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Galvanized Steel
Keeping Decarbonisation On Track
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Foreword From Director William J. Smith
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Sustainability and durability have long been a central concern to the galvanizing industry. Before environmental responsibility became the leading priority it is today, Galvanizers Association were focused on the need to extend the design life of public buildings and infrastructure. We also voiced concerns over developments and projects, which despite considerable operational carbon savings, were still hindered by carbon costly maintenance burdens.
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Given the demand for growth to be sustainable and clean, UK construction can no longer rely on single life components and disposable materials, and GA welcomes the idea that the principles of circular economics will underpin all future construction, including transport and infrastructure.
The planned investment in UK rail is vital to the development of an efficient and effective national transport infrastructure. HS2 and the further modernisation of existing rail infrastructure, aligned with UK Rail’s ambitious decarbonisation plan, have the potential to be real agents for change, reaching an extensive supply chain, and impacting diverse communities across the UK. The electrification of UK Rail, additional green
traction projects and a low carbon delivery of HS2 are central to the UK’s transition to a sustainable, healthier future. We are hopeful they will offer up a model of regenerative development that can withstand scrutiny from across the globe. Our industry developed an Environment Product Declaration (EPD) in 2008 and Galvanizers Association has since invested in research that examines the environmental benefits of galvanized steel. We offer reliable data that predicts the durability and performance of galvanized steel for a range of atmospheric conditions across the UK.
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Clearly, only materials that offer durable solutions and which are aligned with the circular economy will meet the demands of a climate resilient infrastructure network. This guide outlines how galvanized steel aligns with circular principles and the role it can play in decarbonised public transport design.
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Our industry has a relationship with UK rail spanning centuries. We look forward to many more years of positive collaboration.
Galvanized Steel - Keeping Decarbonisation On Track
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Th is Contents Introduction
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Case study - Vienna Central Station
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1.
Galvanized Steel And The Circular Economy
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2.
Durability Supports Decarbonisation
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2.1
Predictable And Measurable
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Lydlinch Bridge - 80 Years On
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The Eiffel Tower - A Maintenance Legacy
- Vienna Central Railway Station
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Local Supply Chains
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Case study - Haymarket Station, Edinburgh
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Case study - Rail Freight Terminal, Northamptonshire
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A Circular Material
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3.1
Reuse of Steel Structures
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3.2
Design For Reuse of Galvanized Steel
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3.3
Grandstand at Gramsbergen
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3.4
Reuse Of Steel Staircase
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3.5
Biopartner 5 Laboratory
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3.6
Carbon savings with Regalvanizing
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Case study - Crossrail West Gantries - Global Rail
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- Euston Station Walkway, London
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- Leeds Station Southern Entrance (LSSE)
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Galvanized steel - A Complementary Material
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Case study - Crossrail Place Foster + Partners
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Summary
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Image Credits
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Throughout this document the term ‘galvanized steel’ refers to steel articles that have been immersed in molten zinc after the articles have been fabricated or manufactured. This is the process of batch (or ‘general’) galvanizing that is usually carried out according to EN ISO 1461.
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Introduction
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Steel is already one of the most commonly used materials in the railway sector. It is strong, versatile and cost-efficient, plus it offers sustainable solutions for the UK and Ireland as they transition to a more decarbonised, circular economy.
Making the right decisions first Corrosion and maintenance could cost the rail industry many millions of pounds and manhours annually, not to mention unacceptable disruption to services. This is why the valuable steel that is used in railway construction must be protected. The corrosion protection that is chosen for railways today will impact greatly the amount of time and money that must be
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spent tomorrow. Choosing galvanized steel is a cost-effective, efficient way to protect important infrastructure over the long term.
further routine and costly maintenance. At Haymarket in Edinburgh, galvanized steelwork has helped to create a larger passenger friendly station.
No limitations on scale
Galvanized steel helps ensure that our railway is set for the long term. Modernisation should lead to well-designed rail networks and stations, built to last, sensitive to the environment and which harness the benefits of galvanized steel.
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Galvanized steel and railway infrastructure go hand in hand. From historic stations in London like Paddington, to the modern iconic design of international hubs such as Vienna Hauptbahnhof, galvanized steel has been, and remains, a reliable choice, suitable for many building applications.
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If projects are designed with galvanizing in mind, there are no limitations to the scale of ambition. Stations like the Hauptbahnhof in Vienna prove that innovative, super-scaled roof structures can be made using galvanized steel and require no
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Galvanized Steel - Keeping Decarbonisation On Track
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1. Galvanized Steel And The Circular Economy
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Galvanized steel aligns well with the requirements of the new circular economy and is considered a sustainable material, that can deliver multiple life cycles. It is ideally suited to infrastructure projects and can help decarbonise public transport.
