Experimental of Water Mist to Put out Fire in the Electric Compartment of Utility Tunnel

This paper used full-scale experimental tests to study fine water mist system to extinguish fires in the electrical compartment of utility tunnel after cable fires. It used a 250 kW propane burner to ignite the cable. A high-pressure water mist system was implemented for cable fire extinguishing tests. The volume flow rate of fine water spray varied between 7 L/min and 10 L/min. The effect of different water mist volume flow rates on fire extinguishing in the electrical compartment of utility tunnel was investigated. In four cases, the ventilation speed of utility tunnels varied from 0 m/s to 1.2 m/s. The temperature above the ignition source and the lateral temperature distribution at different positions of the ignition source were measured. The effect of different longitudinal ventilation speeds on the fire extinguishing efficiency in the electrical compartment of utility tunnel were studied. The results showed that high-pressure water mist could reduce the internal temperature of the electrical compartment in utility tunnel to below 100 degree celsius within 300 seconds. The high-pressure water mist system had good effects in reducing temperature and preventing re-ignition. Fine water mist system has an important practical significance in the electrical compartment of utility tunnel.