A fire extinguisher is basically a fire safety device used to extinguish or protect small fires, often under emergency conditions. Basically, it is to control small fires and is not intended for use on out-of-order fires which has covered a large area for which experience of fire department is utilized. Usually, a fire extinguisher consists of a �hand-held cylindrical pressure container� containing an expellant which can be discharged to remove fire. The fire extinguishers are mainly divided in two categories �stored pressure� and �generated pressure�. In stored pressure system, the propellant is stored in the same place as the agent itself whereas in the generated pressure units the propellant is stored in a separate cartridge unit.
Types of fire vs. Extinguishing Agents
Class A � This type of fire respond best to water or water type extinguishers is efficient in bringing down the temperature in shortest possible time.
Class B � In this fire responds to dry chemicals, halogenated hydrocarbons, as well as carbon dioxide.
Class C-In this type, the fire occurring due to a fault in the electric circuit is responsible for fire. Therefore fire extinguishers responsible to extinguish fire due to electric circuit are used.
Fire Extinguisher Periodic Check List:
1. Appropriate extinguisher located in proper places.
2. Safety seals unbroken.
3. Remove all external dirt and rust.
4. Gage or indicator in operable range.
5. Check for proper weight.
6. No nozzle obstruction.
Fire extinguishing agents:
(A). �Water as well as water based agents�- Water is ineffective on class B fires and will cause the fire to spread. Water may be combined with antifreeze compounds. It extinguishes the fire bringing down the temperature in shortest possible time.
(B). �Foam�- Foam is effective, especially when used in large quantities. It acts on a fire the same as water by lowering the temperature. It has some effect on a petroleum base fire by preventing oxygen from getting to the fire.
(C). Carbon dioxide- The CO2 equipment must be equipped with a nonmetallic horn to be approved for use on electrical fires. It has a toxicity rating recommended for use on class B and C fires. It extinguishes flames by dissipating oxygen in the immediate area.
(D). Dry chemical- fires on metal require special handling. If water is used in magnesium fire the burning is accelerate. Special dry powders are available for use whenever metal fires are possibilities.
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fire extinguishers,
fire safety and
fire safety equipment.
