Increasing awareness of the pipeline, e.g. land owner liaison and over-ground markers Monitoring of the right-of-way, e.g. flying, walking and or driving the ROW at regular intervals Providing increased resistance to penetration in the pipe itself, e.g. increasing the wall thickness Physically preventing contact with the pipe (see Fig. 3): when this cannot be achieved by exclusion (e.g. by fencing each side of the right of way) or by the use of barriers (e.g. by placing a slab of concrete on top of the pipe), separation from third-party activity can be achieved by increasing the burial depth Legal and voluntary systems that require third parties to consult pipeline and other buried services operators before commencing excavation. Some countries use ‘one-call’ systems to provide a central communication point so that third parties can quickly and easily obtain from a single source detail of all relevant buried services

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Fig. 3 – Concrete slab protecting the pipeline

Avoiding third party interference is essential to protect a pipeline’s integrity. A pipeline failure can have catastrophic consequences both in unpopulated areas (e.g. a major oil release damaging the natural environment) and in populated areas (e.g. an explosion). Fig. 4 shows the aftermath of a pipeline explosion in Ghislenghien, Belgium. Two factories were destroyed, claiming the lives of 24 people and injuring 132. The pipeline was buried 6 m underground, carrying gas at 70 bars. Damage to the pipeline probably occurred as a mechanical soil stabiliser, involved in the final stages of a car park construction project, was driven into the ground causing damage to the wall of the pipeline. The damage took the form of evenly-spaced gouges in the steel wall of the pipeline. Two weeks after the completion of the car park the gas pressure was increased in the pipeline, which then ruptured at a 350 mm long gouge because of the high localised stresses. Fig. 4 – Aftermath of the explosion at Ghislenghien, Belgium

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6.2.2.5 Restraint Applying soil cover on a pipeline provides restraint to movement of the pipe in all directions. The friction between the pipe coating and the soil provides restraint against pipe expansion in the longitudinal direction and can be strong enough to lock longitudinal movement of the pipeline due to thermal expansion caused by temperature changes. Structures installed below the surface of the earth may support the weight of the materials above it, depending upon certain characteristics of the fill and the structureâ&#x20AC;&#x2122;s design. The fill characteristics (principally internal soil friction) tend to influence (positively or negatively) the gross weight of the material above the pipe structure. How much of the vertical load is applied on the pipeline is dependent upon the relative compressibility (stiffness) of the pipe and the soil. For a very rigid pipeline, the side fills may be very compressible in relation to the pipe and the pipe may carry practically all the load. Trench loads on a pipe are often calculated with the widely-recognized and conservative Marston equation which was developed at the Engineering Experiment Station of Iowa State College from a series of experimental studies.

6.2.2.6 Insulation/heat retention Underground temperatures throughout the year vary much less than over-ground temperatures as the soil acts as a buffer to atmospheric temperature variations. Burying a pipeline can therefore be a means of insulating the pipe or the product it contains from extreme temperatures or variations of temperature. This can be used to preserve the pipeline temperature and prevent an energy loss/gain which would require reheating or cooling at the receiving end, or which could simply lead to unacceptable problems such as freezing of the product.

6.2.3 Pipeline Trench Design Please refer to Appendix 6.2: â&#x20AC;&#x153;Pipeline Trench Designâ&#x20AC;? and further design recommendations.

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6.3

Environment

All pipeline construction projects will potentially have impacts on the environment to one degree or other. The degree of impact can depend on the sensitivity of the receiving environment, the construction techniques used, and the size of the project (pipeline length). The degree of impact on the environment is initially identified during the environmental impact assessment (EIA) process. Impacts are given a detailed rating, which takes into account factors including the sensitivity of habitat, proximity to other sensitive receptors, and how the pipeline will be constructed. As part of the EIA process mitigation measures to actively reduce, or offset the environmental impact of the project are suggested, and these measures are incorporated into the projects environmental management plan (EMP). The EMP defines the environmental objectives for the construction project, and provides clear guidance for environmental best practice for all activities for the personnel involved. The EMP can also be used as a basis for the training of site personnel in environmental best practice. The Environmental Impact Assessment (EIA) Process In order that environmental impacts can be reduced, negated, and/or offset as far as is practicably possible, appropriate mitigation measures are agreed as part of the EIA process and incorporated into the overall plan for construction works. The EIA process follows recognised standards that are recognised by national governments, clients, trade associations, World Bank and international finance organisations. If undertaken properly an environmental assessment aids all those involved in the project and planning process (including the project developer). It ensures that the developer has focussed on the environmental considerations of the project at an early stage, rather than being forced to reconsider an alternative solution once construction is underway. The first requirement for assessing the impact of a proposed activity is a survey. A thorough survey, including an assessment of all available evidence, will enable any impacts to be accurately assessed and allow appropriate mitigation to be developed and agreed. Mitigation measures can take a number of forms. The most common forms are outlined in the following table:

Avoidance

Where viable, the project or activity will be redesigned to avoid impacts

Reduction

Reduction will be considered when all options for the avoidance of impacts have been exhausted or deemed to be impractical (e.g. reduced working width, reduced construction hours/ numbers of construction vehicles etc.).

Compensation

Where the potential for avoidance of and reducing impacts has been exhausted, consideration will be given to environmental compensation (e.g. the creation of alternative habitat to offset that which has been disturbed/destroyed).

Remediation

Where adverse effects are unavoidable, consideration will be given to limiting the level of impact by undertaking remedial works.

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Typical Impacts Environmental impacts from pipeline projects depend on local conditions, and the techniques employed in construction. However there are a number of potential impacts that are characteristic for terrestrial pipeline construction spreads:

•

Habitat disturbance – Can take the form of temporary or permanent disturbance/alteration to pre existing habitat over the length of the pipeline spread

•

Soil erosion – Wind or water erosion of the trench slope or stored soils during construction, or of the spread during/following construction. Erosion can vary according to the terrain, soil type, and degree of vegetation cover, construction methods, and weather conditions

•

The spread of weeds/alien/invasive species, and/or contaminated soils through soil tipping and excavation, and by construction vehicles tracking along the pipeline spread

•

Potential impacts to statutory designated areas, protected/vulnerable species, or protected/vulnerable habitats due to construction activities

•

Potential socio-economic impacts, such as construction noise, dust generation, access to public rights-of-way, employment (positive and negative) supply chain, impacts on farming activities, in particular livestock and visual impacts to locals and visitors to an area

•

Health impacts from construction activities, including introduction of new infectious diseases from workforce in remote communities, camp conditions, security and pollution

•

Impacts on watercourses – River crossings and stream diversions have impacts on watercourses. Other impacts could include increased siltation in rivers, and the risk of pollution by construction machinery (fuel/lubes spills)

•

Impacts on known/unknown archaeological sites/artefacts may be damaged or disturbed by construction activities

•

Impacts on wildlife – As well as habitat disturbance, pipeline projects can create direct disturbance to wild animals by noise and dust creation, particularly during sensitive lifecycle periods (such as breeding). Open construction spreads, as well as completely reinstated projects can create linear features in the landscape, which can be a temporary barrier to migration pathways in the same way as roads and railways

Typical Mitigation Measures Many of the following mitigation measures are considered as environmental best practice by the pipeline construction industry. These measures typically apply to pipeline projects undertaken across all habitat types.

•

Habitat disturbance and soil erosion can be mitigated by appropriate soil handling techniques during construction; limiting the amount of topsoil stripped to the absolute minimum required, and for as briefly as possible. In addition regular watering of stripped topsoil areas can help reduce dust generation and surface wind erosion, as can limiting traffic and speed of traffic on the pipeline spread. Appropriate storage of stripped and excavated soil, and limiting the gradients of slopes/trench sides during construction and timing construction works to avoid the wettest times of the year are also important considerations

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•

The spread of invasive or alien species and contaminated soils along pipeline routes can be mitigated by appropriate weed control measures, limiting vehicle movements, appropriate separate soil storage and machinery washing points at regular intervals along pipeline routes

•

Impacts on statutory designated sites can be reduced at the pipeline routeing study stage by avoiding such areas, wherever possible. Other measures include keeping the width of the construction spread to a minimum, and timing works such that they avoid sensitive periods for protected/vulnerable species and/or habitats. Construction techniques such as horizontal directional drilling (HDD) can also be used to avoid particularly sensitive areas

•

Careful selection and maintenance of construction equipment helps to minimise noise and airborne emissions to the local community

•

Sustainable use of resources, including fuel, water, fencing, skids and temporary road material (including associated borrow pits) may have the additional benefit of reducing waste

•

Mitigating impacts to watercourses can be achieved by ensuring appropriate site drainage has silt settlement or filtration prior to discharge. Ensuring that any open-cut river crossings are timed to coincide with periods of lowest sensitivity (avoiding breeding/spawning periods, and periods of highest water flow, as well as undertaking crossing works as quickly as possible); alternatively HDD construction techniques are used, particularly on wider river crossings. Impacts to watercourses from accidental fuel or lube oil spills can be minimised by ensuring that no refuelling of equipment takes place in close proximity to watercourses. The potential for accidental releases of fuel and/or lube oils and grease to watercourses can be further reduced by using machinery that is in a good state of repair (appropriately maintained) and new

•

Impacts to known/unknown archaeological, religious sites and artefacts can be mitigated at the routeing stage by avoiding known areas. An archaeological watching brief can also be maintained during topsoil stripping and trench excavation to prevent undue damage to any previously unknown areas

•

Minimising the extent of open trench allows the passage of wildlife and communities who need access across the working width

•

Careful reinstatement of pipeline working width, following the completion of construction activities, reduces the potential for pipeline projects to have a residual impact on habitats. Consideration of reinstatement should be undertaken early in the construction process, and may entail seed collection, tree felling, specialist machinery for topsoil stripping (such as turfing), the need to source local plant material, or the requirement for water to establish plants. Where possible pipelines are often routed through agricultural land whereby, although there is a temporary disturbance to habitat and farming land, typically due to the seasonality of the land use, complete reinstatement occurs very quickly. Post construction monitoring should be undertaken (for a minimum period of 2 years) to ascertain the overall success of the reinstatement works and assess the recovery of the environment. Monitoring is particularly important in those areas where habitat is of significance for conservation. Careful consideration should be given to ensuring that the ground conditions are conserved, by storing and replacing topsoil and soil layers in the correct order, and controlling decompaction and drainage

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

All the measures aimed at mitigating the impacts from construction activities can form part of a site environmental management plan (EMP). The EMP transfers the commitments made during the routeing, financing and consents identified in the EIA document into practical guidance, for the construction contractors to cost and implement as part of the construction works. It can also form the basis for appropriate environmental training of personnel working on site.

Pipeline Construction in Different Environments There are a number of environmental impacts that are more habitat-specific, and as such require differing approaches to their mitigation strategies.

•

Soft soils – These are prone to compaction during construction works, and can often require the use off bog mats to reduce soil damage. During very wet periods soft soil sections of the pipeline spread can be temporarily closed off to prevent undue compaction. Reinstatement involves the removal of the bog mats and ripping up of the soils, prior to re-profiling to alleviate the compaction

•

Sand dunes – Dune systems are particularly sensitive (particularly in the low-lying more stable areas) and are often susceptible to flash flooding, and as such pipeline routeing should identify such areas and re-route if necessary. Dust generation can be a problem, but this can reduced by keeping vehicle movements and speeds to a minimum. Reinstatement is of particular importance and difficulty in sand dune areas as they are often mobile in nature, and require some specialist reinstatement techniques. The dunes need to be recontoured as close to their original state as possible, also reinstating the original drainage channels and watercourses

•

Peatland – As with other soft soil environments, measures to protect and mitigate compaction will be required. Draining water from the excavation can lead to an imbalance in the peat, which can damage its integrity. As such appropriate water quality and erosion control measures will need to be used, such as geotextiles, straw bales, or rock riprap. There is also the potential for the pipeline trench to act as a drainage channel. To prevent this inert plugs can be placed in the trench at intervals to prevent poor drainage

•

Side slopes – The potential for erosion of the trench on steep slopes can be mitigated by the placing of trench plugs at regular intervals to prevent the free flow of water and silt through the trench. Slopes should be graded to avoid soil creep, and the use of pre-existing planting or erosion control geotextile matting should be maximised to aid slope stabilisation. Early establishment of vegetation is important on side slopes

•

Swampy areas – Similar measures should be taken as in peatland and soft soil environments to mitigate against soil compaction. In addition pipes laid through swamps are susceptible to water build up in the excavated trench; dewatering may be useful but care should be taken of the discharge location. In addition sediment traps or filtration measures to reduce silt in the water should be taken prior to discharge of trench water

•

Forested areas – To minimise the degree of tree clearance required, the working width of the pipeline spread should be reduced as much as possible. Machinery working in such environments should be able to work safely in a reduced space. Where tree roots have been cut, but the trees not felled, the crown of the tree should be reduced accordingly to reduce water stress, and protect the tree from any long-term damage. Measures should also be taken to avoid disturbance to nesting birds, or species/habitats of conservation importance. Account should be taken of tree canopy species that would typically travel across the working width, walkways or access points may need to be provided

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•

Ridge – Ridges are constrained, and as such will require that the working width be reduced. There is a lack of available space for the storage of equipment and excavated material, so activities require careful advance planning. Side casting can have large-scale visual impacts, and although reinstatement of the contours is particularly difficult, it is important to restore the original contours as closely as possible. To stabilise soils and minimise erosion early reinstatement of vegetation should be considered, as well as potentially re-contouring land to minimise the overall visual impact

•

Tundra – Tundra habitats may include permafrost. The working season is first determined by borehole investigations, which provide information about the depth and extent of the permafrost, and in turn help guide appropriate construction and reinstatement techniques. Modelling may need to be undertaken to ascertain the thermal effects of the permafrost on the pipeline and contents, and vice-versa. Insulation measures may be required for the pipeline prior to operation. Accurate reinstatement of the strata profile is particularly crucial in permafrost habitats, as it is important to appreciate how the ground may alter its physical properties seasonally

The tables in Appendix 6.3 give an overview of the measures to reduce the impact of the works on the environment.

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6.4

Health and Safety

Earthworks sites have the potential to be among the most dangerous due to the variety of work that is carried out in and around the area of work. Without appropriate controls one of the greatest risks is the collapse of the sides of excavations. Too often this has and will continue to result in fatalities and serious injuries. The following information highlights the real dangers of earthworks past and present.

• • •

During the period 1990-2000 there were 771 fatalities involving excavations in the USA USA reports that pipeline trenches are one of the major source of fatalities in the pipeline industry 38% of the fatalities that occur are in trenches less than 3 m deep

A large proportion of excavation accidents are avoidable if the correct control measures are put in place. Any organisations and companies involved have a responsibility to protect the health and safety of all personnel (including sub-contractors and visitors), to ensure the health and safety of everyone involved or impacted by the earthworks operation. Although earthworks are carried out in a wide range of environments most of the hazards, and therefore the control measures to reduce the impact of the hazards, are generic irrespective of the work location. Examples of general hazards include:

• adverse weather • heavy loads • work equipment • confined spaces • local community • wildlife

• ground conditions • lifting • working at height • hazardous materials • vibration

• ambient temperatures • pipe movement • emergency response • noise • illumination

During earthworks activities, one of the most significant risks to personnel is the collapse of the walls of excavations or trenches. This can happen quickly, with very little warning, therefore appropriate controls must be put in place before work begins in the area. Great care must be taken in the design of the work area taking into account the soil type and environment. Consideration must also be given to using sloping walls to protect the integrity of the trench walls. In the case of any trench over 1.2 m deep shoring, sloping or stepping must be used to improve the stability of the trench. Once the trench has been dug it should be inspected daily or after any event which may alter its integrity. Adverse weather can greatly increase the risk of earthworks in all environments. All types of soil are likely to become more unstable if very wet or dry which can lead to the collapse of side walls. Shoring of the sides of the excavation or trench boxes can be used to protect workers when they are in the trenches. Heavy rainfall can also lead to the flooding of trenches. Pump systems may be required to remove water from the ground and consideration should be given to the length of the trench dug out if heavy rain is expected. High winds can also hamper lifting and pipe movement operations. These types of operations should be ceased if operators feel it is unsafe to continue or an appropriate limit should be identified and put in place. Lift plans should be in place for all pipe lifting operations. Weather can also affect the ability of machinery to operate so consideration of the best time of year to carry out projects is essential. Extreme temperatures can also impact on the health and safety of personnel. Reactive measures could also include providing appropriate heating, cooling and areas of shade. Ground conditions, heavy loads and vibration can also have an effect on the integrity of the excavations. Unstable ground conditions can lead to problems with the operation of plant and machinery.

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Creating a track for plant to operate on may be the best option to avoid the risks of it sinking or becoming bogged down. Heavy loads such as pipe and excavated material should be placed away from the edge of the excavations so as to avoid exerting extra pressure on the walls which could increase the risk of collapse. Vibration caused by plant movement or machine operation could also affect the ground conditions and the integrity of the excavation. By ensuring appropriate preparations are taken when developing the ROW, acceptable ground conditions can be achieved. Limiting and using the correct size of plant and machinery can also reduce the effects of vibration. Working at height will also be a common hazard across a variety of working environments. This could be the dangers associated with working at the top edge of the trench or access and egress from plant machinery. Suitable barriers can be used to keep people back from the leading edge of the trench. All staff should be given and use appropriate PPE which may include fall arrest equipment. For such equipment personnel must be trained and deemed competent before its use. Specific training must be given to those performing work in confined spaces and it would be advisable to operate a permit-to-work system in those situations due to the high risks associated with this type of work. Another generic hazard is work equipment. Due to the nature of the job there will be a large variety of work equipment in use during earthworks including heavy plant machinery, lifting equipment, generators, compressors, ladders and hand tools. All equipment should be fit for purpose and be given a visual inspection prior to use. Electrical equipment should be inspected on a regular basis and records should be kept. Lifting gear should be certified by a third party and also inspected by operators prior to use. Where applicable guards must be available and in use at all times on machinery. Operators should be trained and competent in the operation of all machinery that they will use. Faulty equipment should not be used in any circumstance. Illumination of the work area must be considered for earthworks as poor lighting can be a hazard in all types of environment, leading to an increase in workplace accidents such as trips and falls. Assessment must be made based on the amounts of natural light available in the area and the requirement for artificial lighting to maintain lighting levels. At the planning stage of the project the requirement for night working should be assessed and suitable lighting plans put in place if required. Ensuring that the health and safety impact on the local community is reduced to as low as reasonably practicable is important in all earthworks. Providing information to the local population regarding the work being undertaken can highlight any potential risks. Another aspect is ensuring good site security is in place to reduce the risk of people entering the work area without authorisation. Risks associated with wildlife can vary widely throughout the different earthworks environments. Where there is a risk to the workforce from disease-spreading or poisonous animals, emergency plans should be in place to control the risks. Where animal attacks are likely fencing can be used to restrict access to the work area. Medication may be required to prevent disease and information must be passed onto the workforce regarding these risks. There is the potential for exposure to hazardous materials with the malfunction of work equipment i.e. oil spills or contact with materials pre-existing on the site. A thorough analysis of the work area should take place before any work is carried out to ensure the land is not contaminated. Monitoring should continue throughout the lifespan of the project. Spill kits should be available to deal with any spillage that occurs on site and personnel should be provided with any necessary RPE or PPE. While digging the trenches workers may also be exposed to excessive levels of dust. Dust suppression through spraying water or use of appropriate RPE can be used if necessary to deal with this issue.

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Due to the remote nature of many earthwork locations employers must develop and regularly test an emergency response policy. This would include ensuring good communication channels, having good first aid/medical provisions and trained first aid providers on site. Planning of the quickest, safest routes to hospitals and other local facilities must also be undertaken. An important feature of this would be identifying and providing the best mode of transport to get to these locations. Regular tests of evacuation and emergency procedures should be carried out to ensure the effectiveness of these plans. There are many other hazards that can arise in certain earthworks operations. The tables in Appendix 6.4 give an overview of how we can employ systems to reduce the risks from the main hazards of the work and maintain the health and safety of all personnel involved. Health and safety relies upon three key elements to ensure safe working practices during earthworks:

•

ENGINEERING – Engineering controls/guarding/automation of systems/preventative maintenance

•

PROCEDURES – HSE policy/procedures/monitoring and measuring/audits/risk assessments

•

BEHAVIOURAL – Communication systems/health and safety as a personal value/leading by example

Although each element is important in its own right the system only works when all three elements work together to ensure the health and safety of all involved in the projects.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Appendix 6.2 Pipeline Trench Design

Follow up from section 6.2 in volume 1: Earthworks Design

Table of Contents Page

6.2.3 6.2.4 6.2.5 6.2.6 6.2.7 6.2.8 6.2.3

Pipeline trench design

Trench depth

Trench integrity

Installation

Dewatering

Backfilling

Pipeline Trench Design

6.2.3.1

General

Many types of trench exist, suited to different purposes and soil conditions. Trench shape and width are discussed in this section. Trench depth is studied in section 6.2.4 and modifications to the trench shape to guarantee its integrity are detailed in section 6.2.5. Geotechnical aspects of pipeline trench design include:

• • •

Trench wall stability • Influence of spoil pile • Influence of equipment track pressure Minimum required width of right of way arising from trench depth, width and spoil heap Trench width

Fig. 5 illustrates a typical V-shaped trench design suited for most soil types. Other trench shapes can be better suited to specific soil types: examples are illustrated for rocky, sandy and cohesive grounds in Fig. 6 to Fig. 8.

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Fig. 5 Typical trench cross-section (general soils).

Fig. 6 Typical trench cross-section (rocky ground).

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Fig. 7 Typical trench cross-section (sand) with berm. The same trench design is used without a berm.

Fig. 8 Typical cross-section (cohesive soil).

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Asymmetric designs can be used to lock the pipeline in horizontal bends. In such case, the trench extends on the outer side of the bend, as shown in Fig. 9. Fig. 9 Asymmetric trench designs. Dimensions in mm.

6.2.3.2

Trench Wall Stability

The main factors influencing trench side slope stability include: 1. Soil undrained shear strength, or soil angle of friction 2. Trench depth and side slope inclination 3. Distance between toe of the spoil pile to the top edge of the trench and the height (or surcharge) of the spoil 4. Equipment track pressure together with the distance from the track to the trench 5. Dynamic vibration impact from equipment 6. Season that work is being carried out in (wet, dry, frozen ground, summer, winter) Based on clay soils as an example, for a clay soil with an average undrained shear strength of about 12 kPa, unstable conditions may occur unless the trench has a slope inclination of greater than 45ยบ, and if the spoil is located approximately 1 m away from the edge of the trench. For clay with an average undrained shear strength greater than 20 kPa, stable trench conditions are likely for vertical trench walls and the spoil placed at the edge of the trench. The angle of the spoil pile also needs to be adequately designed and specified to ensure that spoil does not collapse towards the trench thus comprising the trench itself. The spoil/topsoil height should be limited to about 2 m, and the inclination be about 40ยบ or lower. These are just general guides, and will be affected by trench depth and soil properties. Equipment track pressure will affect the trench stability. Based on two track pressures, 90 kPa and 140 kPa, typical guidelines for a 2 m trench depth include trench slope to be 40ยบ to 60ยบ, and provision that the track set-back be at least 2 m from the edge of the trench. Unless adequately designed for, repeated passage of heavy equipment can lead to remoulding and deep ruts in the soil, thus slowing down the construction, and potentially even equipment sliding into the trench. Fig. 10 shows the typical interaction between clay soil strength, trench slope and equipment track pressure.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 10 Soil Strength vs Trench Slope for Equipment Track Pressure

6.2.3.3

Right of Way (ROW) Width

The ROW width is of prime importance to ensure adequate working conditions whilst minimising cost and environmental impact. The ROW is divided into two parts: the spoil side and the working side. The soil side width is affected by trench design, spoil pile stability and spoil swelling factors (which could be up to 30%). The working side is affected by trench inclination and set-back of the equipment from trench edge, together with construction considerations such as pipe supports, side booms, traffic lane and storage.

6.2.3.4

Trench Width

The trench width is influenced by a number of factors, namely: safety, soil characteristics, outer pipe diameter, trench depth, minimum available width of excavator bucket, type of crossings, and any special purpose requirements. In turn, the trench width affects the loading on the pipe. The width at the trench bottom is dependent on the overall pipe diameter, the coating, the number of pipes in the same trench, and any other services placed in the same trench. The distance between the pipe end and the edge of trench bottom can vary from 150 mm – 300 mm. The trench bottom width must be sufficient to allow for compaction of the soil at the haunches and on the sides. The width at the trench top will depend on the soil that the trench has been cut into and safety requirements. The side slope angle could be as shallow as 10º – 30º, leading to very wide top of trench widths. Trench safety is of paramount importance to ensure that those working in the trench are safe and protected from trench collapse and trench flooding. This is discussed in more detail in section 6.2.5. Crossing of roads and tracks often requires minimum disruption and construction on a short schedule. Consequently, the trench width design at road crossings needs careful consideration, with options of shoring the trench considered (see section 6.2.5.3). Together with the trench depth and characteristics of the fill over the pipe, the trench width will produce the load which must be supported by the pipe and its bedding. Generally speaking, the wider the trench, the greater the load on the pipe. Beyond a certain point this effect stops and widening the trench further does not impact the loading on the pipeline anymore.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

6.2.4

Trench Depth

6.2.4.1

General

Pipelines are often buried under locations where human activity is intense. Vehicle crossing in particular can potentially impose important concentrated loads to a buried pipe and damage it. In areas where vehicle crossing is likely or certain (under a road or track, or under farm land), it can be necessary to bury the pipe at an increased depth. The typical depth range is the following, depending on soil conditions and land use : Main Roads and Light Roads: Fields:

- 1.2 m to 8.0 m - 0.6 m to 8.0 m

The crossing of other buried pipelines also sometimes makes it necessary to bury pipes at greater depth, if only on a limited pipeline length.

6.2.4.2

Ground use

Depending on the land use, pipelines have to be buried at a minimal depth to avoid likely damage from third-parties. For example, under farmland, pipelines may have to be buried deep in order to avoid damage from soil pressure caused by heavy equipment and from earthwork required by cultivation (see Fig. 11). In cities, pipelines should avoid running under private land where the landowner might conduct earthworks that could result in pipeline damage. Fig. 11 Deep burial of pipelines is sometimes necessary under farmland. a) Gravel mole plough. b) Plough shown out of the ground.

(a)

(b)

The American codes ASME B31.4 and ASME B31.8 provides a range of cover depths for various types of land and its use. These are summarised in Fig. 12. These burial depth requirements can be overridden by local regulations, sometimes by company codes, and sometimes by the landowner during negotiations.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 12 Burial depth Vs land use.

Where required minimum cover depths cannot be met, the pipe can be encased, bridged, or designed to withstand any anticipated external loads. The cover depths shown are minimum requirements for guidance only, and actual cover depth requirements will need to take into account actual local conditions, deep ploughing, and any local erosion issues.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

6.2.4.3

External loading

The load exerted on the pipeline by the soil cover can be beneficial for the pipeline system as it can be used to lock the pipe into place and mitigate adverse pressure and temperature effects. The load on a buried pipe is created by the weight of the soil lying above it as well as the above-ground loading. Increasing the trench depth increases the soil load but reduces the traffic load, as illustrated in Fig. 13. An optimum cover depth can therefore be found to minimise the pipeline loading. Road crossings are covered in more detail in the next section. Fig. 13 Soil and traffic loading pressure Vs cover depth to Top of Pipe.

6.2.4.4

Road and railroad crossings

Discussion and research on the cased/uncased approach to pipeline crossings of roads and railroad have been underway since the late 1950s and 1960s. For example, American Railway Engineering Association (AREA) Bulletin #738 provides an extensive review for pipeline crossings of railroads. Where buried piping is subjected to frequent overhead traffic or occasional heavy loads, consideration shall be given to providing the pipe with an external protective sleeve or casing, which is typically made of steel, concrete or plastic. In the past, the use of casing was mandatory for constructing jointed pipelines under all obstacles that could not be constructed by an open-cut method, particularly transportation arteries. Today it is generally considered that an adequate design will provide structural integrity for either cased or uncased crossings. Fig. 14 shows typical cased and uncased crossings for roads and railways. The decision to case a pipeline crossing of a highway or railroad involves the following considerations.

• • • • •

Existing regulations by local, state, and federal agencies Site conditions (soil, water table, traffic, population density, and potential future construction activities) Economic considerations Pipeline function and commodity transported Carrier pipe material

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In recent years, the increasing trend is to install crossings and to change existing regulations to permit such an option. For adequately designed carrier pipe, alternatives to casing include concrete-coated pipe or concrete slabs over the pipeline through the road or the railroad Right Of Way. Advantages of pipeline casings are listed below.

• • • • •

Mechanical protection for pipe from external live and dead loads Easy and cheap future removal or replacement of pipe Frost-line insulation from transported commodity in temperature sensitive soils. Sub-base and crossing protection in the event of a pipe leak Protection from third-party damage

However casings also have disadvantages, which are listed hereafter.

• • • •

Higher cost to owner due to the following requirements: larger bore-hole for casing, two installations, insulators and spacers between pipe and casing, end seals, and annular space grouting. Potential shielding of the pipeline cathodic protection system Potential shorting of the pipeline cathodic protection system Potential exposure of carrier pipe to corrosive condensation inside the casing

Fig. 14 Typical crossings.

Cased crossings

6.2.4.5

Uncased crossings

Waterway Crossings

The installation of underwater crossings is a challenging undertaking. Revisions to the pipeline profile and joint design may be required depending on the installation method. For pipelines pulled along the channel bottom, special pull heads, lugs, sleds and flotation tanks are normally required on the leading end of the pipeline. It may even be necessary to modify the original design if conditions change during construction. Laying from a barge, or floating the pipe into position and sinking requires divers and expensive marine equipment, both of which have limited operational hours. Design and installation of ballast weights, concrete jackets, and flotation devices required for these methods also require special consideration.

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Because of the difficulty associated with repairs, waterway crossings should be hydrotested immediately upon installation completion and prior to connecting to adjacent sections of land piping. The line should then be backfilled by dumping or chuting the backfill material. In certain cases, it is possible to allow natural backfill of the pipeline by water course sediment. River banks and river beds will change with time. Specialist studies should be conducted to determine the pipeline end-of-life condition of the river banks and river bed to ensure that the pipe has sufficient cover to take into account bed erosion, and that the pipe has sufficient burial depth across the width of the crossing to account for any river bank meander (Fig. 15). Additionally, the use of the river should be taken into account for determining the design burial depth. Fig. 15 Evolving meanders of a river

6.2.4.6

Third-party protection

Generally speaking, increasing the depth of cover will lead to a decreased probability of third-party damage incident. Fig. 16 shows the percentage of damage incidents as a function of the depth of cover.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 16 Probability of damage vs cover depth.

6.2.4.7

Restraint/upheaval resistance

In operation, the pressure and temperature of the fluid induces stresses in the pipeline. On one hand the internal pressure, which is normally higher than the atmospheric pressure, creates both â&#x20AC;&#x153;hoopâ&#x20AC;? and longitudinal stress in the pipeline. This will lead to a tendency for the pipe to straighten at bends (the Bourdon effect). This movement can be compounded by the temperature of the fluid which will cause thermal expansion (or contraction) of the pipe. Should the soil not provide enough longitudinal restraint by friction, the pipe will tend to move along its axis. Comprehensive analysis of the restraint, movement and the resulting stresses within the pipeline is required to ensure that pipeline stresses will be within acceptable limits. Analysis often shows high levels of movement at bends and at the ends of a pipeline, where the pipeline comes above ground. Movement can be controlled by additional soil loads or the incorporation of anchors. Alternatively, expansion loops or bends can be incorporated to allow movement without unacceptable stresses. Movement can also result in upheaval buckling. This can occur at an overbend or a vertical imperfection in the bottom profile of a trench and can result in the pipeline coming out of the ground (see Fig. 17) and possibly pipeline buckling. If the pipeline upstream and down stream of the overbend or imperfection is locked in position and expansion of the pipeline occurs from these fixed points then the pipeline relies upon the soil overburden to keep it in place. If this overburden is insufficient then the pipeline could move vertically. Furthermore, the more it moves vertically then the lower the soil overburden becomes, hence allowing even greater movement.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 17 Pipeline upheaval buckling

The greater the burial depth, the greater the restraint on a pipe will be both in the axial and radial directions. This is, however, only true up to a point where the soil load does not increase anymore with soil cover. Fig. 18 illustrates the evolution of soil resistance with the cover height and the pipe diameter.

Soil Resistance [kN]

Fig. 18 Soil resistance as a function of cover and of the outer pipe diameter.