The galvanizing industry in the UK and Ireland welcomes the increasing focus on the creation of a circular economy and embraces flexible design for durability, deconstruction, and disassembly. Galvanized steel readily facilitates the reuse, remanufacturing or recovery of materials and galvanized steel structures and components are ideal circular materials. If a material system was specially designed for the circular economy,
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hot dip galvanizing would be a perfect example because: 1. Hot dip galvanizing of steel products after fabrication delivers the highest levels of corrosion protection – the steel structure will often achieve its design life with no maintenance.
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2. The galvanized coating can follow the steel structure through multiple cycles of reuse. 3. Galvanized coatings are metallurgically bonded to the steel – allowing the steel product to be reused along with the original coating without need for recoating. 4. Galvanized steel components that have reached the end of their design life, or are uninstalled for any other reason, can be regalvanized and returned to the
original use. 5. If the re-use cycles come to an end, both steel and zinc are recycled together in the well-established steel recycling processes. The zinc being returned, without loss of properties, to zinc production plants and eventually back into the galvanizing process.
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Galvanized Steel - Keeping Decarbonisation On Track
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Recycle Steel and zinc are recycled together - without loss of properties - if the long life of galvanized steel eventually ends
Make Galvanizing of steel products is an efficient dip process - giving the highest level of protection. It maximises their durability, reuse and recycling
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Remake Galvanized steel products can be re-galvanized and put back into service - avoiding production of new steel. Repurposing of galvanized steel products possible without regalvanizing
Use Galvanized steel is completely covered with a durable coating that can last the lifetime of the component - avoiding resource use for replacement or maintenance
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Reuse Galvanized steel is robust and easily dismantled for reuse in multiple life cycles. The coating stays with the steel component in its next life cycle
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Fig. 1 Circularity of galvanized steel
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2. Durability Supports Decarbonisation
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In accordance with the hierarchy of approaches in meeting the circular economy, building for net zero should mean building to last. Using products that are reliable and durable can significantly reduce carbon footprint over the lifetime of the construction.
Galvanizing’s ability to optimise the durability of steel structures and components has important environmental, economic and social advantages making it a valuable option when looking to decarbonise a project. In addition, the long-term durability provided by galvanizing is achieved at a relatively low environmental burden in terms of energy and other globally relevant impacts, especially when
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compared to the energy value of the steel it is protecting. Whether it is by reducing maintenance operations or avoiding the premature replacement of steel products, galvanizing will reduce the embodied carbon of construction.
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Hot Dip Galvanizing offers many advantages including: •
Protection of steel for up to 170 years
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Predictability
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Ease of inspection
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Makes steel more reusable
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2.1 Predictable And Measurable
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A galvanized coating offers predictable corrosion protection that weathers in a linear fashion. Coating thicknesses are measurable and offer lifespans that can be easily forecast and relied upon.
The longevity of galvanized steel offers zero maintenance solutions and avoids costly, carbon intensive repairs, which makes it an ideal solution for today’s infrastructure needs. Galvanizers Association can provide up to date information on the performance of galvanizing. A key reference source is the Atmospheric Corrosion Map that provides
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atmospheric performance data for a hot dip galvanized coating across the UK and Ireland.
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Atmospheric Corrosion Rate of Hot Dip Galvanizing
Fig. 2 Atmospheric Corrosion Map
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Rail Freight Terminal, Northamptonshire
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A rail freight terminal in Northamptonshire has become the first in the UK to demonstrate an innovative overhead electrification system, which could spell the end for diesel on electrified rail routes and boost the industry’s net zero ambitions. The Decarbonisation & Electrification of Freight Terminals (DEFT) project, funded by the Department for Transport and Innovate UK, has seen project partners demonstrate a new way of decarbonising rail and lessen freight’s impact on passenger journeys by using galvanized steelwork.
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The system is based on one developed for passenger train depots, used by Eurostar and LNER, and has been installed by SPL Powerlines. The DEFT project is one of 30 ground-breaking initiatives that have won a share of £9 million from the Department for Transport, in partnership with Innovate UK. The competition is focused on developing pioneering technology and exceptional ideas that can improve journeys for travellers, encourage passengers back onto the network and reduce the environmental impacts of rail.
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3. A Circular Material
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Galvanized steel is the perfect circular material to ensure that buildings and structures can be designed with maximum flexibility and to enable construction products to be used across multiple life cycles.
Future designs of steel structures will become more modular and utilise bolted connections to ease deconstruction and make components more widely suitable for reuse. Galvanizing creates more value to these reused components, as they do not require further protective treatment and the components themselves will be in good condition at the point of reuse. Galvanized steel will not suffer from demounting and remounting activities,
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as opposed to painted steel which will need to be repainted or at least repaired. Moreover, galvanizing offers longer lifetime expectations to steel than other coating systems, which allows frequent reuse of the material.
