Mapping fire risk of passenger-carried fire load in metro system via floor field cellular automaton

Rapid urbanization in many large cities around the world fosters the rapid expansion of mass transit rail/metro services. It becomes one of the most important transportation modes in our daily lives and greatly improves the efficiency of travel. Meanwhile, as existing statistics show, fire accidents are one of the serious threats that metro faced with. Of all these accidents, fire risk associated with the fire load carried by the passengers have rarely been studied due to its dynamic nature. To facilitate efficient planning for pedestrian movement and to evaluate the potential fire risk in metro stations, research on the passenger-carried fire load pattern deserves more attention and efforts. In this study, a method for mapping fire risk of passenger-carried fire load is proposed through the combination of pedestrian flow modeling and fire risk assessment. Influencing area of passenger-carried fire load, time interval of fire risk map, and desired velocity of passengers constitute the dynamic nature of fire risk, and they are found to have significant effects on the variation of fire risk. A larger influencing area results in a smoother fire risk surface and a wider range of the risk regions, while a shorter time interval may provide a more accurate distribution of fire risk but have a larger variance. Faster desired velocity of passengers makes a larger fluctuation of fire risk distribution as passengers move quicker. The simulation output could represent not only the detailed features of pedestrian traffic but also the dynamic variation of fire risks in the simulation scenarios. This method can serve as a useful tool to find out high-risk regions and provide information for facility management and design of metro facilities.