Study On The Effects Of Different Smoke-proof Modes On Fire In Subway Stations

With the decreasing of available land at major cities,the trouble of transportation and traffic has becoming increasingly difficult.It is known that subway is safe,fast and punctually,also plays an important role at improving city’s traffic environment.Several lines’ daily^passenger volume have reached their limits,which caused many issues,subway fire is one of them.Smoke prevention and exhaust systems play important role in reducing the impact of fires.At first,an L-shaped transfer station in Shenyang was selected as a prototype,several situations was simulated with different fire sources and different opening methods of exhaust and supply system.The fire locations include platform floor,equipment floor,hall floor and transfer corridor.The smoke spreading range and the change of dangerous indexes at the height of 1.8m and 5m,also the velocity and available evacuation time at stairways were analyzed,the dangers of each different condition were also compared,the results show:(1)platform is the most dangerous place,when the fire happened,open this floor’s smoke exhaust system can effectively erase the risks,but there was little impact for the fire floor if open the adjacent system.(2)with the same volume of supply and exhaust air,when exhaust vents located in the fire smoke proof zone and supply vents located in the adjacent zone,the smoke spread range and dangerous situation is lower than when the supply vents and exhaust vents are evenly distributed.(3)when a fire occurs in the transfer corridor,the danger in the corridor will be increased by turning off the fans and fire shutters on the side near the fire source.However,it can effectively decrease the risks of the closed hall and minimize the affected range of the fire.Considered the most dangerous platform fire,next step analyzed the influence of different smoke-proof partitions and different drop heights of the smoke-proof curtain at the stairway,obtained the following conclusions(1)The time of the smoke spread to upper floor through the stairway were put off by the smoke curtain,but at the same time the accumulation of the platform is more large,which means,the hazard of the fire floor was increased but the hazard of the upper floor was reduced through the installation of the smoke curtain.The higher the drop height of the smoke curtain,the stairway’s available evacuation time is longer;(2)No matter where the fire source is,when the space has been divided into three smoke prevention zones,the hazard is always lower than divided into two smoke-proof zones.However,the risks at the stairway is opposite.Finally,for the platform floor fire,In order to provide reference of fire prevention measures and personnel evacuation plans for subway stations.the influence of water spray system and exhaust system was analyzed.Also the temperature,CO concentration and visibility at different heights in the platform were considered when the spray and smoke are combined into different working conditions.It is concluded that the spray system has great effect in reducing the temperature,the risk of the spray system had not worked area was also reduced,but at the worked area,the temperature reduced,however other hazards were increased,it is recommended to evacuate the personnel around the source of the fire before the sprinkler system ignited.