Environmental Product Declarations (EPDs) are crucial for housebuilders and contractors who want to make informed decisions about building materials, with a focus on embodied carbon.
Many housebuilders have already published their own ‘zero carbon’ targets, prompting manufacturers to calculate the embodied carbon of their products. The expansion of building regulations to include requirements for embodied carbon is also under consideration. A proposed amendment, known as ‘Part Z’, would introduce mandatory assessments of whole life carbon emissions for construction projects if enacted.
EPDs are third party verified documents produced by manufacturers to detail the environmental impact of individual products.
H+H offers EPDs for our Standard Grade Celcon Blocks and our Vertical Wall Panels. We are also in the process of developing EPDs for our specialist grade Celcon Blocks.
Whole life or up front carbon emissions?
EPDs are valuable but only if the reader understands what the information is telling them and considers the context in which the product will be used. Comparing figures from different EPDs is not straightforward and it pays to look closely at the numbers rather than any commentary.
The focus should be on ‘whole life’ carbon emissions. This figure, also known as ‘cradle to grave’, includes: the raw materials and manufacture of a product; transport and construction; the building in use, and disposal of the material at the end of the building’s life. In an EPD these are categorised under sections:
• A1-A3 - Product
• A4-A5 - Construction
• B1-B7 - Use
• C1-C4 - End of life
Any embodied carbon figure quoting only the ‘up front’ manufacture (A1-A3) is not a true reflection of the environmental impact of a product.
For most people the most relevant figure in an EPD is the Total Global Warming Potential (GWP), measured in kgCO2e. This information is often given in a useful ‘Environmental Data Summary’ within the document, however extreme care must be taken to check what information the manufacturer has chosen to include here.
A manufacturer interested in full transparency should report the whole life carbon emissions figure: ‘GWP-total, A1-C4 (KgCo2e)’. The H+H EPD certainly includes this measurement in the data summary. However, manufacturers can decide what information they declare in the summary, so some will choose to publish ‘GWP-total, A1-A3’ here (the ‘up front’ figure), particularly if it shows a lower value than the whole life number.
The ‘Declared unit’ should also be reviewed as not all manufacturers report figures based on the same unit of measurement. For example, the figures for aircrete blocks are based on one metre cubed whereas some other products are measured by a square or linear metre. To compare like with like some additional calculation may be required.
Just as important is to take into consideration how the product will be used in the construction project. For example, the choice of material used for the structural walls will dictate what other materials are needed to complete the wall structure.
For aircrete internal walls the calculation is relatively simple since the wall is built entirely of aircrete. For composite panels the picture is more complicated as the embodied carbon of each individual product: timber, board, waterproof membrane, insulation, for example, will need to be considered. And again, the figure used should be the whole life embodied carbon.
Embodied carbon calculations are relatively new and there can be a lack of consistency in the way the figures are presented. Guidance and regulation will eventually standardise this, but in the meantime, it is down to the user to focus on the detail to make sure that the correct comparisons are being made.
For further advice on how to interpret an EPD and to access EPDs for our products click here.