In addition to burial depth, backfill resistance is also a function of several soil parameters, including soil density, resistance to shearing, and specific cover geometry. Soil properties used to determine the backfill resistance should be taken as lower bound values for the upheaval buckling analysis. The pipesoil resistance will depend on the nature of the backfilling process (see section 6.2.8) and on all the uncertainties related to the backfill behaviour.

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Ratcheting Where below-ground pipeline movement occurs, at locations such as bends, the effects of â&#x20AC;&#x2DC;ratchetingâ&#x20AC;&#x2122; have to be considered. This is where a pipeline moves, eg due to thermal expansion, but does not return to its original location on cooling and then expands from its revised cold location to a new point. That is, the pipeline moves on each pipeline thermal cycle from a different start point. This movement can be caused or compounded or caused by soil falling in the void left by the pipeline when it moves thus removing the space for the pipeline to contract into upon pipeline cooling.

Movement at horizontal bends As previously mentioned, thermal expansion force tend to localise in bends, generating a lateral force on the soil which could then fail. The pipe is restrained by the weight and shear strength of the soil as shown in Figure 19. Fig. 19 Restraint on outside of bend to restrict horizontal movement.

6.2.4.8

Geohazards

Burying a pipeline is also a means of protecting it from geohazards such as adverse weather (lightning, heavy wind, ice showers) but also floods, top-soil landslides, forest fires and erosion of the supporting soil. Burial also acts as a buffer against steep over-ground temperature changes during the day-night cycle but also the seasonal cycles. It is important to take into account the impact of fault lines and earthquakes in the design process. Trench depth, design and backfill compaction can improve a pipelineâ&#x20AC;&#x2122;s response behaviour to fault line movement or an earthquake.

6.2.4.9

Insulation/heat retention

Pipeline burial provides thermal insulation of the pipeline and therefore allows the effects of aboveground ambient temperatures to be reduced and allows heat loss or gain to the transported fluid to be reduced.

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Fig. 20-a shows the evolution of temperatures over a year in Ottawa, Canada, at different depths. The temperature of the ground surface remains almost in phase with the air temperature. Below the surface, the soil temperature follows the same trend, albeit with a delay as it takes time for heat to be conducted through the soil. The time lag increases linearly with depth. At a depth of 5 to 6 m the maximum ground temperature occurs about 6 months later than the average maximum temperature of the surface in summer. Fig. 20-b shows the corresponding temperature variation amplitude change with depth (the “trumpet curve”). The amplitude of a temperature variation at the soil surface is normally about equal to that of the corresponding one for air. The amplitude decreases exponentially with distance from the surface at a rate dictated by the time necessary for one complete cycle. For depths below 5 to 6 m, ground temperatures are essentially constant throughout the year. The average annual ground temperature is practically constant with depth, increasing about 1ºC per 50 m depth due to geothermal heat flow from the centre of the earth to the surface. Fig. 20 Heat insulation from soil cover in Ottawa, Canada: (a) Annual variation of soil temperatures.

(b) Depth dependence of the annual range of ground temperatures.

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In addition to an annual cycle, the ground temperature undergoes both a daily cycle and fluctuations associated with changes in the weather. These variations are confined to the near surface region, daily cycles penetrating about 0.5 m and weather cycles about 1 m below the surface. The "penetration depth" is defined as the depth at which the amplitude of a temperature variation is reduced to 0.01 of its amplitude at the surface. In addition to the nature of the soil, moisture has a significant impact on the penetration depth. Almost every man-made change in terrain modifies both surface and sub-surface ground temperatures, although in most cases such modifications are not made for the express purpose of changing the ground thermal regime. Situations can arise, however, where it may be desirable to modify ground temperatures deliberately, for example to reduce the rate of heat loss from a pipeline. It should be appreciated that these temperatures can be modified only to a limited extent because man has no appreciable control over climate, which determines values on a regional basis. In general, ground temperatures can be modified by changing either surface conditions or ground thermal properties. The most obvious method of changing surface condition is to place an insulating layer near or at the surface to reduce frost penetration. Increasing the snow cover by the use of snow fences is another example. The thermal capacity of the ground can best be altered by changing its moisture content, for example, by flooding. The Overall Heat Transfer Coefficient (OHTC) characterises the heat retention capacity of a pipe-soil system: the lower the OHTC the better the insulation of the pipe. Looking at Fig. 21, increasing cover depth decreases the OHTC and can provide insulation properties in the right soil conditions. However, below the water line heat transfer suddenly increases.

(W/m2-K)

Fig. 21 Heat transfer coefficient Vs Depth of Cover

(m)

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6.2.5 6.2.5.1

Trench Integrity General

Guaranteeing the trench integrity is essential for the safety of the workers in and around the trench as well as being necessary for the completion of pipeline construction. Trench design is key to trench integrity and needs to be considered early within pipeline construction projects, so that adequate costs and schedule are allowed for pipeline construction. Where ground conditions are such that trench walls will not remain vertical, the contractor may choose to use sloping side walls or to use solid sheeting to support the trench walls. In all cases, the critical dimension is the trench width measured at the top of the pipe. Fig. 22 shows the different factors affecting trench stability. Fig. 22 Factors affecting trench stability.

6.2.5.2

Access/safety

Like all construction activities, pipeline construction can potentially be dangerous to workers. However, very high safety standards can prevent most accidents and result in a very safe working environment. Safety statistics from the Australian Pipelines Industry Association are shown below in Table 1. Table 1 Safety statistics of pipelines construction from the Australian Pipelines Industry Association.

Month Sept 2006 Dec 2006 Mar 2007 Jun 2007 Sept 2007 Dec 2007 Mar 2008 Jun 2008

Total man hours Medical Lost time injuries in quarter treatment injury (inc fatalities) 2 1 0 2 1 3 1 2

4 12 4 9 11 15 4 11

461,097 980,097 480,342 447,454 327,654 1,477,182 555,345 1,279.358

LTIF Rate 2.17 1.02 0 4.47 3.05 2.03 1.8 1.56

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Sloping and Stepping Not all work is done outside of the trench: activities such as inspection, joint coating, and welding often require workers to go down in the trench. Workers should not enter a trench with vertical walls over 1.2 m deep as the trench could collapse and pose a safety threat. At greater depths, shoring, sloping, or stepping is required to improve the stability of the trench (its “stand-up” time which is a function of the ratio between depth and width). T-shaped sloping and stepping drastically increases the width of the trench at ground level as the depth of the trench increases, as shown in Fig. 23. Fig. 23 Sloping and stepping.

6.2.5.3

Use of shoring, sheeting and trench boxes

Different soil types behave differently, depending on the condition of the soil at the time of excavation. Typical collapsing behaviours are shown in Fig. 24 for different types of soft soils. Sandy soil will tend to collapse straight down, wet clays and loams tend to slab off the side of the lower trench. Firm, fairly dry clay tends to crack some distance from the trench wall. Wet sands and gravels tend to slide into the excavation at about a 45-degree angle. Fig. 24 Collapsing of trench walls in soft soil.

Wet clays and loams “slab off”

Firm dry clays and loams crack

Wet sands and gravel slide

Sandy soil collapses straight down

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In excavations where the open ditch method (sloped walls) is not sufficient, trench walls likely to collapse must be supported by proper shoring to mitigate the risk of cave-in. Shoring jacks, with or without sheeting, are a quick and efficient shoring system because the excavator can work continuously (Fig. 25). For deep trenches and unstable ground, the best shoring system is a trench box (Fig. 26), a large mobile box with enough strength to withstand the side pressure of deep excavations. The primary concern is for safety, and all applicable regulations should be strictly observed. Fig. 25 Shoring methods

Fig. 26 Typical trench box

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6.2.5.4

Trench bottom preparation

Trench load design for all pipes is based upon stable bedding and firm foundations. It is essential, therefore, that the trench bottom remains stable during backfilling and under all subsequent trench operations. Any departure from a stable foundation can nullify the efforts of both the designer and contractor because it can result in localized pipe stress concentrations which may cause structural failure. When unstable or rocky trench bottoms are encountered, it will be necessary to over excavate and restore the trench bottom to a stable uniform foundation with selected materials capable of properly supporting the pipe. Select native materials, crushed stone, gravel, slag, coral or other granular materials are commonly used for this purpose. The amount of granular material necessary to stabilize the trench bottom will vary according to the field conditions encountered. Adequate compaction must be applied to guarantee a stable reformed pipe bed. Any material that might damage the pipe coating should be removed from the trench bottom, including rubbish left by the construction workers. Organic materials (“biodegradable”) should also be removed as their decomposition could lead to damage to the coating and pipe. The pipe may be laid on a flat or shaped trench bottom of suitable undisturbed native material or, in the case of over-excavating, on a restored flat bedding base. It is important to achieve a smooth trench bottom before laying the pipe to ensure that the entire pipe barrel has a continuous and uniform line bearing support. The soil curvature should be controlled to ensure that the pipe does not deform excessively under its own weight and the backfill load. As stated above, upheaval bucking can be initiated by imperfections in trench bottoms, providing a further reason to ensure correct trench bottom preparation. A trench bottom imperfection may cause the pipeline to form an overbend by elastic bending when installed, and upheaval buckling could occur at such a point in operations, if the pipeline is locked in position upstream and downstream of the imperfections. Pipeline expansion, coupled with insufficient local overburden, can cause the pipeline to move upwards, potentially driving the pipeline locally out of the ground. Expansion to cause upheaval buckling is normally associated with pipeline operating temperatures at least 50°C above the pipeline temperature at backfilling.

6.2.6 6.2.6.1

Installation Right of way

The Right Of Way (ROW) is the actual width of land, usually purchased as an “easement” rather than a fee, required to safely maintain and operate the pipeline and protect it from future development. In order to perform pipeline installation safely and efficiently, a corridor of 20-30 m is typically required (see Fig. 27) for a single line. Once the pipeline has been installed, the permanent ROW is typically only 8-10 m wide. At river crossings, the ROW during construction is typically significantly larger (usually 3050 m). The installation of twin lines would also require a larger ROW.

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Fig. 27 Construction and permanent ROW.

Fig. 28 shows a typical ROW during pipeline installation in agricultural areas. Excavated material is separated in two heaps: the topsoil one is obtained from scraping the area on top and on both sides of the trench (see â&#x20AC;&#x153;topsoil strip widthâ&#x20AC;? in Fig. 28 ). The subsoil heap is made of material excavated exclusively from the trench. This separation is important in non-desertic area to ensure future vegetation growth on the ROW after reinstatement. To prevent decomposition of the organic material into compost, the topsoil heap should not exceed 2 m in height. Developing nearby tree roots are a potential danger to pipelines, thus the felling of trees close to the ROW might be required, not only during construction but also during the life of the pipeline. Fig. 28 Typical ROW cross-section in agricultural areas.

The ROW is often not owned by the pipeline operator and it is therefore necessary to have an agreement with the landowners in place regarding the temporary use of their land; the potential degradation of the topsoil over the pipeline; and future abandonment and re-instatement requirements.

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Fig. 29 Typical ROW cross-section in desert areas.

Fig. 29 shows a typical ROW during pipeline installation in desert, and wasteland areas. Two spoil heaps are not required in this instance. Fig. 30 shows a typical ROW cut through a forest. Fig. 30 Right of way through a forest

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6.2.6.2

Spoil Management

Construction operations produce large volumes of material to store and also surplus excavated materials that will be disposed of or re-used elsewhere. The types of spoil generated will depend on location, depth, and method (e.g. digging, horizontal directional drilling, boring etc.). It can comprise soil or rocks. The stored material needs to be handled with care to allow re-use, with the subsoil stored separately from the topsoil. The handling and disposal of the surplus subsoil also needs careful disposal, or re-use if possible. Spoil that cannot be managed on site will need to be removed. Increased costs on projects in recent years has led to increasing pressure and incentive to minimise the amount of construction spoil sent to landfill sites, but to do so depends on being able to reduce, recycle and reuse more of it. That, in turn, calls for reliable information about how construction sites handle wastes, and spoil from ground engineering operations. Traffic generated by poor spoil management plans will lead to construction delays. Geotechnical surveys will need to define areas of contamination and the type of contaminant early in the design to allow appropriate management strategies to be developed. Contaminated spoils will require carefully-engineered management plans, not to mention the health and safety risks for the site employees. Reduction, reuse or recycling of spoil can be a viable option only if considered early in the design, operation and management of the works taken as a whole and not as a separate activity at a discrete later stage, i.e. this needs to be planned in detail at the design stage. Some examples are given below for spoil management in rugged mountain terrain areas where the excess spoil is used for site restoration or erosion control. Erosion control can only be practiced once the bulk earthworks and major drainage work have been completed. In steep terrain this is not routine, and the spoil management strategy is the key to providing a stable platform for erosion control. It is convenient to review practices in four categories, these are illustrated in Fig. 31, and described more fully in Table 2, in roughly historical sequence: Traditional - The traditional approach, as also used on many low-cost roads and railways, is simple downslope disposal or side tipping. This has a high visual impact, plus risks of ensuing soil instability, loss of natural vegetation, and sediment contaminating streams and rivers. This is now considered environmentally unacceptable in most situations. Stabilised Traditional - This is a development of downslope disposal, with a supplementary stabilisation of the tipped spoil by revegetation and erosion control techniques. This approach is difficult, and usually works out to be an expensive option. Full contour restoration - The full replacement of soil on steep mountain slopes is environmentally attractive, but very difficult to achieve in practice. Engineered spoil tips - Even in severe terrain there will often be stable embayment areas at intervals on or close to the ROW that can be used for engineered disposal, with appropriate compaction, drainage, erosion control and revegetation. This leaves â&#x20AC;&#x153;smoothedâ&#x20AC;? contours along the right of way. This approach appears to be the best environmental option overall. Unexpectedly, from experience this appears to be the minimum cost option in many situations. A good modern alignment will minimise the extent of sidelong cuts and associated spoil volumes. The pipeline industry has tended to look at terrain in two dimensions, but rugged terrain requires the three-dimensional approaches of the roads industry, and careful planning of earthworks. The engineered spoil tip approach that we have come to favour requires the advance location, sizing and licensing of stable engineered tip sites, as part of this planning.

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Fig. 31 Earthworks management – examples of spoil management strategies

Extracts from “Performance management for site restoration in rugged terrain”, by M Sweeney, A Gasca, RPC Morgan and J Clarke, in Int. Conf. on “Terrain and geohazard challenges facing onshore oil and gas pipelines”, London June 2004, pub Thomas Telford Ltd, p 687-700.

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Table 2 Earthworks on mountain pipelines â&#x20AC;&#x201C; spoil management strategies

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6.2.6.3

Trafficability

As part of the ROW design, it is necessary to consider the ability of construction vehicles to travel and operate on the right of way. When the ground is soft, vehicle “trafficability” can be reduced or prevented completely. This problem is of prime importance as it can affect dramatically the construction cost and schedule or even lead to a change of pipeline route. Special equipment might be needed (e.g. low ground pressure vehicles, mats) and special requirements (e.g. time of construction, drainage of groundwater) might need to be considered. For example, in tropical countries, it might be necessary to build the pipeline during the dry season when rainfall is lowest, and the soil is hardest. On the contrary, in permafrost, it might be necessary to construct during the winter when the ground is frozen and has a higher bearing capacity. Construction vehicles can get immobilised on soft terrain in different ways. First, a vehicle can simply sink in the ground at rest if the soil bearing capacity is too low, i.e. the soil simply does not provide sufficient vertical resistance (Fig. 32-a). Once the wheels or tracks of a vehicle are sunk, the vehicle has to climb a very steep local slope and will often be stuck since the soil often does not provide enough traction resistance. Second, insufficient horizontal resistance leads to a reduced or nil mobility (Fig. 32b). Enough traction resistance should be available to overcome the combined resistance of the following.

• • • •

soil slope vegetation obstacles

Third, slipping of the wheels or tracks as the vehicle moves causes the so-called slip-sinkage effect which causes a vehicle to sink gradually as it advances (Fig. 32-c). However tires running in an existing rut can benefit from the pre-compaction of the soil which reduces the slip-sinkage. This is known as the multipass effect (Fig. 32-d). Fig. 32 Tire-soil interaction. (a) Sinkage at rest. (b) Horizontal resistance. (c) Slip-sinkage. (d) Multipass effect

(a)

(b)

(c)

(d)

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Adhesion of soil between ruts can also lead to a dramatic decrease in traction resistance and should therefore be assessed whenever the soil exhibits high cohesion. The mobility of construction vehicles has to be assessed both on the original pristine ground but also after remoulding by traffic which can dramatically reduce trafficability. Hence it might be possible for vehicles to cross a patch of terrain a “few” times but not more. The sensitivity of the soil to remoulding is often expressed as the ratio of the undisturbed and remoulded compressive strengths:

q St = q

undisturbed remoulded

Besides the ability to perform earthworks for the pipeline construction at hand, care should be taken to minimise the environmental impact and avoid damage to nearby buried pipelines which might not be able to bear the pressure of construction vehicles. Notable methods for estimating trafficability are listed below.

• • •

Methods based on Bekker’s work rely on the plasticity theory and soil friction and cohesion factors. These are complex but nevertheless empirical. They are proven to work well and are often used to develop new vehicles or elaborate new soil models. Newtonian methods are relatively new, hence not proven in the field. They are the subject of modern research but are not yet used in practice. WES methods were developed by the US Army waterways experiment station (WES) and are based on soil penetration resistance and wheel numerics. They provide a simple “go” or “no-go” verdict using a single field measurement: the cone index (CI). Like Bekker’s, the WES method is extensively field-proven.

The original WES method is exposed in the NATO Reference Mobility Model (NRMM) which was developed by the US Army during World War II. The full model makes use of the following parameters to assess soil trafficability.

• • • •

Cone index Soil type Stickiness, slipperiness Vehicle characteristics

The full model also allows to calculate an estimate of a vehicle “speed made good” and of its power efficiency. A simplified version of the NRMM is often used to produce only a go/no-go verdict. It makes use of the cone index (CI), the remoulding index (RI) which characterises the behaviour of the soil after remoulding by traffic, and the vehicle cone index (VCI) which has to be determined for every type of vehicle. Reference documents listing the VCI of typical construction vehicles are widespread. Assessment of trafficability should make use of a proven technique but also of sensible engineering judgement regarding parameters like slipperiness (snow, ice), slopes, obstacles, vegetation, etc. Other factors also have to be taken into account, e.g. damage to the environment, damage to adjacent pipelines, building foundations, overhead power lines etc. The ROW trafficability conditions should be examined before the ROW route is finalised. Complex tiresoil interaction (e.g. multipass effect, slip-sinkage) can sometimes determine whether vehicles will be operable or not on soft ground, hence a detailed trafficability analysis is essential whenever conditions seem critical (Fig. 33).

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Fig. 33 Soil trafficability

(a) Pipeline laying in wet soil

(b) Excavators which sunk due to poor soil conditions.

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6.2.7

Dewatering

6.2.7.1

General

Removal of ground water in the trench is required for different reasons. First dewatering is necessary to be able to excavate a flat, smooth, and stable bottom to lay the pipe. Furthermore, a dry soil is needed during installation to ensure a firm stable foundation. Groundwater movement can also cause material to run off from under the pipe, which could then bend under its own weight as could be unevenly supported. Groundwater removal is also necessary to allow safe and convenient access to the workers who will often perform various tasks in the trench such as inspecting, welding, coating, or repairing. Pipeline buoyancy can also be a problem if water accumulates at the bottom of the trench (Fig. 34). Migration of fine materials (“fines”) in or out of the pipe zone can result in loss of pipe support and must be prevented. This can be accomplished through the use of waterstops or geofabrics. Water should be removed from the trench before final grading of the bedding. The trench should be kept dry during all phases of pipe installation. This can be done in several ways:

• •

•

Over-excavate the trench bottom and fill with crushed stone or other angular material to provide a French drain under the pipe. This drain will carry the water to interceptor sumps where it can be pumped away The groundwater table can also be lowered with well points wherever soil conditions permit. They should be located at intervals dictated by soil properties and placed reasonably close to the trench walls. They should be sunk to a depth below the elevation of the trench bottom. Several well points can be joined together to be handled by one pump In some cases the trench dewatering system may consist of a geotextile in addition to opengraded crushed rock. Fine sands in a fluctuating water table environment are vulnerable to foundation problems and may require a geotextile encapsulation of the drain

Depending on the nature of the soil, the water might contain a lot of silt. Special measures have to be taken in that case such as the use of specialised pumps or filter sumps. Removing the water from the trench is only half of the problem: the water has to be carried and disposed of. For this, permits from authorities may have to be obtained. It is also necessary to perform an analysis of the extracted water to ensure it will not contaminate its disposal area. Fig. 34 Groundwater in pipeline trench (requiring buoyancy control)

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6.2.7.2

Wellpointing

Sub-ground dewatering or wellpointing is a method of controlling or lowering the level of sub-ground water. When faced with having to excavate below the existing sub-ground water level the simplest and most costeffective method would be to deploy a wellpoint system. In modern practice wellpointing is considered most suitable for relatively shallow excavations up to 6.5 metres deep in stratified soils, especially where the water table must be lowered very near to an underlying bed of clay or impermeable rock. Wellpoint systems typically consist of the following (Fig. 35):

•

A small diameter pipe (known as a riser pipe) fitted with a fine filter (wellpoint filter) this filter prevents fines entering into the system and being removed from the ground in the pumped water

•

This riser pipe would be connected above ground to a flexible pipe via a control valve to the header pipe which in turn connects to the suction connection of a specialist vacuum wellpoint pump

•

The discharge side of the wellpoint pump is connected via the discharge pipe to a settlement tank (which further collects any fines) and then on through the discharge pipe to the discharge point

•

Once the pump is switched on it creates a vacuum and pulls water out of the ground thus lowering the sub-ground water level and pumps the water to the designated discharge point

•

The wellpoints are jetted into the ground using a high-pressure water pump (jetting pump) delivering water down a steel tube (jetting tube) to a maximum working depth of 6.5 metres

•

The wellpoint filter and riser pipe are installed, along with a granular filter pack to aid drainage, and then connected to the system

Wellpoint systems are very effective in a wide range of soils from fine silty sand to coarse gravels. Single stage wellpoint systems are used to a maximum depth of 6.5 metres. For deeper excavations twin stage wellpoint systems can be deployed. The equipment used falls into two categories the above-ground equipment which can be reused and is usually hired or rented; and the equipment below ground (risers and filters) which are normally regarded as disposable items and as such are sold to the customer. The pumps that are required for wellpointing duties are critical to the efficiency of the system and must have excellent air handling and air separation capabilities. As such they are regarded as specialised units. If well pointing is implemented, a location to dispose of the water must be found and appropriate permits must be obtained. Fig. 35 Wellpointing

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6.2.7.3

Water run-off control

Installing an interceptor drain (Fig. 36-left) allows water flow and prevents material from running off from under the pipe. It is a gravel trench that is excavated into a relatively impermeable soil layer and installed to collect and remove groundwater as it flows across the impermeable layer. The trench is typically placed across a contour of a slight to moderate sloping area to intercept groundwater to prevent it influencing slope stability. Generally, trenches are constructed 2-3 feet wide and are lined with a quality geotextile that does not clog. There is a 1-2 foot overlap of the geotextile above the gravel and below the backfill in the trench. Alternatively, a French drain (Fig. 26 right) can be installed. It is a ditch covered with gravel or rock that redirects surface and groundwater away from an area. In order to prevent rainwater from running off in slopes during construction and create the same problems as groundwater (See Section 6.2.2.7.1), some measures should be taken in regions where such problems could arise. Fig. 37 shows trench breakers placed at regular intervals in a slope. Fig. 36 Interceptor drain (left) and French drain (right).

Fig. 37 Water run-off control with trench breakers.

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6.2.7.4

Buoyancy

During construction, the pipe is filled with air. If the wall thickness to pipe diameter ratio is low (typically for large diameters), the pipeline can be lighter than water and therefore float, making the pipe laying impossible. If dewatering is not possible, buoyancy control is achieved by adding weight to the pipe (concrete, sandbags, slabs) or by anchoring the pipe to the ground at regular intervals.

6.2.8

Backfilling

6.2.8.1

General

Once the trench has been excavated and water has been extracted, backfilling can commence as proper bedding needs to be put in place before the pipe can be laid. The terminology for various parts of a trench is shown in Fig. 38. Once the bedding is in place, the pipeline is installed. The upper bedding and the sidefill can then be installed by workers. Finally the main backfill can be applied in lifts with minimal direct intervention by workers. The layers can be made of different materials and the main backfill itself can be composed of several layers of different materials. This would allow, for example, using fine soil close to the pipe not to damage it, and coarser soil on top. It is crucial for all the backfill layers close to the pipe to be carefully installed as the soil settlement caused by the load of the main backfill could lead to excessive pressure on the pipe, which would then deform and become oval. Excavators often have to observe a maximum soil drop height to avoid damaging the pipe. Fig. 38 Pipe trench installation terminology

6.2.8.2

Backfill material

If the in-situ soil is not suited for the backfilling operation, it might be necessary to import soil. For this, permits have to be obtained from the relevant authorities and a location has to be found to dispose of the excavated soil. In-situ material can sometimes be crushed and screened to then be used as backfill. The selection of a suitable backfill material is made according to the following criteria.

• • • •

Nature of the soil (cohesion, permeability) Granulometry (presence of rocks, clods, or boulders and abrasion properties) Density Suitability to compaction by normal methods

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

The financial, environmental, social and logistical problems associated with the importation of selective bedding and backfill materials has contributed to the drive to introduce coatings which minimise the use of imported materials. Examples of the problems associated with the importation of selective bedding and backfill materials are

• • • • • •

The high material costs The cost of removing excess spoil from site Aggregate taxes Damage to roads and the environment Local disruption and adverse public relations Inaccessibility

The alternative to importing backfill is to employ crushing and screening equipment to process indigenous spoils. This alternative has become common on many construction projects and has overcome many of the problems associated with laying pipe in difficult ground conditions and the expense of removing excess spoil from site.

6.2.8.3

Coating interaction

In some cases, the type of pipe coating has to be matched to the selected type of backfill material to avoid damage to the coating due to rock penetration or excessive abrasion. Additional protective measures can be used to protect the pipe such as using geotextiles (see Section 6.2.8.9) to separate a layer of fine material around the pipe from a layer of coarser material on top (generally denser and/or cheaper). A conservative approach is often taken in the selection of bedding and backfill materials used to create the pipeline habitat, particularly in a trench containing many rock outcrops or a high percentage of flint. A detailed assessment of the interaction between the coating system and the backfill can lead to a relaxation of the bedding and backfilling requirements, hence decreasing the costs. On one hand, processing of spoils on site, or the importation of selective materials to create a suitable habitat around the pipe is extremely expensive and can be impractical in more remote locations. On the other hand, multilayer (3-layer polyethylene, 3LPE) coating systems that may limit the use of processed or imported materials are more expensive than their thin film (fusion bonded epoxy, FBE) counterparts. Cost savings may accrue if the higher cost of the coating system is counterbalanced by the savings associated with the following:

• • •

A reduction in the amount of coating damage sustained during transportation, handling and construction A reduced requirement for imported or site-processed bedding and backfill to create the pipeline habitat A reduction in the amount of indigenous material requiring removal from site due to importation of selective material

Early consideration of geotechnical conditions in coating selection and backfill design can prove beneficial technically, environmentally and economically as illustrated in the figures below. Fig. 39a compares the cost of importing bedding and backfill (and removing spoil from site) for varying percentages of a 100 km, 610 mm diameter pipeline, and hence the potential cost saving associated with reducing the amount of imported material employed. Fig. 39b shows the same comparison but for processed bedding and padding in the case of the FBE coating. It has been assumed in this assessment that an FBE coating would always require imported or processed material for bedding and backfilling in adverse ground conditions, and that the 3LPE coating would be capable of being bedded and backfilled in indigenous spoil.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 39 Cost associated with bedding and padding

(a) Cost associated with using imported materials for bedding and padding for a 24â&#x20AC;? 100 km pipeline.

(b) Cost associated with using site-processed materials The economic viability of a more expensive coating depends on being able to recover the increased application costs through a reduction in the amount of imported or site-processed bedding and backfill required to prepare the pipeline habitat. An early study is therefore essential to optimize the technical solution as well as minimise the costs.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

6.2.8.4

Rock excavation

When it is necessary to dig a trench in rocky soil, two solutions exist: rock trenching using specialised equipment and blasting with explosives (Fig. 40). Blasting is commonly used because of its cheap cost and speed of operation but the excavated trench is irregularly sloped and requires greater excavation efforts. Furthermore, irregular trench walls resist compaction. Specialised rock trencher machinery is available and produces high quality trenches albeit at a greater cost. Fig. 40 Rock blasting

6.2.8.5

Types of bedding

When an imported bedding material is used, the bottom of the trench should be over-excavated. The proper amount of bedding material is then added to achieve the final grade. The bedding material may be crushed stone or other angular material placed on the trench bottom or by using the natural material providing it is properly compacted. The depth of the material should be at least one-eighth of the pipe diameter but in no case less than 4 inches. The bottom of the excavated trench must be firm, even, and stable to provide uniform support.

6.2.8.6

Trench foundation

When the bottom of the trench is not sufficiently stable or firm to prevent vertical or lateral displacement of the pipe after installation, the first step is to develop a non-yielding supplementary foundation for the pipe, irrespective of other bedding requirements. Supplementary foundations may be of various types to provide an adequate and non-yielding base (e.g. made of concrete).

6.2.8.7

Initial backfill/coating damage

Initial backfilling takes place after the pipe has been installed according to the engineering specifications. The initial backfill extends from the bedding material, up the sides of the pipe, to a level approximately 12 inches over the top of the pipe. The initial backfill should be carefully placed as soon as possible to maintain proper pipe alignment and to protect the pipe. This material should free from large stones or clods. The bedding or initial backfill should be sliced under the "haunches" of the pipe to fill the voids and consolidate the material in this area. This assures uniform support of the pipe. (Fig. 41). Backfilling in lifts should be done when the bedding material is no higher than about one quarter of the pipe diameter if it is to be effective.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Multi-layer pipeline coatings such as dual powder systems and 3-layer HDPE have been shown to provide superior resistance to damage, both accidental damage during handling and transportation and resistance to the increased loads arising from the use of larger trench backfill. Fig. 41 Pipe bedding

6.2.8.8

Final backfill

The final backfill extends from the initial backfill to the top of the trench. Final backfill shall be placed in lifts of typically 300 mm. No rocks or stones should be present in the final backfill within one meter of the top of the pipe. Selected backfill material may be required for the top 300 mm or more as specified by the engineer. Usually a front end loader or a bulldozer is used to push the spoil bank into the trench at an angle so that impact on the pipe zone is minimized. The surplus material should be stored over the trench. After the compression (after approx. four weeks) the remaining surplus material will either be spread out on the working strip or removed from the construction site to a material disposal site.

6.2.8.9

Geotextiles

Crushed rock or other coarse aggregate is recommended and used as a bedding material to improve the load bearing capacity of pipe. Deeper layers of these materials have been employed to stabilize the base of the trench. Loss of pipe support can occur when open-graded materials are used on sites having fine to medium sands at the base of the trench and a water table which fluctuates rapidly in the pipe zone. This is caused by water moving rapidly through the fine to the coarse material and carrying the fine sands with it. To prevent movement of the fine sands into the voids of the open-graded bedding material, the material can be encapsulated in a geotextile material. Geotextiles are also used to prevent damage to the pipe from pebbles or rocks which might migrate from another layer of the backfill (Fig. 42). Fig. 42 Controlling migration of bedding material with geofabric

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

6.2.8.10

Compaction

Soil compaction can be required for different reasons. To prevent soil settlement due to over-ground traffic, a high level of compaction is needed, especially at road crossings. Compaction also increases the pipeline restraint and is therefore often necessary to avoid burying the pipeline too deep, especially in side-bends and over-bends where the restraint needs to be highest. When it is necessary to achieve a high degree of compaction, it may be advisable for the design engineer or contractor to consult a geotechnical engineer. Success in the mechanical compaction of backfills is entirely dependent upon the control exercised during this operation. The selection and use of suitable compaction equipment must be made with care so that the pipe will not be disturbed or damaged. Pneumatic tampers, vibratory pads (hand-held and walk-behind) and self-propelled trench compactors are specifically designed for this work. Extreme care should be taken when using heavy mechanical equipment such as sheepsfoot rollers, dozers and loaders. Most soil materials may be compacted by mechanical means in lifts. However, it is necessary to determine if the field moisture content is in the optimum moisture range in order to obtain the desired compaction with normal compactive effort. If the soil permits, adequate compaction may be obtained by careful water flooding as discussed in the following section. Proctor tests provide curves like the one shown in Fig. 43. They allow the maximum density of a soil to be quantified as a function of water content. Achieving a 100% Proctor compaction level would equate to being on the horizontal dashed line shown in Fig. 43. It is not uncommon to require 90-95% Proctor density for sensitive pipelines prone to upheaval, or when the design requires a fully-restrained system. Fig. 43 Maximum compaction Vs. water content.

