Environmental performance of off-site constructed facilities: A critical review

During the recent decades, off-site construction (OSC) has gained a rapid growth worldwide. It has been reported that OSC, as an alternative construction method, has a variety of benefits. However, there is lack of critical review of the building performance (e.g. energy consumption and carbon emissions) of off-site built facilities. Life cycle approach and bibliometric analysis are adopted in this study to review existing research on the environmental performance of off-site built facilities. The results show that most existing studies chose to employ LCA method to systematically analyse carbon emissions and energy consumption of prefabricated residential buildings by using sub-assembly components as functional units. The detailed investigation of volumetric construction and building operational stage are rare. The sensitivity of thermal property caused by offsite manufacturing and onsite assembly in comparison to the traditional cast-in-situ method remains unexplored. It is encouraged to cover various environmental impacts in building performance assessment, to develop a sustainability rating system applied in OSC, to adopt Internet-of-Things in OSC monitoring by using real-time data, and to establish an indicator system for the evaluation of OSC performance. The findings of this study can facilitate the understanding of status quo and shed lights on future research direction in OSC.