In the first of a new series, engineer Anna Beckett shows how some fresh thinking could solve apparently intractable issues
Each year in the UK we demolish 50,000 buildings and from each of them there is a wealth of material that we should be able to reuse but… don’t. Reuse is one of the key principles of the circular economy and has advantages over recycling because the energy required to reuse something in its current form is so much less than the energy required to break it down, process it and then reform it into something useable.
Take steel, for example. Steel is manufactured in standard section sizes and standard grades that have changed very little over the last 50 years. So it would make sense that if you’re demolishing a building you should be able to remove steel sections with the intention of reusing them elsewhere. And yet we don’t. Recycle it? Yes, we do that a lot. But reuse? Not so much.
So what’s stopping us? Well, the Steel Construction Institute (SCI) and Cambridge University researched the barriers to steel reuse and found that a combination of issues makes the process much more difficult than it needs to be.
One of the main issues is certification. To meet the requirements of the Eurocodes, every steel section used in a building should have a steel test certificate. This certificate sets out the grade of the steel (based on testing), confirms that the dimensions are correct and provides traceability of the actual materials used. Without the certificate you could re-test to confirm the properties of the material, but you’d never be able to confirm where the steel originally came from.
But this seems like a problem we should be able to solve in 2021. We have centralised databases for everything else and we’ve all spent the last year learning how to use a QR code – so surely every piece of steel could be marked with a QR code that’s connected to a database of certificates?
Fantastic, maybe we can solve this issue for future engineers, but what about the steel we’re taking out of buildings that already exists? Buildings that either never had any certificates or for which the testing certificates have long been lost to the sands of time in a basement cupboard that no one even knows exists. If the steel was produced after 1970 and you’re prepared to carry out some fairly extensive testing, then you probably can still reuse it. It’s not a straightforward process but it is possible, and it is defined in the Eurocodes.
The availability of sections and difficulties storing steelwork are also often listed as issues with re-using steelwork, and yet both of these could be easily overcome. What if the engineering design was approached from the opposite direction? Instead of the engineer specifying the sizes of steelwork they require, the contractor defines the sections that they can get and then the engineer finds a way to make it work. Yes, it requires your engineer to be a bit more creative and it might affect your floor plan, but it’s not impossible. Storing steelwork is a bit more difficult, but potentially doesn’t require a huge amount more space than storing new steelwork. And if your engineer is prepared to design based on what’s available then the amount of time you need to store the steelwork should also be reduced.
Perhaps the most difficult argument to overcome is that it’s an uncommon practice – that it’s not the way we normally do it. No, it isn’t. And maybe we have to work a little bit harder to make it feasible. But that doesn’t mean we shouldn’t try, and this isn’t a totally unprecedented way of working in the UK. During and following the Second World War steel and iron were rationed and as a result the reuse of steel sections was far more common.
So maybe what we’re really missing is the motivation.
With climate activists and world leaders coming together this week to discuss immediate and drastic actions to reduce emissions, we need to dig deep to find creative solutions to global problems. Maybe it’s a bit more difficult, maybe it will take a little bit longer. But if we can find a way to efficiently reuse materials then the long-term savings in terms of both energy and cost could be huge.
Anna Beckett is an associate at Webb Yates Engineers