Life cycle environmental assessment of light steel framed buildings with cement-based walls and floors

Abstract

The objective of this paper is to apply the life cycle assessment methodology to assess the environmental impacts of light steel framed buildings fabricated from cold formed steel (CFS) sections. The assessment covers all phases over the life span of the building from material production, construction, use, and the end of building life, in addition to loads and benefits from reuse/recycling after building disposal. The life cycle inventory and environmental impact indicators are estimated using the Athena Impact Estimator for Buildings. The input data related to the building materials used are extracted from a building information model of the building while the operating energy in the use phase is calculated using an energy simulation software. The Athena Impact Estimator calculates the following mid-point environmental measures: global warming potential (GWP), acidification potential, human health potential, ozone depletion potential, smog potential, eutrophication potential, primary and non-renewable energy (PE) consumption, and fossil fuel consumption. The LCA assessment was applied to a case study of a university building. Results of the case study related to GWP and PE were as follows. The building foundations were responsible for 29% of the embodied GWP and 20% of the embodied PE, while the CFS skeleton was responsible for 30% of the embodied GWP and 49% of the embodied PE. The production stage was responsible for 90% of the embodied GWP and embodied PE. When benefits associated with recycling/reuse were included in the analysis according to Module D of EN 15978, the embodied GWP was reduced by 15.4% while the embodied PE was reduced by 6.22%. Compared with conventional construction systems, the CFS framing systems had much lower embodied GWP and PE.