Pool Fire Suppression Performance By Twin-Fluid Water Mist Under Low Pressures In An Altitude Chamber

Fire suppression tests using low pressure twin-fluid water mist under low pressure environments were carried out to exam the performance of water mist systems at low pressure environments. The experiment results show that the suppression time gets shorter for lower chamber pressure, and relevant total weight of water and nitrogen used decreases as the chamber pressure gets lower. For the case of 30-cm diameter pool fire, the suppression times are 20.19, 7.5, and 2.24 under the chamber pressure of 60, 38, and 24 kPa, respectively. In case of a cargo compartments fire, it is suggested to open the ventilation valve of the cargo compartment at a high cruising altitude to relieve pressure, so as to achieve rapid fire suppression. When a fire happens at the position off the center below the water mist nozzle, the water mist suppression effects will be weakened. The fire size has little effects on the fire extinguishing process under pressure of 24 kPa. Under the critical atomization condition with the pressure differential between the inlet and outlet of the nozzle for water as 0.05 MPa (5.04 L/min), and the pressure differential for nitrogen as 0.10 MPa (10.97 L/min), the suppression time is the shortest as 18.66 seconds.