Best Practices for Combining CO2 Emissions from EN 15804+A1 and A2 EPDs in Total GWP Calculation

Data & Construction Materials
1

Hello One Click LCA Community,

I’m currently working on a project where we are assessing the environmental impacts of various construction materials. We’ve encountered a situation where some of our materials have EPDs conforming to the EN 15804+A1 standard, while others follow the EN 15804+A2 standard. Given the methodological differences between these two standards, especially in how CO2 emissions are categorized and reported, I’m seeking advice on how to approach the calculation of total Global Warming Potential (GWP) for our project.

My specific question is: Can we calculate the CO2 emissions for materials based on A1 and A2 EPDs separately and then sum these emissions to estimate the total GWP of our materials? If so, are there any specific adjustments or considerations we should be aware of to ensure that this approach is methodologically sound and compliant with the current standards?

I’m particularly interested in hearing about any best practices, tools, or methodologies recommended for integrating these differing datasets. Insights on how to accurately reflect the true environmental impact of our materials, while ensuring compliance and robustness in our LCA results, would be incredibly valuable.

Thank you in advance for sharing your experiences and advice!

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Hi and welcome to the One Click LCA Community Forum!

Great question and the short answer is yes but only partially. The EN15804+A2 amendment is not just an amendment to the 15804 standard but rather a significant rewrite, which means certain indicators were not present in the +A1 version and have only been introduced with the launch of +A2.

If you want to compare GWP emissions between a +A1 and +A2 EPD you can compare GWP from +A1 to GWP-FOSSIL from +A2. The other GWP emissions (Biogenic and LULUC) were not mandatory under +A1 which means in practice that 99% of the EPDs published with +A1 did not have these emissions reported.

While GWP and GWP-FOSSIL are not calculated the same way, they are close enough to be considered equivalent for most assessments. Any other +A1 indicator (e.g. ODP, ADP, etc) cannot be compared with +A2 unfortunately as the unit of measurement and the method of calculation is different in all cases.

Let me know if you have any other questions!

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