Developing an empirical phase-based greenhouse gas emission distribution model for building construction projects

Abstract

The construction sector consumes substantial materials and energy and generates significant greenhouse gas emissions. However, existing studies and inventory practices generally focus on total emissions, emission sources, or life-cycle modules, whereas construction management in practice is organised by schedule and construction phase. This study develops an empirical phase-based greenhouse gas emission distribution model for building construction projects. The research combines surveys of 32 projects/sites across four building project groups with six-month greenhouse gas inventory data from 40 projects/sites managed by a general contractor. The results propose a procedure for defining the construction phase structure, establish seven main phases, develop a coded list of detailed construction activities, and formulate a quantitative model linking emission data with actual construction phases. Model application shows that emissions are concentrated mainly in the structural construction phase, accounting for approximately 40%, followed by the building envelope and architectural rough-in phase at approximately 20%, the remaining phases contribute 5-12%. The model supports emission hotspot identification, carbon budgeting, and project/site-level emission reduction strategies.