Subway and Railway Ventilation Systems
If the train is still stationary in the station or tunnel, passengers must arrive at a safe area by evacuating the train as soon as possible. This situation is defined as "Emergency". In the event of an emergency, tunnel ventilation fans connected to underground public transport systems must be activated, providing both smoke evacuation and cooling of the station or tunnels, as well as a smoke-free clean space for the fire brigade and fleeing passengers, by pushing smoke in a certain direction. In other words, emergency ventilation systems in underground public transport systems should be selected in such a way that the capacities of the other projected fans, in the case of a fire, drive the hot and toxic gases emitted in the station in one direction, to provide the required air velocities in the station and in the tunnel.