Uncertainties related to the replacement stage in LCA of buildings: A case study of a structural masonry clay hollow brick wall

The construction of even simple buildings, such as housing, consumes great amounts of nonrenewable resources throughout their service life. Generally, a building has a long life-cycle, determining the impact generated due to the production of materials and building use is only part of the problem. To predict the building elements that must be replaced over the life span of a building into a model is complicated and this step often receives less attention than expected. As a part of its use stage in a Life Cycle Assessment (LCA), the research reported herein aims to quantify the uncertainties related to incorporating a building's replacement and repair needs into a model and defines different substitution scenarios based on international data. Inventory data uncertainty was also analyzed by comparing Global life cycle inventory with Brazilian regionalized data. One square meter of structural clay hollow brick wall was studied, with a scope encompassing a cradle-to-grave scenario, assuming a 50-year life span. Results obtained indicate the life cycle inventory choice affects the results significantly. How the service life is modeled may cause high variations the LCAs results. The use stage impact ranges from between 6% and 72%, depending on the assessed scenario, life cycle inventory, and impact category. Scenarios that applied the design life criteria generated greater impact than those based on documented service life data. Definitions about the service life used to model building elements replacement are essential to reduce uncertainties and will set the stage to refine these models, thereby improving their accuracy. (C) 2019 Elsevier Ltd. All rights reserved.