Fogging Technology

According to some of the earliest tests conducted by Chief Lloyd Layman of the US Coast Guard Firefighting School in the 1940s, fog nozzles perform better in battling fire than straight stream nozzles. The test consisted of 20 experiments in the engine room of a liberty ship. They released 5,000 to 7,000 gallons of fuel to create around 1,900 square feet of burning surface. The fire was allowed to burn for 30 minutes to achieve the worst possible fire situation. When the fog nozzle was used on the fire for a maximum of 40 minutes, it created steam which continuously decreased the temperature to below the flash point of the fuel.

Chief Layman found that the expanding steam pushed the un vaporized water particles throughout the room to burning areas beyond the immediate space of the nozzle. This process continued until all of the available atmospheric space was filled with steam, extinguishing the fire. More recent tests by Commander John. P. Fairly and the U.S. Navy agree with the findings of Chief Layman.

Water mist technology has gained acceptance over halon gas, in most cases. The following list contains current and future application for water mist fire protection technology as compiled by Factory Mutual Research, an affiliate of commercial and industry property insurer FM Global. FMR has noted that the effective fire fighting qualities of water mist have led to its use in a number of challenging fire protection applications.

• Local applications
This category includes isolated applications of water mist to protect a specific area or device. This may include motors, transformers, oil filters, and stand alone machinery.
• Ordinary hazard occupancies
Examples include stockrooms, small warehouses, and other small storage areas. Fire control is their goal.
• Flammable liquid storage areas
• Combustion turbine enclosures
• Machinery enclosures
• Industrial oil cookers
• Light hazard occupancies
• Wet bench and other processing equipment