Hot smoke tests for smoke propagation investigations in long rail tunnels

Smoke propagation in an enclosed facility is always a matter of concern whenever the evacuation of people is necessary. The construction of long rail tunnels has made evacuation an even greater challenge. Long rail tunnels are equipped with emergency stop stations so that evacuation may still occur even when trains are on fire and incapable of leaving the tunnel. However, should a train breakdown occur between the portal and the emergency station, passenger evacuation has to be performed via cross passages and into the non-affected (safe) tube. This requires a balanced pressure regime between the two tunnel tubes and/or across the cross passages. The paper describes field tests which were performed in order to investigate smoke propagation in tunnel tubes and over cross passages in the event of severe fires. Fire tests up to 21 MW peak heat release rate were performed, and smoke propagation was monitored, with a strong focus on the situation at cross passages.