Whole-wall building sustainability index for IEA Annex 32 Integral Building Performance.

IEA Annex 32 Integral Building Envelope Performance is developing a number of test procedures and measures that can be used to compare and rate the thermal performance of alternative whole-wall construction technologies for residential structures. In this paper, we address sustainability issues and potential impacts building materials may have on the environment. Specifically, we describe the development of a whole-wall sustainability index. The index includes a number of specific measures of material sustainability-environmental emissions and impacts, material embodied energy, resource efficiency and recycling, and indoor air quality. The index is based on a life cycle analysis (LCA) perspective that encompasses the extraction of resources used in the manufacture of building materials, the impacts during construction, the impacts over building service life (including thermal performance), and the impacts associated with the disposition and recycling of the whole-wall components. To illustrate, we provide an example whole-wall sustainability index for two competing systems-a standard 2x4 dimensional lumber-framed whole-wall and a conventional cold form steel-framed whole-wall. In the future, we expect to develop databases, refine the sustainability index, and apply it to most of the 40 advanced wall systems already thermally evaluated. We also review related work by the American Institute of Architects (AIA), National Institute of Standards and Technology, and the Royal Architectural Institute of Canada.