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Top1. Introduction
Construction activities are leaders in consumption of world’s total energy and resource capacities and lead to huge consumption of raw materials, nonrenewable energy and generation of pollution and wastes (Ashfaq and Gencturk, 2014; Radivojević and Nedić, 2008). Buildings globally consume around 40% of the materials entering the global economy, 40-60% of fossil fuels driven energy, 16% of water; and generate 40–50% of the global output of greenhouse gases and the agents of acid rain, and 40-50% of wastes (Kofoworola, 2008; Arena and Rosa, 2003). The impacts caused by buildings can be grouped into direct and indirect impacts (Figure 1). Most of the products or materials used in building construction are manufactured. The indirect impact of buildings comes from the extraction, processing, manufacturing and packaging of materials utilizing natural resources and energy leading to emission of various pollutants and generation of harmful wastes. The direct impact is caused by the transportation of building materials and products up to the site, fuel and energy consumed during the construction and energy and water consumed for living during the occupancy of building (Sartori and Hestnes, 2007; Cabeza et al., 2014). The demolition of building also generates large amount of wastes which are simply land filled and may have long term environmental impacts.
As per the report by Global Construction Perspectives and Oxford Economics, 2013, the construction market in India is forecasted to grow to become globally third by 2022 and majority of growth is predicted in the residential sector. Urbanization in India has increased from 27.81% to 31.16%, with this rate of growth about 50% of population is estimated to be in the urban areas by 2050 with middle class growing at the fastest rate. It is projected that India will see an unprecedented escalation of floor area of around 400% and will have added about 35 billion m2 of new building floor area by 2050 (Shnapp and Laustsen, 2013). A fast-growing middle class will prompt the growth of cities throughout the country, which in turn will trigger a rise of new buildings, especially housing (Caleb et al., 2017). Different housing projects under various schemes like Prime Minister’s Scheme for Housing for All, have been launched in which millions of houses are projected to be constructed. The aesthetic and cost aspects of buildings still remain the main criteria with little concern on their life time environmental impact. Building sector in India is responsible for 30–50% of SO2 emissions and 15–18% of total CO2 emissions (Vyas and Jha, 2017). In order to reduce the adverse impacts on environment and increase the sustainability of buildings, an objective and quantifying assessment method for decision-making is needed (Sev, 2011). Minimizing energy, material, and land use by considering potential impacts to the environment on a life cycle basis are the basic steps in designing an energy-efficient and environment-friendly building (Atmaca, 2015). In global context issues of environmental problems are becoming serious, more comprehensive building evaluation procedures are required to evaluate performance of building across a range of environmental considerations (Banani et al., 2013). For this purpose, an evaluation methodology including total analysis of the raw materials, resources and energy used and generation of waste during the life cycle of a building must be evolved. Current thrust area of concern for building sector especially in developing countries is to assess the environmental impact of buildings in quantifiable way for implementing sustainable measures and achieving sustainability. The main goal of this paper is to assess the environmental impact of a residential building at the planning stage itself, on the basis of life cycle assessment (LCA), considering various stages of building like construction, operation (for service life) and demolition, and to identify the hotspots.
Figure 1.
Impacts of building construction