Simulation Analysis of Personnel Evacuation Environment in Fire at Subway Platform with Different Suspended Ceiling Forms

Abstract

Taking the island platform layer of a subway station in Xi’an as the research object, the dynamic simulation sortware FDS is used to constructs the physical model of the platform layer with three different suspended ceiling forms (flat, square concave and grille). Under the condition of 5 MW fire source intensity at the platform layer, The parameters related to the personnel evacuation environment, such as the smoke spreading process, the temperature distribution of the ceiling layer, the temperature distribution at human eye characteristic height layer, the CO concentration distribution and the wind speed at the stairway, were simulated under each model, and the smoke emission effect under three different ceiling forms was compared and analyzed when the platform layer in the subway station was in fire. The results show that the square concave ceiling form can effectively slow down the flue gas spreading process and reduce the flue gas concentration outside the stairway, but it will cause local fluctuation of temperature and CO concentration distribution. The grille ceiling form can enhance the height of the smoke layer and make the evacuation in a safer environment before and during the middle stage of the fire, but too high smoke layer is not conducive to smoke exhaust.