Abstract: Real-scale hot smoke experiments were conducted to study the smoke spread characteristics in an operation depot of subway vehicle base. The smoke propagation velocity, smoke temperature, and height of the smoke layer in the depot under different smoke exhaustion conditions were compared and analyzed. The smoke control and exhaustion effects of the mechanical smoke exhaust system has also been verified on site. The test results show that, in case of fire occurred in the depot, even if the mechanical smoke exhaust system activated and performed effectively, the smoke could not be completely confined within the smoke prevention zone where the fire started. The smoke would spread out from the original zone, cool down and descend in the area away from the fire source. Increasing the exhaust volume could decrease the propagation rate of smoke, but the smoke could not be confined completely within the fire smoke protection zone. Besides, increasing the exhaust volume has little effect on reducing the temperature of smoke layers. As shown in the tests, the smoke layer could be maintained at a relatively ideal height (about 7 m), when the mechanical smoke exhaust system was properly activated (the smoke exhaust volume was 44.8, 29.1 or 16.7 m3/（h.m2） , respectively). The smoke exhaust system could provide favorable conditions for occupant evacuation and fire rescue operation in the initial stage once a fire occurs in the subway operation depot.

Key words: subway, vehicle base above the subway, operation depot, hot smoke experiment, mechanical smoke exhaust, exhaustion volume