اثرات زیست محیطی بخش مسکونی بریتانیا: ارزیابی چرخه عمر خانه ها

This paper presents for the first time the results of a full life cycle assessment (LCA)1 study for the three most common types of house in the UK: detached, semi-detached and terraced. All life cycle stages are considered, including house construction, use and demolition after 50 years. The results indicate that the use stage has the largest contribution to most environmental impacts. For example, the global warming potential (GWP)2 over the 50-year lifetime of the detached house is 455 t of CO2 eq.; 374 t CO2 eq. of the semi-detached; and 309 t CO2 eq. of the terraced house. Around 90% of the GWP is from the use, 9% from construction (embodied carbon) and 1% from the end-of-life waste management. A similar trend is noticed for all other impacts. Recycling the building materials at the end of life leads to an overall reduction of the impacts. For instance, the GWP reduces by 3% for the detached and semi-detached houses (to 441 t of CO2 eq. and 363 t CO2 eq., respectively) and by 2% (to 302 t CO2 eq.) for the terraced house. The main environmental benefit is from reusing the bricks and recycling the aggregates. At the housing sector level, the total GWP is 132 million tonnes of CO2 eq. per year with the semi-detached houses contributing 40%, terraced 37% and detached houses 27%. Over the 50-year lifetime, the total GWP from the sector is nearly 6.6 billion tonnes of CO2 eq. The results also highlight the importance of decisions made in the design and construction stages as they determine the impacts of the house in the use and end-of-life stages.