Abstract: Focusing on a typical subway platform, the fire smoke behavior under combined effects of a water sprinkler system and a smoke exhaust system has been simulated by means of FDS. The impact of the height of smoke vent on the smoke exhaust has also been discussed. The results showed that the sprinkler system can induce the smoke moving downward inside the sprinkler zone and the visibility was reduced to less than 10 m, which dangers the evacuators around the fire location; on the other hand, the cooling and entrainment effect of water sprinkler is able to reduce the smoke momentum spreading along the platform which benefits the evacuators outside the sprinkler zone; the smoke exhaust efficiency
is higher with the vent height, but its impact is limited to the sprinkler zone visibility.

Key words: subway fire, sprinkler systems, smoke movement, FDS