Synergising Circularity and Temporal Dynamics into Life Cycle Sustainability Assessment of Prefabricated Buildings: A System Dynamics-based Assessment with Static–Dynamic Comparison

The rapid growth of the building sector, alongside its significant contribution to the climate crisis, has heightened the need for technologies that improve sustainability. Prefabricated buildings (PBs) offer a major solution, whose benefits can be evaluated through Life Cycle Sustainability Assessments (LCSA) to support informed decision-making. However, conventional LCSA approaches often overlook circularity (disassembly and reuse potential) and temporal dynamics (time-dependent changes), leading to incomplete evaluations. This study addresses this gap by integrating circularity and temporal dynamics into the life cycle sustainability of PBs, through two main contributions: (1) evaluating sustainability via a system dynamics-based LCSA framework under circularity and dynamism-informed design scenarios, and (2) performing a comparative static–dynamic analysis to quantify the impact of temporal variations on sustainability. Applied to a disassemblable prefabricated building in Western Australia, ambitious end-of-life strategies that prioritise reuse and recycling increased circularity by nearly 20%, though higher circularity did not always guarantee environmental gains (e.g., an 11% increase in circularity accompanied a 1% reduction in carbon footprint, while a 14.2% increase led to a 1.3% rise in embodied energy), highlighting the need for multi-objective optimisation. Comparative static versus dynamic assessments showed that static approaches overestimate impacts, with discrepancies up to 14% for a 20-year service life, whereas dynamic simulations captured long-term benefits, including up to 80% reductions in operational emissions under decarbonisation scenarios. The framework is proposed to be integrated into design-stage decision-making, enabling stakeholders (designers, engineers, construction managers, policymakers, and clients) to minimise long-term financial risks.