Understanding Fire Extinguisher Classes
Not all types of fire and fire extinguishers are the same. Optimize your chances of putting out a fire quickly and safely by learning the different fire extinguisher types and pairing the correct model with its associated fire type.
Class A Fire Extinguishers: Combustible Materials
A-Type fire extinguishers, or Class A fire extinguishers, are used for fires involving the following materials:
- Wood
- Paper
- Cloth
- Rubber
- Plastic
Numerical fire extinguisher ratings on Class A products indicate their water equivalency. To determine a product’s capacity, multiply the number that precedes the letter A by 1.25. For example, a 4-A rated fire extinguisher would be equivalent to 5 gallons of water (4 X 1.25 = 5).
Class B Fire Extinguishers: Flammable Liquids
Class B fire extinguishers can put out fires that result from these substances:
- Alcohol
- Gasses
- Oil
- Ether
- Paint and stains
The numerical rating on Class B fire extinguishers indicates the range they can cover expressed in square feet. For example, a 20B extinguisher can cover 20 square feet if discharged correctly using a side-to-side sweeping motion.
Class C Fire Extinguishers: Electrical
A Class C fire extinguisher is used for fires caused by the following electrical malfunctions:
- Short circuits
- Overloaded outlets
There is no numerical size rating for Class C extinguishers.
Class D Fire Extinguishers: Metals
Class D fire extinguishers are mostly used in research laboratories and industrial settings and are capable of extinguishing combustible metals such as:
- Potassium
- Sodium
- Titanium
- Magnesium
Class D products do not have a standard size rating and can vary in terms of effectiveness, so carefully read the label to determine if a product is best for the risk you face.
Class K Fire Extinguishers: Combustible Cooking Liquids
Class K fire extinguisher are most often used in commercial kitchen settings to put out fires started by the following:
- Fat
- Grease
- Oil
ABC Fire Extinguishers
In addition to the above types of fire extinguishers, there is also a combination ABC fire extinguisher available which covers types A, B and C fires. This type of extinguisher works well in home applications where different types of fires can break out. Because a house might see any category of fire, an ABC fire extinguisher is a good, multipurpose option.
Selecting a Fire Extinguisher
Here are some important points to consider when shopping for a fire extinguisher:
- When it comes to reuse, there are two different types of fire extinguishers: rechargeable and disposable. Rechargeable extinguishers may be refilled after service. Disposable extinguishers must be replaced after the pin has been pulled.
- Select the largest size extinguisher you and your family members can lift and operate. Once you have a new fire extinguisher(s) at home, follow the manufacturer’s instructions for placement, mounting and proper use.
- Experts recommend storing at least one fire extinguisher on each floor of your home, with one being placed close to the living areas. It’s best to choose a combination ABC fire extinguisher for kitchen or garage use, where it’s likely that a mix of flammable materials and sources may combust.
How to Use a Fire Extinguisher
For safe operation of most household fire extinguishers, remember PASS:
P – PULL the pin.
A – AIM low at the base of the fire.
S – SQUEEZE the lever slowly and evenly.
S – SWEEP the nozzle from side to side.
Fire safety professionals offer these additional tips:
- Keep the room’s exit to your back, so you can get out quickly if needed.If the room you’re working in fills with smoke or the fire becomes hard to control, leave immediately.
- Check your home’s fire extinguishers monthly to ensure their pressure meter reads green or full.
- Replace or recharge extinguishers immediately after use.
- Always evacuate the premises and dial 911. Never re-enter your home until the fire department says it's safe. Let the professionals determine if the fire is truly extinguished. Something dangerous could be out of view waiting to reignite.
For more information on creating an evacuation plan for your family, read Make a Fire Escape Plan.
Don’t wait until a fire breaks out to learn how to use a home fire extinguisher. Make sure to familiarize yourself with the P-A-S-S operation mentioned above for safe operation.