Abstract
•The switch modes of fully enclosed Platform Screen Doors are obtained.•The modes prove that reasonable opening of the end doors is beneficial to control smoke.•The air exhaust system in the platform floor and tunnel is critical during emergency fires.•Switch mode analysis helps to find solutions for smoke control in underground metro station.
Fire is a major hazard in an underground metro station. Faced with challenges from fires in metro stations, platform screen doors (PSDs) are usually installed on the ground, which are critical to passengers’ life safety. In case of a platform fire, in order to get optimal control of smoke and provide better environmental conditions for evacuation, the operation of those PSDs needs to be systematically studied. In this work, Fire Dynamics Simulator (FDS) was used to investigate the smoke exhaust effect during fires in underground island-type platform under twenty-four different PSD switch modes. The parameters that influence evacuee life safety, such as temperature and visibility contours at the stair entrance, were computed to compare the performance of different switch modes for the underground metro station with fully enclosed PSDs. The simulation results show that the optimization of the PSD switch modes in the underground metro station depends significantly on the cooperation of the air supply system in the lobby floor, the air exhaust system in the platform floor and the tunnel. Three potential fire sources in the platform floor have been studied. When the fire source is in the center of the subway platform, it is better to open four end doors and 12 PSDs in one side, or open all PSDs in one side during the developing stage of fire. As for its stable stage of fire, it is better to open four end doors or all PSDs in one side. When the fire source is near the ends of the platform, it is better to open all PSDs in one side or open four end doors during the developing stage of fire. As for its stable stage of fire, it is better to open all PSDs in both sides near the fire sources. Those results can provide some guidance to the smoke control design in case of platform fire in the underground metro station.