How to Use a Fire Extinguisher

Keeping fire extinguishers in good working order can be critical to the safety of employees and guests. To help with this, it is important to understand how to use a fire extinguisher and have regular training on the type of fires that might occur in an environment. Different businesses face different risks, so assessing those hazards can guide the type of fire extinguisher needed and how to operate it correctly.

The fire extinguisher is a hand-held device that can be used to put out a small fire or keep it from spreading. It works by displacing the oxygen from the fuel source and cooling the fire with a liquid or smothering it with a dry agent. Some extinguishers also have a mechanical mechanism to remove heat from the fire by drawing it away.

There are five different classes of fire extinguishers based on the types of materials they can be used on, and each is labeled with standard picture symbols or letters. The classes of fires that each can extinguish are as follows:

Class A – Ordinary combustibles like wood, paper, cloth, rubber and many plastics. Class B – Flammable liquids like gasoline, oil and grease. Class C – Electrical fires involving energized equipment or wires. Class D – Metal fires such as iron, steel and brass.

To use a fire extinguisher, it is important to remember the PASS method: P – Pull the pin to release the tamper seal and aim low at the base of the fire. Aiming the nozzle low and moving slowly toward the fire is important to avoid the flashback effect that can happen when the fire extinguisher is used on a fuel fire. S – Squeeze the lever slowly and evenly to discharge the fire extinguishing agent. After the fire is extinguished, sweep the area with the nozzle or hose from side to side to make sure the flames are completely out.

The most common hand-held extinguisher is a carbon dioxide unit, which looks like a small cylinder with a handle on top. It is effective on Class A, B and Class C fires and is very easy to use. Simply pull the pin to release the tamper Seal, point the nozzle low at the base of the fire and squeeze the handle.

Other hand-held units include foam, aqueous gel and dry chemical (classes ABC and BC) models. Foam extinguishers are red in color and work by creating a frothy blanket or seal over the fuel, which stops it from absorbing oxygen and burning. Aqueous gel fire extinguishers are blue in color and smother fires by soaking the surface with a liquid. Dry chemical fire extinguishers contain monoammonium phosphate, which is yellow in color and looks similar to talcum powder.

Cartridge-operated fire extinguishers are essentially the same as stored pressure units, but they hold compressed carbon dioxide instead of nitrogen. They are also available in foam, wetting agent and dry powder types and are used in Class A, Class B and Class C areas.