Evaluating 'reuse' in the current LCA framework - Impact of reuse and reusability in different life cycle stages

Abstract

In the context of circular construction, the (potential) reuse of construction materials and building products is set forward as a general concept to reduce the environmental impact of buildings. But does this really lead to reduced impacts? A standardised framework to calculate the environmental impact of buildings over their life cycle is available through the European standards EN15804+A2 and EN15978 for life cycle analysis (LCA) in construction. The concept of reuse does however intrinsically focus on multiple use or life cycles. A correct quantification of the environmental impacts of reuse in buildings, requires a better understanding of the different mechanisms and issues at play. By means of critical assessment of the LCA methodology, in combination with a simplified case study, this paper provides insights in how different reuse options for products are valorised (or not) when calculating the environmental impact. It is shown that the LCA standard EN15804+A2 allows to quantify the impact related to different concepts of reuse at the beginning or the end of the considered life cycle. In general reused products will lead to larger environmental gains as the production stage (A1-A3) can be avoided. The environmental benefit related to the reusability of a product is typically reflected in a smaller difference in the end-of-life (EOL) stage (C1-C4). Also the relevance of existing concepts, such as module D, is discussed for each of the considered reuse options. Results show that module D can provide insights in the future potential of reuse (at EOL) for virgin products, but that the numbers are difficult to interpret and even misleading for reuse products. The results and discussion show the limitations of the current LCA framework for these types of products and identify the need for the integration of additional concepts to correctly valorise the potential of reusable products using LCA.