Research On Life Cycle Environmental Impact Assessment Of Prefabricated Housing

With the continuous advancement of urban and rural planning in China,the development of urban housing has promoted the rapid growth of the national economy,but it has also brought serious environmental pollution.Compared with traditional castin-place housing,prefabricated housing has the advantages of low energy consumption,less pollution and high efficiency,which is an effective means to realize the sustainable development of housing industry.At present,China ’s prefabricated houses are in a stage of rapid development.The corresponding environmental pollution management policies are not perfect,the environmental protection measures are not mature,the quantitative evaluation system of environmental impact of prefabricated houses is not perfect,and the environmental management work lacks scientific basis.Therefore,it is necessary to systematically study the environmental impact assessment of the whole life cycle of prefabricated houses,and provide a theoretical basis for improving the environmental pollution management level of prefabricated houses.On the basis of literature investigation and theoretical analysis,the basic framework and method of LCA(Life Cycle Assessment)are clarified,and the life cycle environmental impact assessment model of prefabricated housing is established.Firstly,the life cycle assessment scope including the materialization stage,the operation and use stage and the waste demolition stage is determined.According to the characteristics of each stage of prefabricated housing,the inventory analysis and database are established from two aspects of energy consumption and pollution emission.Then,according to the results of the inventory analysis,seven types of environmental impacts including greenhouse effect and acidification were identified,and the environmental impact assessment index system of prefabricated residential buildings was constructed.Taking2020 as the base year and 2025 and 2030 as the target years,the environmental policies of the target years are sorted out,and the dynamic index weight system is established based on the target distance method.According to the influence proportion of the construction industry in the seven environmental types in the past five years,the weight system is revised.Based on Spring Boot framework and Vue.js framework,LCEI-PH(Life Cycle Environmental Impact Assessment)system is developed to realize the automation of evaluation process and visualization of evaluation results.Taking a prefabricated housing project as an example,the environmental impact analysis is carried out.The results show that in the whole life cycle analysis,the evaluation results under the revised weight system are 22.91 person equivalent higher than those before the revision,with an increase of 22.04 %.The environmental impact of the materialization,operation and use,and waste demolition stages accounted for 19.54 %,69.22 %,and 11.24 %,respectively;in the phased analysis,the types with the greatest environmental impact in the three stages are solid waste discharge,water eutrophication pollution and solid waste discharge.On the basis of the results of the impact analysis,the sensitivity analysis of the three factors including the prefabrication rate,the transportation distance of building materials and the recycling rate of building materials is carried out,and the effects of different factors on the environmental impact assessment results are obtained.Environmental improvement measures are proposed for each stage.