Greenhouse gas emissions of buildings designed for disassembly across multiple life cycles

Abstract

Planning and building for future disassembly and the reuse of materials have been identified as promising design strategies for the implementation of circular economy principles in the construction sector. These strategies are expected to contribute to reducing material related greenhouse gas (GHG) emissions. Yet, the potential of circularity strategies to lower GHG emissions should be further explored in regional case studies. Several life cycle assessment frameworks enable calculating material related GHG emissions arising from circular strategies. This study conducts a scenario analysis of an office building to test two calculation frameworks, FutureBuilt ZERO and the Circular Footprint Formula (CFF), with special focus on concrete and steel, as they account for a large share in global emissions caused by the construction industry. The CFF considers market mechanisms such as demand and supply of high-quality recycled materials, while FutureBuilt ZERO employs a dynamic approach to evaluate future emissions. The results differ by up to 230% depending on the framework and assumptions. Most of the results favor the reuse of secondary materials, i.e., downstream reuse, over the design of buildings for future disassembly, i.e., upstream reuse. Design for disassembly principles are preferred when market mechanisms are considered, and the supply of high-quality secondary material is lower than the demand. The magnitude of the results is correlated with assumptions about future technological improvements in material production. In policy making, market mechanisms and production efficiency pathways should be included in circularity assessments to best depict and understand the GHG emissions reduction potentials at play.