Consistent BIM-led LCA during the entire building design process

Life Cycle Assessment (LCA) is a suitable method to analyse the environmental impact of buildings' design choices. However, the nature of the building design process leads to a dilemma when applying LCA in early phases. LCA can be fully performed only in the later design phases when complete information is available, but it is too costly to make changes. As a result, LCA is scarcely employed as a decision-making tool. Building Information Modelling (BIM) can assist LCA during the design process. So far, two different approaches are usually adopted to perform the BIM-based LCA of buildings. The first approach concerns performing LCA with a detailed BIM at the end of the building design process. The second approach involves simplified methodologies for early design stages with uncertain data. This study proposes a novel approach for applying a consistent BIM-led LCA from the early design stages to the detailed ones based on lower to higher level of accuracy. Since the BIM elements are specified with increasing level of detail in each design phase, the method uses different LCA databases for the Level of Developments (LODs) of the building elements. Accordingly, LCA calculations are based on mixing the databases in every design phase. This is possible as long as the databases use identical background data. The framework helps to provide consistent information for decision-making throughout the whole design process, both in the later design phases and early ones with a simplified BIM.