A sustainability-oriented approach for performance assessment of existing buildings and a case study.

The practice of sustainable buildings has become a general trend in urban development. Yet, with the rapid development of urban renewal, the performance of existing buildings often fails to meet the actual needs of sustainable urban development. To improve the performance of existing buildings, it is urgently needed to transform the existing structures and upgrade their functions and facilities. However, the pertinent guidelines have often been unclear for assessing the performance of existing structures, and a sounder and quantitative sustainable performance assessment approach has been lacking to guide decisions on the restoration, protection, or demolition of existing buildings. Based on a multi-expert consultation methodology, we proposed a revised flexible comprehensive assessment system and a comprehensive sustainability assessment approach. The system includes 4 categories, 7 quantitative and 47 qualitative indicators. Specifically, the assessment system involves a series of steps: 1) building a hierarchical model, 2) defining assessment indicators/items and constructing a judgment matrix, 3) determining the weight coefficients of the indicators, 4) collecting/calculating quantitative and qualitative data, 5) analyzing the data and results, and 6) drawing the assessment conclusions. A case study was presented to demonstrate the application of the approach. Compared to current practices, this comprehensive assessment system may serve as a scientifically sounder and quantitative approach to guide sustainable development of existing urban buildings.