LCA in building certification
Experiences from Germany
Life Cycle Assessment (LCA) increasingly gains attention and is used more and more in the building sector throughout the world. Strong support for LCA is given by both International and European standardization activities - e.g. CEN TC 350 ("sustainability of construction works") defined LCA as the core method to describe the environmental performance of buildings. In addition to standardization, different approaches to assess the sustainability performance of buildings are installed through building certification bodies and some of them include LCA as a mandatory instrument for building assessment. The German Sustainable Building Council (DGNB) as a non-profit organization to promote sustainable construction was founded in 2007 and subsequently released a sustainability certification scheme for buildings. The life cycle based and performance oriented approach to building assessment is seen as a major feature of the DGNB certification scheme. With an increasing number of certified buildings, the certification yields the rare opportunity to evaluate and compare LCA results for a significant number of different buildings, where the LCAs have been done under the same boundary conditions. Basis for the comparability of LCA results of certified buildings are consistent and complete definitions to conduct the LCA calculation of the different buildings. On this basis, LCA results evaluated and the results are presented in this work. For the purpose of continued development and improvement of building certification rules, adequate benchmarks and metrics, the results are evaluated and will be statistically analysed in the future. Currently a limited number of datasets for certified buildings is available that allow initial impressions and insights in the LCA results for certified buildings. The findings indicate the appropriateness of the benchmarks currently in place, while it is also indicated that benchmarks may and probably should undergo a development towards tightened values. With increasing numbers of certified buildings in the future, systematic analyses will be possible, yielding a structural understanding of LCAs of buildings, core influencing factors and good benchmark levels.