A simplified calculation method on maximum smoke temperature under the ceiling in subway station fires

To assess the impact of smoke on the ceiling in subway stations, the maximum smoke temperature under the ceiling was studied theoretically and experimentally with two sets of small-scale experiments conducted. The results show that the maximum smoke temperature under the ceiling complies with the Alpert equation in which fire keeps distant from the walls in subway stations whereas fire adjacent to the end wall leads to the maximum smoke temperature under the ceiling decaying exponentially against the increased distance between the fire and the wall. In addition to the Alpert equation, a correlation determining the maximum smoke temperature is developed by taking the end wall effect into account. Consequently, a simplified calculation method involving the Alpert equation and the correlation is established. The method is applicable to practical fire engineering designs for subway stations.

Research highlights
► A representative small scale model for typical subway stations has been built.
► A set of small-scale experiments has been conducted.
► We validated the Alpert equation with a confined ceiling.
► The effect of the side and end walls on the maximum temperature has been investigated.
► A simplified method to predict the maximum temperature under ceiling has been developed.