Application Of Water Mist To Extinguish Large Oil Pool Fires For Industrial Oil Cooker Protection

Abstract

Large oil fires occurring in industrial oil cookers are very challenging to extinguish due to their size and the large amount of hot oil involved. This paper reports a study to use water mist for large industrial oil cooker protection. The extinguishing mechanisms of water mist and corresponding criteria required for extinguishing large pool cooking oil fires were investigated both theoretically and experimentally. Based on the extinguishing mechanisms and required criteria, two water mist systems were developed in the present work. A series of full-scale fire tests were conducted in a large industrial oil cooker mock-up. The study showed that the two water mist systems presently developed worked effectively to extinguish large cooking oil fires and prevented them from re-igniting. Their extinguishing performance was determined by the type of water mist system, discharge pressure and hood position in the oil cooker.

Concept Design and Testing of Multi-Nozzle Water Mist Fire Suppression System

“…Although there were some temperature increase during the initial period of mist introduction, however in general the fires can be extinguish in a relatively short period of time. In addition, according to the literature the spray characteristics of individual nozzle, as well as multi nozzle arrangements, which are represented by spray coverage area, fluxs of water mist, and spray momentum are also important factors for extinguishing cooking oil fires [1][2][3][4]10]. Water mist coverage must be large enough to cover the entire oil surface and extinguish the whole flames over the oil surface at once, otherwise the flames will not be extinguished.…”

“…Usually the average burning rates of cooking oils are higher than those of other hydrocarbon oils, and cooking oil fires (K class fire) are more difficult to extinguish than other liquid fires [2,3]. During a cooking oil accident, the oil could be heated up to a temperature above its flash point.…”

“…Drawbacks on the use of excessive amount of water in a sprinkler system, and a ban on the use of ozone depleting Halon 1301 would make research on finding an alternative protection system for fire control become a necessity [2].…”

“…The use of fine water sprays as alternative method for fire control has been widely recognized [1][2][3][5][6][7][8][9]. The smaller size water mist droplets offer larger surface area for the same amount of water, allowing faster evaporation of the droplets, and more effective heat extraction from a fire.…”

Cooling characteristics of hot oil pool by water mist during fire suppression

“…The current authors have conducted a series of full-scale fire experiments and water mist was used to extinguish cooking oil fires in both commercial deep fat fryers and industrial oil cookers [26][27][28][29][30]. Fine water droplets effectively extinguished the fires and cooled the oil to prevent it from re-igniting.…”