Production areas, pump rooms and machinery spaces typically use the open water mist nozzles in a zoned configuration to provide a powerful knockdown of a fire. Closed heat-activated fusible water mist sprinklers are typically used in non-process areas such as living quarters, corridors and cafeterias. Special water mist nozzles are used to protect the food cooking appliances and exhaust hood.
Total flooding and local application water mist systems are typically activated by automatic fire detection systems utilising flame detectors. The detectors are monitored by a fire alarm control panel that provides the logic for starting the pumps and opening the proper section or zone valve. The sprinklers used in non-process areas are activated by heat and provide flow only through the sprinklers that are activated by the heat. The use of water mist sprinklers offshore can drastically reduce water damage that can be caused by conventional sprinklers.
Figure 2
The systems utilise fresh potable water in very small quantities to suppress and extinguish fires. Compared with a conventional sprinkler system, a water mist nozzle will flow approximately 90% less water. The small water requirement coupled with the use of small bore tubing rather than large diameter piping can result in a weight savings of up to 90% compared with a conventional sprinkler system. Since every pound or kilo of weight has a high price-tag offshore, this feature cannot be overlooked. The stainless steel tubing used in water mist systems will be around long after the steel pipe and when used in sprinkler systems water leaks within a water mist system are very rare.
Figure 3
Even though high pressure water mist systems have been in production for approximately 11 years, the offshore oil industry has been slow to utilise water mist systems for complete facility coverage. Recently, several large offshore projects have incorporated water mist systems in their designs. The offshore oil industry exists in an environment that requires fire and safety systems to be dependable, efficient and to work quickly when they are needed. One cannot pick up the telephone and call the fire department and expect a response in five minutes. Water mist systems provide an excellent solution for fire protection needs offshore. Look for high pressure water mist systems to be the new dawn for offshore fire protection.
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