Briefing: Life-cycle carbon assessment of prefabricated buildings: challenges and solutions

Abstract

Buildings contribute to significant carbon dioxide emissions over their life cycle. The prefabrication approach has been promoted and increasingly integrated into building engineering and construction, which has attracted increasing research into the life-cycle carbon assessment (LCCA) of prefabricated buildings. However, there exist challenges. This paper examines the challenges and, through rethinking their theoretical fundamentals, proposes solutions with the aim to enhance the reliability and validity of research into the LCCA of prefabricated buildings. The challenges are found to be implicit system boundaries of prefabrication and LCCA: inconsistent methods, models and units of analysis of estimating buildings’ life-cycle carbon dioxide emissions and LCCA being a labour-intensive process with limited accountability. The proposed solutions are a regression model of relating buildings’ LCCA to 12 system boundaries, expressed by the system boundaries’ inconsistency ratio (I R), which shows the level of difference between any two system boundaries; a five-level framework of units of analysis consisting of material, component, assembly, flat and building; and a smart-technology-integrated approach for automatic LCCA. The solutions are important and timely to help reduce buildings’ life-cycle carbon dioxide emissions effectively for achieving long-term sustainability of society.