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Steel protection in the environment

I am known as a radical advocate of green and natural building. So my recent decision to co-author a guide on the use of galvanized steel in construction was met in some quarters with a degree of suspicion and surprise.

But it is virtually impossible to build or renovate buildings and infrastructure without having some impact on the environment, and even the greenest of projects has some environmental drawbacks.

Being responsible for construction decisions, our task is to select materials carefully and ensure we do everything possible to minimise negative environmental outcomes.

But where the use of a material is inevitable, it does not mean that we should turn a blind eye towards its environmental credentials.

Steel, for example, is a vital and necessary part of modern construction. While alternative materials can replace its use in some applications, it is often the preferred option for a number of valid reasons.

One downside of steel, of course, is that it will corrode in exposed situations so must be protected from the elements, typically by either painting, alloying or galvanizing. So when assessing its suitability for a sustainable application, not only must we examine the lifecycle impact of steel but also the lifecycle impact of the protection method.

Galvanizing, for example, requires the use of zinc, which must be mined, processed and transported before its application on to steel. Other systems have their own complex lifecycles, and some finishes in certain situations will require an ongoing maintenance schedule. This creates its own environmental burden which must be included in the decision-making process.

So how do you make a sound judgment against such a complex process without access to comparable data? When looking at steel protection systems, it is debatable as to whether this information is either readily available or provides an accurate reflection of the full picture.

With this in mind, the Galvanizers Association briefed me to develop a guide that would help architects, specifiers, engineers, developers and their clients consider how to use galvanizedsteel in the context of sustainable construction.

The association was clear in wanting to avoid producing a marketing report which would be perceived as applying a greenwash stamp of approval on the galvanizing process.

Rather, it is part of an ambition to help inform decision makers that sustainability is dependent on a wide range of factors.

The guide draws on pan-European academic and scientific studies on the environmental performance of galvanized products and their alternatives, uses a number of proven assessment tools, and examines the issue on a full lifecycle basis, from raw materials extraction to final disposal. The facts are presented in a format that allows meaningful comparisons and decisions to be made.

But readers won’t find a concluding chapter that states ‘galvanizing is green’. Indeed, any guide offering such an answer should be treated with extreme caution because the uncomfortable reality is that sustainability is a grey area. If nothing else, this is my message to you.

Tom Woolley is professor of architecture at the Centre for Alternative Technology and was editor of the Green Building Handbook