Developing a life cycle assessment-based framework for module-based impact distribution in adaptive reuse of modular buildings

Abstract

Modular construction offers a sustainable alternative to traditional construction by reducing waste, lowering carbon emissions, and enhancing flexibility through the relocation, renovation, and repurposing of modules. Aligning with circular economy principles, adaptive reuse of modular buildings emerges as an effective strategy to minimize resource and energy demands associated with producing raw materials and new modules. However, quantifying the environmental impacts of reused modules presents significant challenges due to the complex reconfiguration of modules into different building systems and the limitations of existing life cycle assessment (LCA) frameworks. To address these challenges, this research proposes a novel three-step framework that integrates LCA, Production Environmental Footprint method with a module-based impact distribution formula. In this framework, each module is allocated primary production and disposal impacts for its first and last use cycle, along with environmental credit and load for subsequent cycles. The framework was tested through a use case involving a relocatable modular school building (L1) in South Korea, which was partially reconfigured into a new building (L2). After applying the proposed framework, the net carbon emissions assigned to L1's life cycle were offset by 30.55 %. The framework also demonstrated its effectiveness in quantifying and allocating impacts of reused modules in four scenarios of L2 building, thereby enabling a more nuanced assessment of adaptive reuse strategies. This innovative framework not only facilitates improved environmental impact assessments of the adaptive reuse of modular buildings but also supports the construction industry's transition towards greater circularity and sustainability. © 2025 Elsevier B.V., All rights reserved.