Experimental Study On Fire Smoke Spread Control By Water Mist Curtain

The study was undertaken to find out the effect of water mist curtain on suppressing fire smoke. The paper reports a summary of the current methods of fire smoke control, the majority of which are natural or mechanical ventilation, but these methods always strictly depends on location of the ventilation openings, difference in pressure in fire buildings, total air rate volume and so on. Although smoke barrier, fire doors, and roller blinds can play a role in blocking the smoke, they either blocked the smoke in a limited time or completely blocked the evacuation channel at the same time. Nowadays, as an alternative to halon fire extinguishing agent, water mist is becoming more and more popular because it is environmental friendly and only leads to light water damage. The curtain of water mist would better the smoke control.In the study, a water mist curtain nozzle was invented and the bench was also built up to simulate the corridors. In consideration of the characteristics and the influence of water mist curtain on the environmental conditions of the experiment, three tasks were carried out:(1) suppressed the smoke under different water mist pressures by Type I nozzle;(2) suppressed the smoke under different water mist pressures by Type Ⅱ nozzle;(3) when the smoke volume was increased, water mist curtain formed by Type II nozzle suppressed the smoke under various pressures.The results show that water mist curtain effectively suppressed the fire smoke, the temperature of which was reduced by75%. The nozzle of Type II better suppressed the smoke than Type I. It lowered the optical density of smoke from0.91dB/m down to0.15dB/m under2.0MPa pressure, which means the visibility of fire scene was promoted from less than2m to8.5m. Type I nozzle inhibited the smoke significantly only under2.5MPa pressure, with the smoke optical density reduced to0.17dB/m, which means the visibility was7.5m. Under2.0MPa pressure, the curtain formed by Type II nozzle delayed the time of smoke passing through as long as25s, while that formed by Type I did not even under2.5MPa pressure. As the volume of smoke increased, water mist curtain faced more difficulties. When the pressure reached at3.0MPa, the smoke was blocked at the other side.