Classes of Fire Extinguishers
To safely put out a fire and minimize fire damage, it's important to understand that there are different types of fire extinguishers designed to effectively douse different types of fires. There are five different classes of fires, each designated by a letter:
Class A: The most common type of fire, Class A fires have combustibles that include paper, wood, cloth, plastic, trash, and other ordinary materials that may be found in any home or business.
Class B: Fires caused by flammable liquids are considered Class B fires. These flammable liquids include gasoline, paint, and oil. A Class B fire may also include combustibles such as propane or butane, which are flammable gases.
Class C: Electrical fires are Class C fires and include fires that originate from outlets, wires, and other electrical components.
Class D: Any fire caused by combustible metals such as magnesium, sodium, aluminum, and potassium, also known as chemical fires, are Class D.
Class K: Combustibles such as cooking oils, grease and fats are Class K fires.
It's important to understand that no single fire extinguisher can safely and effectively douse every type of fire. OSHA states, "The three most common types of fire extinguishers are: air pressurized water, CO2 (carbon dioxide), and dry chemical." There also are wet chemical fire extinguishers.
Air Pressurized Water Fire Extinguishers:
The air pressurized water fire extinguisher or APW extinguisher is best for a Class A fire or one with combustibles that include items such as paper, wood, trash, and other everyday items. The APW fire extinguisher is filled with a mixture of water and pressurized air. Some also contain a detergent that creates a foam when activated. Every home and business should have this type of fire extinguisher handy. It's typically an inexpensive type of fire extinguisher and is considered eco-friendly.
Safety tip: Do not use an air pressurized water fire extinguisher on a Class B, C, or D fire as it actually can cause the flames to spread.
CO2 Fire Extinguisher:
A CO2 fire extinguisher is recommended for offices, computer labs, mechanical rooms, and industrial spaces because it can be used safely around electronics and other similar equipment. Carbon dioxide, or CO2, is a non-flammable gas that can douse a fire by displacing the fire’s oxygen, which feeds the fire. Use a CO2 fire extinguisher to put out Class B and Class C fires only.
The carbon dioxide fire extinguisher doesn't leave behind any dangerous residue and is considered environmentally friendly.
Dry Chemical Fire Extinguishers:
The dry chemical fire extinguishers douse the fire by "interrupting the chemical reaction of the fire triangle," states FEMA. The multi-purpose dry chemical fire extinguisher, safe and effective for Class A, B and C fires, is one of the most widely used fire extinguishers. It's ideal for homes, businesses, schools, and hospitals. This unit uses ammonium phosphate as a dousing agent. The regular dry chemical fire extinguisher isn't as versatile and only is effective for Class B and Class C fires. It uses sodium bicarbonate as a dousing agent. A regular dry chemical fire extinguisher can be used in kitchens, garages, and laboratories.
Wet Chemical Fire Extinguishers:
Designed to douse Class K fires safely and effectively, use the wet chemical fire extinguisher to douse deep fryer fires and grease fires in a kitchen or similar environment. It uses potassium acetate as its dousing agent. It's an essential safety device that should be in every restaurant or commercial kitchen.
Help protect your home and business by having the right fire extinguisher ready and available should a fire break out.
Once you understand the different types of fire classes, and the different types of fire extinguishers, the next thing to learn is when to use one, and how to properly. Portable fire extinguishers are designed to help control small fires that may break out in a home, business, school, or other setting. From an errant fireplace spark to an overturned candle, knowing how to properly way to use a fire extinguisher is essential and can help prevent the spread of the fire and fire damage. Many small fires can be controlled and doused with the right portable fire extinguisher. Only use the fire extinguisher if it's the right one for the fire.
Remember: Class A air-pressurized water (AWP) fire extinguisher can only be used on paper/wood/trash fires. Never use it on a grease or electrical fire. Only attempt to use a fire extinguisher if you are not in any imminent danger. Never allow smoke, heat, or fire to cut off your evacuation path.
How To Use A Fire Extinguisher
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Step 1: Sound the fire alarm and call 911/fire department if appropriate. Have others in the room/building evacuate as needed and identify your own escape path.
Step 2: Identify the type of fire and select appropriate the fire extinguisher. All homes should be equipped with a standard ABC fire extinguisher. This model can be used to douse Class A (wood/paper/trash), Class B (flammable liquids) and Class C (electrical) fires. A Class D fire extinguisher is needed for combustible metals. All commercial kitchens should have a Class K fire extinguisher to specifically fight any deep fryer (cooking oils/fats) fires.
Step 3: Quickly inspect the fire extinguisher before using. Read the manufacturer's instructions and warnings, check that the pressure gauge needle is in the green, check for cracks along the hose and make sure the nozzle isn't clogged.
Step 4: Use the P.A.S.S. acronym to discharge the fire extinguisher.
P = Pull the pin, which also breaks the tamper seal (this is okay.)
A = Aim the extinguisher at the base of the fire, taking aim from about six to eight feet away.
S = Squeeze the handle to release the dousing (extinguishing) agent.
S = Sweep the hose back and forth at the base of the fire until it appears out or until the fire extinguisher is empty.
Safety tip:If using a CO2 (carbon dioxide) extinguisher, avoid touching the plastic discharge horn as it becomes extremely cold and can harm bare skin.
Step 5: If the fire extinguisher is empty and the fire is not out, evacuate immediately. If it seems like you're not gaining control of the fire by using the fire extinguisher, evacuate immediately. Never put your life in danger. After the fire has been extinguished and it's time to assess the damage, let ServiceMaster Restore help.
If the unthinkable does happen and your home or business suffers a fire, let the professionals at ServiceMaster Restore be there for you to help get everything back to normal as quickly as possible. Our professional teams are fully trained for all levels of smoke and fire damage remediation.