Fire-induced smoke control via hybrid ventilation in a huge transit terminal subway station

Abstract

Hybrid ventilation is the building ventilation system that integrates natural and mechanical ventilation components to create a high efficiency and healthy ventilation system for a building. Here, hybrid ventilation is used to control fire-induced smoke in a huge transit terminal subway station. Four different grid systems are compared, and the sensitivities of these gird systems are analyzed. The effect of hybrid ventilation on carbon monoxide (CO) concentration reduction and its suppression effect on horizontal dispersion of smoke are also analyzed. Heat release rate, smoke temperature in the vertical direction, smoke layer height and CO concentration are validated with previous experimental data, and good agreement is achieved. Preliminary results show that the average CO concentration in the hall decreases significantly with increasing roof window size and air change rate (ACH). However, little CO concentration difference in the atrium can be observed. Comparing with the conventional mechanical ventilation, hybrid ventilation can inhibit the dispersion of smoke more effectively. The CO concentration in the subway station in the horizontal direction is significantly lower than that with conventional mechanical ventilation. It suggests hybrid ventilation by setting roof window in the ceiling of the atrium with size of 3 m × 3 m or larger can be an effective method to exhaust fire-induced smoke.