Environmental Impact Analysis Of Office Building Based On Life Cycle Assessment

With the rapid improvement of society and economy in the last decades,the construction industry has experienced tremendous development and brought huge impacts on economy,environment and society at the same time.During the Tenth Five-Year Plan and the Eleventh Five-Year Plan,the development scale and speed of construction industry in our country have reached an unprecedented level,energy and resource consumption and waste emission experience a sharp increase,but a lot of environmental problems merge.Due to the range of material input,energy consumption and environmental impact of construction industry is very large,more and more domestic and foreign scholars use life cycle assessment method to study the environmental impact of buildings,highlight the importance of environmental factor in the development of a country,and improve the sustainability of buildings.Based on life cycle assessment method,we build the model of office building life cycle assessment and choose two office buildings in Beijing and Tianjin as two case studies.With the help of life cycle assessment software named "GaBi",we calculate the environmental impact of building material production stage,building operation stage,and waste building material disposal stage,identify important stage and element of each environmental impact.Then we propose specific emission reduction measures in different stages of an office building and analyze the environmental benefits of all the measures.The results show that,building operation stage is the biggest contributor to environmental impacts of an office building in which power consumption is dominant.The environmental impact of building material production stage rank second with concrete,steel,aluminum alloy have greater contribution than other materials.In terms of ODP and HTP,steel and aluminum alloy play decisive roles respectively in these two kinds of environmental impacts.Replace 20% thermal power with hydro power of electricity power structure,environmental benefits of GWP,AP,EP and HTP are more than 10%,and environmental impacts of AP can be reduced by 20.45%.Switching off the light and air conditioning timely during breaks usually for 1 hour,environmental benefits of GWP,AP,EP and HTP are 2.66%,3.39%,3.26% and 2.37% respectively.By recycling 60% of the selected waste materials and landfilling the rest 40% in the waste disposal stage,all the five environmental impacts can be reduced by 7.28%,23.16%,3.48%,4.11% and 21.84% respectively.In terms of GWP,AP and EP,the environmental benefits of changing electricity power structure in the building operation stage is much greater than the improvement of material production process and waste material recycling.With regard to ODP and HTP of which building material production is the larger contributor,the situation is quite the reverse,that’s to say,improving material production process and recycling waste materials have greater environmental benefits potential than taking measures in building operation stage.