What are some points regarding proper use of fire extinguishers?

If you expect your workers to use fire extinguishers to put out a fire, OSHA requires that they be trained in proper extinguisher use. Proper training includes teaching them how to gauge the severity of the fire, how to select the correct type of extinguisher, and how to effectively employ the extinguisher in an emergency situation. Above all, when a fire is first detected, even if it appears to be small, the facility’s fire alarm should be activated, and employees told to evacuate the area.

According to the National Fire Protection Association (NFPA), there are five primary classes of fires. All extinguishers should be labeled using standard symbols for the classes of fires for which they can be used. Some extinguishers can be used on several different types of fires, such as an A–B–C type of extinguisher, which can be used on Class A, B, and C types of fires. An explanation of the types of fires is as follows:

Class A — Fires involving ordinary combustibles, such as wood, cloth, paper, and plastics.

Class B — Fires involving flammable liquids, such as gasoline, oil, and oil–based paints.

Class C — Fires involving energized electrical equipment, such as wiring, fuse boxes, circuit breakers, appliances, and machinery.

Class D — Fires involving combustible metals, such as magnesium or sodium.

Class K — Fires involving combustible cooking media (vegetable or animal oils and fats).

In terms of safe extinguisher use, the first step is for the employee to evaluate whether the fire can be put out using a portable extinguisher; only trained employees should make this determination. Instruct your employees to:

1. Know what types of materials are burning, and ensure that they are using the correct type of extinguisher for that fire.
2. Consider the possible danger posed by hazardous or highly flammable materials.
3. Always have an unobstructed route away from the fire.
4. Use proper techniques for extinguishing small fires, such as the PASS method. To extinguish a small fire using the PASS method:
   • Pull the pin to unlock the extinguisher’s operating lever to allow discharge of the extinguisher.
   • Aim low, and point the extinguisher toward the base of the fire.
   • Squeeze the lever to begin discharging the contents of the extinguisher.
   • Sweep back and forth as you move closer to the fire. Keep the extinguisher pointed at the base of the fire until the fire appears to be out.