Why isn’t an embodied carbon assessment done as standard on every project, asks engineer Anna Beckett
So, you’ve just finished construction on an office refurbishment project and you’re feeling pretty pleased with how it’s gone. The client is happy, the building looks great, and you managed to use some low carbon alternatives. But is it actually as low carbon as you think? How can you know for sure?
Carbon counting and embodied carbon assessments are increasingly being applied to quantify the materials used in construction, but how accurate do we need to be and what should we be including?
At Webb Yates we have a relatively simple carbon counting spreadsheet that we ask our engineers to use on every project – even those we know will perform badly. The Institution of Structural Engineers has a very similar tool available for anyone to download for free on its website.
But this is just the structural part of the picture; we then need to consider the internal and external walls, the finishes and the services, and compare that to the new floor area we’ve created. The calculated values can then be compared with targets set by the RIBA. Or LETI. Or the UK Green Building Council … and that is part of the problem.
Does it really matter which targets you use? As long as you’re assessing embodied carbon and trying to reduce it, then you’re heading in the right direction and can start to compare similar projects. Plus, you’re still going to get a pretty good idea whether the concrete frame your engineer specified has completely annihilated the gains from your triple-glazed windows.
We’re all familiar with and would contribute to a risk register – isn’t the climate emergency currently the biggest risk of all?
How much detail should we be looking at? If we can’t get the materials that we need in the UK and we have to import them, how do we take that into account? How do we, as engineers and architects, even find out where the materials have come from?
Embodied carbon assessments need to be something that everyone involved in the project has an interest in and contributes to. Projects that achieve the biggest savings in terms of carbon are those where the contractor puts that at the top of its agenda – where it is willing to adhere to the specified products because it knows the embodied carbon is important, where it will source materials responsibly and modify its processes – such as changing the fuel its vehicles are using to reduce emissions.
What’s stopping us? Why aren’t we assessing embodied carbon, as a whole team, on every project? We’re all familiar with a host of other assessments that we do as standard: Breeam, energy assessments, flood risk assessments and so on. Can’t we add embodied carbon to that list?
A group of professionals from across the industry have come together to try and make that happen with Part Z – a proposed amendment to the Building Regulations that would make assessing and reducing embodied carbon and whole-life carbon a legal requirement. The short-term targets are relatively limited but the proposals suggest that these should become more ambitious as people become more familiar with the process.
Assessing and reducing carbon needs to have a collective approach and collective support throughout the industry. We’re all familiar with and would contribute to a risk register – isn’t the climate emergency currently the biggest risk of all?
The main aim of the discussions that took place at COP26 was to limit the increase in global temperature, and in order to do this we need to reduce carbon dioxide emissions. Taking into account operational emissions, the building industry accounts for 38% of total global energy-related CO2 emissions, so we have a huge part to play in trying to meet those targets.
If we can work together and consider buildings in a more holistic way, then there’s no reason why we can’t reduce the embodied carbon of every building. But the starting point is knowing how much embodied carbon is in our buildings to begin with – if we’re not even assessing it, how can we ever know if we’re managing to reduce it?
Anna Beckett is an associate at Webb Yates Engineers