Multi-Dimensional evacuation risk evaluation in standard subway station

Abstract The performance-based approach using Required Safety Egress Time / Available Safety Egress Time concept is the most common method in fire safety evaluation. However, this one-dimension approach cannot fully evaluate the performance of a complex scenario with thousands of occupants in subway stations. Therefore, this paper develops a four-dimension parameter system that includes Required Safety Egress Time, Average Evacuation Time, Average Waiting Time, and Average Moving Distance to quantify the evacuation performance from four aspects. The convergence test approach is adopted to validate the accuracy of simulation results. A dimensionless parameter Risk Index (RI) is proposed to support multi-dimensional risk evaluation and comparison. One realistic standard subway station in Guangzhou metro system is modeled to testify the applicability of the proposed method. Totally twelve evacuation scenarios are designed and simulated, results indicate that: 1) Repeated simulations are necessary. Up to 629 simulation run times are required to meet the acceptance criterion of 0.01% for mean and 1% for standard deviation. 2) The Risk Index of Average Waiting Time is distinctly higher than other Risk Indexes. A long waiting time at bottlenecks increases the risk level in all scenarios. 3) The risk evaluation result of comprehensive RI is consistent with but not the same as the evaluation conclusion of RSET. The difference between RI and RSET shows that RI integrates more aspects of evacuation risk than RSET. The method proposed could support safety evaluation capacity improvement and standard revision in metro system.