Poor compaction and weight of soil on pipe can cause the pipe to ovalise over time due to poor side support, and introduce ovalisation bending stresses in the pipe. A typical percentage pipe deflection over time for a range of compaction densities is shown in Fig. 44.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 44 Deflection of pipe due to compaction

6.2.8.11

Water compaction

The water method of compaction, known as flooding or jetting, when conducted in lifts, produces supersaturation of the backfill material, which, for any given soil, will produce a degree of consolidation that can be predicted with reasonable accuracy. The desired range of compaction can be obtained with water in native granular or sandy materials which would include most sandy and silty soils and even those with some clay content. However, materials which are predominantly clay cannot be satisfactorily compacted by supersaturation because of cohesion and low permeability of the soil. Water jetting should not be allowed to disturb the initial backfill or the bedding which can result in pipe displacement or damage.

6.2.8.12

Compaction abuse

The selection and use of suitable compaction equipment must be made with care so that the pipe will not be disturbed or damaged. A falling weight "stomper" or drop hammer should never be used for compacting even with a substantial cover over the pipe. These impact devices can damage the pipe and/or force it out of alignment.

6.2.8.13

Compaction measurement

Compaction is typically calculated by comparing the measured soil density to the maximum soil density for a given level of moisture content. The most reliable method to measure density and water content is to extract a sample and carry it to a laboratory. A nuclear density gauge (Fig. 45) provides an alternative which has the advantage of providing immediate readings, albeit of a lower precision.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 45 Nuclear density gauge to measure soil density.

6.2.8.14

Berming

Two reasons motivate the building of a berm on a right of way. On one hand, it provides an easy way of locating the exact pipeline location for maintenance and/or repair purposes, and helps reduce accidental third-party damage by providing a clear indication of the pipelineâ&#x20AC;&#x2122;s location. A typical bermed pipeline is shown in Fig. 46. On the other hand, a berm can be used as additional cover to restrain the pipeline. Fig. 46 Berm on a pipeline ROW

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.2

Fig. 47 Lateral pressure at bends

Looking at Fig. 47, a berm can be placed on the outside of a bend to strengthen the soil in the direction of the slip surface and increase lateral restraint. Capping (typically 300 mm thick) is normally applied to avoid erosion from wind and rain.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Appendix 6.3 Environmental Control Measures

66 Top and sub-soil must be stored separately to preserve the seed bank for reinstatement purposes. If the soils are to be stored for a long period of time, they must be re-seeded or protected by silt fencing or stock pile berms and geo-jute matting to aid reinstatement and prevent any soil erosion/loss. The topsoil, normally stored on the right of the running track, must not exceed 2m in height to prevent degradation of the soil structure. Subsoil comprising the excavated trench material are stored separate from the topsoil to preserve the integrity of the soil structures and ensure successful reinstatement of the pipeline spread. Trench plugs or shuttering can be installed along certain intervals of the trench vulnerable to erosion to help support the sides of the open trench, allowing the free flow of people/traffic along the adjacent running track. If soil erosion is likely to lead to trench collapse during the lower-and-lay exercise then trench boxes must be installed at vulnerable locations to prevent this happening. Installation of trench plugs and in-trench drainage on slopes as erosion can continue after backfilling if the trench becomes a preferred path for groundwater or seepage leading to tunnelling, cavitations and collapse of backfill. Where there are known invasive species, they should be dealt with according to industry best practice and disposed of as set out in any statutory guidelines. Contaminated soils must be stored separately from any uncontaminated soil, and stored prior to disposal or treatment on an impervious membrane to prevent mixing or leaching in the host area. Minimise the time for topsoil storage. Weed control should be considered where alien species are identified or weeds are likely to create a problem in adjacent areas (to be used in accordance with instructions). Separate and store topsoil adjacent to spread for reinstatement. Post construction monitoring to ensure reinstatement is successful and control excessive weed growth.

Soil strata should be kept separate to avoid crosscontamination and loss of the seed bank for reinstatement purposes. Soils stored for long periods of time may also be subject to erosion.

There is the potential for erosion within the trench leading to trench collapse.

There is the potential for mixing and contamination of alien/invasive species through soil excavation and top-soil stripping.

Erosion of stored soils by wind/water must be minimised

Soil erosion within trench slope

Weeds/alien/inva sive species and contaminated soils

All Habitats

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Particular attention should be given to the individual landowner biosphere. Soils from within animal disease affected areas must be stored separately from uncontaminated areas/fields and must not be moved from one area/field to another. Advice should be sought from local agricultural and vetinary specialists. Wheel washing and protective clothing may be required in some areas. Care to be taken with construction workforce hygiene to avoid spread of plant and animal diseases. Contractors must ensure that they adhere to and comply with the legal requirements for the protection of wildlife and habitats. Particular attention must be made to those commitments detailed in the environmental statement/impact assessments and approved method statements, applicable planning conditions and/or licence conditions. A policy of no hunting/fishing/gathering to be implemented and rigorously enforced. New access roads may provide access to previously inaccessible protected areas and precautions should be put in place to prevent unauthorised persons using the access roads (e.g. install security posts or locked gates).

All relevant consents must be obtained from appropriate agencies before any trench de-watering is carried out. The use of sediment traps or water treatment/filtering methodologies should be used to ensure that there is no pollution of water bodies. Where practicable and with the consent of the owners discharge to neighbouring fields via silt buster and filtered through a series of sediment traps. All severed land drains to be re-connected across the pipeline spread.

Potential for air, soil and other vector-transmitted pests and diseases being transmitted along the pipeline route

Construction activities have the potential to impact/destroy habitats and the associated flora & fauna. Disturbance to nesting birds and breeding wildlife at certain times of the year or impact of areas of ecological importance.

Water may build up in the trench in heavy rainfall or from ingress of groundwater from surrounding water table.

Pests and diseases

Statutory designated areas/protected species/ vulnerable habitats

Drainage

All Habitats

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Noise

All Habitats

Machinery should be checked to ensure it is working efficiently and working hours agreed with local environmental health officers (or equivalent) so as not to cause unnecessary disturbance. Where there are statutory guidelines for the control of noise on construction sites these must be adhered to. Ambient noise levels should be recorded at noise sensitive locations prior to commencement of the pipeline construction works and again as various construction activities likely to cause a problem take place.

Noise can be a nuisance to local populations and cause disturbance to wildlife.

Consultation should be held with relevant landowner, land users and local communities to agree a diversions or alternative access points. Fencing or suitable arrangements should be made where animals are kept in adjacent land. Vehicles/machinery should not be re-fuelled within specified distances of any watercourses, wells or source protection zones. Fuel and chemicals (such as bentonite or polymers) to be stored outside the specified distances of any watercourses, wells or source protection zones. Route all right of way drainage away from watercourses and ensure adequate means of sediment settling and filtration prior to discharge near watercourses. Schedule open cut crossings of rivers at time of lowest sensitivity (i.e. outside of breeding/spawning periods), impose time limits on construction of sensitive river crossings and maintain river flow across the construction area.

Such as neighbouring land, access tracks etc

Nearby watercourses have the potential to be contaminated by fuel or chemical spills. Increased turbidity due to run-off from right of way can pollute rivers.

Temporary obstruction of other land users

Protection of watercourses from pollution.

Fuel tanks and oils stored on site should be bunded and stored away from sensitive areas. Spill kits should be readily available throughout the construction area carried by vehicles, and particularly where a mobile plant is located and employees trained in their use and application.

Mitigation

Justification

Possible soil/watercourse Storage of fuels/oil, refuelling contamination from fuel/oil leakages. of vehicles and plant.

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Bog mats (a series of connected wide sleepers, sourced from sustainable hardwoods) temporary roads or trackway can be used on soft ground e.g. areas of peat/tree roots. Standard reinstatement procedures include sub-soiling or ripping to remove the compaction of the working width prior to reinstatement. Minimise access along the spread (use muster points and buses for moving staff to working areas). Prevent driving off the right of way by ensuring an adequate number and suitable location of access points and maintaining the right of way access roads (including the road along the ROW).

Policies relating to reuse, recycling and minimisation of the use of natural resources should be implemented. Consideration to be given to alternative use of materials in locations to minimise waste, transport and use of natural materials (such as for skids, collection of stone for slope stabilisation, translocation of vegetation, crushing excavated material for pipeline padding etc). Local recycling programmes (i.e. timber). Maintenance of machinery to ensure efficient running. Use of local supply chain/employment where possible.

Soil can become compacted through machinery tracking.

Protection of local resources

Compaction

Energy efficiency and protection of natural resources

All Habitats

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

70 Route surveys and preconstruction record of conditions should be undertaken. Reinstatement should endeavour to return the areas affected by pipeline construction to their original condition. Reinstatement of sensitive ecological areas should be in accordance with agreements with relevant authorities, the environmental statement. Conflicts with landowner’s requests for ‘improvements’ in these areas should be carefully controlled. Post-construction monitoring should be undertaken for a minimum of 2 years. Operation of the pipeline should include land liaison and remediation specialists. Translocation, seed collection, use of locally-sourced plant material, temporary plant nurseries and seed suppliers to be in accordance with EIA, landowner and regulatory authorities requirements. Replacement of subsoil and topsoil should match adjacent contours. Installation of erosion control measures where required, such as geojute erosion control matting, to enhance reinstatement on slopes or highly erodible soils. Clear demarcation as to contractor and client responsibilities. Provision of liaison personnel to ensure that local communities, landowners and land users understand how the construction activities will affect them. Agreement of mitigation measures and methods to be used for community liaison. Engage local employees in the local community liaison process where possible. Bog mats (a series of connected wide sleepers, sourced from sustainable hardwoods) can be used on soft ground e.g. areas of peat/tree roots. Standard reinstatement procedures include removal of the bog mats followed by sub-soiling or ripping to remove the compaction of the working width. In extreme wet conditions sections of the pipeline spread can be temporarily closed to prevent compaction by vehicle movements along the running track, and re-opened once the surface has dried out. Prevent driving off the right of way by ensuring an adequate number and suitable location of access points and maintaining the right of way access roads (including the road along the ROW).

Reinstatement should endeavour to return the pipeline working width to its original condition

Engage in local liaison during construction to advise on construction activity

Soil can become compacted through machinery, people, natural processes, e.g. rain where bare ground is left for long periods of time.

Reinstatement

Community liaison

Compaction

All Habitats

Soft Soil

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Mitigation

If a definite separate strata has been identified and logged this should be stored separately to preserve the seed bank (if there is any present, particularly in stable dune valleys) for reinstatement purposes. Because of the potential mobility of the excavated material it should not be stockpiled for long periods, and the trench backfilled as soon as is practical after the lower and lay operation. Tie-in locations should always be guarded with trench boxes to prevent trench wall collapse.

Pipeline routing should identify areas subject to potential flash flooding. Construction in areas identified should be undertaken at times of low risk. Equipment and pipe should not be stored in risk areas for longer than absolutely necessary Dust generation should be kept to a minimum by restricting the movements of all vehicles along the running track and strict speed restrictions for through site traffic. That traffic engaged with the direct construction activities such as spread preparation, excavation, lower-and-lay should not generate too much dust in calm conditions. Recontour sand dune areas to as close as original contours as practicable, reinstating original drainage and watercourses. Consider sand stabilisation techniques during reinstatement such as erosion control materials. Appropriate water quality management plan and erosion control measures shall be adopted for discharge water. Erosion protection may include water discharge flow dissipaters such as rock riprap, geotextiles or straw bales. Manage the discharge of silty water appropriately and provide filtration methods.

Justification

Depending on the type of sand dune environment strata may need to be kept separate to avoid cross-contamination and loss of the species mix for reinstatement purposes. Stored material will be subject to wind erosion.

Flash floods can wash pipe, personnel and equipment away

Dust from the sand dunes/desert has the potential to impact on construction activities.

Potentially sand is highly mobile and is difficult to reinstate.

Potential to unbalance the integrity of the peat area by dewatering isolated sections.

Flash flooding

Dust generation

Reinstatement

Environmental Considerations

Peat Area

Dewatering of trench

Sand Dune Area Separation of strata

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

72 Inert plugs can be placed at specified intervals along the trench to prevent poor drainage.

Pipeline is laid within a stone road, provide support and a stable platform from which the machinery can excavate the trench. It also reduces erosion and compaction. Removal of vegetation (which stabilises the underlying peat) should be minimised (i.e. pipe trench only). Consideration should be given to removal of turfs and laying temporary roads over existing vegetation (timely removal of the road is vital for successful reinstatement). Turfs must be watered if they are being stored for considerable periods to avoid shrinkage, turfs should not be stacked so as to avoid compaction and destruction of the seed bank. Reinstate subsoil layers in original order when backfilling. Minimise amount of material imported into the peat bog during backfilling or reinstatement. Turfs should not be stored above a maximum height away from flooding areas and should have gaps in between them to allow the free flow of water.

Bog mats (a series of connected wide sleepers, sourced from sustainable hardwoods) can be used on soft ground e.g. areas of peat/tree roots. Keep vehicle movement to a minimum and use low pressure ground vehicles where possible. Fencing can be put in place to prevent encroachment and damage to bog outside working width. Ensure an adequate number and suitable locations of access points and maintain the right of way access roads (including the road along the ROW). Trench plugs that prevent erosion can be installed along certain intervals of the trench, that allow the free flow of people/traffic and the exit of wildlife should it become trapped. The slope should be graded to avoid soil slip/creep and maximise the use of existing planting to aid slope stabilisation. Ensure an adequate compaction of backfill material during trench infilling. Install in-trench drainage on slopes.

Potential for pipeline to function as a field drain and alter bog ecology.

Use of the â&#x20AC;&#x2DC;stone roadâ&#x20AC;&#x2122; method.

Removal and replacement of vegetation.

Turfs stored in a flood plain have the potential to re-direct or block water flow during a flood event.

Turfs can become compacted through machinery tracking.

There is the potential for erosion within the trench and on the slope.

Drainage

Erosion

Reinstatement

Turfs stored in flood plain

Compaction

Side Slope

Erosion/Soil creep

Peat Area

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Water may build up in the trench in heavy rainfall events.

Trenching may affect previously unknown ground water locations.

Drainage

Effect on ground water sites

Forested Areas

A reduced working width to minimise damage to surrounding trees/roots will be required. Machinery must be compact enough to work within reduced spaces without being unsafe. A general rule of thumb is that the roots extend to the edge of the canopy. Where roots are cut there should be equivalent crown reduction to prevent water stress and long term damage. Consider additional space requirements for deep trenches or crossings where additional excavated material may need to be stored. Contractors should ensure that they adhere to method statements outlined as part of the EIA regarding work within designated areas. Disposal of wood arising from vegetation clearance should be in accordance with land agreements. Canopy bridges to be considered in forestry areas where animal communities may not be able to access feeding areas.

Woodland topsoil to be stored and replaced following construction in accordance with agreements and environmental requirements. Careful routing to avoid opening up permanent access routes through forests and minimise long term visual effects.

Reduced working Working width is reduced to minimise impact on width any trees, roots or overhang.

Construction activities have the potential to disturb nesting or breeding wildlife at certain times of the year or impact of areas of ecological importance.

Access for pipeline operations and inspection often require easement to remain free of trees.

Protected species/ woodland restrictions/ requirements

Reinstatement

Swampy Areas

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Tundra

Seasonal restrictions to Working in permafrost zones working.

Reinstatement

Reinstatement to original contours may not be possible.

Thorough borehole investigation of pipeline route and a full assessment of the depth and extent of permafrost pior to construction to determine the most effective construction period, construction and reinstatement methods. Modelling of permafrost effect on pipeline route and pipeline route on permafrost areas (e.g. increased thaw as a result of heat generated from pipeline). Consider chilling of oil/gas to minimise thaw. Carefully consider the location of pump and compressor stations as they can alter the temperature of the oil/gas being transported. Reinstate subsoil layers in original order when backfilling, especially in wetland areas. Ensure sufficient trench padding around pipe and consider the use of pipe supports within the trench (i.e. sandbags). Insulate areas/slopes that are unstable if thawed quickly with woodchips or other suitable materials. Install geotechnical monitoring at locations that become unstable when thawed. Install monitoring for pipeline movement (i.e. heave). Consider weighting pipe in permafrost areas where land heave may occur.

Reinstate as close as practicable to original contours. Consider recontouring adjacent land on the ROW to minimise visual impact. Install adequate drainage on cut side slopes to minimise erosion due to run-off and surface water.

Provision for storage and replacement of excavated material needs to be carefully planned, side casting can have large-scale visual effects.

Reduced working Narrow ridges require reduced working width width and lack of space for effective storage of excavated material.

Ridge

Restrictions to access to be implemented to prevent unauthorised logging, hunting, diseases etc being introduced to remote locations.

Opening up cleared routes through forests creates access.

Access

Forested Areas

Mitigation

Justification

Environmental Considerations

Conditions of Excavation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.3

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Appendix 6.4

Appendix 6.4 Health and Safety Control Measures

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Soft Soil Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions e.g. very hot or cold

Appropriate rest shelters to be in place with appropriate cooling/heating facilities. Regular access to liquids and food as appropriate – warm

temperatures, high winds etc, and protection from the elements is limited.

water recommended in extreme cold and non-iced water in high temperatures. Restricted areas or access identified if the soil becomes

Soil becoming unstable if very wet or dry and people/equipment being in direct contact with this.

unstable, keep unnecessary personnel away from leading edges or trench and backfilling/soil stockpiles. Lifting operations should cease

Cranes lifting during high winds.

when the gusting or wind strength reaches 20mph or when the operator feels that it is too dangerous to continue.

Extremes of temperature and the effect that it will have on personnel in the work area.

Appropriate rest shelters to be in place with appropriate cooling/heating facilities. Regular access to liquids and food as appropriate – warm

Additionally the effect that it may have on the soil structure and stockpiling and the likelihood of the

water recommended in extreme cold and non-iced water in high temperatures. Restricted areas or access identified if the soil becomes

soil becoming unstable.

unstable, keep unnecessary personnel away from leading edges or trench and backfilling/soil stockpiles.

Unstable conditions if very dry or very wet, which would apply equally to people in the work area,

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

crawler cranes, pipe delivery trucks, particularly if working at the trench edges/surfaces. The

backfilling/soil stockpiles. Appropriate ground support to be put in place for crawler cranes and trucks to safely access and egress the work

access/egress routes to the specific work area also need to be considered if the track is

area, especially when carrying loads. Cranes to use outriggers during all lifting operations. Ground to be assessed by a competent person

unsupported and likely to move.

prior to equipment/machines accessing area and being used for lifting heavy loads. Personnel to be provided with clear access and egress

Potential for the trench walls to become dislodged or erode.

routes to their work areas to avoid any soil slippage areas. Appropriate compaction of trench walls or shuttering to be put in place to

Ambient temperature

Ground conditions

prevent collapse of walls onto people in the area. Confined space

The trench itself may be identified as a confined space, especially if personnel are required to work

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

within or near to the trench.

the restricted area through use of fencing/barriers. Have appropriate emergency response plan in place and trained first aiders available. Appropriate rescue equipment should also be located near to the work area.

Heavy load

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment. Only trained

for the skids to collapse or move unexpectedly, with personnel and other equipment in the area.

and competent personnel to operate equipment and to be allowed access to work area.

Contact between the pipe-handling equipment, the pipe and personnel and other

Slinger/signaller to be in place and to co-ordinate and control all lifts. Ensure the ground at the leading edge of the trench is sufficiently

vehicles/machines in the area may be made if uncontrolled. Top soil and backfilling material which

compacted to withstand additional weight. Never lift loads over anyone’s head or other equipment/vehicles in the area. Ensure that

is stockpiled on either side of the trench and work area must be controlled due to potential contact

stockpiles of backfill materials and top soil are appropriate in size e.g. have a wide enough base and not be so high that it would promote

with machines, personnel, equipment and wildlife.

unnecessary slippage of soil – ensure that personnel are prevented from climbing up stockpiled materials or walking/working too close to the base.

Illumination

Lifting

Poor illumination from dawn, dusk and night-time activities may impact on operational

Ensure that adequate lighting is put in place if working in hours or dusk or darkness – use of generators and tower lights as appropriate.

requirements; includes potential impact between equipment/machines, contact with personnel,

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them. Remove any

machine operators not able to see signallers’/slingers’ instructions.

excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc.

Includes all lifting activities from trenching machines removing excess soil, pipe movement from

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

flatbed to skids to trench, crane and other machine operations.

available. Daily visual inspection to be completed by operator (including reporting any defects). Appropriate maintenance programme to be

The infilling process of the trench with backfill and topsoil and the interface between people,

in place and used. Only use certified lifting equipment and tackle. Skids to be in place and constructed/positioned by trained and

materials and equipment.

competent personnel prior to lifting. Taglines to be used on pipe ends, particularly when windy. All lifting activities to be co-ordinated by slinger/signaller. Appropriate communications system to be in place between slinger/signaller, machine operators and any other relevant personnel. Only lift with equipment that has an appropriate lifting capacity for the load – the SWL should be identified on the equipment.

Noise

Generated from the machines and equipment on site. If personnel are working close to equipment

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

their hearing may be affected as a result. Additionally any machine/vehicle operator may be

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

impacted depending on the cab’s soundproofing.

requirements or best practice. Silencers to be installed on equipment where possible e.g. compressors/generators etc. All equipment to be inspected and regularly maintained to ensure excessive noise is not generated.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Soft Soil Hazard

Hazard description

Control measures

Pipe movement

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

the trench. See lifting and heavy load details. Additionally personnel will be working in and around

Slingers/signallers to co-ordinate any lifting activities. Open communications between each group of personnel in the work area through

the pipe joint when positioning is taking place within the trench area, becoming susceptible to

appropriate means (radio with separate channel).

being trapped or struck by the pipe joint.

Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil etc. Pre-determined access/egress routes and appropriate communications on the details to all personnel.

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or

Any soil at the top or edges of the trench shall be compacted and free from loose areas/materials.

leading edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

Appropriate access/egress shall be made to machine/crane cabs. Soles of boots should be free from muck or be scraped prior to climbing access ladders. Avoid standing on pipeline or pipe being moved as its surface may be slippery and the pipe may shift unexpectedly. Use appropriate ladders/man basket to access/egress pipeline as necessary. Personnel not to be positioned inside trench when there are activities at the surface of the trench. Fall arrest equipment to be used when deemed necessary by risk assessment and only to be used by trained, competent personnel.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

generators, compressors etc.: all must be considered for any potential defects such as oil leaks,

defects should be reported.

damaged cables, missing guards and contact with moving parts; be appropriate for the job/task

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

and be used correctly.

available. Only certified lifting tackle to be used and to be inspected daily by operators, and periodically by third-party inspectors. Appropriate preventive maintenance programme to be in place and records kept. Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to prevent contact with chemicals. Only trained and competent personnel to operate any equipment whether machines, cranes, grinders etc. Only approved parts to be used when replacing items and to be fitted by trained, competent personnel.

Hazardous materials â&#x20AC;&#x201C; personal

Contact with diesel through refuelling process, hydraulic and pneumatic oils from refilling or leaks,

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

exposure

contact with any degreasers or cleaners used during the operations.

prevent contact with chemicals.

Exposure to dust when infilling the trench.

Refuelling to be done via diesel bowser or approved fuel containers. Only trained, competent personnel to dispense/refuel machines and equipment. Appropriate waste receptacles to be available for contaminated PPE or rags. Chemicals to be used with drip tray/spill mat in case of spillage. If very dry and excessive dust on roads, dust suppression to be in place e.g. water bowser. RPE to be used if necessary.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain

assistance.

available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls â&#x20AC;&#x201C; procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location â&#x20AC;&#x201C; procedure to be in place and tested.

Impact with local community/area

See noise above. Restricted access/egress points or safe walk routes etc. to be identified. Consider agricultural works in area and how pollution and contamination can affect the local businesses.

Wildlife

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Sand Dune Area Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions e.g. very hot/cold

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

temperatures, high winds etc. and protection from the elements is limited.

Regular access to liquids and food as appropriate – warm water recommended in cold and non-iced water in high temperatures. Restricted

Sand becoming unstable if very dry and people/equipment being in direct contact with this.

areas or access identified. Lifting operations should cease when the gusting or wind strength reaches 20mph or when the operator feels that

Cranes lifting during high winds.

it is too dangerous to continue. Suitable PPE to be made available for the weather type to protect the employee from the elements e.g. sun umbrellas etc.

Ambient temperature

Extremes of temperature and the effect that it will have on personnel in work area.

Appropriate rest shelters to be in place with appropriate cooling/heating facilities. Regular access to liquids and food as appropriate – warm

Additionally the effect that it may have on the sand structure and stockpiling and the likelihood of

water recommended in cold and non-iced water in high temperatures.

the sand becoming unstable and shifting.

Restricted areas or access identified if the sand is likely to be unstable, keep unnecessary personnel away from leading edges or trench and backfilling/sand dunes.

Ground conditions

Unstable conditions if very dry or very wet, which would apply equally to people in the work area,

Restrict areas or access if the sand becomes unstable, keep unnecessary personnel away from leading edges or trench and backfilling/sand

crawler cranes, pipe delivery trucks, particularly if working at the trench edges/surfaces.

stockpiles. Appropriate ground support to be put in place for crawler cranes and trucks to safely access and egress the work area,

The access/egress routes to the specific work area also need to be considered if the track is

especially when carrying loads. Cranes to use outriggers with appropriate ground support underneath during all lifting operations. Ground to

unsupported and likely to move.

be assessed by a competent person prior to equipment/machines accessing area and being used for lifting heavy loads, and appropriate ground coverings to be put in place prior to accessing area. Personnel to be provided with clear access and egress routes to their work areas to avoid any sand slippage areas or areas of potential encasement.

Confined space

The trench itself may be identified as a confined space, especially if personnel are required to work

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

within or near to the trench.

the restricted area through use of fencing/barriers. Use appropriate CSE equipment as deemed necessary. Have appropriate emergency response plan in place and trained first aiders available. Appropriate rescue equipment should also be located near to the work area.

Heavy load

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment. Only trained

for the skids to collapse or move unexpectedly, with personnel and other equipment in the area.

and competent personnel to operate equipment and to be allowed access to work area.

Contact between the pipe-handling equipment, the pipe and personnel and other

Slinger/signaller to be in place and to co-ordinate and control all lifts. Ensure the ground at the leading edge of the trench is sufficiently

vehicles/machines in the area may result if uncontrolled.

supported to withstand additional weight. Never lift loads over anyone’s head or other equipment/vehicles in the area. Have a “ready to lift”

Sand and backfilling material which is stockpiled on either side of the trench and work area must

warning siren or similar in place. Ensure that stockpiles of backfill materials and sand are appropriate in size e.g. have a wide enough base

be controlled due to potential contact with machines, personnel, equipment and wildlife.

and not be so high that it would promote unnecessary slippage of sand – ensure that personnel are prevented from climbing up stockpiled materials or walking/working too close to the base. Cover if appropriate. Also see “confined space” above.

Illumination

Poor illumination from dawn, dusk and night-time activities may impact on operational

Ensure that adequate lighting is put in place if working in hours or dusk or darkness – use of generators and tower lights as appropriate.

requirements; includes potential impact between equipment/machines, contact with personnel,

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them. Ensure that

machine operators not able to see signallers’/slingers’ instructions.

appropriate eye protection is worn in the event of excessive natural light to prevent being dazzled and burning to the eye. Remove any

Not being able to see due to the brightness of natural light.

excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc.

Lifting

Includes all lifting activities from trenching machines removing excess sand, pipe movement from

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

flatbed to skids to trench, crane and other machine operations.

available. Daily visual inspection to be completed by operator (including reporting any defects). Appropriate maintenance programme to be in

The infilling process of the trench with backfill and sand and the interface between people,

place and used. Only use certified lifting equipment and tackle. Skids to be in place and constructed/positioned by trained and competent

materials and equipment.

personnel prior to lifting. Taglines to be used on pipe ends, particularly when windy. All lifting activities to be co-ordinated by slinger/signaller. Appropriate communications system to be in place between slinger/signaller, machine operators and any other relevant personnel. Only lift with equipment that has an appropriate lifting capacity for the load – the SWL should be identified on the equipment. Always use appropriate lifting tackle for the task.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Sand Dune Area Hazard

Hazard description

Control measures

Noise

Generated from the machines and equipment on site. If personnel are working close to equipment

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

their hearing may be affected as a result causing tinitus. Additionally any machine/vehicle operator

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

may be impacted depending on the cab’s soundproofing.

Pipe movement

Working at height

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

the trench. See lifting and heavy load details. Additionally personnel will be working in and around

Slingers/signallers to co-ordinate any lifting activities. Open communications between each group of personnel in the work area through

the pipe joint when positioning is taking place within the trench area, becoming susceptible to

appropriate means (e.g. radio with separate channel). Suitable and stable grounding to position pipe in new location e.g. skids, sand with

being trapped or struck by the pipe joint.

appropriate ground supports etc. Pre-determined access/egress routes and appropriate communications on the details to all personnel.

Any drop from or to a different level may potentially cause harm e.g. working at the surface or

Any sand at the top or edges of the trench shall be cordoned and appropriate shuttering installed, and be free from loose areas/materials.

leading edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

generators, compressors etc.: all must be considered for any potential defects such as oil leaks,

defects should be reported. All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right

damaged cables, missing guards and contact with moving parts; be appropriate for the job/task

certification in place and available. Only certified lifting tackle to be used and to be inspected daily by operators, and periodically by third-

and be used correctly.

party inspectors. Appropriate preventive maintenance programme to be in place and records kept. Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to prevent contact with chemicals.. Only trained and competent personnel to operate any equipment whether machines, cranes, grinders etc. Only approved parts to be used when replacing items and to be fitted by trained, competent personnel.

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from refilling or leaks,

Spill kits to be available on site in case of spillage, including any required additional PPE (safety glasses or goggles) and RPE e.g. impervious

personal exposure

contact with any degreasers or cleaners used during the operations.

gloves and suits etc. to prevent contact with chemicals. Refuelling to be done via diesel bowser or approved fuel containers. Only trained,

Exposure to sand being blown, potential for eye damage.

competent personnel to dispense/refuel machines and equipment. Appropriate waste receptacles to be available for contaminated PPE or rags. Chemicals to be used with drip tray/spill mat in case of spillage. If very dry and excessive dust on roads, dust suppression to be in place e.g. water bowser. RPE to be used if necessary.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain

assistance.

available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location/country – procedure to be in place and tested.

Wildlife

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Peat Area Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions e.g. high winds,

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

heavy rain etc. and protection from the elements is limited.

Regular access to liquids and food as appropriate – warm water recommended in extreme cold and non-iced water in high temperatures.

Soil becoming unstable if very wet and people/equipment being in direct contact with this.

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

Cranes lifting during high winds.

backfilling/soil stockpiles.

Trenches being waterlogged and machine/personnel access to this.

Lifting operations should cease when the gusting or wind strength reaches 20mph or when the operator feels that it is too dangerous to continue. Trenches to be drained of excess water. Earth to have appropriate erosion protection in place to prevent unplanned movement of trench walls.

Ground conditions

Unstable conditions if very dry or very wet, which would apply equally to people in the work area,

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

crawler cranes, pipe delivery trucks, particularly if working at the trench edges/surfaces.

backfilling/soil stockpiles.

The access/egress routes to the specific work area also need to be considered if the track is

Appropriate ground support to be put in place for crawler cranes and trucks to safely access and egress the work area, especially when

unsupported and likely to move.

carrying loads. Cranes to use outriggers during all lifting operations. Ground to be assessed by a competent person prior to equipment/machines accessing area and being used for lifting heavy loads. Personnel to be provided with clear access and egress routes to their work areas to avoid any soil slippage areas.

Confined space

The trench itself may be identified as a confined space, especially if personnel are required to work

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

within or near to the trench.

Heavy load

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment.

for the skids to collapse or move unexpectedly, with personnel and other equipment in the area.

Only trained and competent personnel to operate equipment and to be allowed access to work area.

Contact between the pipe-handling equipment, the pipe and personnel and other

Slinger/signaller to be in place and to co-ordinate and control all lifts.

vehicles/machines in the area may be made if uncontrolled.

Ensure the ground at the leading edge of the trench is sufficiently compacted to withstand additional weight.

Peat/turf stacks may be stacked too high, increasing the likelihood of the stack falling, thus coming

Bog mats to be used for access/egress to the work area by all vehicles to improve stability of vehicles/machines and to help prevent tipping.

into contact with personnel and/or equipment.

