Does the Modular Construction Project Outperform the Traditional One? A Comparative Life Cycle Analysis Study in Hong Kong

Hong Kong faces critical construction challenges, including workforce aging, land shortages, and near-capacity waste disposal. Modular Integrated Construction (MiC) offers a promising solution. As Hong Kong has just recently adopted the MiC, quantitative studies that explore the actual performance differences between MiC projects and conventional on-site construction projects in Hong Kong are lacking. To fill this knowledge gap, this study utilizes an extended life cycle assessment–Life Cycle Performance Assessment to conduct on-site investigations and case studies on a MiC pilot residential project and a conventional on-site construction residential project in Hong Kong from multiple dimensions: cost, time, safety, and environment. The assessment indicators include five types of greenhouse gas emissions, cost performance, schedule performance, and safety-level index. This study found that the greenhouse gas emissions of the MiC project during the entire construction period were reduced by approximately 21.60% compared to traditional on-site construction projects. The most significant part of the greenhouse gas emissions of the two methods was the embodied emissions of construction materials, accounting for 83.11% and 87.17%. Compared with the conventional construction project, the factors that actively promote the reduction of greenhouse gas emissions in the MiC project are the embodied greenhouse gas emissions of building materials, the transportation of construction waste, and the resource consumption of equipment. In addition, there is no significant difference in the safety performance index of the two construction methods, but MiC projects have more efficient schedule performance management. Surprisingly, the cost control of MiC projects is not as good as that of conventional construction projects, which differs from existing research results in other regions.