Analysis of Risk Evolution Mechanism of Fire Disaster Chain in Building Construction and Optimization of Emergency Procedures

Fire risks during the construction phase remain one of the most critical challenges in the construction industry, often leading to property losses, casualties, project delays, and long-term reputational damage. To address these issues, this study proposes a risk-informed emergency optimization framework for construction fire scenarios. Utilizing a disaster chain network framework derived from previous case analyses, including 25 secondary events and 59 causal connections, the study focuses on identifying high-risk transmission paths and optimizing emergency response. Through risk-based edge evaluation, high-risk transmission pathways—particularly those linked to casualties—were detected, forming the basis for targeted intervention strategies. An optimized multi-agency collaborative rescue process was designed to address these critical links. Using Colored Petri Net (CPN) simulation, the proposed process was validated on a representative major fire case, demonstrating a 36.3% reduction in overall emergency response time and a 19.5% decrease in firefighting duration. The results highlight that integrating disaster chain analysis, risk-weighted edge disruption, and CPN-based simulation can significantly enhance emergency coordination and operational efficiency. This study provides actionable insights for policymakers and project managers to strengthen fire risk management strategies and build more resilient emergency systems for the construction sector.