Delivering low embodied carbon

At a technical level, there is a challenge in ensuring robustness in measuring and reporting the actual embodied carbon for all the elements as proposed and installed. Although the methodology for undertaking whole-life carbon is standardised, there is a gap in the level of scrutiny applied during technical verification.

It is becoming common now to see various embodied carbon numbers presented in awards submissions and marketing materials for schemes. Many of these appear to report figures that are low for the construction type and build scope, which makes one question the technical quality of these assessments and whether we need a better system for verification.

Product-specific environmental information in the supply chain is currently limited. An Environmental Product Declaration might be in place for one supplier but not others. This imbalance in what information is available makes it difficult to compare low-carbon solutions.

The embodied carbon approach for MEP systems is even more challenging. We are working from first principles and, where feasible and available, we utilise manufacturer-specific data or CIBSE TM65 information. Refurbishment, re-warrantying and reuse of MEP equipment form part of this strategy.

In the future, publicly available realistic benchmarks for different build types should make comparison more meaningful and useful. The Net Zero Carbon Buildings Standard will provide a single definition of what constitutes a net zero carbon building and set targets for carbon in the design, construction and operation of buildings.

For now, we should adopt a lean design approach, with optimised materials demand, and then look for low-carbon materials to deliver the design. Retrofit and reuse of materials are at the heart of delivering low-embodied-carbon buildings.

Kiru Balson is principal sustainability consultant for engineering consultancy firm Max Fordham