Never lift loads over anyone’s head or other equipment/vehicles in the area.

work area must be controlled due to potential contact with machines, personnel, equipment and

Ensure that stockpiles of backfill materials and top soil are appropriate in size e.g. have a wide enough base and not be so high that it would

wildlife.

promote unnecessary slippage of soil – ensure that personnel are prevented from climbing up stockpiled materials or walking/working too close to the base.

Illumination

Poor illumination from dawn, dusk and night-time activities may impact on operational

Ensure that adequate lighting is put in place if working in hours or dust or darkness – use of generators and tower lights as appropriate.

requirements; includes potential impact between equipment/machines, contact with personnel,

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them.

machine operators not able to see signallers’/slingers’ instructions.

Remove any excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc. Ensure that any excessively boggy areas are marked appropriately to avoid contact in dull or dark conditions.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Peat Area Hazard

Hazard description

Control measures

Lifting

Includes all lifting activities from trenching machines removing excess turfs, pipe movement from

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

flatbed to skids to trench, crane and other machine operations.

available.

The infilling process of the trench with peat turfs and the interface between people, materials and

Daily visual inspection to be completed by operator (including reporting any defects).

equipment.

Appropriate maintenance programme to be in place and used.

Additionally the potential for the machines/cranes to become unbalanced, and their loads

Only use certified lifting equipment and tackle.

dislodging due to soft ground conditions.

Skids to be in place and constructed/positioned by trained and competent personnel prior to lifting. Taglines to be used on pipe ends, particularly when windy. All lifting activities to be co-ordinated by slinger/signaller. Appropriate communications system to be in place between slinger/signaller, machine operators, and any other relevant personnel. Only lift with equipment that has an appropriate lifting capacity for the load – the SWL should be identified on the equipment. “stone road” or other suitable platform to be in place to provide suitable ground support for machines/vehicles.

Noise

Generated from the machines and equipment on site. If personnel are working close to equipment

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

their hearing may be affected as a result. Additionally any machine/vehicle operator may be

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

impacted depending on the cab’s soundproofing.

Pipe movement

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

the trench. See lifting and heavy load details. Additionally personnel will be working in and around

Slingers/signallers to co-ordinate any lifting activities.

the pipe joint when positioning is taking place within the trench area, becoming susceptible to

Open communications between each group of personnel in the work area through appropriate means (radio with separate channel).

being trapped or struck by the pipe joint.

Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil etc.

Mud on road affecting trucks delivering pipe – may slide/slip if excess mud on road surface.

Pre-determined access/egress routes and appropriate communications on the details to all personnel. Put in place appropriate wheel wash stations for all vehicles to use prior to accessing public roads.

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or

The edges of the trench shall be free from loose areas/materials and appropriate “stone road” or similar be in place to aid stability and

leading edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

prevent unnecessary erosion. Appropriate access/egress shall be made to machine/crane cabs. Soles of boots should be free from muck or be scraped prior to climbing access ladders. Avoid standing on pipeline or pipe being moved as its surface may be slippery and the pipe may shift unexpectedly. Use appropriate ladders/man basket to access/egress pipeline as necessary. Personnel not to be positioned inside trench when there are activities at the surface of the trench. Fall arrest equipment to be used when deemed necessary by risk assessment and only to be used by trained, competent personnel.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

generators, compressors etc.: all must be considered for any potential defects such as oil leaks,

defects should be reported.

damaged cables, missing guards and contact with moving parts; be appropriate for the job/task

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

and be used correctly.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Peat Area Hazard

Hazard description

Control measures

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from refilling or leaks,

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

contact with any degreasers or cleaners used during the operations.

prevent contact with chemicals. Refuelling to be done via diesel bowser or approved fuel containers. Only trained, competent personnel to dispense/refuel machines and equipment. Appropriate waste receptacles to be available for contaminated PPE or rags. Chemicals to be used with drip tray/spill mat in case of spillage.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain

assistance.

available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location – procedure to be in place and tested.

Impact with local community/area

See noise above.

Unauthorised access to working area by local community.

Restricted access/egress points or safe walk routes etc. to be identified.

Potential pollution and contamination of agricultural crops which may enter the food chain.

Consider agricultural works in area and how pollution and contamination can affect the local businesses.

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions e.g. dry, high winds

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

or excessive rain etc. and protection from the elements is limited.

Regular access to liquids and food as appropriate – warm water recommended in extreme cold and non-iced water in high temperatures.

Soil becoming unstable if very wet or very dry and people/equipment being in direct contact with

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

this. May cause landslides.

backfilling/soil stockpiles.

Cranes lifting during high winds.

Lifting operations should cease when the gusting or wind strength reaches 20mph or when the operator feels that it is too dangerous to

Wildlife

Side Slope

continue. Ambient temperature

Extremes of temperature and the effect that it will have on personnel in the work area.

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

Additionally the effect that it may have on the soil structure and stockpiling and the likelihood of the

Regular access to liquids and food as appropriate – warm water recommended in extreme cold and non-iced water in high temperatures.

soil becoming unstable.

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and backfilling/soil stockpiles.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Side Slope Hazard

Hazard description

Control measures

Ground conditions

Unstable conditions if very dry or very wet, which would apply equally to people in the work area,

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

crawler cranes, pipe delivery trucks, particularly if working at the trench edges/surfaces.

backfilling/soil stockpiles.

The access/egress routes to the specific work area also need to be considered if the track is

Appropriate ground support (bog mats) to be put in place for crawler cranes and trucks to safely access and egress the work area,

unsupported and likely to move.

especially when carrying loads. Cranes to use outriggers during all lifting operations.

Dust likely to be generated in dry conditions causing slip hazards for machines and potential damage

Ground to be assessed by a competent person prior to equipment/machines accessing area and being used for lifting heavy loads.

to health

Personnel to be provided with clear access and egress routes to their work areas to avoid any soil slippage areas.

There may also be the remnants of tree roots etc. which could be a trip hazard to personnel or a

Appropriate use of PPE/RPE (respirators, goggles/glasses).

collision point for vehicles/machines.

All tree roots above the surface should be clearly identified through hazard tape/barriers etc. or removed where possible.

The trench itself may be identified as a confined space, especially if personnel are required to work

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

within or near to the trench.

the restricted area through use of fencing/barriers.

Confined space

Have appropriate emergency response plan in place and trained first aiders available. Appropriate rescue equipment should also be located near to the work area. Heavy load

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment.

for the skids to collapse or move unexpectedly, with personnel and other equipment in the area.

Only trained and competent personnel to operate equipment and to be allowed access to work area.

Contact between the pipe-handling equipment, the pipe and personnel and other vehicles/machines

Slinger/signaller to be in place and to co-ordinate and control all lifts.

in the area may be made if uncontrolled.

Ensure the ground at the leading edge of the trench is sufficiently compacted to withstand additional weight.

Top soil and backfilling material which is stockpiled must be controlled due to potential contact with

Never lift loads over anyone’s head or other equipment/vehicles in the area.

machines, personnel, equipment and wildlife, it may slip from its stored position.

Ensure that stockpiles of backfill materials and top soil are appropriate in size e.g. have a wide enough base and not be so high that it would promote unnecessary slippage of soil – ensure that personnel are prevented from climbing up stockpiled materials or walking/working too close to the base.

Illumination

Poor illumination from dawn, dusk and night-time activities may impact on operational requirements;

Ensure that adequate lighting is put in place if working in hours or dust or darkness – use of generators and tower lights as appropriate.

includes potential impact between equipment/machines, contact with personnel, machine operators

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them.

not able to see signallers’/slingers’ instructions.

Remove any excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc.

Lifting

Includes all lifting activities from trenching machines removing excess soil, pipe movement from

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

flatbed to skids to trench, crane and other machine operations.

available.

The infilling process of the trench with backfill and topsoil and the interface between people,

Daily visual inspection to be completed by operator (including reporting any defects).

materials and equipment.

Appropriate maintenance programme to be in place and used. Only use certified lifting equipment and tackle. Skids to be in place and constructed/positioned by trained and competent personnel prior to lifting. Taglines to be used on pipe ends, particularly when windy. All lifting activities to be co-ordinated by slinger/signaller. Appropriate communications system to be in place between slinger/signaller, machine operators and any other relevant personnel. Only lift with equipment that has an appropriate lifting capacity for the load – the SWL should be identified on the equipment.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Side Slope Hazard

Hazard description

Control measures

Noise

Generated from the machines and equipment on site. If personnel are working close to equipment

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

their hearing may be affected as a result. Additionally any machine/vehicle operator may be

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

impacted depending on the cab’s soundproofing.

Pipe movement

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

the trench. See lifting and heavy load details. Additionally personnel will be working in and around

Slingers/signallers to co-ordinate any lifting activities.

the pipe joint when positioning is taking place within the trench area, becoming susceptible to

Open communications between each group of personnel in the work area through appropriate means (radio with separate channel).

being trapped or struck by the pipe joint.

Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil etc. Pre-determined access/egress routes and appropriate communications on the details to all personnel.

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or

Any soil at the top or edges of the trench shall be compacted and free from loose areas/materials.

leading edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

Appropriate access/egress shall be made to machine/crane cabs.

This will also include personnel working towards the top of the work area and the potential for

Soles of boots should be free from muck or be scraped prior to climbing access ladders.

slipping/sliding to lower level.

Avoid standing on pipeline or pipe being moved as its surface may be slippery and the pipe may shift unexpectedly. Use appropriate ladders/man basket to access/egress pipeline as necessary. Personnel not to be positioned inside trench when there are activities at the surface of the trench. Fall arrest equipment to be used when deemed necessary by risk assessment and only to be used by trained, competent personnel.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

generators, compressors etc.: all must be considered for any potential defects such as oil leaks,

defects should be reported.

damaged cables, missing guards and contact with moving parts; be appropriate for the job/task

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

and be used correctly.

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from refilling or leaks,

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

contact with any degreasers or cleaners used during the operations.

prevent contact with chemicals.

Exposure to dust when infilling the trench.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain

assistance.

available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location – procedure to be in place and tested.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Side Slope Hazard

Hazard description

Control measures

Impact with local community/area

See noise on previous table.

Unauthorised access to working area by local community.

Restricted access/egress points or safe walk routes etc. to be identified.

Potential pollution and contamination of agricultural crops which may enter the food chain.

Consider agricultural works in area and how pollution and contamination can affect the local businesses.

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

e.g. very hot or cold temperatures, high winds, humidity etc. and protection from the elements is

Regular access to liquids and food as appropriate â&#x20AC;&#x201C; warm water recommended in extreme cold and non-iced water in high temperatures.

limited. Land becoming unstable if very wet/flooded and people/equipment being in direct contact with

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

this.

backfilling/soil stockpiles.

Cranes lifting during high winds.

Lifting operations should cease when the gusting or wind strength reaches 20mph or when the operator feels that it is too dangerous to

Wildlife

Swampy Area

continue. Ambient temperature

Extremes of temperature and the effect that it will have on personnel in the work area.

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

Additionally the effect that it may have on the soil structure and stockpiling and the likelihood of the soil

Regular access to liquids and food as appropriate â&#x20AC;&#x201C; warm water recommended in extreme cold and non-iced water in high temperatures.

becoming unstable.

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

Higher risk of biting, disease-ridden insects.

backfilling/soil stockpiles. Appropriate insect-based information, instruction and training to be given on appropriate behaviour, repellent, clothing colour, vaccinations, treatment etc.

Ground conditions

Unstable conditions if very wet, which would apply equally to people in the work area, crawler cranes,

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

pipe delivery trucks, particularly if working at the trench edges/surfaces.

backfilling/soil stockpiles.

The access/egress routes to the specific work area also need to be considered if the track is

Appropriate ground support (bog mats) to be put in place for crawler cranes and trucks to safely access and egress the work area,

unsupported and likely to move/equipment able to sink.

especially when carrying loads. Cranes to use outriggers during all lifting operations.

Excess water build-up in trench area causing access concerns and emergency concerns should

Ground to be assessed by a competent person prior to equipment/machines accessing area and being used for lifting heavy loads.

anyone fall in.

Personnel to be provided with clear access and egress routes to their work areas to avoid any soil slippage areas. Suitable drainage system/water removal system to be put in place to remove or control excess water within trench area. Personnel may benefit from wearing life vests if working in close contact with deep or fast-running water.

Confined space

The trench itself may be identified as a confined space, especially if personnel are required to work

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

within or near to the trench.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Swampy Area Hazard

Hazard description

Control measures

Heavy load

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment.

for the skids to collapse or move unexpectedly, with personnel and other equipment in the area.

Only trained and competent personnel to operate equipment and to be allowed access to work area.

Contact between the pipe-handling equipment, the pipe and personnel and other

Slinger/signaller to be in place and to co-ordinate and control all lifts.

vehicles/machines in the area may be made if uncontrolled.

Ensure the ground at the leading edge of the trench is sufficiently compacted to withstand additional weight.

Top soil and backfilling material which is stockpiled on either side of the trench and work area must

Never lift loads over anyone’s head or other equipment/vehicles in the area.

be controlled due to potential contact with machines, personnel, equipment and wildlife.

Ensure that stockpiles of backfill materials and top soil are appropriate in size e.g. have a wide enough base and not be so high that it would

Large capacity of water being removed from the trench is also a heavy load which may impact or

promote unnecessary slippage of soil/materials – ensure that personnel are prevented from climbing up stockpiled materials or

affect personnel in work area or area of discharge.

walking/working too close to the base. Ensure that personnel are kept away from excess water levels through barriers and acceptable process of waste water removal and storage.

Illumination

Poor illumination from dawn, dusk and night-time activities may impact on operational

Ensure that adequate lighting is put in place if working in hours or dust or darkness – use of generators and tower lights as appropriate.

requirements; includes potential impact between equipment/machines, contact with personnel,

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them.

machine operators not able to see signallers’/slingers’ instructions.

Remove any excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc.

Lifting

Includes all lifting activities from trenching machines removing excess soil, pipe movement from

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

flatbed to skids to trench, crane and other machine operations.

available.

The infilling process of the trench with materials and the interface between people, materials and

Daily visual inspection to be completed by operator (including reporting any defects).

equipment.

Noise

Generated from the machines and equipment on site. If personnel are working close to equipment

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

their hearing may be affected as a result. Additionally any machine/vehicle operator may be

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

impacted depending on the cab’s soundproofing.

Pipe movement

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

the trench. See lifting and heavy load details. Additionally personnel will be working in and around

Slingers/signallers to co-ordinate any lifting activities.

the pipe joint when positioning is taking place within the trench area, becoming susceptible to

Open communications between each group of personnel in the work area through appropriate means (radio with separate channel).

being trapped or struck by the pipe joint.

Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil etc. Pre-determined access/egress routes and appropriate communications on the details to all personnel.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Swampy Area Hazard

Hazard description

Control measures

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or leading

Any soil at the top or edges of the trench shall be compacted and free from loose areas/materials.

edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders, generators,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

compressors etc.: all must be considered for any potential

defects should be reported.

defects such as oil leaks, damaged cables, missing guards and contact with moving parts; be

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

appropriate for the job/task and be used correctly.

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

refilling or leaks, contact with any degreasers or cleaners used during the operations.

prevent contact with chemicals.

Exposure to dust when infilling the trench.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical assistance.

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up to date – particular attention should be paid to waterborne diseases, insect bites and water based injuries e.g. drowning. Repatriation of IP to suitable location – procedure to be in place and tested.

Impact with local community/area

Wildlife

See noise above.

Unauthorised access to working area by local community.

Restricted access/egress points or safe walk routes etc. to be identified.

Potential pollution and contamination of agricultural crops which may enter the food chain.

Consider agricultural works in area and how pollution and contamination can affect the local businesses.

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Forested Area Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

e.g. high winds etc. and protection from the elements is limited.

Regular access to liquids and food as appropriate – warm water recommended in extreme cold and non-iced water in high temperatures.

Cranes lifting during high winds.

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and backfilling/soil stockpiles, damaged trees. Lifting operations should cease when the gusting or wind strength reaches 20mph or when the operator feels that it is too dangerous to continue.

Ground conditions

Unstable conditions if very dry, very wet, and potentially not be free from obstruction

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

e.g. tree roots which would apply equally to people in the work area, crawler

backfilling/soil stockpiles.

cranes, pipe delivery trucks, particularly if working at the trench edges/surfaces.

Removal of any surplus tree roots which will not further damage the forest area.

The access/egress routes to the specific work area also need to be considered if the track is

Appropriate ground support to be put in place for crawler cranes and trucks to safely access and egress the work area, especially when

unsupported and likely to move.

carrying loads. Cranes to use outriggers during all lifting operations.

Excess mud being transferred to the public highway and causing slip hazards for

Ground to be assessed by a competent person prior to equipment/machines accessing area and being used for lifting heavy loads.

work vehicles and general public.

Personnel to be provided with clear access and egress routes to their work areas to avoid any soil slippage areas. Suitable wheel wash station to be put in place to remove any excess mud/materials from wheels or area or appropriate diversion to be put in place.

Confined space

The trench itself may be identified as a confined space, especially if personnel are required to work within

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

or near to the trench.

the restricted area through use of fencing/barriers.

Also relates to the available work area being restricted in order to limit the impact on the forest.

Have appropriate emergency response plan in place and trained first aiders available. Appropriate rescue equipment should also be located near to the work area. Machines to be of an appropriate size (compact) so as not to cause further or unnecessary damage to the forest or adversely impact personnel sharing the work area.

Heavy load

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential for

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment.

the skids to collapse or move unexpectedly, with personnel and other equipment in the area. Contact

Only trained and competent personnel to operate equipment and to be allowed access to work area.

between the pipe-handling equipment, the pipe and personnel and other vehicles/machines in the area

Slinger/signaller to be in place and to co-ordinate and control all lifts.

may be made if uncontrolled.

Ensure the ground at the leading edge of the trench is sufficiently compacted to withstand additional weight.

Top soil and backfilling material which is stockpiled on either side of the trench and work area must be

Never lift loads over anyone’s head or other equipment/vehicles in the area.

controlled due to potential contact with machines, personnel,

Ensure that stockpiles of backfill materials and top soil are appropriate in size e.g. have a wide enough base and not be so high that it would

equipment and wildlife.

promote unnecessary slippage of soil – ensure that personnel are prevented from climbing up stockpiled materials or walking/working too

Potential of trees to fall if dislodged during work activities or weakened coming into contact with people,

close to the base.

plant, equipment etc.

All trees in the surrounding work area to be monitored and checked to ensure they are of strong standing and rule out the likelihood of falling unexpectedly.

Illumination

Poor illumination from dawn, dusk and night-time activities may impact on operational requirements;

Ensure that adequate lighting is put in place if working in hours or dust or darkness – use of generators and tower lights as appropriate.

includes potential impact between equipment/machines, contact with personnel, machine operators not

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them.

able to see signallers’/slingers’ instructions.

Remove any excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Forested Area Hazard

Hazard description

Control measures

Lifting

Includes all lifting activities from trenching machines removing excess soil, pipe movement from flatbed

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

to skids to trench, crane and other machine operations.

available.

The infilling process of the trench with backfill and topsoil and the interface between people, materials

Daily visual inspection to be completed by operator (including reporting any defects).

and equipment.

Noise

Generated from the machines and equipment on site. If personnel are working

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

close to equipment their hearing may be affected as a result. Additionally any machine/vehicle operator

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

may be impacted depending on the cabâ&#x20AC;&#x2122;s soundproofing.

Pipe movement

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within the

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

trench. See lifting and heavy load details. Additionally personnel will be working in and around the pipe

Slingers/signallers to co-ordinate any lifting activities.

joint when positioning is taking place within the trench area, becoming susceptible to being trapped or

Open communications between each group of personnel in the work area through appropriate means (radio with separate channel).

struck by the pipe joint.

Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil etc. Pre-determined access/egress routes and appropriate communications on the details to all personnel.

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or leading

Any soil at the top or edges of the trench shall be compacted and free from loose areas/materials.

edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

Appropriate access/egress shall be made to machine/crane cabs.

Tree felling at the preparation stage.

Soles of boots should be free from muck or be scraped prior to climbing access ladders. Avoid standing on pipeline or pipe being moved as its surface may be slippery and the pipe may shift unexpectedly. Use appropriate ladders/man basket to access/egress pipeline as necessary. Personnel not to be positioned inside trench when there are activities at the surface of the trench. Fall arrest equipment to be used when deemed necessary by risk assessment and only to be used by trained, competent personnel.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders, generators,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

compressors etc.: all must be considered for any potential

defects should be reported.

defects such as oil leaks, damaged cables, missing guards and contact with moving parts; be

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

appropriate for the job/task and be used correctly.

available.

Confined work area which will increase the potential of impact between machines/personnel and trench

Only certified lifting tackle to be used and to be inspected daily by operators, and periodically by third-party inspectors.

works.

Appropriate preventive maintenance programme to be in place and records kept. Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to prevent contact with chemicals. Only trained and competent personnel to operate any equipment whether machines, cranes, grinders etc. Only approved parts to be used when replacing items and to be fitted by trained, competent personnel. Appropriate equipment to be selected to suite the size of the work area but also the scope of activities.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Forested Area Hazard

Hazard description

Control measures

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

refilling or leaks, contact with any degreasers or cleaners used during the operations.

prevent contact with chemicals.

Exposure to dust when infilling the trench.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical assistance.

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location – procedure to be in place and tested.

Impact with local community/area

See noise above.

Unauthorised access to working area by local community.

Restricted access/egress points or safe walk routes etc. to be identified.

Potential pollution and contamination of agricultural crops which may enter the food chain.

Consider agricultural works in area and how pollution and contamination can affect the local businesses.

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions due to

Appropriate rest shelters to be in place with appropriate cooling/heating facilities.

the open nature of the surroundings with limited protection e.g. high winds, torrential rain etc. and

Regular access to liquids and food as appropriate – warm water recommended in extreme cold and non-iced water in high temperatures.

protection from the elements is limited.

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

Soil becoming unstable if very wet or very dry and people/equipment being in direct contact with this.

backfilling/soil stockpiles.

Cranes lifting during high winds.

Lifting operations should cease when the gusting or wind strength reach 20mph or when the operator feels that it is too dangerous to

Wildlife

Ridge

continue. Ground conditions

Unstable conditions if very dry or very wet resulting is potential landslide situation,

Restricted areas or access identified if the soil becomes unstable, keep unnecessary personnel away from leading edges or trench and

which applies equally to people in the work area, crawler cranes, pipe delivery trucks, particularly if

backfilling/soil stockpiles.

working at the trench edges/surfaces.

Appropriate ground support to be put in place for crawler cranes and trucks to safely access and egress the work area, especially when

The access/egress routes to the specific work area also need to be considered if the access track is

carrying loads. Cranes to use outriggers during all lifting operations.

narrow, has little space for vehicle manoeuvring.

Ground to be assessed by a competent person prior to equipment/machines accessing area and being used for lifting heavy loads.

Tree roots and other items may cause uneven ground conditions for people and

Personnel to be provided with clear access and egress routes to their work areas to avoid any soil slippage areas. Any tree roots/trunks to

vehicles.

be removed where possible or clearly identified if no alternative. Appropriate support mechanisms to be in place prior to any vehicular or personnel access to support the ridge sides and reduce slide potential and ground to be suitably compacted – this also applies to backfill material and having appropriate barriers in place to prevent slippage of materials.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Ridge Hazard

Hazard description

Control measures

Confined space

The trench itself may be identified as a confined space, especially if personnel are required to work within

Permit to work system may be used, only trained and competent personnel to enter the trench, all other personnel to be kept away/out of

or near to the trench.

Heavy load

Illumination

Pipe being lifted from flatbed by crawler crane to the skids and then again into the trench. Potential for

Remove all excess personnel from the area and cordon off the lifting radius to remove unnecessary personnel and equipment.

the skids to collapse or move unexpectedly, with personnel and other equipment in the area. Contact

Only trained and competent personnel to operate equipment and to be allowed access to work area.

between the pipe-handling equipment, the pipe and personnel and other vehicles/machines in the area

Slinger/signaller to be in place and to co-ordinate and control all lifts.

may be made if uncontrolled.

Ensure the ground at the leading edge of the trench is sufficiently compacted to withstand additional weight.

Top soil and backfilling material which is stockpiled on either side of the trench and work area must be

Never lift loads over anyone’s head or other equipment/vehicles in the area.

controlled due to potential contact with machines, personnel,

Ensure that stockpiles of backfill materials and top soil are appropriate in size e.g. have a wide enough base and not be so high that it would

equipment and wildlife.

promote unnecessary slippage of soil – ensure that personnel are prevented from climbing up stockpiled materials or walking/working too

Potential impact on neighbours, other vehicles and personnel in work area if for example, a pipe is

close to the base.

dropped from the ridge area.

Work area to be restricted access in order to minimise impact should any materials or equipment go over the edge of the ridge.

Poor illumination from dawn, dusk and night-time activities may impact on operational requirements;

Ensure that adequate lighting is put in place if working in hours or dust or darkness – use of generators and tower lights as appropriate.

includes potential impact between equipment/machines, contact with personnel, machine operators not

Ensure that lighting is not positioned in a manner that will cause a hazard to machine/crane operators by dazzling them.

able to see signallers’/slingers’ instructions.

Remove any excess or unnecessary personnel from the work area. Ensure that all personnel wear reflective stripes on coveralls, vests, hard hats etc.

Lifting

Includes all lifting activities from trenching machines removing excess soil, pipe movement from flatbed

All lifting equipment and lifting tackle to be regularly inspected by third party (as per country requirements) and have appropriate certification

to skids to trench, crane and other machine operations.

available.

The infilling process of the trench with backfill and topsoil and the interface between people, materials

Daily visual inspection to be completed by operator (including reporting any defects).

and equipment.

Noise

Generated from the machines and equipment on site. If personnel are working

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

close to equipment their hearing may be affected as a result. Additionally any machine/vehicle operator

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

may be impacted depending on the cab’s soundproofing.

Pipe movement

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within the

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

trench. See lifting and heavy load details. Additionally

Slingers/signallers to co-ordinate any lifting activities.

personnel will be working in and around the pipe joint when positioning is taking

Open communications between each group of personnel in the work area through appropriate means (radio with separate channel).

place within the trench area, becoming susceptible to being trapped or struck by the pipe joint.

Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil etc. Pre-determined access/egress routes and appropriate communications on the details to all personnel.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Ridge Hazard

Hazard description

Control measures

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or leading

Any soil at the top or edges of the trench and ridge shall be compacted and free from loose areas/materials.

edge of the trench, access or egress to cranes, trenching machines, working at the edge of the ridge

Appropriate access/egress shall be made to machine/crane cabs.

etc, positioning pipe etc.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders, generators,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

compressors etc.: all must be considered for any potential

defects should be reported.

defects such as oil leaks, damaged cables, missing guards and contact with moving parts; be

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

appropriate for the job/task and be used correctly.

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

refilling or leaks, contact with any degreasers or cleaners used during the operations.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical assistance.

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location – procedure to be in place and tested.

Wildlife

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions e.g. very cold

Appropriate rest shelters to be in place with appropriate heating facilities.

temperatures (-50C), high winds etc. and protection from the elements is limited.

Regular access to liquids and food as appropriate – warm water recommended in extreme cold temperatures.

Winter sees permafrost on the ground so solid underfoot, in summer the top layer of permafrost

Restricted areas or access identified if the soil becomes unstable during summer time, keep unnecessary personnel away from leading

melts which can make the ground soggy/slippery and people/equipment being in direct contact

edges or trench and backfilling/soil stockpiles.

with this.

Lifting operations should cease when the gusting or wind strength reach 20mph or when the operator feels that it is too dangerous to

Cranes lifting during high winds.

continue.

Tundra

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Ridge Hazard

Hazard description

Control measures

Working at height

Any drop from or to a different level may potentially cause harm e.g. working at the surface or leading

Any soil at the top or edges of the trench and ridge shall be compacted and free from loose areas/materials.

edge of the trench, access or egress to cranes, trenching machines, working at the edge of the ridge

Appropriate access/egress shall be made to machine/crane cabs.

etc, positioning pipe etc.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders, generators,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

compressors etc.: all must be considered for any potential

defects should be reported.

defects such as oil leaks, damaged cables, missing guards and contact with moving parts; be

All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right certification in place and

appropriate for the job/task and be used correctly.

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

refilling or leaks, contact with any degreasers or cleaners used during the operations.

Emergency response

The location of the work area may be detrimental due to the time it may take to get medical assistance.

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach them. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location – procedure to be in place and tested.

Wildlife

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks

Hazard

Hazard description

Control measures

Adverse weather

Personnel and equipment coming into direct contact with extreme conditions e.g. very cold (-50C),

Appropriate rest shelters to be in place with appropriate heating facilities.

high winds etc. and protection from the elements is limited.

Regular access to liquids and food as appropriate – warm water recommended in extreme cold temperatures.

Winter sees permafrost on ground so solid underfoot, summer top layer of permafrost melts which

Restricted areas or access identified if the soil becomes unstable during Summer time, keep unnecessary personnel away from leading

can make the ground soggy/slippery and people/equipment being in direct contact with this.

edges or trench and backfilling/soil stockpiles.

Cranes lifting during high winds

Lifting operations should cease when the gusting or wind strength reach 20mph or when the operator feels that it is too dangerous to

Tundra

continue.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 2 Appendix 6.4

Tundra Hazard

Hazard description

Control measures

Noise

Generated from the machines and equipment on site. If personnel are working close to equipment their

Use of hearing protection if operators are not contained within sound-proof booths/cabins.

hearing may be affected as a result. Additionally any machine/vehicle operator may be impacted

Noise assessment to be completed in immediate work area to determine if hearing protection is required to satisfy local legislative

depending on the cab’s soundproofing.

requirements or best practice. Silencers to be installed on equipment where possible e.g. compressors/ generators etc. All equipment to be inspected and regularly maintained to ensure excessive noise is not generated.

Pipe movement

Working at height

Through lifting from trucks, positioning on skids, transferring to trench and then positioning within the

Only limited personnel in the work area and suitable barriers to be in place to prevent unauthorised access.

trench. See lifting and heavy load details. Additionally personnel will be working in and around the

Slingers/signallers to co-ordinate any lifting activities. Open communications between each group of personnel in the work area through

pipe joint when positioning is taking place within the trench area, becoming susceptible to being

appropriate means (radio with separate channel). Suitable and stable grounding to position pipe in new location e.g. skids, compacted soil

trapped or struck by the pipe joint.

etc.

Any drop from or to a different level may potentially cause harm e.g. working at the surface

Pre-determined access/egress routes and appropriate communications on the details to all personnel. Any soil at the top or edges of the

or leading edge of the trench, access or egress to cranes, trenching machines, positioning pipe etc.

trench shall be compacted and free from loose areas/materials. Appropriate access/egress shall be made to machine/crane cabs. Soles of boots should be free from muck or be scraped prior to climbing access ladders. Avoid standing on pipeline or pipe being moved as its surface may be slippery and the pipe may shift unexpectedly. Use appropriate ladders/man basket to access/egress pipeline as necessary. Personnel not to be positioned inside trench when there are activities at the surface of the trench. Fall arrest equipment to be used when deemed necessary by risk assessment and only to be used by trained, competent personnel.

Work equipment

Lifting equipment, cranes, trenching machines, trucks and trailers, all hand tools, ladders, generators,

All work equipment shall be fit for purpose and shall be visually inspected and tested on a daily basis (normally by the operator), and any

compressors etc.: all must be considered for any potential defects such as oil leaks, damaged cables,

defects should be reported. All machines and lifting equipment shall be inspected by a third party at appropriate intervals and have the right

missing guards and contact with moving parts; be appropriate for the job/task and be used correctly.

certification in place and available. Only certified lifting tackle to be used and to be inspected daily by operators, and periodically by third-party inspectors. Appropriate preventive maintenance programme to be in place and records kept. Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to prevent contact with chemicals. Only trained and competent personnel to operate any equipment whether machines, cranes, grinders etc. Only approved parts to be used when replacing items and to be fitted by trained, competent personnel.

Hazardous materials –

Contact with diesel through refuelling process, hydraulic and pneumatic oils from

Spill kits to be available on site in case of spillage, including any required additional PPE and RPE e.g. impervious gloves and suits etc. to

personal exposure

refilling or leaks, contact with any degreasers or cleaners used during the operations.

prevent contact with chemicals. Refuelling to be done via diesel bowser or approved fuel containers. Only trained, competent personnel to

Exposure to dust when infilling the trench.

dispense/refuel machines and equipment. Appropriate waste receptacles to be available for contaminated PPE or rags. Chemicals to be used

Increased levels of carbon dioxide being released into the atmosphere is common in the

with drip tray/spill mat in case of spillage. If very dry and excessive dust on roads, dust suppression to be in place e.g. water bowser. RPE to

arctic tundra, during the summer months, when permafrost melts – the levels would

be used if necessary. Atmospheric testing to be completed periodically to test CO2 levels – appropriate RPE to be put in place as deemed

not be expected to be a hazard to personnel.

necessary.

