Application of life-cycle assessment to early stage building design for reduced embodied environmental impacts

Decisions made during a buildingʹs early design stages critically determine its environmental impact. However, designers are faced with many decisions during these stages and typically lack intuition on which decisions are most significant to a buildingʹs impact. As a result, designers often defer decisions to later stages of the design process. Life-cycle assessment (LCA) can be used to enable better early stage decision-making by providing feedback on the environmental impacts of building information modeling (BIM) design choices. This paper presents a method for applying LCA to early stage decision-making in order to inform designers of the relative environmental impact importance of building component material and dimensioning choices. Sensitivity analysis is used to generalize the method across a range of building shapes and design parameters. An impact allocation scheme is developed that shows the distribution of embodied impacts among building elements, and an impact reduction scheme shows which material and thickness decisions achieve the greatest embodied impact reductions. A multi-building residential development is used as a case study for introducing the proposed method to industry practice. Results show that the method can assist in the building design process by highlighting those early stage decisions that frequently achieve the most significant reductions in embodied carbon footprint.