The survey seeks to ascertain how building designers engage with Environmental Product Declarations (EPDs) and how they are being used to evaluate environmental impacts
The survey is part of a wider research project that the University of Bath is investigating how to improve uncertainty when predicting the whole life carbon (WLC) of construction products through better EPDs, and building projects through better life cycle assessments.
Current models and calculators produce a single-point estimate for WLC, with any uncertainties or gaps in knowledge conveniently ignored. At its simplest levels this could be a plus or minus percentage degree of uncertainty in WLC predictions.
The university team is partnering with other international initiatives to look at developing and testing a probabilistic approach to predicting WLC through better authoring of EPDs by manufacturers and suppliers. This would effectively introduce metrics such as margin for error, to represent uncertainty within EPDs. The aim is to introduce probabilistic approach into the design process for individual buildings, and the ultimate goal is to deepen the industry’s understanding of embodied carbon data, calculations and methodologies to enable beneficial low carbon decision making in the design process.
EPDs: Helping to work towards low carbon targets
Environmental Product Declarations (EPDs) can support architects in their selection of low impact materials and to help achieve carbon reduction targets. Many architects using whole life carbon calculators are using EPDs indirectly, because the calculator tools are usually built from EPD databases such as the University of Bath’s own ICE Database, but may not have a fully developed understanding of how the EPDs have been produced.
Matt Roberts, research assistant at the University of Bath, says that the project team is hoping to capture the widest possible range of experiences, from expert users of EPDs who are competent at life cycle assessments and carbon footprinting to those who are too scared to use EPDs with any level of confidence.
Jess Hrivnak, the RIBA’s Practice Technical Adviser on Sustainability, says the survey provides RIBA members with an opportunity to feedback on their experiences and concerns with embodied carbon. The RIBA is represented on the University of Bath’s research project’s Steering Group.
How confident can designers about the environmental impact of material they specify?
Architects familiar with EPDs will know that they can be based on different methodologies. Manufacturers and materials suppliers have a number of different technical standards to work from. EPDs can range from representing the industry average impact of a generic type of material manufactured in a specific way, down to impacts from a product manufactured at a specific location, thereby allowing transportation carbon impact to be calculated. Many novel products or materials will not have an EPD.
‘The current situation leaves many questions about how confident designers can be about the environmental impact of materials they specify, and whether they are a genuinely low carbon solution,’ says Roberts.
Members can find more information on the University of Bath’s research project and complete the survey. The questions seek to identify how building designers currently use EPDs, what pieces of information from an EPD are being used and what can be done to EPDs to better support the building design process. The closing date for the survey is 31 March 2023.
Roberts says the stand out guides for architects looking for more information on embodied carbon and life cycle assessment tools are still the LETI Embodied Carbon Primer and the RICS Whole Life Carbon Assessment for the Built Environment (currently on its second edition of consultation), which sets out the mandatory principles and supporting guidance for WLC assessments that meet the industry standard EN 15978 methodology.
‘We ultimately hope to see the research give designers a better understanding of the underlying assumptions in the EPD databases they are using in their tools, with the results trickling down to even the most basic users of EPDs,’ Roberts adds.
Thanks to Matt Roberts, Research Assistant, University of Bath
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