A comprehensive database of environmental flow coefficients for construction materials: closing the loop in environmental design

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.