Fire Extinguisher Ratings: What Do They Mean and Which One Should You Buy?
A fire extinguisher’s label can clue you in to its capacity
Highlights
The ABC powder fire extinguisher is a popular choice for homes.
The letter on an extinguisher label is the class of fire it can put out.
Class D and K are for restaurants, manufacturing, and workshops.
Smoke detectors and sprinkler systems are just two measures for keeping fires from getting out of control. In addition, a fire extinguisher is useful to always have near your kitchen to quickly put out a small fire so that it doesn’t spread or cause more damage. Plus, fire extinguishers can work on fires where water can’t put them out, such as fires caused by electrical, grease, gas, or oil sources. Read on for all the need-to-know details about selecting the right fire extinguisher for your home.
Fire Extinguisher Classes
A fire extinguisher's letter class-action identifies the types of fire it can put out. The Underwriters Laboratory (UL) assigns ratings according to the extinguisher's use. Here's a list of common types of fires that ratings are associated with:
Class A: Fires in combustible materials like wood, cloth, rubber, plastic, or paper
Class B: Fires in flammable liquids like gas, oil, lacquers, alcohols, flammable gasses, and more
Class C: Electrical fires or fires involving energized electrical equipment
Class D: Fires in combustible metals (i.e., magnesium, titanium, potassium, and sodium)
Class K: Kitchen fires in cooking appliances that involve oil or grease
You might want to include an ABC (a combination of Class A, B, and C extinguishers) extinguisher on your home safety checklist because it can snuff out most common home fires, including electrical fires, by using a fine power to suffocate a fire and prevent reignition.
Restaurants, manufacturing facilities, and workshops typically have class D or K extinguishers on site.
How to Determine the Fire Extinguisher Rating
The number rating has to do with which fires the extinguisher can handle and accompanies the letter classification. For example, a standard model may have a label that reads, "1-A:10-B:C."
Let's break down what that means:
“A” refers to the water equivalency of the foam or powder inside the extinguisher. Each number is 1 and 1/4 gallons of water, so with this example, "1-A" equals about 1 and 1/4 gallons of material. Likewise, “2-A” would mean there are roughly 2 and 1/2 gallons.
“B” equals the square footage of flaming material, so "10-B" would equal approximately 10 square feet of surface area.
"C" (the last letter after the colon) means the fire extinguisher uses a non-conductive agent that is safe to use on electrical fires. (This is simply the fire extinguisher’s class).
Types of Fire Extinguishers
Fire extinguishers come in a variety of ingredients and canister configurations, depending on their function and what types of fires they’re designed to put out. It’s important to understand how fire extinguishers are labeled and how they work so that you don’t inadvertently select the wrong fire extinguisher and risk an even larger fire or accident with the wrong application. Improve your home’s safety with knowledge about these common types of fire extinguishers:
Carbon dioxide extinguisher: A CO2 extinguisher works best on electrical fires and flammable liquids.
ABC powder fire extinguisher: This packs a multipurpose punch and uses a fine chemical powder to blanket the fire and remove oxygen. It has non-conductive material, so it’s safe to use on electrical fires and is also a popular choice for most homes.
Wet chemical fire extinguisher: Since this extinguisher uses mist to cool the fire and covers the area with a solution to prevent reigniting, it is ideal for Class K (or commercial kitchen) fires involving animal and vegetable fats.
Water mist fire extinguisher: This extinguisher emits tiny water molecules to suppress the fire and works on most fire classes, including electrical fires.
Foam fire extinguisher: This type of extinguisher is most effective on class A and B fees by blanketing the fire with foam, preventing vapors from rising and cooling the surface. It’s not suitable for gaseous fires.
Clean agent fire extinguisher: This extinguisher works best on class B and C fires. Plus, it’s safe to use around animals and people and leaves no residue.
What’s Next If I Use My Fire Extinguisher to Put Out a Small Fire?
If you have to use a fire extinguisher to put out a small fire, such as on top of a kitchen appliance, you’ll first want to call your local fire department to ensure the fire is extinguished correctly and won’t reignite.
Next, you’ll want to clean up the residue by sweeping or vacuuming and then scrubbing with a solution of 1-to-1 water to isopropyl alcohol. If there’s a significant amount of lingering smoke damage or residue, you may want to consider calling a smoke restoration company near you.
Finally, you’ll want to replace the used fire extinguisher with a new extinguisher.
Frequently Asked Questions
Testing a fire extinguisher by discharging even a small amount will void the warranty on the product. Pushing down the pressure pin on top and waiting to see if it pops up is the best way to ensure it’s still pressurized. If you’re concerned about your extinguisher, hire an expert to do a professional inspection.
Yes; fire extinguishers eventually expire. However, the good news is that a properly stored fire extinguisher can last a decade or longer. Typically, they don’t have an expiration date on the canister, but you can check the manufacturing date on the “UL” nameplate near the classification information. Maintenance will also give your fire extinguisher longevity. Check the gauge at the top of the extinguisher every month. You'll want to make sure the gauge needle is in the green section, and if a hose or nozzle has been used or damaged, you need to replace it.