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Are these useful little things on the move
I had two key takeaways from a recent roundtable discussion on EPDs:
Not all EPDs are equal
Some new EPDs are turning dynamic
The first one might be obvious. But do you ever question the quality of EPD or information your project team is using to generate your carbon figures? Didn’t think so, but you probably should.
The second is about using more project, site and even batch specific information, making for a more accurate as-built carbon model. It also got me thinking about material reuse and EPDs that could be specific and capture the history of a material - like a material passport.
The event was organised by the Council on Tall Buildings and Urban Habitat (CTBUH) and hosted by SOM.
Let’s just clear up what EPDs actually are. An Environmental Product Declaration is a document which summarises the environmental performance or impact of a product or material over its Life Cycle Assessment (LCA) - think scope A through to D. They are a useful way to help make informed decisions and model overall performance on projects, plus they should drive competitive behaviour of the manufacturers to find efficiency in the footprint of their products. They are voluntary, however the use of EPDs is growing, as is the demand in specifications for materials with EPDs. Public projects might require them and if you are targeting the likes of LEED or BREEAM they will undoubtedly play a part.
Any manufacturer might want to (and can) create an EPD for their product, which is why it is crucial to get an independent third party verification before it can be published. Such verification will check that Product Category Rules (PCR) have been followed.
Not all EPDs are the same
I find it easiest to think about the design evolution that occurs in a project and imagine how the detail of an EPD might need to increase or change with the design.
Take a concrete foundation element for example. At early stage design (RIBA 1/2) the carbon model for this element will likely be modelled with basic criteria - a non-specific EPD. Later on in the design when carbon is being driven out of the scheme and mixes are specified, different data will be needed in order to update the carbon model. When the contractor is on board, the model might be further updated based on the supply chain that is procured, with data for the selected products/mix.
Has this got you thinking? Are the EPDs in your project as accurate as they can be? Could they result in better metrics, or be the difference between an approval or rejection. Offset payments are often derived from these, aren’t they?
This made me question how a client or other project team member can quickly understand the quality and detail behind the carbon metrics on their project? I don’t know if there is an easy way for this to be done, but I would like a score. For example, if my project is hitting 500kgCO2e/m2 at RIBA 4, does this have a high EPD score or a low score. High would signal a finely tuned carbon model with detailed EPDs, whereas a low score would suggest the EPD data is basic and could be improved.
A quick warning… firstly just because a product or material has an EPD, doesn’t mean it is an environmentally friendly or sustainable product; and secondly some products are made to look like they have EPDs but they are fake and not verified.
A Dynamic EPD takes things a step further and will populate some data with more project or batch specific information. This should better reflect the as-built situation.
That concrete element from earlier has now hit RIBA 5 (construction) could include the outdoor temperature when the concrete was mixed, the specific batch of aggregate used and the details of the journey from plant to site.
Surely as a result of this we can expect more accurate as-built carbon footprints for our projects as a result of more detailed and dynamic EPDs.
A final thought on material reuse and the circular economy. If EPDs are going dynamic, could these be the thing to hold and transfer information on reused materials such as where they were used in a previous life. Take steel as an example, could every reused steel element have a dynamic EPD which captures previous use, transport (from old site to yard, yard to fabricator, fabricator to new site), de-fabrication and re-fabrication. I don’t see why not and then it really does start feeling like a form of material passport.