Environmental product declarations in accordance with EN 15804 and EN 16485 - how to account for primary energy of secondary resources?

As a core product category rule (PCR), EN 15804 defines rules for conducting the life cycle assessment (LCA) of building products in the context of environmental product declarations (EPDs). This European standard is complemented by EN 16485, which provides further guidance for specific aspects for the LCA of wood and wood-based construction products. For all life cycle stages under consideration, the renewable and nonrenewable primary energy employed for energy generation or material use is accounted for. Furthermore, the inputs and outputs of secondary materials (SM), renewable secondary fuels (RSF) and non-renewable secondary fuels (NRSF) have to be reported. Especially in the end-of life stage as well as in the production stage, the standards do not exactly rule the accounting method of the primary energy contained in SM, RSF and NRSF. As both standards leave room for interpretation, we wrote this discussion article to introduce this issue to the LCA community and to present our developed accounting specifications. In general, we consider EN 15804 and EN 16485 as helpful tools for the LCA of building products. We hope that our ideas on certain aspects contribute to a better understanding of the standards, possibly leading to further improvement in the course of the standardization process.