This has onward impacts on the type of suppression or extinguishing materials which can be classification of fire extinguishers pdf. Class letters are often assigned to the different types of fire, but these differ between territories. There are separate standards in the United States, Europe, and Australia.
Class A fires consist of ordinary combustibles such as wood, paper, fabric, and most kinds of trash. These are fires whose fuel is flammable or combustible liquid or gas. The US system designates all such fires “Class B”. C, while burning gases are separately designated “Class C”. A solid stream of water should never be used to extinguish this type because it can cause the fuel to scatter, spreading the flames. Montreal Protocol declares that Halon should no longer be used.
Australian system designates them “Class E”. This sort of fire may be caused by short-circuiting machinery or overloaded electrical cables. Electrical fire may be fought in the same way as an ordinary combustible fire, but water, foam, and other conductive agents are not to be used. While the fire is or possibly could be electrically energized, it can be fought with any extinguishing agent rated for electrical fire. PKP should be a last resort solution to extinguishing the fire due to its corrosive tendencies. Once electricity is shut off to the equipment involved, it will generally become an ordinary combustible fire. In Europe, “electrical fires” are no longer recognized as a separate class of fire as electricity itself cannot burn.
The items around the electrical sources may burn. Metal fires represent a unique hazard because people are often not aware of the characteristics of these fires and are not properly prepared to fight them. Therefore, even a small metal fire can spread and become a larger fire in the surrounding ordinary combustible materials. Generally speaking, masses of combustible metals do not represent great fire risks because heat is conducted away from hot spots so efficiently that the heat of combustion cannot be maintained. In consequence, significant heat energy is required to ignite a contiguous mass of combustible metal.
Generally, metal fires are a hazard when the metal is in the form of sawdust, machine shavings or other metal “fines”, which combust more rapidly than larger blocks. Metal fires can be ignited by the same ignition sources that would start other common fires. Care must be taken when extinguishing metal fires. Water and other common firefighting agents can excite metal fires and make them worse. The two are not the same, and only dry powder should be used to extinguish a metal fire. Using a dry chemical extinguisher in error, in place of dry powder, can be ineffective or actually increase the intensity of a metal fire.
Laboratory simulation of a chip pan fire: a beaker containing wax is heated until it catches fire. A small amount of water is then poured into the beaker. The water sinks to the bottom and vaporizes instantly, ejecting a plume of burning liquid wax into the air. Class K fires involve unsaturated cooking oils in well-insulated cooking appliances located in commercial kitchens. Water mist can be used to extinguish such fires. Appropriate fire extinguishers may also have hoods over them that help extinguish the fire. Stillwater, OK: International Fire Service Training Association.
This page was last edited on 25 November 2017, at 18:55. Fire extinguishers manufactured with non-cylindrical pressure vessels also exist, but are less common. In the United States, fire extinguishers in all buildings other than houses are generally required to be serviced and inspected by a fire protection service company at least annually. Some jurisdictions require more frequent service for fire extinguishers. There are two main types of fire extinguishers: stored-pressure and cartridge-operated. Depending on the agent used, different propellants are used. Stored pressure fire extinguishers are the most common type.
Cartridge-operated extinguishers contain the expellant gas in a separate cartridge that is punctured prior to discharge, exposing the propellant to the extinguishing agent. This type is not as common, used primarily in areas such as industrial facilities, where they receive higher-than-average use. They have the advantage of simple and prompt recharge, allowing an operator to discharge the extinguisher, recharge it, and return to the fire in a reasonable amount of time. Cartridge operated extinguishers are available in dry chemical and dry powder types in the U.
Handheld extinguishers weigh from 0. Fire extinguishers in a museum storeroom, cut to display their inner workings. A glass grenade-style extinguisher, to be thrown into a fire. A US copper building type soda-acid extinguisher. A US building-type chemical foam extinguisher with contents. Bell Telephone CO2 extinguisher made by Walter Kidde, 1928. Du Gas cartridge-operated dry chemical extinguisher, 1945.