A fire extinguisher is a device used to control small fires that would otherwise be out of control. It is usually rated for use on one or more types of fire. Fire extinguishers are generally categorized by their expected application on the four classes of fire: Class A fires involve ordinary combustibles such as wood, cloth, and paper; Class B fires involve flammable liquids such as gasoline, solvents, paints, and oils; and Class C fires involve electrical equipment like appliances, tools, or plugged-in electronic devices.
In order to fight a fire, you need to know where the fire is located and how large it is. This information helps you determine whether you can safely fight the fire or if it is in a place that must be evacuated immediately. The first thing to do is sound the fire alarm and call the campus police by activating an alarm pull station located in corridors or calling 911 on a campus phone or cell phone.
Identify a safe evacuation path and get to it. Once the area has been cleared, it is time to fight the fire. Select the appropriate type of fire extinguisher and discharge it using the P.A.S.S technique. If the fire is still burning, it should be backed up away from you and you should continue to use the extinguisher until it appears to have been put out or the flames are out of sight.
Dry chemical fire extinguishers contain a combination of sodium bicarbonate, potassium carbonate, or ammonium dihydrogen phosphate base agents. They work by excluding oxygen, slowing the release of flammable vapors, or interrupting the chain reaction of combustion. Most multipurpose fire extinguishers are rated for use on Class A, B, and C fires.
Foam fire extinguishers contain aqueous film-forming foam agent that releases an expansive layer of foam when it is discharged. It works by excluding oxygen, slowing the release, or interrupting the chain reaction of combustion and is able to penetrate deep into a fire. Foam extinguishers can also be used on Class B and Class C fires.
Water mist fire extinguishers use a fine spray of water to cool the fire, which displaces the oxygen and stops the burning process. They are the most common type of fire extinguisher and can be found in office buildings, schools, hotels, and shops. Water mist extinguishers are not effective on Class A or Class D fires, and they may not be able to penetrate very deep fires.
When shopping for fire extinguishers, make sure they are certified by a recognized testing laboratory (UL or ULC) and have the kite mark or LPCB mark. Also, make sure that the supplier offers on-site commissioning/certification after delivery. The price of fire extinguishers varies widely, so it is important to shop around. The future cost of servicing will also need to be considered. Typically, a fire extinguisher is serviced every 5 years. It is best to purchase from a supplier that provides this service for a reasonable fee.