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Durability, Robustness and Adaptability of Galvanized Steel
Current end-of-life scenarios for two of the most common construction materials, steel and concrete, show that 93% of steel is recycled and 6% is reused – a growing natural resource as opposed to concrete which is 20% recycled and 75% down cycled.
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Avoid Maintenance
Avoid Replacement
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Facilitate Reuse
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Save Carbon
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Carbon Efficiencies on Site
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The unique nature of the galvanizing process provides a tough and abrasion resistant coating which means less site damage and speedy erection of structures. Cohesion
shock of an initial impact during handling. The alloy layers beneath are generally harder than the base steel itself. This combination provides a robust and abrasion resistant coating.
Unlike most protective coatings, which rely solely on the preparation of the steel to obtain adequate adhesion, hot dip galvanizing produces a coating which is bonded metallurgically to the steel. In other words, the iron and the zinc react together to form a series of alloys which make the coating an integral part of the steel component or article with excellent cohesion. Toughness Resistance to mechanical damage of protective coatings during handling, storage, transport, erection and reuse is very important. It can save cost and carbon. The outer layer of pure zinc is relatively soft and absorbs much of the
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Barrier protection
Galvanizing provides a barrier between all internal and external steel surfaces and their environment. Hot dip galvanizing provides fabricated iron or steel products with maximum protection through a continuous, tough, metallurgically bonded coating.
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Fig. 4 Micro-section of hot dip galvanized coating showing variations in hardness through the coating. The zinc-iron alloys are harder than the base steel.
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Vienna Central Railway Station
Vienna Hauptbahnhof is a recent, landmark project which harnesses the zero maintenance benefits of galvanized steel. It has one of the most ambitious roof structures in contemporary station design in answer to a design specification stipulating a 120 year lifespan with essentially a zero maintenance burden. The station is a central hub in the transEurope rail network, which aims to be used by more than 1,000 trains and by 145,000 people every day. The station’s steel and glass lozenge roof, 200 metres long and 120 metres wide, has become a symbol of modern mobility and functionality, and distinguishes the building from everything around it.
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The roof structure, which is made up of 14 individual diamond shapes, arches over five platforms and varies in height between six and fifteen metres. The entire roof (including the forecourt canopy) is made up of more than 57,000 sections, 286,000 sheets of metal, and almost 340,000 screw fittings which are concealed beneath the cladding.
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each subsection of the roof. The result is a towering example of zero maintenance brilliance. Each of the 14 diamond trusses in the station canopy measure 76 metres and are all supported by solid twin supports every 38 metres. In the centre of the lozenge, the structure opens up to provide a skylight in the form of a crystal shaped opening measuring 6 x 30 metres which alongside the integrated glass elements make it translucent. The building’s interior is flooded with daylight and at night, special lighting gives the roof a remarkable 3D effect.
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The creation of the gigantic structure was a demanding challenge for the contractors and the steel construction company Unger Steel, not only from the technological point of view, but also with regard to the logistics of the project. As the complexity of the roof structure meant that it would be virtually impossible to maintain, the design allowed for individual members to be galvanized and bolted together to form the complex rhombus for
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4. Local Supply Chain
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As we decarbonise our transport system, the entire supply chain will need to withstand scrutiny through the lens of the circular economy.
If your galvanizing is prioritised in the same way that other parts of a project are, hot dip galvanizing will be a seamless, time-efficient process.
There is a wide spread of galvanizing plants across the UK and Ireland that offer an integrated service with local fabricators and manufacturers. With the right communication, you can get steel galvanized within 24 hours.
Galvanizing can take place locally and has a fast turnaround
Galvanizing is not a time-consuming process and in reality, it can take just a few minutes to dip prepared steelwork into molten zinc to form a durable, reliable coating.
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The Galvanizing Process
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Turnaround time can be minimized if you follow a few simple steps:
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It pays to communicate with your galvanizer and a quick phone call a few days ahead is all it requires to plan work into a busy galvanizing schedule.
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Sending in ‘clean’ steelwork will save preparation time. Work that is contaminated with material which will not be removed by the normal galvanizing pre-treatment, will need special steps to remove it.
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The same applies for venting and drainage. As a dip process, galvanizing will protect the inside of steel sections as well as the outside. Ensuring that there are correct vent and drain holes in hollow steelwork and that these holes are in the right places, saves the galvanizer valuable time, as they would have to complete that work for you.
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Map of galvanizing plants across the UK and Ireland
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Finally, it pays to liaise on transport. If the galvanizer is providing transport, liaise about the regular runs and plan around them. Galvanized steelwork may even be able to go directly to site.
Galvanizing plants across the UK and Ireland
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GALVANIZERS ASSOCIATION Wren’s Court, 56 Victoria Rd Sutton Coldfield B72 1SY +44 (0) 121 355 8838 ga@hdg.org.uk www.galvanizing.org.uk
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