Life cycle assessment of residential building in Iran: a case study on construction phase and material impacts

Buildings are a basic requirement for human beings and an essential part of the built environment, with significant environmental impacts. In addition to their complex and diverse material use, buildings are expected to have a long lifespan, typically more than 50 years. This paper aims to evaluate the environmental performance of materials and construction activities for a typical residential building. Life cycle assessment methodology was applied using Simapro (c) software. A cradle-to-gate analysis was carried out. The results were analyzed based on the Ecoinvent 3.8 database and Eco-Indicator 99. The results show that reinforcing steel (21%) and concrete production (16%) are the most dominant processes, accounting for almost 37% of the overall environmental impact. Transportation also had an overall impact of around 15%. Brick production and use accounted for 11.23% of the overall impact, followed by lime mortar production (11%). Asphalt coating production and use had the 6th highest impact with 9.7% of the overall impact. Ceramic production accounted for 5% of the overall impact, followed by cut stone products with 3.58% of impact. Steel use, plaster mixing, excavation processes, laminate, fiberboard, paint, and glass production and use had around 7% of the overall impact in total. Besides, the resource depletion impact category showed the highest value among the three main impact categories. On the other hand, fossil fuels and respiratory inorganic impact categories were the most affected sub-impact categories among the 11 study impact categories. As material and designing codes, technology, and construction methods differ based on regions and countries, this paper demonstrates the importance of even smaller portions of materials such as Laminate production in the Land use and asphalt felt production in the Fossil fuels impact categories in, especially for countries with insufficient studies and databases for construction activities.