The effect of longitudinal ventilation on tenability during egress from passenger trains in tunnels during fire emergencies

摘要

If a fire occurs on a passenger train in a tunnel, it is possible that passengers will be present both ahead of and behind the fire location. If the circumstances of the fire force the train to stop in the tunnel, the ventilation system should be used in such a way as to facilitate egress for as many passengers as possible. A study has been carried out which compares the tenability of the tunnel environment on both sides of a fire on a passenger train, along the length of the egress paths, for the duration of the evacuation process. Tenability conditions are compared in scenarios using longitudinal ventilation to control smoke, with scenarios using only natural ventilation. The effect of ventilation on fire growth is considered. It is shown that the use of longitudinal ventilation will rapidly lead to untenable conditions for any passengers downstream of the fire, whereas natural ventilation should allow sufficient time for egress of all passengers, on both sides of the fire, to reach a cross-passage before untenable conditions are reached.