Study on smoke control scheme for platform floor fire inisland subway stations

During the hot smoke test of an island subway station, it is found that the platform smoke control scheme of starting the platform smoke exhaust system first, and after 2 minutes manually opening the platform door to start the tunnel fan for combined smoke exhaust will lead to a large range of smoke settlement, and reduce the visibility of the platform, threatening the safety of evacuees. In this paper, three platform smoke control schemes are presented by numerical simulation, and the smoke spread process, temperature field distribution, CO concentration distribution, and visibility are analysed. It is found that under the condition that the downgoing wind speed is satisfied, the smoke control scheme of setting side smoke outlets on the rail top hot air exhaust duct above the platform door and using the station tunnel exhaust fan and the platform smoke exhaust system to jointly exhaust smoke has the best effect. However, if the smoke control scheme is to open the front and rear sliding doors on both sides of the platform door to start the joint smoke exhaust of the tunnel fan and the platform smoke exhaust system, and the smoke control scheme is to open the platform door near the fire source to start the joint smoke exhaust of the tunnel fan and the platform smoke exhaust system, the visibility of the platform will not meet the requirements of safe evacuation of personnel about 40 to 50 seconds after the platform door is opened. For the stations that are completed and put into operation and adopt a smoke control scheme of opening the platform door near the fire source to start the joint smoke exhaust of the tunnel fan and the platform smoke exhaust system, the thickness of the smoke storage bin can be appropriately deepened under the condition of meeting the minimum clear height, and the time of manually opening the platform door to start the tunnel fan for auxiliary smoke exhaust should be strictly controlled.