BIM-integrated LCA to automate embodied carbon assessment of prefabricated buildings

Abstract

Building information modeling (BIM) has been leveraged to reduce manual efforts in the life cycle assessment (LCA) of buildings. However, data interoperability between BIM and LCA tools remains a significant challenge because of disparate data structures, leading to a deficiency in automatic data mapping methods. Few studies have adopted professional BIM and LCA tools to evaluate the embodied carbon of prefabricated buildings at multiple spatial levels. Thus, this paper developed a BIM-integrated LCA solution to automate the embodied carbon assessment of prefabricated buildings based on a five-level framework: material, component, assembly, flat, and building. The solution framework involved three modules: (1) BIM data preparation, (2) data extraction and integration, and (3) embodied carbon assessment. An Industry Foundation Classes (IFC)-enabled data transfer tool was developed to adapt BIM data to the LCA data structure automatically. A real-life prefabricated building in Hong Kong was used to validate the feasibility of the developed solution by comparing it with the traditional LCA method. Embodied carbon was reported in five levels. The cradle-to-end-of-construction embodied carbon of the case building was calculated as 561 kg CO2/m2, showing an acceptable 1% discrepancy with traditional LCA results owing to inevitable quantity differences between design and construction. The results also indicate a dramatical time reduction in the LCA modeling process from 729 min to 62 min, achieving a 91.5% efficiency improvement. It can thus practically increase practitioners’ willingness to conduct LCA at an early design stage with quick feedback. The developed solution also extends the knowledge on automatic BIM-integrated LCA methodologically by addressing data interoperability using the IFC standard. Further, it provides systematic insights into the embodied carbon emissions of prefabricated buildings based on the five-level theoretical framework, guiding low-carbon designs for prefabricated buildings.