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CRC positions Australia as water infrastructure leader
CRC positions Australia as water infrastructure leader in lining technologies
The Water Services Association of Australia (WSAA) recently led an international project investigating innovation in smart linings for pipes and infrastructure. The $20 million project, including $3 million in funding through the Australian Federal Government’s Cooperative Research Centre (CRC), bought together 35 partners from Australia and overseas and strategically positions Australia as a global leader in smart water infrastructure design, engineering, testing and management.
WSAA is the peak industry body representing the urban water industry. The association’s members provide water and sewerage services to over 24 million customers in Australia and New Zealand, and many of Australia’s largest industrial and commercial enterprises.
The Smart Linings for Pipe and Infrastructure Project researched the effectiveness of pipe liners, focusing on four product categories: cured-in-place pipe (CIPP) and polymeric spray liners for water mains, and calcium aluminate cement (CAC) mortars and alkalai activated binders –including geopolymer cement mortars – for wastewater assets. The project received funding from the Federal Government’s CRC Program. The CRC Program supports industry-led collaborations between industry, researchers and the community.
Australia’s ageing pipeline infrastructure
The value of buried pipe infrastructure in Australia is in the order of $160 billion. As the assets of many water utilities approach the end of their useful life, the effective replacement of aging infrastructure presents a challenge for the urban water industry.
The primary approach to addressing aged pipe infrastructure is removal and replacement of the pipe, a relatively expensive process. In addition, more than 20 per cent of these pipes are made of asbestos cement (AC), presenting additional health and safety risks during removal, and disposal.
Increasing labour and material costs, coupled with overall community affordability pressures emphasised the need for water utilities to do more with less and to innovate cost effective solutions.
Lining technology has the potential to substantially increase asset service life and delay the need for replacement. Furthermore, lining systems reduce community impact, taking less time to install and creating less disturbance than conventional trenching solutions.
Additional benefits to the community include reducing impacts to other authorities’ assets and reduction in waste materials.
Delivering standards and guidelines
While the Australian water industry has used both CIPP and spiral-wound lining systems for the rehabilitation of sewer pipelines since the 1980s, the uptake of new products has slowed. One barrier to the acceptance of new products was the
A CIPP burst test, with no host pipe.
A bending test on a DN300 lined pipe.
lack of standards to assess new products against and provide independent assurance of manufacturer claims.
With this in mind, the aim of the CRC was to provide an environment allowing utilities and contractors to confidently use lining products by providing clear requirements and education for installation, supply, manufacture and application of these products.
By partnering with utilities, research organisations, universities, suppliers, manufacturers and contractors the project obtained the expertise needed to understand the user requirements and material properties as well as undertake independent materials testing in the Australian environment.
Beneficial technology
Lining systems, when compared with traditional replacement, reduce lifecycle costs. By keeping current infrastructure working longer utilities can defer capital expenditure.
In addition to providing an alternative to AC pipe renewal methods, other benefits for application on water pipelines include improved worker safety by reducing interaction with AC, deferring high AC disposal costs, spreading out the expected AC pipe renewal peak and keeping AC under the utility risk management process.
Other benefits include improved customer service by preventing leaks and reducing return to service times, as well as reducing design times by using the existing pipeline alignment. Because these relining technologies require less excavation, rehabilitation has less impact on the community and other underground utility services, such as gas, electricity and communications.
For wastewater pipelines, understanding the chemical reactions that take place in
different sewers plays an important role to allow selection of more targeted liners that interrupt and slow corrosion. A liner acts as a corrosion resistant barrier to protect the host pipe material.
In wastewater applications they also prevent service interruptions by reducing failures and can be applied in live sewers larger than DN 1500 during low flows (above tidal zone). Also, the longer lasting coatings mean less frequent community interruptions and avoiding excavations for repairs and associated traffic interruptions.
Project Overview
The first step was to identify specific products across the four categories for research with project partners, while field trial locations were determined by utilities to target a variety of installation conditions, such as pipe size, material and sewer corrosivity levels. Installations were undertaken using local installers (product suppliers were generally located overseas)
which provided the additional benefit of increasing local capability and experience.
Field trials of the water lining products were undertaken with four CIPP liners and one spray liner, while two additional spray lining products from previous utility field trials were also tested. These trials involved participating utilities selecting a suitable site for a trial of a single product and once installed the products were pressure tested to check for leaks.
A pipe section used in the development of a CIPP defect size measurement sensor at the University of Technology Sydney's iPipes Lab.
