WHAT LIFE CYCLE STAGES ARE ASSESSED FOR EPDS?
A life cycle assessment, or LCA, analyses the environmental impact of a construction product across five stages: product, construction process, use, end of life, and the circular economy.
The results of the assessment are reported in a standardised document, an environmental product declaration (EPD), which can cover some or all of these stages.
The five stages are reported across four modules, A to D, each of which contains several numbered sub-categories. Currently, manufacturers can choose the scope of their reporting, but new rules are being introduced to make reporting across all stages and modules mandatory.
What are modules A, B and C of an EPD?
Together, the ‘product’ and ‘construction process’ stages make up module A of life cycle assessment, covering everything up to the practical completion of a building.
The product stage comprises: A1 (raw material extraction and supply), A2 (transport to manufacturing plant), and A3 (manufacturing and fabrication). The onus here is on the product manufacturer to act responsibly, such as by adopting a transparent and traceable approach to raw material sourcing and processing – especially when sourcing from communities and environments that are particularly vulnerable.
A4 (transport to project site) and A5 (construction and installation process) are the construction process stage, covering a product leaving the factory and being delivered to and used on site.
Modules B1 to B7 are the ‘use’ stage, and cover use, maintenance, repair, replacement and refurbishment, together with operational energy use and operational water use.
Some construction products incur relatively low use stage emissions. Insulation, for example, is part of the building fabric and should last for the life of the building. It generally requires little or no maintenance, repair, replacement or refurbishment. On the other hand, some products have shorter life spans and require routine maintenance and replacement, which incurs carbon emissions and other environmental impacts.
The ‘end of life’ stage covers deconstruction and demolition; transport to a disposal facility; waste processing for reuse, recovery or recycling; and disposal across modules C1 to C4.
The topic of how we deal with buildings at the end of their useful life, and how the construction industry can reduce waste associated with demolition, is becoming increasingly important as we look to preserve existing resources and minimise the extraction and use of new ones.
What is module D of life cycle assessment?
The full title of module D is ‘Benefits and loads beyond the system boundary’. It reflects a movement away from the linear economy and towards the circular economy, where the life of materials and products can be extended for use in other projects.
At the moment, many construction products are not designed with reuse, remanufacturing, or even recycling, in mind. As a result, module D is unlikely to be reported in many EPDs. Embodied carbon is a big focus for many within our industry, but it’s possible to choose a low embodied carbon product and still only be able to use it once.
If we choose low embodied carbon products but still need to use a lot of them, is that a ‘sustainable choice’? Construction projects are much more complex than a simplistic question like that, but it’s a helpful way to look at how our thinking needs to shift as we aim for a net zero future.
Over the last ten years, the number of products that have an EPD has grown substantially – but the number of stages reported by each is not necessarily the same. The more stages for which data is reported, the more complete the picture of the environmental impact of the product being assessed.
The focus for the construction industry now, arguably, is ensuring that assessment and reporting are as comprehensive as possible from module A right through to module D.
EPDs from Polyfoam XPS
Polyfoam XPS reports on the environmental impact of its flooring and roofing products through independently verified EPDs produced by BRE Global. Currently, Polyfoam XPS’s EPDs do not report on all LCA modules, but this will be reviewed in future
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