Derivation of reliable simplification strategies for the comparative LCA of individual and "typical" newly built Swiss apartment buildings

This study introduces an approach to the derivation of reliable simplification strategies, which can prospectively be applied to the comparative life cycle assessments (LCAs) of newly built Swiss apartment buildings. These strategies help architects and planners easily, yet reliably to evaluate the environmental impact of apartment buildings in the preliminary design stages. The starting point of this study is the assumption that simplification strategies, which take into account only those building parameters that have the greatest relevance to the overall environmental impact of an apartment building, are adequate for the derivation of reliable LCA results. In order to identify the most influential building parameters, data from a larger sample of 12 individual newly built Swim apartment buildings was collected and analysed with a comparative LCA. The results of the LCA led to proposals for "phase 1" simplification strategies for individual apartment buildings. These strategies consist of various individual and combined approaches, which suggest omitting irrelevant processes in the LCAs (e.g. building parameters, materials and building life phases), as well as applying only selected impact categories/indicators. Subsequently, the sample of individual buildings was sorted by certain building characteristics into groups (clusters). This sorting process was carried out by means of statistical cluster analysis. For each cluster, "typical" building examples have been determined, which re-present the individual buildings of the same cluster. For these "typical" Swiss apartment buildings the LCA results were calculated and presented. Based on the cluster process and the out-comes "phase two" strategies for the identified "typical" apartment buildings have been derived. The investigated sample consists of 12 buildings, which differ significantly in their in-dividual properties. Nevertheless, there are enough similarities to allow an assignment of these individual buildings into two different clusters. Based on the LCA results, it is possible to derive reliable simplification strategies for the individual buildings as well as for the "typical" building in each cluster. It turns out, that for this sample the identification of "typical" buildings offers a viable superordinate level of simplification, which, in combination with the "phase 1" strategies, can procure reliable LCA results. However, in order to allow for results that can be generalised, it is desirable to apply this approach to a larger, statistically representative sample of the whole Swiss building stock of newly built apartment buildings. This study fulfils an identified need by presenting an approach to the derivation of reliable simplification strategies for comparative building LCAs of newly built Swiss apartment buildings. A new idea is the application of statistical cluster analysis for the identification of "typical" apartment buildings in the LCA context. The functionality of this approach is demonstrated in the course of this study and the idea is generally applicable to any type of building.