The location of the work area may be detrimental due to the time it may take to get medical assistance.

Check all communication processes, radios between work groups, cell/satellite phone coverage to ensure that communications remain

Emergency response

available in the event of an emergency situation. Have trained first aiders and/or medics with appropriate equipment available. Check local facilities (hospitals) for quickest/safest route and be aware of time it takes to reach there. Appropriate mode of transport for IP to nearest medical facility to be available and procedure in place at all times. ERP drills to be regularly tested and documented identifying shortfalls – procedures to be updated to reflect findings. Appropriate personnel to be trained in ERP functions and training to be kept up-to-date. Repatriation of IP to suitable location – procedure to be in place and tested. Impact with local community/area

Wildlife

See noise above.

Unauthorised access to working area by local community.

Restricted access/egress points or safe walk routes etc. to be identified.

Potential pollution and contamination of agricultural crops which may enter the food chain.

Consider agricultural works in area and how pollution and contamination can affect the local businesses.

Possible contact between workers and dangerous animals/plants.

If in area with known dangerous animals/plants have appropriate warning systems in place and ensure that the ERPs are suitable and

Being attacked, bitten or affected otherwise by wildlife etc.

consider the potential animal attacks.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

6.5

Onshore Pipeline Survey Requirements by Project Phase

6.5.1 Introduction It should be noted that a major contrast between topographical surveying and geo-technical /geohazard investigations is that of precision & accuracy versus. judgement. The characteristics and behaviour of the ground are inherently more difficult to evaluate than the location of topographical survey features. As a consequence, an important part of geo-technical and geohazard investigations is the exercising of judgement, which must be documented in the investigation reports and taken into account when compiling risk registers and bases of design. It is imperative experienced engineers are used to assist in design or construction, especially where the ground is unknown or contains Hazards that require a detailed understanding. The contractor, however, should understand that the investigations, bore holes, trial pits etc, represent the factual data available at a specific location whereas interpretive results cannot be as definitive and will require some additional judgement in their application.

•

In this section we have tried to adopt the following terminology: o Geo-technical engineering o Geohazard assessment o The term Geo-technical survey is not used but Geo-technical investigation is preferred o The term ground is used to mean soil or rock , soil is used to mean a particulate material potentially containing water and air whereas rock is used to explain the solid

This document has been produced to provide guidance for the collection of topographical, geotechnical engineering and geohazard data for the purposes of design, construction and operation of onshore pipelines. The document has been produced as an aide memoire to the engineer and provides recommendations for the geotechnical engineering and geohazard investigation testing requirements throughout the various project phases from pre-FEED to operation. Due to the varying nature of pipeline design and geographical locations / terrains, the recommendations cannot be exhaustive, but should provide a starting point. The document covers:

• • • • • •

The topographical survey requirements and how topographical survey information can be obtained The investigation of the ground for geotechnical engineering and geohazard mitigation design and construction Guidance on which geotechnical (soil and rock) properties are of importance for particular aspects of design Guidance on what geotechnical (soil and rock) properties are useful for the selection of construction equipment and methods Guidance on the geotechnical investigation and topographical survey requirements for restoration Guidance on the requirements for operation

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

6.5.2 Planning and Scope of Work Objectives The objective of the site survey and investigation for an onshore pipeline is to obtain sufficient reliable information to permit the selection of an appropriate route and enable a safe and economic design and construction of the facility. The site survey and investigations should be designed to verify and expand desktop studies and satellite imagery information collected or assumed in earlier phases of the project as well as provide sufficient additional detail to enable the construction of the facility. The data collected should also provide a sound basis upon which the installation contractor can base their cost and schedule estimate without undue contingency. As the project progresses, the level of detail required increases and additional costs are incurred in acquiring this information. It is important to appreciate that at all times expenditure on the survey activities should be commensurate with the level of detail required. Whilst the data collection primariliy takes place pre-FEED it may be necessary to conduct further studies in the case of unforeseen or additional circumstances arising.

6.5.3 Desktop study The desk study should incorporate a review of all appropriate sources of information and the collection and evaluation of all relevant available types of data for the area of interest. The various types of information that should be gathered and evaluated include, but are not limited to: • Geological maps and databases; • Published and unpublished reports and technical papers on the geology, geotechnical engineering and geohazard characteristics of the project area; • Topographical information (maps); • Land use information; • Potential constraints (as seen on maps and identified from other sources of published and unpublished literature.

6.5.4 Pre-FEED At the initial stages of a project development, it is necessary to assess the topographical, geotechnical and geohazard aspects (constraints and opportunities) in sufficient detail to demonstrate the feasibility and suitability of the preferred pipeline route and the associated design and construction concepts. This level of detail can often be achieved by a desk study which collates the available published and unpublished data, including information from previous surveys and investigations. The various types of information that should be gathered and evaluated include, but are not limited to: • Geological maps and databases, such as databases of landslides, quarry materials, karstic (collapsible) ground • Topographical information (Satellite images and terrain models) • Meteorological data • Geophysical data; Geotechnical data • Geohazard data, for example: seismicity (vibrations, ground liquefaction, active faults); landsliding, erosion, collapsible ground (soils and rocks), aggressive ground chemistry, high water table, rivers • Performance of existing pipelines • Human activities • Land use and potential environmental constraints and opportunities, such as villages, infrastructure, wooded areas, town planning restrictions, national parks, and future planning

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

The initial routing is best chosen by the use of an integrated team comprising:• Pipeline engineers • Construction engineers • Environmental specialists • Geotechnical engineering and geohazard specialists

6.5.5 FEED FEED is the phase of the project development following which the investor makes the decision to proceed based on technical feasibility, costs and schedule. During FEED all the key decisions are taken which define the pipeline routing, EIA impact, construction methods and the requirements for restoration. It is in this phase that the main topographical, geotechnical, resistivity, and geohazard site surveys and investigations are performed. These surveys must be sufficient to enable the project to proceed to detailed design whilst minimizing uncertainty The survey should also be conducted at the start of FEED so that the data is available during FEED for inclusion into the completion of the FEED, and detailed design The obtained survey and investigation data are included in the construction contract such that the installation contractor can utilize the data for the construction engineering, e.g. trench slopes, compaction, spoil heap design

6.5.6 Topographical Survey The topographic survey provides data on the topography along the route of the pipeline and also surface features along the route to be used for the design and construction of the pipeline, including land use, buried and above ground infrastructure, and features of the natural landscape. Surveying is undertaken by work on the ground using theodolites and GPS equipment, (for example) and airborne and/or satellite methods, including photogrammetry and LiDAR (radar) methods. The topographic survey is carried out on the basis of a network, suitable to represent the nature of the site. Normally, the distance between adjacent survey lines is set according to the complexity of the terrain. All features of the ground are surveyed to define the actual ground topography. The orientation and positioning of the surveys in the concerned area is linked to the the national geodetic system. For each road, building, overhead and buried network, watercourse, boundary, etc. included in the area, the following particular characteristics shall be surveyed, in order to highlight all significant natural and manmade features within the limits of mapping: 1. Existing buildings a. Above ground and underground dimensions b. Population density c. Distance from the ROW

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

2. Roads / Rails in general a. Dimensions of the roadway; b. Typical sections; c. Dimensions of road works, if any (e.g. bridges, culverts, etc.); d. Elevations of the roadway centre lines. 3. Networks in general a. Indication of the network type (overhead or buried); b. Surveyable dimensions including pits; c. Use (e.g. water, gas and oil pipeline, low or high voltage electric lines, telephone lines, lighting, etc.). 4. Watercourses and sewer headers a. Characteristic sections (at each change of wet section) including pits; b. Level of the water surface at the surveying date; c. Possible maximum level surveyable on the banks. 5. Slopes, walls, embankments, etc. a. Elevations of the upper and lower edges. 6. Woods a. Limits of woodIand areas or areas planted with trees. 7. Various a. Walls, fences, etc. b. Monuments c. Areas of special interest d. Environmentally sensitive areas

6.5.7 Geotechnical Investigation The geotechnical investigation provides sub-surface data along the pipeline route, including the soil and rock engineering data that is required for the pipeline design and construction. A geotechnical investigation comprises site and laboratory operations that may include; 1. Exploratory holes (in addition to detailed description (logging) of samples, drill cores, and exposed soil and rock faces) a. Boreholes b. Cone penetration tests c. Trial pits d. Trial trenches 2. Geophysical investigations a. Surface investigations using (for example) shallow seismic and resistivity methods b. Borehole investigations using geophysical tools in boreholes 3. In situ geotechnical testing a. In boreholes, for example standard penetration tests, pressuremeter tests, permeability and pumping tests b. With cone penetration tests, such as piezo-cone c. In Trial pits and trenches, for example density tests and scan-line surveys of rock fractures

100

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

4. Geotechnical monitoring a. Groundwater conditions, e.g. piezometers in boreholes b. Ground movements, e.g. inclinometers in boreholes, surface movement markers 5. Laboratory testing (of samples and drill cores of the ground and of ground water) a. Index tests, such as grain size, plasticity, moisture content, mineral composition b. Shear strength of soils, tested in drained and undrained conditions, including tests to determine residual shear strength c. Compressive strength of rocks, including the point load index test and tests of residual shear strength d. Compressibility e. Compaction, including the use of soil and rock as fill materials f. Durability of rocks for use as fill, aggregate and amour stone g. Permeability h. Geochemistry and groundwater chemistry, including aggressive and contaminated ground i. Thermal and resistivity properties Table 1 lists data collected during a geotechnical investigation, and the design aspect it is used for.

6.5.8 Geohazard Investigation Geohazard investigations provide information on earth surface processes and geological hazards that might pose a threat to pipelines and associated infrastructure. Hazards are usually considered as a series of groups, with each group being investigated and assessed by a specialist team. A typical set of groups is as follows: 1. Earthquake (seismic) hazards: a. Earthquake vibrations b. Ground liquefaction, including lateral spreading c. Fault rupture d. Tsunami 2. Ground settlement and collapse: a. Swelling, shrinking ground and collapsible soils b. Ground solution and collapse (karst) 3. Landslides and erosion: a. Pre-existing landslides and erosion areas b. Landslide-prone and erosion-prone terrain 4. Rivers and coasts: a. Coastal erosion and deposition b. River behavior, including channel changes and bed erosion c. High watertable and flooding

101

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

5. Contaminated land and ground geochemisty: a. Naturally aggressive ground and groundwater b. Former and current industrial uses c. Contamination of soil and rock d. Contamination of groundwater and surface water Table 2 lists data collected during a geohazard survey, and the design aspect it is used for.

6.5.9 Reference Documents The following ASTM standards listed below provide a description of the methods, equipments and tests for the topographical, geotechnical, geohazards, and resistivity surveys. ASTM is the American society for testing and materials.

102

ASTM

Title

D420

Standard guide to site characterization for engineering, design and construction purposes

D653

Standard terminology relating to soil, rock and contained fluids

D1195

Standard test method for repetitive static plate load test of soils and flexible pavement components, for use in evaluation and design of airport and highway pavements

D1196

Standard test method for non repetitive static plate load tests of soils and flexible pavement components, for use in evaluation and design of airport and highway pavements

D1452

Standard practice for soil investigation and sampling by auger borings

D1556

Standard test method for density and unit weight of soil in place by the sand-cone method

D1586

Standard test method for penetration and split-barrel sampling of soils

D1587

Standard practice for thin-walled tube sampling of soil for geotechnical purposes

D1883

Standard test method for CBR (California bearing ratio) of laboratory-compacted soils

D2113

Standard practice for rock core drilling and sampling of rock for site investigation

D2167

Standard test method for density and unit weight of soil in place by the rubber balloon method

D2487

Standard classification of soils for engineering purposes (unified soil classification system)

D2488

Standard practice for description and identification of soils (visual-manual procedure)

D2573

Standard test method for field vane shear test in cohesive soil

D3441

Standard test method for mechanical cone penetration tests of soil

D3550

Standard practice for thick wall, ring-lined, split barrel, drive sampling of soil

D3740

Standard practice for minimum requirements for agencies engaged in the testing and/or inspection of soil and rock as used in engineering design and construction

D4043

Standard guide for selection of aquifer test method in determining hydraulic properties by well techniques

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

ASTM

Title

D4044

Standard test method (field procedure) for instantaneous change in head (slug) tests for determining hydraulic properties of aquifers

D4050

Standard test method (field procedure) for withdrawal and injection well tests for determining hydraulic properties of aquifer systems

D4083

Practice for description of frozen soils (visual â&#x20AC;&#x201C; manual procedure)

D4220

Standard practice for preserving and transporting soil samples

D4394

Standard test method for determining the in situ modulus of deformation of rock mass using the rigid plate loading method Standard test method for determining the in situ modulus of deformation of rock mass using the flexible plate loading method

D4395 D4403

Standard practice for extensometers used in rock

D4428

Standard test method for crosshole seismic testing

D4429

Standard test method for CBR (california bearing ratio) of soils in place

D4506

Standard test method for determining the in situ modulus of deformation of rock mass using a radial jacking test

D4553

Standard test method for determining in situ creep characteristics of rock

D4554

Standard test method for in situ determination of direct shear strength of rock discontinuities

D4555

Standard test method for determining deformability and strength of weak rock by an in situ uniaxial compressive test

D4623

Standard test method for determination of in situ stress in rock mass by overcoring method-USBM (US Bureau of Mines) borehole deformation gage

D4645

Standard test method for determination of the in-situ stress in rock using the hydraulic fracturing method

D4719

Standard test method for preboard pressuremeter testing in soils

D4750

Standard test method for determining subsurface liquid levels in a borehole or monitoring well (observation well)

D4914

Standard test methods for density of soil and rock in place by the sand replacement method in a test pit

D4959

Standard test method for determination of water (moisture) content of soil by direct heating

D4971

Standard test method for determining the in situ modulus of deformation of rock using the diametrically loaded 76-mm(3ÂŹin.) borehole jack

D5030

Standard test method for density of soil and rock in place by the water replacement method in a test pit

D5079

Standard practices for preserving and transporting rock core samples

D5434

Standard guide for field logging of subsurface exploration of soil and rock

D5777

Standard guide for using the seismic refraction method for subsurface investigation

D5778

Standard test method for performing electronic friction cone and piezocone penetration testing of soils

D5876

Standard guide for use of direct rotary wireline casing advancement drilling methods for geoenviromental exploration and installation of subsurface waterquality monitoring devices

103

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

ASTM

Title

D5878

Standard guide for using rock-mass classification systems for engineering purposes

D6026

Standard practice for using significant digits in geotechnical data

D6032

Standard test method for determining RQD (rock quality designation) of rock core

D6066

Standard practice for determining the normalized penetration resistence of sands for evaluation of liquefaction potential

D6230

Standard test method for monitoring ground movement using probe-type inclinometers Standard guide for selecting surface geophysical methods

D6429

104

D6431

Standard guide for using the direct current resistivity method for subsurface investigation

D6432

Standard guide for using the surface ground penetrating radar method for subsurface investigation

D6519

Standard practice for sampling of soil using the hydraulically operated stationary piston sampler

D6635

Standard test method for performing the flat plate dilatometer

G57

Standard test method for field measurement of soil resistivity using the wenner four-electrode method

D7012

Standard test method for compressive strength and elastic moduli of intact rock core specimens under varying states of stress and temperatures

X X

105

X X X

X X

X X X

X X

X X X X X X X X X X X X

X X X X X X X X

X X X X

X X

X X X X

X X X

X X

X X X

X X X X X X X X X X X X

X X

X X X

X X

X X X

X X

X X X

X X X X

X X X

X X X X X X X X X X X X X X X

X X X X X X X X X X

X X X X

X X X

X X

X X X X X

X X X

X X

HDD – boreholes ranging from 15m – 30m deep (extending at least 6m below lowest anticipated elevation of the HDD crossing), spaced from 100m – 500m apart and approximately 10m offset of the HDD crossing’s alignment depending on crossing configuration Crossing – boreholes ranging from 5m – 10m, boreholes at each crossing Trial pits – ranging from 1m – 3m depending on pipe diameter and cover depth, spaced from 500m – 1km apart depending on pipeline length and soil heterogeneity along the route.

X X X

X X

X X X

Rock Unconfined compressive strength Mohs Hardness of Rock Atterburg Limits (Liquid and Plastic Limits for cohesive soils) Information on existing buried lines Cone penetration tests (CPT) Standard penetration tests (SPT’) Soil bearing capacity Water sample analysis Water / moisture content Water table Backfill properties Thermal conductivity (in-situ, disturbed) Electrical conductivity / resistivity Chemical analysis Rock quality (if applicable) Liquefaction resistance Cyclic strength Coated pipe-soil Friction Factor (lateral, longitudinal, uplift) Sensitivity (estimate to maintain original strength when remoulded) Compressibility Permeability Elastic modulus Particle size distribution Relative density (bulk, dry, particle) Friction angle Shear strength (for cohesive soils) Soil Description / classification Topographical profile

Pipeline routing Hydraulic / flow assurance analysis Expansion / anchoring analysis Buried bend / tee analysis Road crossing analysis Rail crossing analysis River / stream crossing analysis Flotation / sinkage analysis Third party services crossing analysis Upheaval buckling analysis Horizontal directional drill Cathodic protection design Trench slope angles Compaction Construction equipment Restoration Operation

TABLE 1 - Topographical and geotechnical information required for onshore pipeline design

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 6

106

Seismicity and faulting

Liquifaction potential

Ground rupture

Seismic compaction and settlement

Seismic shaking

Slope instability and landslides

Flooding

Subsidence

Seismic zone and soil profile coefficient

TABLE 2 - Geohazard survey information required for onshore pipeline design

Pipeline routing

Earthquake analysis

Fault line analysis

Terrain analysis

Foundation analysis

Earthwork and foundation analysis

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6.6

Site Investigation Process

6.6.1 General The ideal pipeline route is a straight line between two endpoints. However, the installation of all pipelines is subject to a variety of manmade and natural constraints. The challenge of geoscientists and engineers (geomorphologists, geologists, geotechnical engineers), pipeline engineers and environmental specialists is to ensure that these constraints are identified and the shortest and most cost effective pipeline route is defined. This is best achieved through the development of terrain models during the earlier phase of pipeline routing. This analysis should identify significant geohazards that should be avoided and the mitigation of other geohazards through engineering design and hence assessment in terms of cost. The aim is to reduce financial risk and mitigate environmental impacts at an early stage in order to avoid costly rerouting during the construction phase or (worse still) during operation of the pipeline. For any pipeline route investigation the more comprehensive the front end studies are, the more effective and targeted are the field data acquisition programmes later on.

6.6.2 Front End Loading Stage 1 – Business Planning The aim of this stage is to define the regional context of the pipeline route and identify a suitable 10km (or narrower) pipeline corridor. Datasets should be gathered and presented in a preliminary Desk Top Study (DTS). This DTS is a ’dynamic’ document and should be updated regularly during the Front End Loading (FEL) stages. Public domain data such as topographic, geological and soil maps and remote sensing images should be acquired to generate regional terrain models and identify any geo-political, manmade or environmental constraints. Remote Sensing images provide the following information: • Digital Elevation Models (DEM) • Land cover • Land usage • Geological interpretation (structural & lithological) • Drainage networks • Environmental risks Geohazards e.g. Landslides, subsidence, flooding, active faulting This information can then be used to identify and characterise geological geohazard features (such as areas of erosion and landsliding) and develop preliminary terrain maps from which initial terrain models can be produced. In seismically active areas probabilistic seismic hazard analysis should be carried out to evaluate associated risk posed to the pipeline. At this stage a GIS (geographical information system) should be implemented. The advantage of GIS is that it allows data to be stored and easily retrieved for future reference. The GIS is a useful tool to visualise the regional constraints and develop a series of 10 km pipeline route corridor options. A more detailed terrain analysis, constraint map and geohazard register can be drawn up for each route option to evaluate the best option from both financial and technical (geoscience and geotechnical and pipeline engineering) points of view.

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Once this process is complete, ideally a single 10km (or narrower) pipeline corridor of interest should have been selected. At this stage the GIS can be used to provide visualisation packages for stakeholders and potential investors. With access to detailed remote sensing techniques, it should be possible to gage a comprehensive overview which should greatly aid and minimise the work load when deploying personnel to the field. Working with remote sensing (images) does not completely remove the necessity for ground thruthing the potential routes before the final decisions are made. Conceptual engineering designs for river crossings and facilities can be produced together with a preliminary assessment of the installation costs and schedule can be drafted. Environmental impact assessments should be planned together with the application of local and national permits.

6.6.3 Front End Loading Stage 2 – Facility Planning The aim of this stage is to further reduce the pipeline corridor width to 500m (or narrower), to identify the placement of facilities along the route and develop the scope of work for a targeted site investigation. This is achieved by further detailed investigation of the data acquired during the preliminary DTS stage and the acquisition of more local data and verification of existing data through site visits. The site visit should be carried out by a team of pecialists compromised of geoscientists and pipeline engineers. They should walk/drive/fly the route to refine the terrain models, verify and screen the features on the geohazard register and refine the constraint map. During this stage the accuracy of the remote sensing images can be improved by establishing several Ground Control Positions (GCP’s) along the proposed corridor. These GCP’s are obtained by utilisations of GPS or similar to ascertain the exact locations of features that can be established in the field for example crossroads, bends in rivers etc. These images can then be warped to fit these locations and thus increase the accuracy of the image. There may be a requirement to carry out some trial pitting to improve the understanding of features identified in the terrain models and provide an initial quantitative assessment of some of the cost drivers such as trenchability. On completion of this stage, the desk top study (DTS) should be updated, the geohazard register refined and the constraint map re-evaluated. River and infrastructure crossings and areas where the pipeline will cross potential geohazards or landslips should be identified. Conceptual designs of the pipeline crossing these features and the associated facilities should be refined. Geohazards not necessarily within the chosen corridor but which could have an impact on the pipeline in the event of failure should be assessed. A preliminary zonation of the route in terms of trenchability and layrate (access to plant) along the corridor should be carried out in order to further refine the installation costs and schedule. A targeted scope of work for the field data acquisition should be drawn up to allow the quantification of geohazards and other features in the vicinity of the route through geotechnical analyses of samples and integration of the data. This document should clearly identify the aim of the investigation at each facility (temporary or permanent), crossing and geohazard feature. Based on the terrain models, recommendations for the most appropriate investigation technique(s) to be used should be made and details of likely soil/rock conditions and geological / geomorphological features to be encountered should be provided.

6.6.4 Front End Loading Stage 3 – Project Planning The aim of this stage is to gather field data to allow the quantification of the terrain models, finalise the geohazard register and constraint maps in order that a centre line within the ROW can be defined for pipeline installation. Prior to any geotechnical or terrestrial geophysical campaign, an airborne survey and a ground thruthing visit may be performed to assist in further characterisation. Surface mapping of the pipeline corridor

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can be carried out using fixed wing aircraft or helicopters using LiDAR (Light Detection and Ranging). This technique maps the ground surface and other features to engineering accuracy, thus complementing, and minimising labour intensive field surveys or photogrammetry. The survey data can be used to establish any Rights of Way (ROW) for field teams, landownership, identify critical slopes and mapping of High Consequence Areas (HCAâ&#x20AC;&#x2122;s) and progress the design of infrastructure crossings. Airborne techniques are a very effective tool for acquiring data for large pipeline projects and routes traversing remote regions. The airborne techniques will assist in the further refinement of the terrain models and scoping of the ground geophysics and geotechnical investigations. Soil and rock samples from the field are taken to the laboratory for further analysis and testing. The geophysical data is processed and interpreted with the use of the geotechnical data. Geotechnical engineering parameters are derived from the laboratory results. The geotechnical data provides essential information for engineering design of river and infrastructure crossings and for the installation of temporary and permanent facilities. The terrain maps can be finalised and the zonation of trafficablity and layrates can be refined to establish more detailed cost estimates and schedules. The data is presented on alignment sheets with plan views, cross-sections and engineering data. This integrated dataset and finalised terrain map is used to assist in the quantification of total project risk.

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Desk Studies Field Studies Terrain Evaluation Constraints Mapping Define Role, Strategies & steps for next stage Detailed Geohazard Studies Risk Assessments Route Ranking Integration with ESIA Field Investigations Cost driver Studies Geohazard Mitigation actions Geotechnical and Geophysical Procurement Monitoring and Inspection

Pipeline Project Stage Terrain Studies

Resources

Geoscience Team Activities

Front - End Loading FEL 3: Project Planning FEED / Route Definition

Determine slope & ground stability

Aerial photgraph interpretation Evaluate significance of terrain problems: Severe constraints and potential showstoppers Refine cost drivers, trenchability, trafficability, corrosivity, erodibility, etc Refine scope of detailed field investigation Prepare geotechnical contract documents Selection 500 m wide corridor Cost estimate expected confidence range (ECR) typically <+/- 30% / Approx. UAP: 15%

Develop Initial terrain models possibly at regional level Develop routing strategy with pipeline engineers

Anticipate potential hazards, showstoppers and cost drivers Site visit fly/drive/walk route

Access local data Refine terrain models

Develop initial constraints maps

Assemble geoscience & pipeline engineering Team of specialists

Cost Order of Magnitude / Confidence range typically <+/- 50% / Approx UAP: 15%-25% Anticipate potential problems select a 10km Corridor

Corridor Comparison & selection (10km wide)

Verify occurrence of terrain modesl within corridors Identify Corridor alternatives deifinitions at regional level (10km wide) Initial scope of future investigations

Sub-surface ground investigations: Borehole, trial pits, in-stu and laboratory testing, program to include major crossings and facility locations Detailed Geohazard Studies

Mapping of problem Areas with limited pitting and geophysics etc.

Integrate with preliminary EIA

Geotechnical QA/QC & Monitoring Individual Specialists

Establish mitigating actions Full time geotechnical supervision / Specialists as required SI Contracts / Full time geotechnical supervision & overview by specialists

Individual or team specilaists as required by problems sub-contracts for pitting, geophysics etc

Detailed site specific work to suit problem (if required)

Evaluate the terrain problems & assess risks. Select a construction corridor

Equipment performance monitoring Records for payment Cost estimate: ECR typically: <+/10% / Approx. UAP: <5%

Excavation logging

Detailed design of minor structures Design changes to meet geoproblems

Monitoring & Inspection

Flexible response to construction requirements Suplementary site investifgations

Remedial investigation and mitigation measures

Remedial Investigation

Operation & Maintenance

Start-up and Operations

Construction Monitoring

Construction

Project Execution

Refine terrain Models. Select a 500 m Corridor

Early Define: narrows the corridor from 500m to 100m and Late Define: construction corridor selection and definition Finalise Cost Drivers: Cost estimate ECR typically <+/- 15% to 20% / Approx. UAP: < 10% Quantified risk assessments for all hazards. Integrated in project wide risk assessment.

Earth works management plan including licensed soil areas Provide database on materials, slope geohazards, etc. Diagnose and design for specific problems Provide geotechnical data for sites of temporary and permanent works Design temporary and permanent works

Detailed mapping of problem areas

Preliminary Site Investigation

Route refinement Preliminary Investigation Route Definition Detailed Investigation

FEL 2 : Facility Planning FEED / Route Refinement

Gather & assess existing data

Pre-feasibility / Corridor Assessment

FEL 1: Business Planning Concept

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6.7

Non-Intrusive Survey Techniques

6.7.1 Introduction Pipelines are planned and built in widely varying terrains that pose a variety of natural and/or manmade constraints. The challenge of geoscientists and pipeline engineers is to ensure that these constraints are identified and the shortest and most cost effective pipeline route is defined. Non-intrusive survey techniques provide valuable information about surface terrain and sub-surface ground (or utilities). When properly planned, designed, and usually combined with others (intrusive) methods (drilling or Cone Penetration Testing for example), non-intrusive survey can help to address some of the challenges that planners and designers are facing during the whole pipeline life cycle from routing of new pipelines to inspection, repair or maintenance of existing ones. The term â&#x20AC;&#x153;non-intrusiveâ&#x20AC;? includes a wide range of techniques from remote sensing technologies using satellite imagery to land based geophysics. Some of the techniques are relatively straightforward to practice; others are highly sophisticated and require significant technical expertise both during field operations, data processing and interpretation. This chapter will present some of these techniques, namely: airborne LiDAR, land geophysics, and satellite imagery and InSAR surveying.

6.7.2. Airborne LiDAR 6.7.2.1. Introduction Airborne LiDAR is now an accepted and proven technology, used in a range of survey and mapping applications. The laser scanner can be mounted in the fuselage of a fixed wing aircraft for the measurement of digital terrain models of wide area subjects. In the late 1990s a number of commercial operators recognised the potential of mounting the laser scanners on a rotary wing platform, which enabled data acquisition to be undertaken at a considerably lower altitude, therefore improving accuracy and increasing point density. Since this time, the use of rotary wing LiDAR has grown steadily and is now routinely used for pipeline routing projects and to a lesser extent for land use mapping in the inspection, repair and maintenance of pipelines. The much higher laser point density that can be achieved from lower flying heights enable the extraction of large scale topographical mapping in addition to terrain data. The principle of LiDAR (Light Detection and Ranging) is that a sensor transmits and receives infrared light. By accurately measuring the time between sending out and receiving the pulse of light the system is able to calculate the distance to the object that generates the reflection. To successfully coordinate each laser point, other critical components are required; an Inertial Measuring Unit (IMU) detects the rotational elements of the aircraft whilst GPS receivers record the position of the sensor. By combining this information with the time of flight distance from the LiDAR sensor, an X,Y,Z coordinate can be determined for each laser point. Modern systems are able to capture up to 400,000 points per second and the IMU and GPS updates the rotations and position many times per second. Deploying ground based GPS receivers / base stations into the project area increases the accuracy achievable. By combining the GPS data from both the aircraft and the ground base stations.

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Figure 1: Optimal construction of pipelines requires detailed surveying.

6.7.2.2. Commentaries on LiDAR The main application areas for airborne LiDAR are in pipeline routing, both selection and design. Within these categories, airborne LiDAR is also the preferred solution for terrain and topographic mapping offering identification of anthropological (roads, buildings, land cover, etc) and natural constraints (wetlands delineation, water bodies, rock outcrops, etc).

6.7.2.3. Key benefits Airborne LiDAR surveys operate with minor safety risks as no (or limited) personnel are required on the ground in potentially dangerous situations such as inhospitable environments such as deserts, jungles or areas prone to civil unrest or community resistance to infrastructure development. Using this survey technique it is possible to capture relatively large amounts of terrain data per day meaning large traces can be acquired in a relatively short period of time. Data processing is quick and thus turnaround times are short. Modern systems are capable of capturing multiple returns; each outbound pulse of light diverges as it travels towards the ground. When the light hits the top of a tree canopy a first reflection is generated and returned to the sensor. However, although some energy is absorbed from the first reflection, some of the laser light is able to continue its path the through the canopy with each object in turn generating a reflection which is received by the sensor. In this way, even in the most densely vegetated areas it is possible to record the heights of bare earth terrain.

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Figure 2: LiDAR penetration in densely forested areas. Downward and forward oblique imagery is usually acquired simultaneously with the laser data to provide value added aerial photography that can be orthorectified and used in a desktop environment to view imagery of the area or as a backdrop to GIS or CAD engineering data. Some LiDAR sensors are able to attribute RGB colour values to each laser point enabling the production of easy to interpret colour laser point clouds that can be used to generate visualisation tools and fly-throughs of the proposed pipeline development. The laser point cloud data can be readily exported to a range of industry standard formats or delivered as simple ASCII text files. Similarly, if mapping is required, the topographical survey data can be extracted from the point cloud and delivered as 3D AutoCAD, Microstation or other proprietary CAD format and be represented exactly as a design engineer would expect to receive from a land or aerial photogrammetric survey. Modern computing enables easy management and manipulation of the large LiDAR datasets and the recent proliferation of a number of free viewers and inexpensive processing software provide end users and design engineers to use the data without the requirement to be a LiDAR data processing expert. The LiDAR data will provide topographical information to be collected regarding roads, buildings, structures, boundaries, vegetation, landforms and water features that are of critical importance to the routing of new pipelines. The resolution achieved from helicopter based surveys will supply information relating to micro topographical detail including utility poles, posts, street furniture and even service covers and manholes.

Figure 3: Excerpt from a route plan drafted using LiDAR data, with integrated height contours Unlike other forms of survey, LiDAR with its ability to penetrate vegetation will yield high accuracy terrain and surface models from a single dataset. The terrain models can be of sufficient resolution to be used as source for 3D models and virtual world visualisations, particularly when combined with aerial or terrestrial sourced imagery.

