Smoke spreading analyses in a subway fire scale model

This paper is an experimental study of smoke spreading in a subway station. A subscale model based on the Fr Froude number similitude was elaborated. Smoke spreading was analyzed according to subway geometry (number of openings) and ventilation volumetric flow rate. In this context, evacuation way must remain smoke-free to ensure the safety of passengers in case of fire on the platform. As the vertical of hot air may initiate stack effect, which is to be avoided, appropriate ventilation conditions needed to be determined. With this in mind, three main parameters were considered: ventilation mode (push-pull or extraction mode), stairway number, and railway network. The efficiency of push-pull and all extraction modes were compared to a single extraction mode with a reduction of critical volumetric flow approximating 19 and 13% respectively. The influence of pressure loss in tunnel opposite to ventilation on the stack effect was also studied. The outlet temperatures of stairways and free smoke areas were our major concern, and the safety criterion pointed out.