LCA benchmarks for decision-makers adapted to the early design stages of new buildings

ABSTRACT When employing Life Cycle Assessment (LCA) in the building design process a number of difficulties arise. In early design stages, not all material information are available yet and assumptions are needed to replace missing data. Furthermore, designers find it difficult to use the LCA results to improve the design. Therefore, this paper introduces a method to derive benchmarks for individual architectural elements (walls, roof, etc.) using statistical data on the market share of materials or type of constructions for new residential buildings in Switzerland. Assuming a lognormal distribution, target benchmarks based on the 5th percentile are calculated. Using the provided results in a real building case study shows that the benchmarks can be reached. However, the benchmarks and even the minimum values corresponding to the currently best available technology are far from the global goal of 1t CO₂ per person.