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Figure 4: 3D visualisation of a pumping station based on laser and RGB colour-data

6.7.2.4. Main limitations As this survey technique is light based, a clear line-of-sight is required to the ground. As such, poor weather conditions such as low cloud and rain prohibit survey acquisition. Likewise, strong winds adversely affect the operation of the aircraft and the sensor components in the aircraft resulting in potential accuracy loss during a survey mission. A conventional airborne LiDAR will not have the capability to penetrate bodies of water. Therefore, it is not possible to determine the bed levels of rivers, lakes and canals and if the survey is conducted in flood conditions there is the potential to have large areas of void in the data. Similarly, the system cannot be used when snow is lying on the ground. When operating in very remote locations such as deserts, it is not always feasible to achieve a high accuracy due to restrictions and practical constraints associated with placement and manning of GPS base stations. Whilst it is possible to transit fixed wing aircraft for international projects over very large distances, for helicopter projects the system components are sent by air freight to a local airport and a locally leased helicopter used to complete the project. In both scenarios, the system that includes military grade hardware will need to be cleared for export and import by the relevant authorities. Some countries are unsuitable for import of the sensor components and in others the logistics associated with customs and state clearances can result in delays. Additionally for helicopter projects, although systems are cleared for a number of helicopter types, a suitable aircraft will need to be available locally in order to proceed with the project.

6.7.2.5. Accuracy The accuracy achieved during a survey depends on several factors of which survey altitude and GPS base station deployment has the biggest influence. Lower survey altitudes deliver higher accuracy; a typical survey at 200 metres above ground level results in a vertical point accuracy of approximately +/0.035 m (1 sigma) whereas a higher survey altitude of above 750 metres would result in a vertical accuracy of +/-0.1 m (1 sigma). Horizontal accuracies range from 0.05 m (1 sigma) to 0.2 m (1 sigma). These accuracies are based on a GPS base station deployment with the aircraft or helicopter being no further than 30 km from a base station.

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6.7.2.6. Typical Cost Typical acquisition and pre-processing costs for a pipeline will depend on project location, size and local operational factors. However, in Continental Europe costs for a suitable task will range from €150 to €500 per km2 for a fixed wing project and €150 to €700 per linear km for a high resolution/accuracy helicopter project. Post processing and mapping costs vary greatly according to the complexity of the survey/mapping that is required to be extracted from the laser point cloud.

6.7.2.7. Timing The complexity and width of the chosen route, terrain, accuracy and resolution requirements as well as local climate all affect the daily acquisition rate. Typical helicopter surveys are able to acquire 120 km per day and typical fixed wing surveys about 350 km.

6.7.2.8. Future trends and innovation Continuous improvements are being made to improve the accuracy, resolution and quality of the LiDAR data through improving the effective frequency and ranging accuracy of the laser and introducing a multiple return capability whilst also upgrading the integrated imaging and video systems. Future trends in acquisition are increased resolution and accuracy at higher altitudes (covering larger areas per day) as well as improved GPS processing techniques requiring no personnel on the ground to man GPS base stations. Other trends and innovations are the processing of LiDAR data containing full waveform information, which effectively allow an unlimited amount of returns for each beam emitted (majority of current systems allow up to four returns). In data processing improved algorithms allow for increased automatic classification and mapping meaning reduced costs and an improved turnaround time on data deliveries. Other advances are an increase in 3D vectorisation for visualisation purposes. Data handling applications are also always being improved allowing for greater amounts of data to be displayed and modelled simultaneously.

6.7.2.9. Example A recent project in In Salah region of Algeria combined aerial imagery, airborne LiDAR and photogrammetry to carry out the task of mapping a remote, inaccessible area in the Algerian desert. The project required a lot of preparation as it was quite inaccessible and a detailed safety risk analysis was undertaken, which highlighted constraints such that the work could only be undertaken during daylight hours and the location meant that the fuel supply for the aircraft needed to be worked out carefully before operations began. After the acquisition of the LiDAR, the dataset was filtered to distinguish between ground and non-ground points and final deliverables including bare-earth DTM, orthophotos and mapping produced.

Figure 5: Building of the pipeline network – survey aircraft fitted with LiDAR

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6.7.2.10. Some examples produced using the FLI-MAP laser- and imagery data

Figure 6: Example of a new line visualization including third party lines/objects

Figure 7: Example of visualization the construction area left and right of the pipeline route

Figure 8: Example of a real 3D visualization of a route by using laser data and RGB colour values

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Figure 9: Integration into a GIS where the data has been mapped in 3D

Figure 10: Example of forward and downward photo imagery

Figure 11 Integration of laser and photo data

Figure 12 Determination of non-ground objects

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Figure 13 Processing the FLI-MAP data

Figure 14: 3D visualisation and interpretation

Figure 15 Final route plan with detailed topographic information

6.7.3. Land geophysics 6.7.3.1. Introduction Established geophysical investigation methods can provide valuable subsurface information throughout the life-cycle of a pipeline. Information pertaining to ground conditions can add value and improve decision making during various planning stages from preliminary corridor choice through to final route investigation and decommissioning. Pipelines are planned and built in widely varying geological, geotechnical, hydrogeological, geomorphological and topographical terrains. As such the challenges of pipeline applications form part of a broad family of generic applications relevant to the very near surface. The geophysical challenges of pipeline applications are generally met in many other engineering and developmental contexts. Pipelines investigations are generally characterised by long and relatively narrow surface survey areas, except where targeting of specific features may be required. Depths of investigation are generally limited to the very near surface but extend over long distances of several to hundreds of kilometres; information for trench-related engineering properties is generally required within 8 m below ground level (bgl) whereas investigation of geohazards such as mine workings or faulting as subsidence agents may extend to 50 m depth or more. Pipelines may cross different cultural areas but are more likely to traverse remote and sometimes inaccessible areas rather than urban developments.

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In general, geophysical methods can map variations in physical or chemical conditions along a pipeline corridor or route as a function of lateral position and depth. Such variations can yield absolute values of quantifiable properties but in most cases some form of ground truthing is required to calibrate and verify geophysical response as a robust diagnostic tool and to provide an objective means of extrapolation or interpolation away from control locations. A geophysical investigation is invariably more valuable to decision making when programmed prior to an optimised, objectively targeted borehole program. Geophysical tools should be considered at the very early stages of a project rather than an afterthought when ground conditions, during direct investigation or construction, are frequently found to be at variance with planning expectation such as unexpected rockhead depth or strength.

6.7.3.2. Commentaries on land geophysics 6.7.3.2.1. Rockhead depth The depth to the rockhead may be determined using geophysical methods both in absolute and relative terms. Rockhead is commonly characterised by a boundary across which acoustic, mass and electrical properties change rapidly. In general, seismic velocity, density and electrical resistivity will tend to increase in a downwards sense across the rockhead boundary. Seismic refraction methods can effectively map relatively complex rockhead topography to an accuracy of better than 15% from a metre or so below ground level to tens of metres by analysis of seismic energy that has been critically refracted at the rockhead boundary. However, the technique will not be viable if a velocity increase is not present. Seismic reflection techniques can be used to map rockhead but are only suitable where rockhead has a minimum depth of about 20 â&#x20AC;&#x201C; 30 m. A minimum depth limitation arises because at shallow depths it is very difficult to separate reflected energy from energy that has been refracted or has propagated through the ground surface using currently available, finite bandwidth seismic sources. A further limitation for seismic methods is the presence of unsaturated, compressible soils such as dry sands that afford poor source coupling - consideration should be made as to whether surface or buried seismic sources should be used that will have a bearing on productivity. In addition, saturated soils may have compressive seismic velocity characteristics similar to that of saturated, weathered bedrock; shear wave refraction techniques can overcome this problem in that shear wave energy propagates only through the skeletal components of geological media and not through fluids in pore spaces. Electrical resistivity tomography (ERT) yields profiles of resistivity against depth and lateral distance and can be particularly effective where electrically conductive soils overly electrical resistive rockhead such as clays over sandstone. Key limitations with ERT include weak resistivity contrasts, presence of saline groundwater masking lithological contrasts, and the presence of very dry surface materials leading to high contact resistances when injecting electrical current. High contact resistance may lead to noisy data at best and may prevent ERT investigation in arid and semi-arid regions unless electrolyte is added at each injection point; this would again have a detrimental effect on productivity. Seismic and ERT techniques are frequently used in combination to constrain rockhead interpretation and afford productivity rates of about 500 linear m per day per field team to investigate rockhead to about 15 m bgl. Other techniques for absolute rockhead depth determination include ground penetrating radar (GPR), which in highly electrically resistive materials can penetrate to depths of 15 m or more. In the presence of saturated surface media or weathered clays, penetration may be limited to less than a metre due to ohmic losses through conduction currents; saline pore waters will prevent radar propagation below the saturated zone. Electromagnetic conductivity profiling provides a rapid means to evaluate rockhead depth along a route or corridor; when used in conjunction with real-time dGPS positioning, several linekilometres of conductivity mapping can be carried out in a single day. The technique provides a bulk

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estimate of electrical conductivity down to a specific depth of 1 to about 20 m dependent upon the instrumentation deployed. The technique can be highly effective where bedrock topography varies in the top 6 m bgl; rockhead conductivity tends to be lower than that of overlying soils and a conductivity profile can give a rapid means of visualising rockhead topography to target subsequent direct investigation. Where rockhead is expected to comprise igneous or metamorphic strata, the presence of magnetite in certain lithologies can be exploited by magnetic surveying to visualise relative rockhead depth in a similar manner to electrical conductivity profiling. In areas of extreme subsurface topography such as in some karstic terrains, microgravity provides a means to determine rockhead variation with likelihood of success dependent upon adequate density contrasts in the sub surface and the existence of an adequate digital elevation model to provide vital corrections. Gravity data acquisition is relatively slow (about 100 stations per day per instrument) and is better suited to targeted investigations where profiling methods indicate anomalous responses.

6.7.3.2.2. Rockhead rippability The strength of geological materials at very high strains has been empirically related to compressive wave seismic velocity. Studies have been performed relating rippability to bulldozer power (D6, D9 etc). For specific rock types, thresholds are provided that indicate those seismic velocities at which ripping with particular plant is likely to be effective and those velocity thresholds beyond which blasting may be required. The most effective means to determine rock rippability is through the seismic refraction technique. Seismic refraction generally provides an indication of layer geometry and the compressive (Pwave) seismic velocity of those layers. Seismic refraction may be difficult to conduct in cases of extreme subsurface topography and provides rippability information only from the very upper parts of the rockhead mass that will inevitably underestimate the rippability of deeper, less-weathered rock. Although requiring more complex and therefore slower field procedures and processing, wave equation tomography (WET) uses more components of the raw data and can determine velocity gradients within geological layers and therefore a better indication of rippability. A field team would be expected to achieve about 500 linear metres per day of continuous refraction profiling for rippability purposes.

6.7.3.2.3. Rockhead stiffness Rockhead stiffness information may be required when ground behaviour due to surface loading needs to be assessed. Surface wave seismic is a profiling technique similar to seismic refraction. Rather than record body wave information, surface wave techniques such as multichannel analysis of surface waves (MASW) record relatively low frequency surface waves whose behaviour is related to the shear wave characteristics of the ground. Surface wave techniques yield one-dimensional stiffness profiles to a depth of about 20 m bgl when using a sledgehammer seismic source. Many 1D depth profiles can be merged into a 2D profile to yield a shear wave velocity profile. Small strain stiffness values (shear modulus) can then be derived based upon an estimate of density; shear wave velocity can be a sensitive indicator of stiffness variation being proportional to the square root of the stiffness. Key limitations for surface wave seismic techniques include the presence of very stiff near-surface layers such as caliche or fericrete; strong contrasts in the elastic properties of near-surface media can effectively guide seismic source energy between layers greatly reducing the depth of investigation. A field team would be expected to achieve about 500 linear metres per day of continuous MASW profiling for ground stiffness investigations.

6.7.3.2.4. Voiding/low density ground Voiding and low density ground can arise from natural and cultural processes. Voiding has a significant effect on the physical properties of the subsurface that can be exploited by a number of geophysical techniques. Shallow voids represent mass deficiency in the near surface. Gravity techniques can detect mass deficiency as anomalously weak features in the gravitational field as measured at the Earth's

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surface. Resistivity techniques such as ERT can detect changes in electrical properties that arise due to the presence of anomalous air above the saturated zone and anomalous presence of liquids below the saturated zone; both arise as a function of increased porosity with extreme cases represented by airand water-filled voids. Detecting and characterising voiding remains a key issue for near surface geophysics. Microgravity and ERT are given ratings that reflect their common use worldwide for void and cavity detection. Like many other techniques that are based upon potential fields, surface-based gravity and ERT methods suffer significant loss of both vertical and lateral resolution with depth. Proper planning of an investigation to detect and characterise voiding should involve forward modelling of the likely target to determine expectation levels as a function of, inter alia, target depth, size, shape and fill characteristics. Seismic reflection has the potential for determination of near surface voiding but few practitioners have the technical skills for void investigation in the near surface that may require advanced processing and interpretational methods such as spectral decomposition. Significant shallow seismic reflection pitfalls such as the separation of refracted and reflected arrivals from the top 20 m of the ground have been previously described. In addition to mass and electrical contrasts, the presence of voiding may provide suitable targets for GPR investigation. Radar energy is reflected from interfaces across which there is a contrast in dielectric properties. Air-soil and air-rock interfaces provide very good radar-reflecting boundaries provided conditions are suitable to propagate GPR energy to the boundary. Unfortunately, in many geological terrains, near-surface materials have significant clay fractions and moisture saturation that may preclude the use of GPR for void investigation. GPR has been successfully applied in dry conditions to depths in excess of 10 m. A field team would be expected to achieve 250 â&#x20AC;&#x201C; 500 linear metres per day of continuous GPR profiling to investigate shallow voiding. Voiding is often associated with weak ground due to a loss of stiffness of the rock/soil matrix. Variations in ground stiffness, for example microvoiding associated with gypsum dissolution within mudstones, can be investigated using seismic surface wave methods as previously described.

6.7.3.2.5. Statigraphic mapping Pipelines frequently traverse terrains where the physical and chemical characteristics of the ground change as a function of lateral variations in lithology, particularly in areas with significant structural dip. For example, difficult trenching conditions may change as a function of lateral position through a dipping coal measures sequence of cyclothems comprising coal, mudstone, sandstone and limestone units. Reconnaissance mapping of near-surface lithology can help predict ground characteristics and both optimise and add value to both further geophysical investigation and / or direct investigations. Reconnaissance techniques that can be carried out with rapid ground coverage by the use of real time dGPS positioning include electromagnetic ground conductivity (mapping water and clay content), magnetic gradiometry (mapping magnetite distribution). Helicopter-towed airborne electromagnetic systems using multiple frequencies from about 400 Hz to 100 kHz can provide very rapid coverage of pipeline corridors and routes and can determine bulk conductivity to many tens of metres; for example to differentiate between mudstone and sandstone strata. Airborne systems are particularly useful in steep topography (drape coverage) or where ground access is problematic. Higher system frequencies can be used to rapidly map variation in the surface distribution of recent deposits to differentiate sandprone from clay-prone strata. Ground productivity rates of reconnaissance techniques with real time dGPS control between 1 and 5 line-km per day per instrument may be achievable assuming a single profile subject to access and topography.

6.7.4. Satellite imagery and InSAR surveying Earth observation techniques, using both optical and radar satellites, offer solutions in both pipeline route planning and pipeline monitoring, particularly where integrity is under threat from a range of geohazards. These same monitoring techniques can also be used as part of the route feasibility assessment. This section focuses more heavily on the satellite radar monitoring techniques which are less easily replicated by airborne operations.

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6.7.4.1. Pipeline routing Geographic and geomorphological data derived from satellite imagery can greatly increase efficiencies in pipeline construction both at initial planning and at more detailed engineering design stages. Relatively low cost mapping data from has contributed significant cost-benefit in route selection by early identification of geomorphological factors. Satellite imagery can provide reliable, up-to-date and low cost terrain visualisation and general infrastructure assessment in the early project planning phases. Practitioners are able to source and digitise topographic maps from around the world to provide a very inexpensive source of elevation data useful for assessment of general terrain altitude and slopes that would be encountered by different route options or alternatively, where available maps do not meet required specifications, produce elevation data from stereo satellite imagery.

Figure 16: Satellite imagery and elevation data, represented as gridded models or contours, for pipeline routes Satellite imagery is able to facilitate an assessment of both geomorphological and geological considerations and contribute data on the following: slopes, slope deposits, rock-fall and landslips; wetlands, water bodies, channels and flood risk; sites and controls on erosion and deposition; subcrop and solid/drift geology; fault zones and historic/active seismicity; volcanic activity and risk. Where needed satellite imagery is able to assist with the land cover classification requirements as part of the route planning process.

Figure 17: Geomorphological interpretation of satellite imagery

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6.7.4.2. Pipeline monitoring Monitoring ground movement with radar satellites has evolved in the last decade from conventional differential InSAR to intensive InSAR processing techniques such as â&#x20AC;&#x2DC;persistent scatterer interferometryâ&#x20AC;&#x2122;. The following section gives a short introduction to InSAR principles and techniques, respectively, and illustrates applications for monitoring pipeline.

6.7.4.2.1. InSAR principles SAR interferometry (InSAR) is a technique in which the returning radar signals of two or more radar scenes of the same location are processed to allow the detection of ground movements to millimetric accuracy. Although satellites travel in very precise orbits there will be slight differences in the position of the satellites when two images of the same location are acquired. These differences allow for angular measurements similar to the principle used in optical photogrammetry, here with the angles not being measured directly, but inferred from distance measurements using trigonometry. For InSAR, the phase rather than the amplitude information is used from the returning signal to increase the accuracy of the measurement.

6.7.4.2.2. Data sources There five SAR satellites sources namely ERS-1 and ERS-2, Envisat, Radarsat-1 and -2. TerraSAR-X, Cosmo SkyMed and ALOS. ERS-2 and its precursor ERS-1 have built up a regularly updated archive of more than 1.5 million scenes with the focus on Europe dating back to 1992 and the Envisat satellite enables continuity of SAR image acquisitions world-wide. The Canadian Radarsat-1 and Radarsat-2 instruments work on an image request basis and as a result archives are not as extensive. With InSAR, measurements are generally limited to the characteristics of the sensor used to acquire the data. For example, measurements are only possible in the line-of-sight of the sensor and scene updates depend on the repeat cycle frequency of the satellite. For long-term historical measurements, the data archive of the sensor needs to be checked for availability of sufficient SAR data. For the ground motion to be resolved unambiguously in the resulting maps, ground movement should not exceed a quarter of the wavelength of the sensor. For example, for ERS with a wavelength of 5.6 cm, subsidence rates should not be larger than 1.4 cm per shortest consecutive repeat image acquisitions (35 days).

6.7.4.2.3. InSAR techniques There are three core InSAR methods summarized as differential SAR interferometry (DifSAR), persistent scatterer interferometry (PSI) and corner reflector (CR) or compact active transponder (CAT) interferometry.

6.7.4.2.4. Differential InSAR (DifSAR) DifSAR maps wide-area relative ground deformation and can cover an area of 100 km by 100 km area in a single process. The output is a map of ground deformation showing sub-centimetric displacements in the line-of-sight (LOS) of the satellite. DifSAR requires that during the two (or more) acquisitions the response characteristics of the area of interest have not changed. Consequently, depending on the ground cover, only relatively short measurement periods from 24 days (rural environment) to 8 years (urban or arid areas) can be processed to fulfil this requirement.

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Figure 18: Differential interferometric displacement map showing impact of mining subsidence across a proposed pipeline route. Image copyright Fugro NPA 1999. SAR data copyright ESA 1999.

Figure 19: Deformation map showing mining subsidence in Dorsten, Germany. The interferometric colour cycles are overlain on IKONOS imagery. The colour range shows subsidence levels in mm over 35 days from purple 30mm to red at 60mm. Image copyright Fugro NPA 2004. SAR data copyright ESA 1998. IKONOS data copyright European Space Imaging 2003.

6.7.4.2.5. Persistent scatterer interferometry (PSI) The persistent scatterer interferometry (PSI) technique uses large numbers of co-registered SAR images (50 to 100) to identify time persistent radar scatterer points and to derive an atmospheric phase screen for each scene. Derivation and accounting of the atmospheric effects in the processing produces much finer measurements than the DifSAR technique. Subject to data acquisition it is possible that a motion history from 1992 onwards can be derived. PSI maps wide-area relative ground movements with sub-millimetric accuracy along the satelliteâ&#x20AC;&#x2122;s LOS and its precision is beyond that achievable with GPS. The absolute spatial accuracy is about 15m, while the relative spatial accuracy is about +/- 5m in East-West and +/-2m in North-South direction. PSI therefore represents a cost and time effective measure of ground motion over large areas.

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PSI requires a large number of ERS SAR scenes (minimum 20) and for a small number of locations outside of Europe, not enough data may be available to apply this technique. A feature of the technique is that the number and location of persistent scatterers cannot be predicted before processing, and measurement success can only be guaranteed over built-up (urban) areas or over dry and rocky regions. To complement the distribution of persistent scatterer points, artificial radar reflectors may be installed at specific locations of interest, as described below.

6.7.4.2.6. Corner reflectors and compact active transponders Corner reflectors (CRs) are purpose built triangular reflecting metal plates angled upwards towards the satellite and installed at specific locations of interest. The CR is about 1.2m in all three dimensions and attaches to a flat base-plate which itself is anchored to the ground or structure of interest. Subcentimetric ground movements are detectable at each CR location. The absolute spatial accuracy is about 20m or better, but can be precisely ascertained at the time of installation by GPS surveying. To receive a clear CR response, CRs need to be sited away from other potential scatterers such as buildings or metallic structures, or overhead obstructions. An alternative to CRs are compact active transponders (CATs) which are smaller than CRs and do not suffer as much from environmental impact such as strong winds or the accumulation of snow or debris. While the CRs can only be oriented to suit either the ascending or descending viewing modes of the satellite CATs can be used for both modes, thus potentially increasing temporal measurement sampling.

6.7.4.2.7. Concluding remark Optical satellite imagery offers considerable insight into the route planning process particularly in classification and assessment of geomorphological and geological factors. For pipeline monitoring satellite radar offers a range of techniques to assess integrity and geohazard threat. Radar interferometry has matured to a widely used geodetic technique for measuring the topography and deformation of the earth. Three ground motion measurement techniques are available that complement each other for pipeline monitoring: 1) Conventional interferometry to map wide-area movements within a short time frame at low cost. 2) Persistent scatterer interferometry to provide a time series dating back to 1992 for each persistent radar reflector found in the scene. 3) Corner reflector and compact active transponder interferometry to measure ground and structure motions at specific locations and geohazard target areas.

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6.8

Buoyancy Control

6.8.1 Purpose The purpose of this specification is to list methods for controlling pipeline buoyancy, with associated pros and cons for each method.

6.8.2 General Pipelines will cross different areas along the project route in which the presence of water may produce a flotation medium for the pipeline. Therefore, pipelines may be subject to uplift forces and make them float above their burial depth. According to Archimedesâ&#x20AC;&#x2122; principle any body, fully or partially submerged, will be pushed with an upward force equivalent to the weight of the volume of the displaced medium. This force is also called hydrostatic uplift. If this force is greater in magnitude than the submerged pipe weight, there is a risk of the pipeline being vertically displaced, threatening its stability and integrity. Therefore, there is a need to control the pipeline sections that may be subject to buoyancy forces in the different stages of design, construction and operation. The next sections in this chapter introduce different buoyancy calculation methodologies to assure adequate stability of flooded pipes. It must be clearly understood that for valid results, the calculations methodologies shall not be mixed, for example one should not select formulae from one method and safety factors from another.

6.8.3 Development 6.8.3.1 Free body diagram The concrete-coated pipe section is a combination of concentric rings as shown in Figure 1. Assuming this configuration and polar symmetry of the analysed body, all gravitational forces and hydrostatic uplift will pass through the barycentre of the section. Furthermore, all the directions of these forces will be vertical. This is seen in Figure 1, which shows a free body diagram of a concretecoated and submerged pipe, where the forces shown are: â&#x20AC;˘ đ?&#x2018;ˇđ?&#x2019;&#x2030;: Linear concrete coating weight (perpendicular to the section) or ballast load â&#x20AC;˘ đ?&#x2018;ˇđ?&#x2019;&#x201C;: Linear anticorrosive coating weight (perpendicular to the section). â&#x20AC;˘ đ?&#x2018;ˇđ?&#x2019;&#x201E;: Linear pipe weight (perpendicular to the section). â&#x20AC;˘ đ?&#x2018;Ź: Linear hydrostatic uplift upon submerged pipe, including coatings (perpendicular to the section). â&#x20AC;˘ đ?&#x2018;: Resulting hydrostatic thrust (perpendicular to the section), usually known as â&#x20AC;&#x153;negative buoyancyâ&#x20AC;?. If the sum of forces gives a downward result the value will be negative.

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The worst scenario (the one requiring the greatest concrete coating thickness) will consist of an empty pipeline, without transportation of internal fluid. Therefore, the force corresponding to the internal fluid weight is not indicated in the free body diagram. The negative buoyancy is an estimated value (generally around 30 kg/m or 0,3 KN/m) which aims to provide a certain security given that the assumed hypothesis of this calculation corresponds to an ideal case which is unlikely to occur in real conditions (with the actual dimensions, specific weight, etc, but assuming an empty pipe).

6.8.3.2 Deducing the free body formula Developing the equilibrium of vertical forces from the free body diagram shown in Figure 1, we find: Equation 1: đ?&#x2018;&#x192;â&#x201E;&#x17D;+đ?&#x2018;&#x192;đ?&#x2018;&#x;+đ?&#x2018;&#x192;đ?&#x2018;?=đ??¸+đ??š

6.8.3.3 Common density values The following table gives (indicative) mean density values for materials frequently used in buoyancy calculation. Density of concrete Concrete with iron ore Concrete

29.82 21.97

kN/m3 kN/m3

3040.0 2240.0

kg/m3 kg/m3

Density of immersion fluid Fresh water Sea water River crossing in open cut Pipe-laying in soils with liquefaction

9.81 10.06 9.91 11.77

kN/m3 kN/m3 kN/m3 kN/m3

1000.0 1025.0 1010.0 1200.0

kg/m3 kg/m3 kg/m3 kg/m3

Density of coating FBE 3LPP 3LPE

13.93 8.83 9.32

kN/m3 kN/m3 kN/m3

1420.0 900.0 950.0

kg/m3 kg/m3 kg/m3

Density of sack filling Aggregate for pipe sack

23.54

kN/m3

2400

kg/m3

6.8.4 Design by minimum buoyancy Equation 1:

đ?&#x2018;&#x192;â&#x201E;&#x17D;+đ?&#x2018;&#x192;đ?&#x2018;&#x;+đ?&#x2018;&#x192;đ?&#x2018;?â&#x2C6;&#x2019;đ??¸â&#x2C6;&#x2019;đ??š=0

đ?&#x2018;&#x2020;đ?&#x2018;&#x17D;đ?&#x2018;&#x201C;đ?&#x2018;&#x2019;đ?&#x2018;Ąđ?&#x2018;Ś đ?&#x2018;&#x201C;đ?&#x2018;&#x17D;đ?&#x2018;?đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;&#x;=đ?&#x2018;&#x192;â&#x201E;&#x17D;+đ?&#x2018;&#x192;đ?&#x2018;?+đ?&#x2018;&#x192;đ?&#x2018;&#x;đ??¸

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6.8.5 Continuous concrete coating: design by minimum thickness Here, we expand the first four terms in Equation 1, expressing the terms as sections (areas): Equation 2: đ??´â&#x201E;&#x17D;đ?&#x203A;žâ&#x201E;&#x17D;+đ??´đ?&#x2018;&#x;đ?&#x203A;žđ?&#x2018;&#x;+đ??´đ?&#x2018;?đ?&#x203A;žđ?&#x2018;?+đ??´đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2019;đ??š=0 Where: â&#x20AC;˘ â&#x20AC;˘ â&#x20AC;˘ â&#x20AC;˘ â&#x20AC;˘ â&#x20AC;˘ â&#x20AC;˘ â&#x20AC;˘

đ??´â&#x201E;&#x17D; : Concrete section (area). đ?&#x203A;žâ&#x201E;&#x17D; : Concrete specific weight đ??´đ?&#x2018;&#x; : Anticorrosive coating section. đ?&#x203A;žđ?&#x2018;&#x; : Anticorrosive coating specific weight. đ??´đ?&#x2018;? : Pipe section. đ?&#x203A;žđ?&#x2018;? : Pipe specific weight đ??´: Total section (area delimitated by the external concrete boundary). đ?&#x203A;žđ?&#x2018;&#x161; : Surrounding medium specific weight (fluid producing hydrostatic uplift).

Figure 2: Typical section of a concrete-coated pipe Concrete load The first term on the left side of Equation 2, can be expanded as the following expression (see Figure 2): Equation 3: đ??´â&#x201E;&#x17D;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;= đ?&#x153;&#x2039;4 đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;+đ?&#x2018;&#x2019;â&#x201E;&#x17D;2â&#x2C6;&#x2019;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;2â&#x2C6;&#x2014; đ?&#x203A;žâ&#x201E;&#x17D; Where: â&#x20AC;˘ đ??ˇ: Pipe nominal diameter â&#x20AC;˘ đ?&#x2018;&#x2019;đ?&#x2018;? : Pipe wall thickness â&#x20AC;˘ đ?&#x2018;&#x2019;đ?&#x2018;&#x; : Anticorrisive coating thickness â&#x20AC;˘ đ?&#x2018;&#x2019;â&#x201E;&#x17D; : Concrete coating thickness The only unknown in Equation 3 is the concrete coating thickness "eh"; the other terms are known inputs at this stage. Developing the quadratic binomial in Equation 3, cancelling equal terms and then reordering according to the unknown â&#x20AC;&#x153;đ?&#x2018;&#x2019;â&#x201E;&#x17D;â&#x20AC;?, the following expression is obtained Equation 4 đ??´â&#x201E;&#x17D;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;= đ?&#x153;&#x2039;â&#x2C6;&#x2014; đ?&#x203A;žâ&#x201E;&#x17D;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D;2+ đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;â&#x2C6;&#x2014;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D; Anticorrosive coating load Proceeding in the same way, the second term of Equation 2 can be written as (see Figure 2): Equation 5 đ??´đ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x;= đ?&#x153;&#x2039;4 đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;2â&#x2C6;&#x2019;đ??ˇ2â&#x2C6;&#x2014; đ?&#x203A;žđ?&#x2018;&#x; Developing the quadratic binomial, cancelling and reordering Equation 5, we obtain Equation 6 đ??´đ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x;= đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;â&#x2C6;&#x2014;đ??ˇ+đ?&#x2018;&#x2019;đ?&#x2018;&#x;

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Pipe section load The third term of Equation 2can be written as (see Figure 2): Equation 7 đ??´đ?&#x2018;?â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;?= đ?&#x153;&#x2039;4â&#x2C6;&#x2014;đ??ˇ2â&#x2C6;&#x2019;đ??ˇâ&#x2C6;&#x2019;2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;?2â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;? Developing the quadratic binomial, cancelling and reordering Equation 7, we obtain Equation 8 đ??´đ?&#x2018;?â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;?= đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;?â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;?â&#x2C6;&#x2014;đ??ˇâ&#x2C6;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;? Medium uplift load The fourth term of Equation 2 can be expressed as (see Figure 2): Equation 9 đ??´â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x161;= đ?&#x153;&#x2039;4â&#x2C6;&#x2014;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;+đ?&#x2018;&#x2019;â&#x201E;&#x17D;2â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x161; Developing the quadratic binomial, cancelling and reordering according to the unknown coat thickness â&#x20AC;&#x153;đ?&#x2018;&#x2019;â&#x201E;&#x17D;", we obtain:: Equation 10 đ??´â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x161;= đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D;2+đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2014;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D;+đ?&#x153;&#x2039;4â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2014;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;2 Main equation Replacing Equation 4, Equation 6, Equation 8, and Equation 10 (developing the terms) into Equation 2 and grouping according to the unknown "ehâ&#x20AC;? (the coat thickness we seek to minimise), we obtain Equation 11 đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;â&#x2C6;&#x2019;đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D;2+đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;â&#x2C6;&#x2019;đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D;+

đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žđ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;â&#x2C6;&#x2014;đ??ˇ+đ?&#x2018;&#x2019;đ?&#x2018;&#x;+đ?&#x203A;žđ?&#x2018;?â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;?â&#x2C6;&#x2014;đ??ˇâ&#x2C6;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;?â&#x2C6;&#x2019;đ?&#x203A;žđ?&#x2018;&#x161;4â&#x2C6;&#x2014;đ??ˇ+2â&#x2C6;&#x2014;đ?&#x2018;&#x2019;đ?&#x2018;&#x;2â&#x2C6;&#x2019;đ??š=0 Equation 11 is a quadratic polynomial of unknown â&#x20AC;&#x153;đ?&#x2018;&#x2019;â&#x201E;&#x17D;â&#x20AC;?, where â&#x20AC;&#x153;Aâ&#x20AC;?, â&#x20AC;&#x153;Bâ&#x20AC;? and â&#x20AC;&#x153;Câ&#x20AC;? are the coefficients of the different terms, e.g. đ??´=đ?&#x153;&#x2039;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;â&#x2C6;&#x2019;đ?&#x203A;žđ?&#x2018;&#x161;. To solve the expression and get the results for â&#x20AC;&#x153;đ?&#x2018;&#x2019;â&#x201E;&#x17D;ehâ&#x20AC;?, the quadratic polynomial formula is used Equation 12 đ?&#x2018;&#x2019;â&#x201E;&#x17D;+,đ?&#x2018;&#x2019;â&#x201E;&#x17D;â&#x2C6;&#x2019;=â&#x2C6;&#x2019;đ??ľÂąđ??ľ2â&#x2C6;&#x2019;4â&#x2C6;&#x2014;đ??´â&#x2C6;&#x2014;đ??ś2â&#x2C6;&#x2014;đ??´ The concept of adding a coating weight (in this case the concrete) is that such a coating has a greater specific weight than the surrounding medium which produces the hydrostatic uplift. Then, coefficient "A" will be always positive (đ?&#x203A;žâ&#x201E;&#x17D;>đ?&#x203A;žđ?&#x2018;&#x161;). In the same way, coefficient "B" will also always be positive. In order to obtain a real value for đ?&#x2018;&#x2019;â&#x201E;&#x17D;, the discriminant (term under the root) must be positive, i.e. đ??ľ2>4â&#x2C6;&#x2014;đ??´â&#x2C6;&#x2014;đ??ś.. Considering the previous statements and analysing Equation 12, only the first root of that solution will be positive (when the discriminant is added). Therefore, the theoretical thickness for concrete coating is obtained by using the following formula: Equation 13 đ?&#x2018;&#x2019;â&#x201E;&#x17D;=â&#x2C6;&#x2019;đ??ľ+đ??ľ2â&#x2C6;&#x2019;4â&#x2C6;&#x2014;đ??´â&#x2C6;&#x2014;đ??ś2â&#x2C6;&#x2014;đ??´ where "Aâ&#x20AC;?, "B" and â&#x20AC;&#x153;Câ&#x20AC;? are the previously-mentioned coefficients in Equation 11.

