The application of life cycle assessment for the optimization of pipe materials of building water supply and drainage system

The selection of pipe of the building water supply and drainage system in buildings is important for energy conservation. In the past, the building designer mainly considered the use performance and one-time cost of pipes in building water supply and drainage system but ignored the differences in resources, energy consumption and pollutant emissions in the whole life cycle of different pipes. This paper combines the life cycle assessment with the analytic hierarchy process to analyze the energy consumption, resource consumption and its impact on the environment of different pipes in the building water supply and drainage system. The results showed that the energy consumption of PVC-U pipe in the building water supply system could be reduced by 86 % and 91 % compared with that of galvanized steel pipe and copper pipe, and the reduction value in the drainage system was about 86 %.Galvanized steel pipes, copper pipes, and cast iron pipes are approximately 7.3 to 11.3 times larger than PVC-U pipes in a single indicator for comprehensive environmental impact assessment. This study shows that replacing other metal pipes with PVC-U can significantly reduce the environmental impact, which also implies the importance of life cycle assessment in the design of building pipes.