M10 AM Building Life-Cycle Capacity in the Greening of Buildings and Construction Consideration
Monday, 14 November 2005: 8:00 AM - 11:40 AM in 341-342

(BIL-1117-744671) A Hybrid Life Cycle Assessment of the Environmental Impacts of Construction—.

Bilec, Melissa¹, Ries, Robert¹, Matthews, H. Scott², Sharrard, Aurora², ¹ University of Pittsburgh, Pittsburgh, PA, USA² Carnegie Mellon University, Pittsburgh, PA, USA

ABSTRACT- Design and construction industries, along with owners, have an increasing interest in and responsibility for the environmental impacts of buildings as evidenced by the growing use of green building rating systems such as Leadership in Energy and Environmental Design (LEED). The environmental impacts over an entire life cycle of a building – design, raw material extraction, processing, construction, use, and end-of-life – are considerable. Quantification of all building phases is important, including the often disregarded and overlooked construction phase. While some existing research has assumed that the impacts of the construction phase are negligible (Junnila and Horvath 2003), others have indicated that life cycle assessments (LCA) tend to underestimate the environmental impacts associated with construction (Hendrickson and Horvath 2000). Part of the reason the construction assessment has not been previously advanced is due to the lack of and inconsistency of data supplied by the construction industry. This research focuses on the construction phase by using the methodological framework of LCA. Generally, the life cycle inventory created in performing an LCA is developed using either a process-based or input-output approach; both techniques have distinct disadvantages. The main disadvantage of the process-based model is the subjectivity and inconsistencies of the boundary selection, and the input-output method produces results that are highly aggregated. A hybrid approach to LCAs for construction has been developed. Existing proposed hybrid models are reviewed, along with a recommendation of a hybrid model for construction. A preliminary case study of the construction phase of a precast concrete parking using hybrid LCA methodology is presented. Preliminary investigations indicate transportation, equipment activity, and support functions have the largest effects on the environment.

Key words: construction, hybrid LCA, buildings, evironmental impacts