Research On Fire Simulation And Evacuation Of Metro Transfer Station Based On FDS

Metro transfer stations are complex in structure and crowded in traffic.Once a fire accident occurs,it is easy to cause large-scale casualties.Compared with the ordinary subway station,the fire hazard of the subway transfer station is greater.Therefore,it has important practical significance for the study of fire smoke diffusion and evacuation of subway transfer stations.This paper chooses a metro transfer station in Guangzhou as the research object.The main research contents include the following points:(1)Obtain the relevant building structure information of the transfer station through investigation and consulting data.The fire simulation model of the transfer station is established by using the numerical simulation software PyroSim;referring to relevant information,the fire source is set as a fast-growing fire with heat release rates of 2 MW and 5 MW respectively,and the fire source is located in the middle of the underground platform,the left side of the platform and the right side of the platform;the stairway entrance should have a descent of not less than 1.5m/s when a fire occurs according to the Design Code for Metro(GB50157-2013).Five groups of fire scenarios were designed to simulate the smoke diffusion process in each fire scenario of the transfer station.(2)Visibility,smoke layer height,smoke concentration and smoke temperature are selected as safety evaluation indicators.According to the fire simulation results,the critical time of four indicators in each fire scenario is calculated and analyzed.The minimum critical time corresponding to the four indicators is regarded as the available evacuation time(ASET,Available Safe Egress Time).At the same time,according to the fire simulation results,the transfer stairs can be used for evacuation time.(3)According to the actual situation of the transfer station,the number of evacuation simulators is determined to be 4432 according to the most disadvantageous principle.The distribution of evacuators,the proportion of people,the walking speed and the effective width of the exit are determined in turn.The start time of evacuation is set by Tstart according to the number of people getting off the train is 0 s and the rest of the area is 60 s.The evacuation simulation model is established by using the evacuation simulation software Pathfinder.Five groups of evacuation scenarios are designed according to the five groups of fire scenarios set in this paper.(4)The evacuation time(REST,Required Safety Egress Time)under different evacuation scenarios and the completion time of evacuation for all personnel are obtained by evacuation simulation;according to the comparison of the available evacuation time(ASET)and the evacuation time(REST)when fire occurs,and in combination with the requirements of relevant regulations for the evacuation of subway fire,the evacuation requirements should be completed within 6 minutes for each evacuation.The scenario results are used to determine the safety and analyze the unsafe factors.Finally,according to the summary of the fire smoke diffusion law and the weak links of evacuation,some optimization suggestions on the evacuation of the subway transfer station are put forward.The research results of this paper can provide a reference for reasonable planning of escape routes,formulating safe and effective escape plans,reducing casualties and property losses in the fire as much as possible,and also hope to provide ideas for future research.