Whole building circularity indicator: A circular economy assessment framework for promoting circularity and sustainability in buildings and construction

Circularity is finding its feet in construction. Several Building Circularity Indicators (BCIs) have been developed to measure buildings' Circular Economy (CE) potential, but none of them has been standardized. Currently, the BCIs methodologies lack consensus on CE definition and scope, Key Performance Indicators (KPIs), and various other technical aspects. New research is hardly building upon the existing works and this lack of incrementalism hinders the standardization process. The current research addresses these limitations by developing a comprehensive and innovative Whole-Building Circularity Indicator (WBCI). WBCI consolidates the existing advancements by including the best features of various methodologies (like VBCI, MCI, Flex 4.0, etc.) and covering a wide range of KPIs. It has been developed from a life cycle perspective, taking into account all material flows from the point of origin to disposal or waste treatment. The adopted methodology complements popular sustainability tools like Life Cycle Assessment (LCA). The validation is done through a case study of a typical Italian residential building. WBCI along with an existing popular tool is applied to the case study using the actual building data to validate and highlight the improvements made in the developed framework. The building performed poorly in terms of circularity, scoring 0.243 on a scale of 0 (fully linear) to 1 (fully circular). It is found that resource-intensive construction processes and longer service life can substantially affect CE performance. Recommendations for improving the building circularity are given. From the methodological point of view, results emphasize that WBCI is a multilevel framework capable of identifying the best-performing CE solution at the material, element, system, and whole-building levels. Contractors, consultants, and policymakers may leverage WBCI's features to assess the circular performance of buildings at early stages. Researchers can also use the findings to further expand and standardize the BCIs.