Abstract:

In order to avoid the casualties caused by subway fires, the idea of active disaster relief with coordinated and centralized control of multiple facilities such as ventilation, smoke exhaust, smoke blocking and isolation was proposed. Fire dynamics simulator (FDS) was used to model the conventional and interchange metro stations. The scenario of a fire in the middle of the station platform was simulated. When smoke exhaust fans and smoke retaining walls were partially and fully opened, the smoke flow control effect of key parts were compared and analyzed. The fractional effective dose (FED) model was used to analyze the fatality factors of personnel. The subway normal ventilation and fire smoke flow cooperative centralized control system were proposed. The results show: for a fire in the middle of a conventional subway station, smoke spreads to the middle stairway entrance after 120 s and fills the entire platform level at 180 s under normal ventilation. With all smoke extraction facilities turned on and smoke barrier walls closed, fire smoke can be effectively contained in the middle and right side of the platform. For interchange subway stations, smoke contaminates all platform and concourse areas at 300 s under normal ventilation. The available evacuation times for the middle and left stairways are 130 and 185 s respectively. After opening all smoke extraction facilities and closing the smoke retaining walls, a small amount of smoke flow from the lower platform spreads to the upper platform, but does not spread to the station hall. The available evacuation time of the two staircases increased to 150 and 230 s respectively. Visibility at the stairway entrance is a key factor affecting the escape of people, while the lethal factor of fire is CO concentration.

Key words: subway fires, smoke flow characteristics, collaborative control system, numerical simulation, personnel evacuation