Field trials of wastewater products included five CAC products, three geopolymer products and one control product. Participating utilities selected a single site for in-pipe application or multiple adjacent sites for maintenance hole application.
Each of the five wastewater trials involved the application of all eight coatings plus the control coating. This tested the products under the same sewer conditions with any minor fluctuations picked up by the control product.
Core hole samples were taken of each coating after curing and at intervals following the installation to allow the rate of corrosion to be measured. A key element in the wastewater lining products testing was the monitoring of the sewer environmental conditions (H2S, CO2, gas temperature and relative humidity) and comparing the different environments with the difference in corrosion of the coating core samples.
Additional testing was undertaken on some older CAC installations to help validate the long term effectiveness of CAC products.
Water liner testing at Monash University and wastewater lining testing at the University of Sydney determined how long the materials would last once installed in various environments and conditions.
Learnings from the field trials and findings from the materials testing were codified in the Codes of Practice and Product Standards developed by the project. In addition, tools were developed to make accessing this information efficient for the water industry.
The University of Technology Sydney identified key parameters to measure for quality control in installed liners: • CIPP – defect size. • Spray liners – thickness. • CACs and Geopolymers – thickness and acid penetration over time.
Sensors were developed to measure these key parameters, prototyped in the iPipes lab and tested in field trials. Resources and training materials were developed and made publicly available to ensure the lessons and project outcomes remain accessible to the water industry.
New corrosion classification
Sewers are generally classified as ‘severe’ in terms of corrosion; however, a single category does not allow for the nuance that is found in sewer environments. For example carbonic acids may be more prevalent in sewers with a less corrosive environment than sulfuric acid.
The University of Sydney developed a corrosion classification system with five levels based on the environmental conditions in the sewer. The basis of the levels is the measured impact of the sewer environmental conditions on the functionality of the concrete, e.g. loss of alkalinity, material and strength.
This allows utilities to undertake monitoring of the sewer environment and then make predictions about when sewer repairs are required, what lining products will perform well and how long the liners should last.
learnings from the research at universities, field trials and sensor development is captured across six key documents, as well as in two decision tools.
Two codes of practice were developed aimed at asset managers, project managers and contractors with detail on installation requirements. The water liners code of practice is a standalone manual (WSA 202), while the wastewater linings code of practice has been incorporated into WSAA’s Manual for Selection and Application of Protective Coatings (WSA 201).
The codes of practice detail information about the liner types, quality assurance, selection of liners, surface preparation, liner application, quality control, return to service and maintenance requirements.
Four product standards were developed – one for each product type assessed in this project –focused on the requirements of product appraisers, suppliers and manufacturers. The product standards provide the performance requirements of the liners as well as the tests required to demonstrate the material properties.
In order to make the codes of practice and product standards more accessible, two decision tools were developed. The water decision tool, called the Pipe Evaluation Platform, provides a great resource to asset managers, project managers and contractors, allowing them to use the pipe data available from utilities to prioritise pipes for renewal based on likelihood of
Spray lining machine head. failure, as well as determine what liner types will be suitable for a particular pipe and provide an expected life of an installed liner.
The wastewater decision tool, called the Sewer Rehabilitation & Prioritisation Decision Platform, works by inputting the sewer environmental measurements and calculating the corrosion category of a sewer. This allows users to find out which concrete assets should be prioritised for rehabilitation, what type of liner will provide the required level of protection, and provides the required thickness of application to meet the selected service life.
This research has delivered the foundation to enable uptake of liners by the water industry through Codes of Practice to detail product installation requirements, Product Standards to provide clear guidance on material requirements to utilities and product manufacturers, and tools to allow efficient decision making when incorporating liners into rehabilitation programs.
A CIPP liner lining through a previously repaired section of pipe (PVC pipe repair removed).
KEY TAKE-AWAYS • Investigated CIPP & polymeric spray liners for water mains. • Investigated CACs & geopolymers for wastewater pipes and assets. • 4 water industry standards developed. • 2 codes of practice. • 2 decision tools. • Sensors developed for quality control.
INTERESTED IN MORE DETAILED INFORMATION ABOUT THIS PROJECT? WSAA has collated the learnings and information developed from the CRC into a knowledge hub to provide ongoing benefit to the water industry. The project’s findings, deliverables, training materials, recordings of presentations, fact sheets and additional resources can all be found at www.water360.com.au/projects/smart-linings/ or contact WSAA: linings@wsaa.asn.au