6.8.5.1 Results Conveniently introducing diameters, thicknesses, specific weights and desired negative buoyancy in Equation 13 (see Equation 11 for coefficients â&#x20AC;&#x153;Aâ&#x20AC;?, â&#x20AC;&#x153;Bâ&#x20AC;? and â&#x20AC;&#x153;Câ&#x20AC;?), the theoretical concrete coating thicknesses â&#x20AC;&#x153;đ?&#x2018;&#x2019;â&#x201E;&#x17D;â&#x20AC;? are obtained. Due to constructability issues, the adopted concrete coating thickness đ?&#x2018;&#x2019;â&#x201E;&#x17D;đ?&#x2018;&#x17D;đ?&#x2018;&#x2018;đ?&#x2018;&#x153;đ?&#x2018;? is also considered. These are related by the safety factor previously given in section 4: đ?&#x2018;&#x2019;â&#x201E;&#x17D;đ?&#x2018;&#x17D;đ?&#x2018;&#x2018;đ?&#x2018;&#x153;đ?&#x2018;?=đ?&#x2018; đ?&#x2018;&#x17D;đ?&#x2018;&#x201C;đ?&#x2018;&#x2019;đ?&#x2018;Ąđ?&#x2018;Ś đ?&#x2018;&#x201C;đ?&#x2018;&#x17D;đ?&#x2018;?đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;&#x;â&#x2C6;&#x2014;đ?&#x2018;&#x2019;â&#x201E;&#x17D;

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6.8.5.2 Conclusions In order to avoid pipeline flotation, the concrete coating thicknesses should be equal or greater than đ?&#x2018;&#x2019;â&#x201E;&#x17D;đ?&#x2018;&#x17D;đ?&#x2018;&#x2018;đ?&#x2018;&#x153;đ?&#x2018;?. The previous statement is valid for the considerations detailed in this document.

6.8.6 Ballast load design by minimum load In this case, we rewrite Equation 1 (đ?&#x2018;&#x192;â&#x201E;&#x17D;+đ?&#x2018;&#x192;đ?&#x2018;&#x;+đ?&#x2018;&#x192;đ?&#x2018;?â&#x2C6;&#x2019;đ??¸â&#x2C6;&#x2019;đ??š=0) as follows: Equation 14: đ?&#x2018;&#x160;đ?&#x2018;&#x2020;â&#x2C6;&#x2014;đ?&#x203A;žâ&#x201E;&#x17D;â&#x2C6;&#x2019;đ?&#x203A;žđ?&#x2018;&#x161;đ?&#x203A;žâ&#x201E;&#x17D;+đ??´đ?&#x2018;&#x;đ?&#x203A;žđ?&#x2018;&#x;+đ??´đ?&#x2018;?đ?&#x203A;žđ?&#x2018;?â&#x2C6;&#x2019;đ??´đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2019;đ?&#x2018;&#x201C;=0 Where: â&#x20AC;˘ đ?&#x2018;&#x160; : Ballast weight in air. â&#x20AC;˘ đ?&#x203A;žâ&#x201E;&#x17D; : Ballast specific weight in air â&#x20AC;˘ đ?&#x2018;&#x2020;: Spacing between two ballast â&#x20AC;˘ đ??´đ?&#x2018;&#x; : Anticorrosive coating section. â&#x20AC;˘ đ?&#x203A;žđ?&#x2018;&#x; : Anticorrosive coating specific weight. â&#x20AC;˘ đ??´đ?&#x2018;? : Pipe section. â&#x20AC;˘ đ?&#x203A;žđ?&#x2018;? : Pipe specific weight â&#x20AC;˘ đ??´: Total section (area delimitated by the external diameter). â&#x20AC;˘ đ?&#x203A;žđ?&#x2018;&#x161; : Surrounding medium specific weight (fluid producing hydrostatic uplift). Here, the safety factor is defined as follows: đ?&#x2018;&#x2020;đ?&#x2018;&#x17D;đ?&#x2018;&#x201C;đ?&#x2018;&#x2019;đ?&#x2018;Ąđ?&#x2018;Ś đ?&#x2018;&#x201C;đ?&#x2018;&#x17D;đ?&#x2018;?đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;&#x;=đ?&#x2018;&#x192;â&#x201E;&#x17D;đ??¸â&#x2C6;&#x2019;đ?&#x2018;&#x192;đ?&#x2018;?â&#x2C6;&#x2019;đ?&#x2018;&#x192;đ?&#x2018;&#x;

6.8.7 Safety factor on medium density As the main uncertain is on medium density a valid alternative design is to apply the safety factor only on the density of the medium (the fluid providing the hydrostatic uplift). đ?&#x203A;žđ?&#x2018;&#x161;đ?&#x2018;&#x17D;đ?&#x2018;&#x2018;đ?&#x2018;&#x153;đ?&#x2018;?= đ?&#x203A;žđ?&#x2018;&#x161;â&#x2C6;&#x2014; đ?&#x2018; đ?&#x2018;&#x17D;đ?&#x2018;&#x201C;đ?&#x2018;&#x2019;đ?&#x2018;Ąđ?&#x2018;Ś đ?&#x2018;&#x201C;đ?&#x2018;&#x17D;đ?&#x2018;?đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;&#x;

6.8.8 Back-filling Care should be taken if backfill is intended to be used as a means to ballast the pipeline for buoyancy control, as the nature of soil could vary significantly, e.g. in density and type of soil. For back filling below the water level the density of flooded material shall be used.

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6.8.9 Span lengths and stresses for ballast loads 6.8.9.1 Common definition Various stresses for are presented below, which all share the following symbol definitions: đ??źđ??ˇ [m] Inside diameter đ?&#x2018;&#x201A;đ??ˇ [m] Outside diameter đ?&#x2018;Ą [m] Pipe thickness đ??ż [m] Span length of bending member đ??¸ [Pa] Modulus of elasticity đ??¸=207,000,000 [đ?&#x2018;&#x192;đ?&#x2018;&#x17D;] đ?&#x2018;&#x203A; [-] Poisson ratio đ?&#x2018;&#x203A;=0.3 đ?&#x2018;&#x17D; [m/m C] Thermal coefficient đ?&#x2018;&#x17D;=1.16Ă&#x2014;10â&#x2C6;&#x2019;5 [đ?&#x2018;&#x161;/đ?&#x2018;&#x161;đ??ś] đ?&#x2018;&#x17E; [N/m]Load per unit length

6.8.9.2 Stress due to distributed load on beam The moment for fixed ends beam is calculated with the following formula M at support= qâ&#x2C6;&#x2014; L212 N m V= qâ&#x2C6;&#x2014; L2 N â&#x2C6;&#x2020; Max= qâ&#x2C6;&#x2014; L4Eâ&#x2C6;&#x2014; I m Ď&#x192;b= Âą Mâ&#x2C6;&#x2014; OD2â&#x2C6;&#x2014; I Nm2= Âą Mâ&#x2C6;&#x2014; OD2â&#x2C6;&#x2014; Iâ&#x2C6;&#x2014; 1,000,000 MPa Where: đ?&#x153;&#x17D;đ?&#x2018;? [MPa] Stress due to bending moment đ??ź [m4] Moment of inertia đ??ź= đ?&#x153;&#x2039;64 đ?&#x2018;&#x201A;đ??ˇ4â&#x2C6;&#x2019;đ??źđ??ˇ4

6.8.9.3 Stress due to saddle According to AWWA publication M11, the stress at the saddle tips can be calculated with the following formula: đ?&#x2018;&#x2DC;= 0.02â&#x2C6;&#x2019;0.00012â&#x2C6;&#x2014; (đ?&#x203A;źÂ°â&#x2C6;&#x2019;90Â°) đ?&#x153;&#x17D;â&#x20AC;˛đ?&#x2018;&#x2020;= đ?&#x2018;&#x2DC;â&#x2C6;&#x2014; đ?&#x2018;&#x2030;đ?&#x2018;Ą2â&#x2C6;&#x2014; đ?&#x2018;&#x2122;đ?&#x2018;&#x153;đ?&#x2018;&#x201D;đ?&#x2018;&#x2019;đ?&#x2018;&#x2026;đ?&#x2018;Ą Nm2

đ?&#x153;&#x17D;đ?&#x2018; = đ?&#x153;&#x17D;â&#x20AC;˛đ?&#x2018; 1,000,000 [đ?&#x2018;&#x20AC;đ?&#x2018;&#x192;đ?&#x2018;&#x17D;]

Where: đ?&#x153;&#x17D;đ?&#x2018;&#x2020; đ?&#x2018;&#x2DC; đ?&#x203A;ź đ?&#x2018;&#x2030; đ?&#x2018;&#x2026;

[MPa] Local bending stress at saddle tips [-] Coefficient [Â°] Contact angle in degrees, normally 120Â° [N] Total saddle reaction [m] Pipe outside radius đ?&#x2018;&#x2026;=đ?&#x2018;&#x201A;đ??ˇ/2

6.8.9.4 Hoop stress Hoop stress is calculated as follow đ?&#x153;&#x17D;â&#x201E;&#x17D;= đ?&#x2018;&#x192;đ?&#x2018;&#x;đ?&#x2018;&#x2019;đ?&#x2018; đ?&#x2018; đ?&#x2018;˘đ?&#x2018;&#x;đ?&#x2018;&#x2019;â&#x2C6;&#x2014; đ?&#x2018;&#x201A;đ??ˇ2â&#x2C6;&#x2014;đ?&#x2018;Ą MPa Where: đ?&#x153;&#x17D;â&#x201E;&#x17D; [MPa] Hoop stress

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6.8.9.5 Poisson stress Poisson stress is calculated as follow đ?&#x153;&#x17D;đ?&#x2018;?= đ?&#x153;&#x2C6; â&#x2C6;&#x2014; đ?&#x153;&#x17D;â&#x201E;&#x17D; MPa Where: đ?&#x153;&#x17D;đ?&#x2018;&#x192; [MPa] Poisson stress

6.8.9.6 Thermal stress Thermal stress is calculated as follow đ?&#x153;&#x17D;â&#x20AC;˛đ?&#x2018;Ą= â&#x2C6;&#x2019;đ??¸â&#x2C6;&#x2014; đ?&#x203A;ź â&#x2C6;&#x2014; đ??ˇâ&#x2C6;&#x2020;đ?&#x2018;&#x2021; đ?&#x2018;&#x192;đ?&#x2018;&#x17D; đ?&#x153;&#x17D;đ?&#x2018;Ą= đ?&#x153;&#x17D;â&#x20AC;˛đ?&#x2018;Ą1,000,000 [đ?&#x2018;&#x20AC;đ?&#x2018;&#x192;đ?&#x2018;&#x17D;] Where: đ?&#x153;&#x17D;đ?&#x2018;Ą [MPa] Thermal stress

6.8.9.7 Combined stress The combinations of stresses which can be calculated can vary from code to code, so an appropriate code must be used to address the combinations of stresses and equivalent pressure calculation criteria applicable to the problem at hand.

6.8.10 Continuous concrete coating A layer of concrete applied continuously to the required length of pipeline can provide weight for buoyancy resistance. The concrete may be applied on site at the ditch side, or remotely. The advantages of this system are that trucking costs may be reduced when local sources of aggregate and concrete are available and mechanical protection is provided to the pipe in cases where installation damage is a concern. The disadvantages of the system are that extra equipment and care are required to handle the pipe, due to the extra weight. If coating off-site, transporting the heavier coated pipe is also more costly. If easily accessible source of aggregate are not available near the right-of-way, onsite concrete coating is generally not an option, as the cost to transport concrete bolt-on weights and concrete coated pipe are comparable, but handling of concrete-coated pipe would have been more onerous than ballast weight.

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6.8.11 Ballast weight Ballast is defined as weight that is added to a floating structure to improve stability. In pipeline contexts, ballast is discrete weights that are distributed along the pipeline at a fixed distance from a starting point that denote the start of flooded or high water table area. As a general rule when installing ballast weights, the separation tolerance is 0.5 metres apart, and laying weights on welds should be avoided.

6.8.11.1 Pipe sack Pipe sacks are woven (or not woven) geo-textile bags that hold aggregate (sand or gravel) and are draped over the pipe to resist buoyant forces, like a set-on weight. Different types of sack are available on the market, and from one manufacturer to another, the geotextile fabric used could change significantly in make, thickness and strength. The advantages of pipe sacks are that trucking costs are reduced and installation is relatively easy. The disadvantages of this system are that sufficient quantities of aggregate must be available nearby and ditch conditions must be suitable for installation. Furthermore, for pipeline with large diameters, the weight of each filled sack is in the order of tons (filled sack weight is approximately 3.1 t for 30” pipeline, and 5.6 t for 42” pipeline), so consideration is needed regarding handling and transport on the ROW.

6.8.11.1.1 Installation For non-freezing conditions, a dry, clean aggregate ballast (less than five per cent silt content) or gravel with diameter of 5 to 20 mm is recommended. For freezing conditions, a screened stone with a diameter between 5 to 20 mm is recommended. Sack filling can take place with the sack in a horizontal or vertical position, depending on the sacks’ design. In both case a skid could be used to facilitate operations.

For long-term storage or freezing conditions it is advisable to cover the filled sacks with UV resistant wraps. Trench depth will be unchanged, but width shall be increase to twice the pipe’s nominal diameter.

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6.8.11.2 Concrete saddle, set-on type Concrete set-on weights, or saddle weights, are masses of pre-cast concrete, set on top of the pipeline after it has been lowered into the trench. The mass of the concrete is used to increase the pipelineâ&#x20AC;&#x2122;s resistance to buoyancy. As a result, ditch conditions need to be relatively firm and dry, not only to prevent the pipe from floating up and out of the trench during installation, but also to prevent the set-on weight from overturning and releasing the pipe. These weights are frequently used whenever buoyancy control is needed for operating conditions, that is, whenever it is anticipated that the local water table will rise and the soil overlying the pipe will be incapable of restraining the pipe from floating.

6.8.11.2.1 Installation Typical drawings for the saddle are shown here. The saddle is designed to optimize the distance between one saddle and the other, and to have a gap between pipe and saddle in order to avoid overstressing the pipe when water is not present. Pipes must be protected with plastic sheets in the area in contact with saddle, in order to avoid damages to pipeline coatings. The sheet shall extend from both sides of the saddle. The saddle shall be designed to avoid the saddle resting on top of the pipe in dry conditions â&#x20AC;&#x201C; after installation a gap of about 20 mm must be present between the inside of the saddle and the pipe surface. The trench where the saddle shall be installed shall be designed to be wider than normal, and with a parallel wall in the bottom, in order to facilitate and guide the saddle during lowering in.

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6.8.11.3 Concrete collar, bolt-on type Bolt-on weights are two-piece pre-cast concrete weights that encircle the pipe with the pieces â&#x20AC;&#x153;boltedâ&#x20AC;? together to prevent detachment from the pipe. They are primarily used for water crossings or where ditches are very wet and/or have no firm bottom. Their main advantage is the certainty they provide that the weight will stay attached to the pipe, and continue to perform its function. Concrete bolt-on weights are similar to set-on weights, except that they are manufactured in two halves. Each half is installed on the pipeline and then bolted together.

6.8.11.3.1 Installation Bolt-on weights are installed on the pipeline before the pipeline is lowered into the trench and are typically used in areas where a large section of pipeline is to be installed in one piece into a submerged trench, as in a large river crossing. Bolts shall be hot-dip galvanized and protected with bibulous coating to protect from corrosion, installed in vertical position with nuts on top. The pipeline shall be protected from contact with concrete by interposing a polyethylene sheet or wood lagging between the two concrete halves and the pipeline.

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6.8.12 Anchor Soil anchoring systems rely on the force developed from the soil in front of the anchor. The stress distribution in front of a loaded anchor can be modelled using foundation theory. The ultimate performance of an anchor is defined by the load at which the stress concentration immediately in front of the anchor exceeds the bearing capacity of the soil. Factors that will affect the ultimate performance of the anchor include: • Shear angle of the soil • Size of the anchor • Depth of installation • Submerged conditions Generally anchors perform exceptionally well in a granular soil, displaying short load lock and extension characteristics, with a broad frustum of soil immediately in front of the anchor and extremely high loads. Stiff cohesive soils, such as boulder clays, can also give good results. However, weaker cohesive soils, like soft alluvial clays, can result in long load settle and extension distances and a small frustum of soil in front of the anchor. Consequently these conditions require a larger size of anchor and if possible a deeper driven depth to achieve their design load.

Standard mathematical models can be used for sizing the anchor and preliminary study for both granular soil (based on Terzaghi’s calculation) and soft cohesive soil (based on Skempton’s calculation), but in any case for a reliable installation only field test results should be relied on.

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6.8.12.1 Screw anchor Screw anchors are pairs of steel helices (screws), with one screw installed on either side of the pipeline, providing an “anchor” into the ground. Helix size and design depend on the type of soil and force required. A polyester strap crosses over the pipe and connects to each of the screws. The advantages of this system are that the materials are relatively light and transportable, anchor spacing is much greater than with conventional set-on weights, are suitable for peat bogs and organic soils, and overall costs are low where significant quantities are involved. An additional advantage of screw anchors is that they only engage if the pipe attempts to move upwards. As a result, they don’t contribute to any settlement loading on the pipe in poor soil conditions. Disadvantages of this system are that ditch conditions must be suitable and a special installation crew is required. Screw anchors, while usually less expensive to procure, transport and install than concrete weights, must be limited to those areas where the pipe can be successfully placed in the bottom of the ditch prior to backfilling. Screw anchors and extra depth are not effective if, during lowering-in, the open ditch is filled with water. However, if the organic layer is too deep to allow “deep ditch” to be used, and the ditch is relatively dry, screw anchors can be cost effective.

6.8.12.1.1 Installation To start anchor design, it is advisable to have a general description of the soil, and SPT-N test results. In principle however, the anchor-developed force is related to the torque force. Generally, a 10:1 ratio exists between the installation torque (measured in foot pounds) and the ultimate holding capacity of an anchor (in pounds). As a general rule an anchor shaft with a rated capacity of 2 times the specified minimum installation torque is recommended in order to avoid breakage, or stopping of operations if during installation glacial tills or other irregular soil types are encountered. This shaft design will enable the installation to proceed even though the anchor may encounter soils slightly firmer than the design soil strength, and also will enable the installation to proceed when the anchor encounters gravel or cobbles. If installation equipment is able to develop a torque in excess of the maximum allowed by the screw shaft, the installation must be equipped with a torque limit device.

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Screws are driven, perpendicularly to pipeline axis, into soil by hydraulic motors. Operators monitor the oil pressure as it is directly related to the torque applied to the screw shaft. The shaft will be extended to allow the screw to enter deeper into the soil until a required minimum pressure and consequently the minimum design torque is achieved. The hydraulic motor is disengaged, coupling on top of shaft is installed and a polyester pipeline saddle is firmly attached to coupling, taking care to leave a gap of 50 80 mm maximum between the pipeline outside diameter and saddle. The final screw assemble shall comprise the shaft with helix (6 feet long) plus as minimum one extension (6 feet long); shorter assemblies shall be evaluated case by case. In areas of permafrost the screw anchor shaft shall be installed below high ice content permafrost to the required depth. A higher installation torque may be specified for anchors terminating within the permafrost. If below the minimum depth, an installation torque for non-permafrost area is appropriate.

As a general rule for anchor installation, the separation tolerance is 0.5 meters, and one should avoid laying a polyester pipeline saddle within 0.5 meter from welds. Final pull testing on 1 in every 10 anchor systems should be done at 115% of design load on both screws. The load shall be held for a minimum of 60 seconds. If the movement is greater than 25 mm or a continuous creep occurs, the screw anchor has failed the test. In case of failing an extension shaft shall be added to the anchor, to run the screw to lower depths. It shall then be retested. In addition the two screw anchors adjacent to the failing assembly (one on each side) shall be pull tested using the same procedure. After failures, the test investigation frequency shall be increased to 1 in every 5 anchor systems.

6.8.12.2 Bath anchor Another earth anchor system is the bath anchoring system. This is mainly set up with anchors similar to that shown. Their shape and dimensions varies depending on the required load. Bath anchors are driven into the soil by percussion rod. In comparison with screw anchors, the bath system can only be installed at shallow depths and the load that can be sustained by each system is less.

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6.8.12.2.1 Installation Installation of the bath anchor system is simple: a hydraulic processor pushes the bath into the soil, and after reaching the required depth the rod is removed and the bath is pulled up to turn and settle the surrounding soil. When the two baths are in place a polyester saddle strip is firmly tied up between them. As no direct correlation exists with the percussion force and minimum load, each bath anchor shall be pull-tested following the same procedure described for the screw anchors.

6.8.13 Comparison From the above it is clear that each solution has strengths and weaknesses that need to be evaluated properly, taking into consideration factors including the location of the production facility, transport, availability on site of aggregate, site condition, trench condition, etcâ&#x20AC;Ś Consequently it is not possible to give a general score based on abstract paper work, but only some general indications: here we summarise the pro and cons of each system.

Cost Transport Installation condition Installation speed Certainty

Pipe sack Set-on type Bolt-on type Continuous concrete + + + +

Screw anchor + + +

Bath anchor + + -

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Crossings

7.1

Trenchless Crossings

7.1.1 Cross Country Obstacles In previous chapters open trench construction methods have been explained. Going forward for cross country pipeline construction these methods are actually the most efficient and fastest pipeline construction methods. But in most projects it will not be possible to trench the whole way. Hence, it is highly likely that the pipeline will come across either surface or sub-surface obstacles along the route that will require specialized construction techniques. Some types of possible obstacles range from:

• • • • • • • •

Rivers or coast line Traffic infrastructure (roads, railways) Logistic infrastructure (e.g. canals, other pipelines, electricity) Buildings Nature protection areas Pipeline security (climate - freezing/thawing ground, damages - other infrastructure, impacts) Topography (inclination, mountain) Alignment design, depths

Each of these obstacles will have their own construction constraints including minimizing environmental impact, pollution prevention, and minimizing disruption. Discussed below are some of the alternative pipeline construction methods available to enable the pipeline to cross obstacles on the route in a safe and environmentally acceptable manner.

7.1.2 Underground Construction Methods Many of the existing construction methods have come from the tunnelling industry or were developed initially for cable installation , but many of these methods are not always suitable for laying underground pipelines especially when most of the upcoming projects have pipeline diameters of 42”or bigger. To give a full overview the following chart lists the whole range of underground construction methods from small to big diameters and for short or long under-ground crossings.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

7.1.2.1 Overview of existing technologies

Most of the common technologies were developed for laying small diameter infrastructure over short distances. For this reason the following chapters will focus on the yellow marked methods which are suitable for most of the underground construction parts of pipeline construction projects. Additionally not all of these technologies are suitable for all underground conditions. At the beginning of each underground project all project conditions have to be analyzed to find the safest and most cost-efficient method. The following chapter presents the most important decision criteria to decide which method is the best to keep the project in time and cost frames.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

Additional issues to be considered include: Comment • Minimizing disruption

The disruption on the environment should be reduced to a minimum. Disruption could be sound, dirt, ground and air pollution etc.

• Crossing type and size

Crossing of artificial infrastructure (streets, rails etc.) or natural obstructions (rivers, special topography etc.) require different regulations and considerations.

• Both surface and sub-surface surveys

Various questions, including: Is there enough area to prepare construction-side?Is the topography sufficient to prepare the pipeline??

• Pipeline design

Has the pipe been adequately designed for the construction conditions, or has it to be modified regarding the chosen method? (e.g. is the pipe wall thickness sufficient to perform a pipe jack operation?)

7.1.2.2 Decision Criteria Geology Analyzing the soil investigation report provided by the client is always the very first step into an underground construction project. Note, however, that prior to developing the requirements of the soil investigation, the pipe alignment must be developed taking into account the requirements of pipe stress, scour, cavitation and obstacles, to ensure the full extent of the trenchless crossing is adequately covered by the survey. Soil properties have an impact on

•

Cutting tools

•

Material conveyance

•

Installed power

•

Drilling fluid

Comment Soft and hard rock cutting tools are customized to soil conditions and provide low wear and long operating time. Depending on the soil condition different conveying methods are available and have to be optimized for each project. Different soil conditions require different technology capacities. Hard rock requires higher excavation energy than soft soil. The drilling fluid properties are defined for the existing soil conditions. The drilling fluid has to stabilize the reamed and drilled hole and to reduce the forces during pull/push in of the pipeline.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

•

Drilling diameter

•

Drilling length

•

Soil stabilization

•

Pipe wall thickness

•

Pipe coating / field joint coating

The required drilling diameter varies, depending on the soil condition and the underground construction method to be chosen. Also the arch effect to make a hole stable is different in different soils. A indirect impact leads into different drilling lengths, because different underground construction methods have different start situations at the launch side which leads to longer or shorter crossings. Stable (standing) or not stable (non-standing) soil conditions have to be supported differently. Support by drilling fluids is limited to hole diameter, cover, drilling length etc. Pipelines are designed additionally to the impact during construction period also to ground and ground water pressures during the operating period. Factory and field coatings should protect the pipeline during operating period against corrosion. But during construction period the coating has to resist different impacts like friction, point loads etc.

To give a safe recommendation as a basis for technology decisions as many as possible of the following sub-surface data should be available. Rock and soft soil samples for laboratory testing should be taken in general from the depth of the planned pipeline but not directly in bore line to avoid vertical transfer of drilling fluid during construction. “The site investigation boreholes should be carried out at a maximum spacing of 50 m […] In special cases, the intervals shall be reduced. The boreholes shall be carried out at least: • • •

Down to 2 m below the pipe invert in ground water free soils Down to 3 m below the pipe invert in ground water bearing soils Down to the planned bottom edge of the sheeting in the area of the starting, intermediate and target pits

and should be continued down to the stable subsoil in the case of insufficiently stable subsoil. All holes that may be caused by this investigation shall be securely filled.” (source: Standard DWA-A125E, Dec 2008).

For Rock Conditions Criteria • Rock type, mineral content

Comment: Examples: Sediment (e.g. sandstone), igneous (e.g. granite) or metamorphic rock (e.g. gneiss); impact on drillability Impact on: Bore diameter, drilling length, cutting tools, wear, machine design

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

•

UCS, uniaxial compressive strength Comment: The higher the compressive strength, the more difficult it is to destroy the rock; low values: below 15 MPa; high values: above 50 MPa Impact on: Bore diameter, drilling length, cutting tools, wear, machine typee

•

Tensile strength or gap tensile strength

Comment: Typical range of tensile strength is from 5 to 30 MPa. High tensile strength means more energy for chipping and higher wear. Impact on: Bore diameter, drilling length, cutting tools, wear, machine design

•

CAI, Cerchar Abrasivity Index

Comment: Range of CAI-index from 0 (not abrasive) to 6 (extremely abrasive). Granite has 5 for example and is extremely abrasive and creates high wear on cutting tools, pumps and lines. Impact on: Wear, drilling length

•

RQD rock quality designation or joint spacing, orientation of joints

Comment: RQD value (0-100%) indicates the quality of a rock-mass: 0-25% indicates very poor rock, 90100% indicates excellent rock. The joint spacing and the orientation of the joints indicates the stability of an open borehole and defines for example the kind of support which affects the machine design Impact on: Cutting Tools, machine design

•

Degree of alteration/weathering

Comment: Gives idea of the drillability and stability, the fresher the rock, the more difficult to bore but the more stable the borehole is. Impact on: Cutting tools, machine design

•

Abrasive mineral content

Comment: Used when no CAI is possible. The higher the percentage of abrasive minerals (e.g. quartz), the higher the wear of cutting tools. Impact on: Wear, drilling length

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

•

Water permeability / k-value

Comment: Indicates groundwater inflow towards the working face of the machine and with possibly the necessity for watertight machines. The water permeability indicates also the loss of drilling fluids into the rock formation. Impact on: Machine design

For Soft or Mixed Soil Conditions Criteria • Particle size distribution curves (PSD)

Comment: Gives overall impression on the characteristics of a soil. Defines the amount of coarse (e.g. gravel) and fine (e.g. silt) material in a soil. Impact on: Cutting tools, machine design, separation equipment

•

SPT values (Standard Penetration Test)

Comment: Indicates the compactness or consistency of a soil. The higher the SPT-N value, the higher the compactness of the soil (e.g. values 0 to 4 indicate very loose soil; values above 50 indicate very dense soil) Impact on: Cutting tools, soil conditioning,

•

Obstacles

Comment: Depending on the diameter of the borehole, sometimes stones, boulders, blocks or timber are referred to as obstacles. If known special equipment can help to clear obstacles. Impact on: Cutting tools, special equipment

•

Water permeability / k-value

Comment: Indicates groundwater inflow towards the working face of the machine and with possibly the necessity of water tight machines. The water permeability indicates also the loss of drilling fluids into the soil formation. Impact on: Machine design

•

Compactness

Comment: Very dense soil indicates different cutting conditions than loose soil Impact on: Cutting Tools

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

•

Atterberg limits, mole firmness

Comment: Need to be tested on samples in the laboratory. They tell about the behaviour (plasticity) of a finegrained soil in different stages of watersaturation. Also clogging risk can be predicted with the Atterberg limits. Impact on: Machine design, conveyance system, soil conditioning

•

Cohesion

Comment: Is important for the frictional forces within a soil – only fine grained soil (clay or silt) exhibits cohesion Impact on: Cutting tools, machine design

•

Shear strength, angle of friction

Comment: Structural analysis, machine selection, thrust bearing. Mostly used for calculations for structural analysis

•

Bulk density

Comment: Structural analysis, machine selection, buoyancy; Important to define shield loads and the tendency to move vertical in very soft soils.

