Sensitivity analysis of the use of Life Cycle Impact Assessment methods: a case study on building materials

The main aim of this research is to perform a sensitivity analysis of a Life Cycle Assessment (LCA) case study to understand if the use of different Life Cycle Impact Assessment (LCIA) methods may lead to different conclusions by decision makers and stakeholders. A complete LCA was applied to non-load-bearing external climate walls for comparative purposes. The LCIA phase of the case study was performed using five different Impact Assessment Methods: EDIP 97/2003 (midpoint), CML 2001 (midpoint), Impact 2002+ (endpoint and midpoint), ReCiPe (endpoint and midpoint) and the ILCD recommended practices for LCIA (midpoint). The endpoint results were compared aggregately, and the midpoint categories concerning similar potential impacts were compared individually for the analysis of possible deviations. The observations and comparisons involved mostly the decision maker's point of view and not the differences among the characterization models. The endpoint LCIA showed that the only two methods which applied such an approach (Impact 2002+ and ReCiPe) provided different results and led to different conclusions. For midpoint LCIA, the results were completely consistent for the following impact categories: General Eutrophication, Aquatic and Freshwater Ecotoxicity, Ionizing Radiation, Particulate Matter Formation, and Resources Depletion. Global Warming, Terrestrial Ecotoxicity, Human Toxicity (except for the Non-carcinogens impact category) and Land Use (except for Natural Land Transformation) showed partially consistent results and pointed out to the same worst environmental alternative, but with a slightly different impact profile among the other alternatives. Ozone Layer depletion and Photochemical Oxidant Formation categories showed discrepant results and the impact profile differences between the older and newer methods were notable. Acidification, Terrestrial and Aquatic Eutrophication, Marine Ecotoxicity and Water Depletion showed substantially inconsistent results.