Circularity evaluation as guidance for building design

Resource scarcity and global warming call for ambitious strategies in the construction sector to meet the ever-growing demand for indoor spaces with minimal resource consumption and positive environmental impacts. In line with the need to introduce circular economy in the construction sector, the German Public Sustainability Certification System (BNB) is revising its indicator for disassembly, separation and reuse. The proposed assessment is intended to guide in the planning process and to point out challenges and potentials of the circular economy by making the complex interactions and requirements comprehensible in detail. The continuity of the assessment from the building material to the building component to the entire building allows users to track the impact of changes made at each level of aggregation. Based on extensive background research, end-of-life categories are assigned to building materials according to their reusability, taking into account assembly techniques and adjacent, associated materials. Example building components illustrate the method and show the impact of design changes. At the building level, the quantity determination of materials in the end-of-life condition allows transparent comparison of different design variants and documents in detail the material inventory for use in building material passports. Future developments envision the inclusion of building services in the circularity assessment, benchmarking of circularity at the building level, and integration of circular qualities into life cycle analysis calculations.