•

Abrasive mineral content

Comment: The higher the percentage of abrasive minerals (e.g. quartz), the higher the wear of cutting tools Impact on: Wear, drilling length

Especially for horizontal directional drilling (HDD) projects but also for microtunnelling projects the soil conditions and ground water have a deep impact on the bentonite lubrication or drilling fluid in general. Therefore the following additional data are needed: Criteria Measurement unit: • pH of the ground water [-] • Ca-hardness of the ground water [mmol/l] • Other contaminants (chlorine, iron… ) [mg/l] • Swelling clays volume increase [%], swelling pressure [psi] • Saltwater salinity [mg/l] or electric conductivity [μS/cm]

Note Even the best jobs will have widely spaced boreholes which can mask potential ground variability. The key step is understanding the geology and its variability, and there should be an interpretation of the boreholes and the geology in terms of ground conditions and variability. Some of the tests and test results are not always available in testing labs. Therefore cores should be kept available for other potential tests.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

Alignment design In underground pipeline construction the product pipeline has to be pushed or pulled along the designed alignment and has to follow all curves or gradients. Especially in urban areas alternative route selection to avoid extreme pipeline configurations is limited by local or environmental conditions and the designed curves or gradients may influence the pipe design itself (e.g. steel quality, wall thickness, stress limits) and the possible construction methods.

Construction time and costs To have a fair and safe decision about the most time and cost-effective underground construction method all construction steps from beginning (jobsite installation) till removal of all equipment from jobsite have to be included. Also space requirements for pipe storage or pipe string, start/target pits, foundations etc. will have deep impact on the overall construction costs. For schedule estimation not only the drilling performance but also the number of construction steps are important. To have a most cost-effective underground construction product especially close to other infrastructure a combined crossing could have advantages. When building a river crossing casing tunnel for a later pressure pipeline installation other infrastructure lines (e.g. gas, water, electricity) could be included. Using such combined crossings the need for additional crossing projects could be reduced and the additional space in such a tunnel could have a commercial benefit (sold or rented)

7.1.3 Main Technologies In section 7.1.2.1 there is a limited overview table on existing underground technologies. Each technology has its eligibility for special project conditions. Three main groups of underground technologies will be focused on, facing the main future pipeline construction challenges, especially regarding capacity, diameter and numbers or lengths of crossings.

7.1.3.1 Horizontal Directional Drilling (HDD) Procedure In the first phase of a horizontal directional drilling (HDD) project a drill bit is pushed through the ground on a designed alignment from an entry point close to the drill rig to an exit point on the other side of the obstacle to be crossed. Established surveying and steering techniques are used and proven drill tools are available for a wide range of soil and rock conditions. Fig 1 â&#x20AC;&#x201C; Pilot drilling

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

The pilot drilling is then enlarged by one or more reaming passes until it has reached the desired diameter. For this purpose, suitable tools like barrel reamers, fly cutters or hole openers are used. During the process, drill pipes are continuously added behind the reamer to ensure that there is an entire drill string from the entry to the exit point at all times Fig 2 – Reaming

In the final step of the operation the product pipe is pulled into the reamed borehole starting at the exit point on the other side of the obstacle. The drill string in the borehole is connected to the pipe by a special pull head with a swivel. As soon as the drill rig has pulled the whole pipeline into the ground and the pull head arrives at the entry point, the pipeline has reached its final and safe position deep in the ground Fig 3 – Pullback

The critical point during the HDD process is the time from finishing the pilot drilling to pulling back the product pipeline into the borehole. During that time when the borehole diameter has to be enlarged from pilot drilling cutting bit diameter (up to approx. 8”) to the diameter where the product pipeline can be pulled in. This final diameter should be the product pipeline diameter plus one third of its diameter, so that the pipeline can be pulled in with minimal friction resistance. During this time the borehole has to be stabilized by special drilling fluids like bentonite plus special additives customized to the soil conditions. Non-cohesive ground (e.g. gravel) below ground water are quite problematic to stabilize using such drilling fluids and need to be analyzed intensively to determine if it is feasible to proceed. As a result the HDD method is a well-proven method in suitable soil conditions but should not be recommended in heterogeneous (soil/rock/soil) geologies. Also appropriate topography on pipe side and rig side is important to achieve bore geometry (curves) suitable for the pipe material flexibility. Major advantages of horizontal directional drilling are: • Direct installation of product pipelines; no casing pipe/tunnel required • Cost effective • Fast pipeline installation • Long distance crossings achievable • Small ratio of borehole diameter/pipeline diameter

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

7.1.3.2 Microtunnelling In the microtunnelling (pipe jacking) process a casing tunnel (usually made of concrete pipes) with the heading machine at its tip is driven by hydraulic cylinders from a launch shaft towards the target shaft. The distance to the target shaft can be as much as 1000 meters or more, depending on the nominal diameters of the pipes, the geological conditions, the pipe materials and the number of intermediate jacking stations. The thrust cylinders are retracted after they have reached their final position. The next tunnelling pipe is let down into the launch shaft, installed and then pushed forward. This process is repeated until the target shaft has been reached. The tunnelling machine is then recovered from the target shaft and prepared for the next operation. When the tunnelling machine has been recovered the casing tunnel has been finished. In a next step the product pipeline could be inserted (by floating or using rollers installed inside the tunnel) into the casing tunnel. The space between product pipeline and casing tunnel will usually be filled with grout to provide pipe and corrosion protection. Additionally to the pipeline other infrastructure could be installed inside the tunnel to minimize the costs and schedules and or an optimal use of the crossing structure. As an alternative to microtunnelling and pipe jacking the casing tunnel could also be constructed using tunnel segments which are combined to form full tunnel rings. This common known tunnelling method allows smaller curve radii and longer drives especially if the casing tunnel diameter is bigger than approx. 2500mm (90”). Tunnelling machine technology is comparable in both tunnelling methods. Fig 4 – Microtunnelling

Trenchless tunnelling has many advantages for the environment, traffic flow and those living in the affected area, because no major earth shifting is necessary at the tunnelling site and only a few shafts are required. Above ground everything carries on as before. Major advantages of microtunnelling are: • Roads do not need to be dug up or cordoned off and there are no traffic jams • Earth moving or construction site traffic (trucks) are kept to a minimum • Groundwater lowering is required only at certain spots resulting in minimum environmental impact

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

• • •

Minimum inconvenience to inhabitants from dirt and noise No danger to historic buildings Sewers and buildings not subject to subsidence.

Facing the upcoming major offshore pipeline projects which have to be brought ashore in the most ecologically friendly manner, the microtunnelling technology opens an additional construction option often used for sea outfalls. To protect the coastline areas the construction starts from a launch shaft back from the shore line. Underground and under the seabed the tunnel or pipeline leads to an exit point where the machine will be recovered by divers and the pipeline will be connected to the offshore pipeline part laying on the seabed. Fig 5 – Microtunnelling technology in a coastline context

7.1.3.3 Combined Technologies In the past, numerous methods and devices have been developed for the trenchless laying of pipelines in the ground to enable sensitive areas on the surface to be crossed. Geological considerations and time and cost budgets are the crucial factors determining the choice of the most suitable laying technique. Underground pipeline laying poses many problems - for example, how to work in a space-restricted area or circumvent possible obstacles both rapidly and cost-effectively. Combination methods, like the direct pipe method, combine the advantages of the established microtunnelling and horizontal directional drilling (HDD) pipe laying methods, thereby opening up potential new applications. One single, continuous working operation is sufficient for the trenchless laying of a pre-fabricated pipeline and the simultaneous creation of the necessary borehole. Fig 6 – A combined technology approach

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

As with pipe jacking, earth excavation is by means of a microtunnelling machine. The machine is navigable and uses a slurry circuit to transport the excavated material to the surface. Modern and proven controlled pipe jacking techniques ensure accurate measurement of the current position along the intended route. The force required to feed the pipeline forward is provided by a new type of feed device known as the pipe thruster. The thrust necessary for the boring process is transferred along the pipeline to the cutter head. Advantages of combined technologies: • Combining advantages of conventional construction methods • Saving construction costs and time • Pushes the boundaries of HDD • Feasible in a wide range of geologies

7.1.4 Technology Decision Chart The following decision chart was developed to get a first intention of feasible technologies to handle upcoming projects as well as a first ranking of possible options. The criteria are mainly qualitative and individual manufacturer solutions have to be developed for each project.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

Comparision Criteria

HDD

Microtunnelling

Combined Methods e.g. Direct Pipe

Simple geology Clay, Silt, Sand

Easy

Non-standing geology Gravel, Bolders, Rock < 300mm

Difficult

Easy

Medium

Hard geology Rock 50-100 MPa

Medium

Easy

Medium

Very hard geology Rock > 100-200 MPa

Difficult

Medium

Difficult

Heterogeneous geology (soil to hard/very hard rock or vice versa)

Difficult

Medium

Drill hole is permanently supported by jacking pipes and annulus is filled with bentonite. No drill hole collapse possible. Microtunnelling technology is very flexible regarding different geologies.

Drill hole is permanently supported by jacking pipes and annulus is filled with bentonite. No drill hole collapse possible. Microtunnelling technology is very flexible regarding different geologies. Annulus is much smaller than using HDD.

Cover has to be calculated based on the comments below

Cover has to be high to prevent collapse and avoid bentonite spilling on surface soil above, because the reamed hole is only stabilised by bentonite (pressure). Depends also on Comment pipeline allowable curvature and soil strength. Must also prevent ground settlement or cavitation, and allow alignment through suitable soils. If under a river must be below scour level.

Cover >2,5 times outer machine diameter. Drill hole permanently supported. Cover only for preventing setting or lifting on surface. To prevent ground settlement or cavitation. Annulus higher than microtunnelling because the pipeline is smoothly flowing in the surrounding bentonite. If under a river must be below scour level.

Very difficult

Easy

Soil and reamed hole is only stabilised by bentonite suspension. Different geologies and crack spacing where Comment bentonite could flow in increase the risk of collapse.

Recommended minimum cover (under surface obstructions road, rail - or rivers)

Direct application of product pipes (steel pipes with protective coating)

Easy

After pilot boring and reaming Comment product pipeline will be pulled direct into reamed hole. Ensure correct coating selection. Welding and quality control (prior to installation of product pipes)

Yes

Jacking of product stell pipelines Product pipeline will directly installed into the drilled hole. is very difficult and costly (welding, coating the field joints). Mostly casing required. Difficult (or only in temporary tunnels)

Pipeline will be prepared outside Pipeline has to be welded and coated in sections in the tunnel Comment of hole and is ready to handle and control. or shaft. Quality requirements of flushing medium (Slurry Water / Bentonite)

Very high

Low

Reamed hole is only stabilised Drill hole is supported by jacking by bentonite. Bentonite has to pipes. Bentonite is only for be very precisely modified to soil reducing friction forces. Comment conditions to prevent hole collapse. Required volume of flushing medium

High

Complete reamed hole has to Comment be filled with bentonite.

Yes Pipeline will be prepared outside on pipe side on surface and is ready to handle and control. Medium No lubrication between tunnelling machine and start shaft possible, so bentonite has two functions: lubrication and annulus suport. But drill hole is also supported by pipeline.

Low

Only small annulus is filled with bentonite.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

Comparision Criteria

HDD

Microtunnelling

Combined Methods e.g. Direct Pipe

Required drill hole size

Medium

Large

Small

Drill hole has to be just 10 cm Drill hole (reamed hole) has to be Drilled hole has to be made for bigger that product pipeline to fill Comment 1,3 times of product pipeline, to the casing tunnel where the later with bentonite and reduce get a smooth pull in. product pipeline will be inserted. friction. In-situ access to the cutting tools (for replacement in case of wearing out)

Not possible

No access to cutting tools in case of high wear. Complete drill string has to be pulled and Comment change tools outside.

Excavation of "obstructions" (for example via cone crusher)

Not possible

No obstructions can be Comment removed out the hole. Retractability of the pipeline / rods (for replacement in case of wearing out) Comment

Achieveable maximum drive lengths

Possible Pipeline can be pulled back by the HDD rig.

Very long (up to 2500m)

Possible (>OD 1500mm, reinforced concrete pipes) Microtunnelling machines are accessible from spec. Diameter regarding to local regulations and change tools inside the machine.

Microtunnelling machines are accessible from spec. Diameter regarding to local regulations and change tools inside the machine. In case of smaller diameters pipeline has to be retracted.

Possible

Obstructions can be removed Obstructions can be removed through tunnelling machine or through tunnelling machine or will be cracked by cutting tools. will be cracked by cutting tools. Very difficult, but possible

Very difficult

Easy

Very big job side required on rig Very small job sides / shafts on both crossing sides. Comment side and pipe side. Construction of shaft / trench

Easy

Very simple launch and Comment reception pits possible. Only anchoring of HDD is required. Tunnel / Pipeline alignment accuracy

Medium

Difficult (due to depths) To come down to tunnel level requires expensive dry shaft construction. Very good

Navigation of pilot boring by Navigation by laser, gyro, water Comment gyro or from surface. Acceptable levelling. Extreme precisely. accuracy. Execution time

Medium quick

Long

Depending on final reamed hole Several working steps: Shaft diameter several reaming construction, jacking of casing Comment processes are neccessary. tunnel, pulling or pushing in of product pipeline

Possible

Pipeline and tunnelling machine Tunnelling machine has to be designed retractable and can be can be pulled back by the pipe pulled through the tunnel. Very thruster. costly. Long to very long Medium to long (by using segmental lining (currently up to max. 1500m, >2500m) ) depending on geology)

Drive length of HDD depends on Economic design of jacking pipeline / reamed hole diameter. pipes to handle the increasing It is necessary to stabilise the jacking forces is the criteria. Comment reamed hole with bentonite.The bigger the hole diameter the more likely collapse becomes. Project access possibility

Possible (>OD 1400mm, steel pipes)

No intermediate jacking stations and lubrication only from machine and shaft is possible.

Easy Very small job sides / shafts on both crossing sides and very flexible. Easy - medium Easy launch pit and reception side, only anchoring of pushing unit /pipe thruster. Very good Navigation by laser, gyro, water levelling. Extreme precisely. Quick Very quick because no reaming procedures and no casing required.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

Note: Not considered in this chart are crossing lengths. In general the HDD method will have advantages in small crossing projects and allows reduced costs and time frames. For large diameters and long crossings alternatives to HDD should reduce the risks of reaming processes and heterogeneous geologies and lead to trustable costs.

General Note: Further, more detailed information and decision criteria for this chapter are available in numerous and international guidelines and standards like ASCE (American Society of Civil Engineers) manuals, PRCI (Pipeline Research Council International) reports, DWA (Deutsche Vereinigung f端r Wasserwirtschaft, Abwasser und Abfall e. V.) working sheets and many others.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Section 7

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Glossary

Glossary The following definitions and abbreviations apply in the context of this Appendix unless otherwise mentioned: AGI Above ground installations AUT Automatic ultrasonic testing CAD Computer-aided design CANBUS Controllerâ&#x20AC;&#x201C;area network bus standard CANDATA CANBUS data CCS Camp control system CMod EDMS contacts module CP Cathodic protection CPM Critical path method CSE Confined space entry DES Discrete event simulation ECI Eddy current inspection EDI Electronic data interface/interchange EDMS Electronic document management system ERP Emergency response plans ERW Electric resistance weld ExTr Expediting and shipment tracking system FBE Fusion bonded epoxy FLUW Facing, lining up and welding (IPLOCA working group) FMS Fleet management system FOC Fiber-optic cables GIS Geographic information system GPRS General packet radio service GPS Global positioning system GSM Global system for mobile HAZID Hazard identification HAZOP Hazard and operability study HFW High frequency induction weld HLA High level architecture HSE Health, safety and environment HSEIA/HSEIS Health, safety and environment impact assessment/study HSES Health, safety, environment and socioeconomic IP Injured person IPLOCA International Pipe Line and Offshore Contractors Association JMS Journey management system KP Kilometer point LLI Long lead items LNG Liquified natural gas MAOP Maximum allowable operating pressure MFL Magnetic flux leakage MMS Material management system MPI Magnetic particle inspection MTO Made to order MUT Manual ultrasonic testing NC/NCI IPLOCA Novel Construction Initiative NDT Non-destructive testing NRT Near-real-time tool OD Outside diameter OEM Original equipment manufacturer PDA Personal digital assistant PDC Planning, design and control (IPLOCA workgroup) PFD Probability to fail on demand PK Point kilometre (see KP) PMV Plant machinery and vehicles POD Probability of detection

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Glossary

PPE PTO QA/QC QRA R&D RFID RFQ ROW RPE RSS RT SAWH SAWL SCADA SIL SIMOPS SIS SMS SMYS UPI UT VOC VPN WBS WiFi WiMax WPS WT XML

Personal protective equipment Power take-off Quality assurance/control Quantitative risk assessment Research and development Radio-frequency identification Request for quotation Right of way Respiratory protective equipment Really simple syndication (web feed format for publishing frequently updated works) Radiographic testing Submerged arc-welded pipe, helical seams Submerged arc-welded pipe, longitudinal seams Supervisory control and data acquisition Safety integrity level Simultaneous operations Safety instrumented system Short message service (texts) Specified minimum yield strength Unique purchase items Ultrasonic testing Volatile organic compound Virtual private network Work breakdown structure Wireless networking technology Worldwide interoperability for microwave access (protocol) Welding procedure specifications Wall thickness Extensible markup language

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Bibliography

Bibliography Section 3.4 1.

ICE:

Conditions of Contract

The ICE Form of Contract - 7th Edition 1999. The Form creates a "Measure for Value" or "Re-Measurement" contract by which the Employer undertakes to pay for the actual quantities of work executed. The Engineering and Construction Contract (Third Edition 2005) known as "NEC 3". "NEC 3" is a Suite of Contract Forms ranging from EPC Contract, with Main Options A-F Clauses, through Term Service Contract, Professional Services Contract, Subcontract and Short Subcontract, Short Contract, Framework Contract Service and Adjudication Agreements, published in twenty-nine books including tailored guidance notes, flow-charts and contract strategies.

Typically a NEC 3 Option "A" - Priced Contract with Activity Schedule, is a bound document composed of :

• • • • • • • • 3.

Schedule of Options; Core Clauses; Option A Clauses; Dispute Resolution Options W1 and W2; Secondary Options X1-7, X12-18, X20, Y(UK)2, Y(UK)3 and Z Clauses; Schedule of Cost Components; Shorter Schedule of Cost Components; Contract Data part one and part two proforma.

FIDIC: The FIDIC Suite of Contracts 1999 and the Gold Book 2008 The Four Principal Contract 1999 Forms are:

The Short Form of Contract 1st Ed (1999 Green Book); The Conditions of Contract for Construction (The 1999 Red Book) ***; The Conditions of Contract for Plant and Design-Build (The 1999 Yellow Book); The Conditions of Contract for EPC Turnkey Projects (The 1999 Silver Book).

Section 6

Earthworks

“Performance management for site restoration in rugged terrain”, by M Sweeney, A Gasca, RPC Morgan and J Clarke, in Int. Conf. on “Terrain and geohazard challenges facing onshore oil and gas pipelines”, London June 2004, pub Thomas Telford Ltd, p 687-700. Geotechnical Aspects of Pipeline Design and Construction in Soft Very Sensitive Clay, J. Sarrailh and L.S. Brzezinski, June 1983.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Bibliography

First Edition Acknowledgements More than 100 persons and 45 companies participated in the preparation of this publication. Each person’s name is mentioned in the main area of her/his participation as follows:

•

as a member of one, or more than one, of the six Working Groups

•

in the coordination and support functions

•

as having given editorial support to members of the Working Groups

•

as having attended one or more Plenary Sessions of the Novel Construction Initiative

This work is the outcome of six Working Groups: 1. Planning, Design & Control (PDC) Co-Chairmen: Mike King *(BP) & Zuhair Haddad (CCC) Participants: Yasser Hijazi* (CCC), John Truhe (Chevron), Paul Andrews* (Fluor), Cris Shipman (GIE), Paulo Montes (Petrobras), Tales Matos (Petrobras) 2. Contract Negotiating & Risk Sharing (CRS) Co-Chairmen: Barry Kaiser* (Chevron) & Bruno de La Roussière* (Entrepose) Participants: Sarah Boyle (Heerema), Barbara de Roo (Heerema), Paul Andrews* (Fluor), Frank Todd (Land & Marine), Jean Claude Van de Wiele (Spiecapag), Daniel Picard (Total) Consultant to IPLOCA and principal writer: Daniel Gasquet* 3. Pipeline Earthworks (EW) Co-Chairmen: Paul Andrews* (Fluor) & Bruno Pomaré (Spiecapag) Participants: Mike Sweeney (BP), Ray Wood (Fugro), Helen Dornan* (Serimax), Sue Sljivic* (RSK Group plc), Flavio Villa (Tesmec), Francesco Mastroianni (Tesmec), 4. Facing, Lining-Up & Welding (FLUW) Co-Chairmen: Frederic Burgy (Serimax) and Bernard Quereillahc* (Volvo) Participants: Zahi Ghantous (CCC), Jim Jackson (CRC-Evans), Marco Laurini (Laurini), Claudio Bresci (Petrobras), Derek Storey (Rosen) 5. External Corrosion Protection System (ECPS) Chairman: Sean Haberer* (Bredero Shaw) Participants: Dieter Schemberger (Akzo Nobel), Vlad Popovici* (Bredero Shaw), Nigel Goward (Canusa-CPS), Michael Schad (Denso), Graham Duncan (Fluor), Damian Daykin (PIH) 6. Lowering & Laying (L&L) Chairman: Marco Jannuzzi* (Caterpillar) Participants: Zahi Ghantous (CCC), Kees Van Zandwijk (Heerema), Peter Salome (Heerema), Marco Laurini (Laurini), Claudio Bresci (Petrobras), Marcus Ruehlmann (Vietz), Lars-Inge Larsson (Volvo)

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Bibliography

โ ข

Overall Coordination and Support to the six Working Groups Coordination was carried out by Luc Henriod* (IPLOCA), Ian Neilson (BP) and Franรงois Pesme (BP), supported by the IPLOCA staff in Geneva who organised the plenary sessions, conference calls etc: Juan Arzuaga*, Caroline Green, Alain Hersent (IPLOCA Consultant), Sarah Junod and Liz Spalding. Roberto Castelli (Bonatti) was in charge of coordinating with the Board of Directors of IPLOCA. *Names of the writing and editing team of the final document are designated in this Acknowledgement by an asterisk (*).

The following persons have given editorial support to members of the Working Groups or have showed their interest and support by attending some of the Plenary Sessions of our IPLOCA Novel Construction Initiative (in alphabetical order by company): Antonio Galetti (Bonatti), Andrea Piovesan (Bonatti), Barry Turner (Borealis), Bill Blosser (BP), Patrick Calvert (BP), Shaimaa Fawzy (BP) , Roger Howard (BP), Hikmet Islamov (BP), John McAlexander (BP), Colin Murdoch (BP), Geoff Vine (BP), Jean-Luc Bouliez (BS Coatings), Ray Paterson (BrederoShaw), Adrian Van Dalen (BS Coatings), Cortez Perotte (Caterpillar), Kurt Wrage (Caterpillar), Issam El-Absi (CCC), Joseph Farah (CCC), Hisham Kawash (CCC), Ramzi Labban (CCC), Fernando Granda (Chevron), Keith Griffiths (Chevron), Karlton Purdie (Chevron), Brad Stump (Chevron), C.S. Sood (CIT), Bo Wasilewski (Conoco-Phillips), Martin Kepplinger (deceased) - (CRC-Evans), Brian Laing (CRC-Evans), Gus Meijer (CRC-Evans), Bernhard Russheim (CRC-Evans), Oliver Zipffel (Denso), Peter Schwengler (E.ON Ruhrgas), Claudia Mense (Elmed), Carlo Spinelli (ENI), Paul Leyland (Entrepose), Jean-Pierre Jansen (Europipe), Daniel Delhaye (Fluor), Sub Parkash (Fluor), Conrado Serodio (GDK), Karl Trauner (HABAU), Marc Peters (Herrenknecht), Frank Muffels (Industrie Polieco MPB), Lorne Duncan (Integrated Project Services), Ed Merrow (IPA Global), Hudson Bell (ITI Energy), Nigel Wright (ITI Energy), Adam Wynne Hughes (Land and Marine), Tom Lassu (Ledcor), Boris Boehm (Maats), Jorge Baltazar (Petrobras), Sergio Borges (Petrobras), Paulo Correia (Petrobras), Ney Passos (Petrobras), Jimmie Powers (PRCI), Max Toch (PRCI), Jie-Wei Chen (Rosen), Mike Mason (RSK Group plc), David Williams (Serimax), Massimiliano Boscolo (Socotherm), Danillo Burin (Socotherm), Lotfi Housni (Somico), Remy Seuillot (Spiecapag), Luis Chad (Tenaris-Confab), Livia Giongo (Tesi), M. Lazzati (Tesmec) Francesco Mastroianni (Tesmec), John Welch (Tesmec), Andrea Zamboni (Tesmec), Paul Wiet (Total), Bart Decroos (Volvo), Jack Spurlock (Volvo).

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Acknowledgements

Second Edition Acknowledgements More than 100 persons and 46 companies participated in the preparation of this Second Edition.

•

The work was divided among six working groups: 1. Planning and Design Co-Chairmen: Criss Shipman (GIE) & Mike King (BP) Participants: Mustafa Abusalah, Firas Hijazi, Ramzi Labban (CCC); Sub Parkash (Fluor) 2. Monitoring & Control Co-Chairmen: Zuhair Haddad (CCC) and Mike Gloven (Petro IT Americas) Participants: Jan Van der Ent (Applus RTD); Aref Boualwan, Firas Hijazi, Antoine Jurdak, Hazem Rady, Khaled Al-Shami (CCC); Abhay Chand (Petro IT); Paul Wiet (Total) 3. Pipeline Earthworks Co-Chairmen: Paul Andrews (Fluor) & Bruno Pomaré (Spiecapag) Participants: Ray Wood (Fugro); Marc Peters (Herrenknecht); Marco Laurini (Laurini); Flavio Villa (Tesmec); Lars-Inge Larsson (Volvo) 4. External Corrosion Protection System (ECPS) Co-Chairmen: Sean Haberer (ShawCor), Vlad Popovici (Bredero Shaw FJS) Participants: Volker Boerschel, Dieter Schemberger (Akzo Nobel); Norbert Jansen, Barry Turner (Borealis); Raphael Moscarello (Bredero Shaw); Adrian Van Dalen (BS Coatings); Paul Boczkowski (Canusa-CPS); Cindy Verhoeven (Dhatec); Bill Partington (Ledcor); Fred Williams (Shell); Dan King, Steve Shock, Dave Taylor (TransCanada); Axel Kueter (Tuboscope) 5. Facing, Lining-Up & Welding (FLUW) Co-Chairmen: Frédéric Lepla (Serimax) and Bernard Quereillahc (Volvo CE) Participants: Subhi Khoury, Ramzi Labban (CCC); Matthew Holt (CRC-Evans); Christian Hädrich (Max Streicher); Mladen Kokot (Nacap) 6. Lowering & Laying Chairman: Marco Jannuzzi (Caterpillar) & Bernard Quereillahc (Volvo CE) Participants: Andreas Clauss, Scott J. Hagemann, Cortez Perotte (Caterpillar); Jim Jackson (CRC-Evans); Marco Laurini (Laurini); Hannes Lichtmannegger, Johannes Mayr (Liebherr); Scott Haylock, Lars-Inge Larsson (Volvo CE)

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Acknowledgements

•

Overall Coordination and Support to the Working Groups Coordination was carried out by Juan Arzuaga (IPLOCA) and Daniel Gasquet (IPLOCA Consultant), supported by the IPLOCA staff in Geneva: Caroline Green, Guy Henley, Sarah Junod and Elizabeth Spalding. Osman Birgili (Tekfen) was in charge of coordinating with the Board of Directors of IPLOCA. Additionally, we thank the following companies and individuals for their valued participation in the Second Edition of the Road to Success (in alphabetical order by company): Paul Harbers, Dirk Huizinga, Niels Portzgen, Casper Wassink (Applus RTD); Maurizio Truscello (Bonatti S.p.A.); SC Sood (CIT); Rita Salloum Abi Aad (CCC); Russell Dearden (Corus); Ryan Fokens, Dennis Haspineall (CRC-Evans); Ivan Gallio, Nicola Novembre, Luca Prandi, Carlo Spinelli (ENI); Andreas Meissner (EPRG); Shiva Vencat (Euro Airship); Graham Duncan, Jason Fincham, Sub Parkash (Fluor); Henk De Haan (Gasunie); John Balch (GIE); Claudio Dolza (Goriziane); Gerhard Wohlmuth (HABAU); Geert Dieperink, Gerben Wansink (Maats); Mark Roerink (Nacap); Greg Rollheiser (PipeLine Machinery); Reiner Lohmann, Ralf Prior (PPS Pipeline Systems GmbH); Peter Döhmer (Techint); Hasan Gürtay, Dinc Senlier, Alpaslan Sumer (Tekfen).

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Acknowledgements

Third Edition Acknowledgements The persons and Companies who participated in the preparation of this Third Edition are presented below.

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The work was divided among five working groups: 1. Earthworks Co-Chairmen: Paul Andrews (Fluor) & Bruno Pomaré (Spiecapag) Participants: Adam Thomas, Jon Baston-Pitt & Raphael Denis (Fugro); Mike Sweeney & David Waring (BP); Marco Albanesi & Vincenzo Calabria (Sicim); Diana Pfeff & Marc Peters (Herrenknecht); Marcelo Texeira & Tales Mattos (Petrobras); Marco Laurini & Livia Giongo (Laurini); Flavio Villa (Tesmec); Johannes Mayr (Liebherr); Lars-Inge Larsson (Volvo); David Shilston (Atkins); George Tuckwell (RSK); Neil Smith (Mears); Rene Albert (Wermeer), Daniel Gasquet (IPLOCA) 2. Pipelines and the Environment Co-Chairpersons: Sue Sljivic (RSK) & Adul Waasay Kan (SNC Lavalin) Participants: Alejandro Sarrubi (Techint); Loek Vreenegoor & Fred Williams (Shell); Goeff Tabor (RSK); Ricardo Marcus (TGP); Barbara Lax (Caterpillar); Martin Coleman (Spiecapag) 3. Future Trends and Innovation Chairman: Zuhair Haddad (CCC) Participants: Mustafa Abusalah, Firas Hijazi, Antoine Jurdak & Ramzi Labban (CCC); Luca Prandi (ENI); Abbay Chand & Mike Gloven (Petro IT); Maurizio Truscello (Bonatti); Paul Andrews & Sub Parkash (Fluor); Bruno Pomaré (Spiecapag); Andrea Trevisanello & Massimo Passarella (Goriziane); Geert Dieperink (Maats); Marco Jannuzzi (Caterpillar); Jan van der Ent (Applus RTD); Idsart van Assema (Dhatec) 4. Logistics Co-Chairmen: Bruno Pomaré (Spiecapag) and Bernard Quereillahc (Volvo CE) Participants: Cindy Verhoeven (Dahtec); Christophe Kapron (Renault Trucks); Jean-Michel Gallois (Vopak); Frédéric Teitgen (TOTAL); Oscar Scarpari (Techint); Firas Hijazi (CCC) 5. Welding Co-Chairmen: Jan van der Ent (Applus RTD) & Gustavo Guaytima (Techint) Participants: Benedict de Graaff, Scott Funderburk & Paul Spielbauer (CRC-Evans); Frédéric Lepla (Serimax); Fabio Rinaldi & François Pesme (PWT); Matt Boring (Applus RTD); Kevin Beardsley (Lincoln Electric); Atilla Madazilioglu (TEKFEN); Ramesh Singh (GIE); Derick Railling & Mike MacGillivray (ITW); Daniel Matarrese (Techint); Anthony Van Der Heijden (Lastechniek Europa); photos courtesy of ESAB.

Onshore Pipelines - THE ROAD TO SUCCESS Vol. 1 Acknowledgements

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Overall Coordination and Support to the Working Groups Coordination was carried out by Juan Arzuaga (IPLOCA) and Daniel Gasquet (IPLOCA Consultant), supported by the IPLOCA staff in Geneva: Caroline Green, Sarah Junod and Elizabeth Spalding. Editing and English review were performed by Guy Henley and Edmund Henley (Consultants). Doug Evans (GIE) was in charge of coordinating with the Board of Directors of IPLOCA. Additionally, we thank the following companies and individuals for their valued participation in the Third Edition of the Road to Success (in alphabetical order by company): Volker Boerschel (Akzo Nobel); Frits Doddema (Seal-for-Life); Norbert Jansen (Borealis); Barry Turner & Pascal Collet (Axon Coatings); Pascal Lafferierre & Nigel Goward (Canusa CPS); (GE Measurement & Control); Frank Muffels (Industrie Polieco (MPB)); Axel Kueter (NOV Tuboscope); Sean Haberer, Vlad Popovici & Alex Durkovics (ShawCor); Rainer Kuprion (TIB Chemicals).