The Underappreciated Lifesaver

Fire extinguishers are effective and simple

Within 30 seconds a small flame can get totally out of control, causing a major fire. Dangerously high levels of black smoke usually fill a structure in minutes. In many cases, the fire will result in injury or death. In fact, 4,000 deaths and 25,000 injuries occur each year from fire. A simple tool, the portable fire extinguisher, is required on every job site and can prevent these deaths. An understanding of fire extinguishers as well as when and how to use them is a must.

Portable fire extinguishers work by applying an extinguishing agent that cools the burning fuel, displaces or removes oxygen or stops the chemical reaction so a fire cannot continue to burn. It has limited use. An extinguisher contains only a small amount of extinguishing agent. Its contents are discharged in a matter of seconds. Use should be restricted to fighting a small fire or to aid in escape.

Before making the decision to fight a fire, make sure everyone is safe. Sound the alarm and ensure someone calls the fire department. The next step is to determine whether or not the extinguisher should be used. Consider the size of the fire. Fires limited to the original material ignited and contained to a small area, such as a wastebasket, are candidates for a fight.

The environment is another factor. The air must still be safe to breathe and the room temperature at a safe level. Do not fight a fire taller than you. Never try to fight a fire unless you can maintain a clear path of escape.

Having the right extinguisher is critical. The type of extinguisher must match the type and size of the fire. A letter classification is associated with the type. A number is used for the rating. An “A” extinguisher is approved for fires involving paper, cloth, wood, rubber and many plastics. A common reference to recall this class is “A for Ashes.” The residue generally left by the material is ash. The contents of the extinguisher is usually water. A “B” extinguisher is for fires involving oils, gasoline, some paints, lacquers, grease, solvents and other flammable liquids. The recall reference is “B for boiling liquids.” For electrical fires, remember “C for current.”

When rating an “A” extinguisher, the number represents how much water the extinguisher is equal to. One unit equals 1.25 gallons. For example, a 2-A rated extinguisher would be equal to 2.5 (2 x 1.25) gallons of water. The rating on a “B” extinguisher represents the area occupied by a fire in square feet that a nonexpert using that extinguisher should be able to put out. Therefore, a 10B extinguisher is rated for a flammable liquid fire covering up to 10 square feet.

The Occupational Safety and Health Administration (OSHA) requires a 2A fire extinguisher for every 3,000 square feet of the protected building area, and it must be stationed within 100 feet of any point in that area. On a multistory building, at least one 2A extinguisher must be available on each floor. If there are 5 gallons of flammable liquids or 5 pounds of flammable gas in the area, the extinguisher must have a 10B rating and a “travel distance” of no more than 50 feet. The standard offers alternatives to the 2A extinguisher. Consult OSHA regulation 29 CFR 1926.150.

With the proper extinguisher at hand and the fire evaluated, action can be taken. The fire extinguisher should be discharged within its effective range using the “PASS” technique. PASS is short for pull, aim, squeeze and sweep. Pull the pin, breaking the tamper seal. Aim the extinguisher nozzle or hose toward the base of the fire. Next, squeeze the handle to release the extinguishing agent. Sweep the nozzle or hose from side to side until the fire appears to be out. Back away. Keep an eye on the area. If the fire reignites and there is still extinguishing agent remaining, aim, squeeze and sweep again. If the extinguisher is empty, evacuate immediately.

Take heed of a final few words of caution when fighting fires. Most substances produce hazardous vapors as they burn. The extinguishing agents in some fire extinguishers can also be harmful. Compressed carbon dioxide (CO2) gas is very cold and can damage the skin. Keep your hands away from the discharge horn. Halon and CO2 fire extinguishers can cause asphyxiation. In areas of confined spaces such as small rooms, closets and motor vehicles these chemicals are more concentrated.

Steps can be taken to minimize these hazards. Look for caution labels on the fire extinguishers. Look for warning signs and be aware when you are entering a confined space. Where needed, use extra-long reach extinguisher nozzles. Use special ventilation, breathing apparatus and other personal protective equipment provided to fight the fire safely. EC

O’CONNOR is with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. Based in Waverly, Pa., he can be reached at 607.624.7159 or


About the Author

Joe O'Connor

Freelance Writer
Joe O'Connor is with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. Based in Waverly, Pa., he can be reached at 607.624.7159 or joconnor@inte...

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.