Extract

Life cycle assessment is increasingly used to quantify and reduce the environmental effects of
buildings. Embodied environmental effects, resulting from material production and replacement as well
as construction, are typically quantified using coefficients from readily available databases. However,
most existing databases of embodied environmental coefficients for construction materials suffer from
limitations, such as inconsistency in the life cycle inventory method used or system boundary
incompleteness. This paper introduces a new database of hybrid environmental flow coefficients for
construction materials, covering flows of energy, water and greenhouse gas emissions for over 100
common construction materials. The hybrid approach used combines bottom-up industrial process data
and top-down macroeconomic input-output data, making it more comprehensive than process analysis
and more accurate and specific than input-output analysis alone. A case study building is used to
demonstrate the importance of using hybrid coefficients for improving environmental performance. This
study shows that the use of process coefficients can lead to a significant underestimation of the total
environmental effects associated with the construction of a building, by up to 64%. This has
considerable implications for decision-making relating to building design, including the focus of
improvement efforts. This database of coefficients will enable building professionals to more effectively
analyse and improve the environmental performance of buildings. This will also help inform the focus of
environmental policy and improve the implementation of life cycle thinking in environmental design.

Keywords: Life cycle assessment; construction; embodied environmental flows, environmental design.