Example of a Hybrid Life-Cycle Assessment of Construction Processes

TLDR

Design and construction industries are increasingly focused on the environmental impacts of buildings, making comprehensive life‑cycle quantification—particularly of the construction phase—essential. The study aims to evaluate the construction phase of a building project using a hybrid life‑cycle assessment approach. The authors propose a hybrid LCA model that merges process‑based and input–output methods, review existing hybrids, and recommend a specific model for construction. A preliminary case study of a precast concrete parking garage shows that transportation, equipment activity, and support functions exert the greatest environmental impacts.

Abstract

Design and construction industries, along with owners, have an increasing interest in and responsibility for the environmental impacts of buildings. Since the environmental impacts of a building's life cycle are considerable, quantification of all phases is important, especially the construction phase, which is often glossed over. This research focuses on the construction phase of a building project. Generally, the life-cycle inventory created in performing a life-cycle assessment (LCA) is developed using either a process or input–output approach; however, both techniques have distinct advantages and disadvantages. A hybrid approach combining both methods' advantages has been proposed and will be demonstrated. Existing hybrid models are reviewed, along with a recommendation of a hybrid model for construction. A preliminary case study of a precast concrete parking garage's construction using hybrid LCA methodology is presented. Preliminary investigations indicate transportation, equipment activity, and support functions have the largest effects on the environment.