What is an ABC Fire extinguisher?

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An ABC fire extinguisher is the most common type of fire extinguisher on the market. It is also the most versatile and best extinguisher for home use in most circumstances. Most fire authorities recommend that all establishments have an ABC fire readily on hand. 

A fire extinguisher would usually have a fire rating sticker clearly stated on its side. If you need an ABC fire extinguisher, search your extinguisher’s label for the ‘A-B-C’ sticker to ensure it meets ABC standard for household fire extinguisher use.

Safety Note: Follow the guidance of your local fire authority about the safety equipment best for you – this does not constitute professional advice. The information in this article is provided for general purposes only and may not best represent your particular needs.

1. What Type of Fire is an ABC Extinguisher used For?

Fire extinguishers are rated based on the classes of fire they are designed to suppress. In the United States, there are 5 classes of fire: Class A, B, C, D, and K.

An ABC fire extinguisher is designed to suppress small Class A, B and C fires. These are the three most common types of household fires.

Class A Fires – Common Combustibles

Class A fires are fires that are fueled by common combustible materials such as wood, paper, plastic, cloth and rubber. When you look around your living room, most objects in the room will fit into this category. The coffee table, couch, desk, bookshelf and books on the shelf will all be Class A combustible materials.

Class A fires can be suppressed using several substances including water, foam and dry chemicals. An ABC extinguisher uses dry chemicals to suppress fires.

Class B Fires – Combustible Liquids and Gases

Class B fires are fires that are fueled by combustible liquids and gases (note that in Europe and Australia Class B is for liquids and Class C for gases). Examples of Class B combustible liquids include gasoline, car oil, oily paints, vegetable oil in your home kitchen and alcohol. Class B combustible gases include natural gas used for heating homes and the butane in your cigarette lighter.

Class B fires can be suppressed using dry chemicals, halogen and some specialized foams. Halogen used to be common in household fire extinguishers until the 1990s when it was discovered they were bad for the Ozone layer. Now, we tend to use the dry chemical monoammonium phosphate which is found in most ABC grade extinguishers.

Note that water is not great for Class B fires because water can cause combustible minerals to splatter and spread the fire. Furthermore, many combustible liquids float on top of water, meaning water is not great at acting as a barrier between the liquid and its oxygen source.

Class C Fires – Energized Electrical Fires

Class C fires are fires that are caused by energized electrical sources. Examples include clothes dryers, space heaters, overloaded power boards, faulty wiring in your walls, and frayed extension cords. While the fire is caused by electrical sparks, usually the fuel for these fires is in fact Class A fire fuels. Thus, once the electrical source is removed, the fire might behave like a Class A fire.

One reason Class C fires have their own classification is that energized electrical sources should not be suppressed by water. Water is an electrical conduit, meaning you may electrify yourself if you attempt to fight the fire using water. The best way to suppress a Class C fire is the dry chemical monoammonium phosphate which is found in most ABC grade extinguishers.

2. Where Should I use an ABC Fire Extinguisher?

An ABC fire can be used in homes, garages, workshops, cars and boats. Industrial settings such as commercial kitchens should use other classes of extinguishers. Always check the rules and recommendations of your local jurisdiction.

ABC fire extinguishers are commonly used in the following situations:

In Homes. Most jurisdictions recommend ABC style extinguishers in homes for common household fires. A common requirement is one on each level of the home. However, the NFPA also recommends other non-ABC type extinguishers for domestic kitchens. Foe example, the Kidde RESSP extinguisher is one designed for domestic kitchens (which has a BC rating with a different type of powder substance insider it). It is currently (at the time of first writing) the only extinguisher on the market with a UL rating for a domestic kitchen use.

On Boats. US Coastguard regulations require most boats and yachts to have fire extinguishers installed. In fact, you may be required to have more than one! Most boats that are less than 26 feet require:

  • One UL-5 rated 2.5 or 5 pound dry chemical ABC fire extinguisher, which
  • Has a visible pressure gauge, and
  • An approved mounting bracket.

For more details about what sort of fire extinguisher you need on your boat, we’ve put together a guide which also looks at some quality certified extinguishers.

In Cars and Trucks. Most jurisdictions don’t have rules that the average car needs an extinguisher (check in your jurisdiction), but many people like to have them present in their car anyway. Sports cars and racing cars are one example of cars that often require extinguishers. An ABC extinguisher is a common one to have in a car, because ABC extinguishers are capable of suppressing gasoline and other liquid fires. There are also some extinguishers that are DOT (Department of Transport) approved. Check out our full guide on car fire extinguishers for more.

In RVs, Caravans and Campers. Campers, RVs and caravans often need fire extinguishers. This is particularly the case in RVs which have a kitchen. Nonetheless, any camper who has a campfire or propane fire pit by their vehicle might like an extinguisher as they’ll be working with open flames. If you’re after a fire extinguisher for your RV or caravan, we have a buyers guide for campers here.

2. What is the Substance in an ABC Fire Extinguisher?

An ABC fire extinguisher usually uses a combination of monoammonium phosphate and ammonium sulfate. It is often colloquially simplified as “ABC Dry Chemical”, “ABE Powder”, or “multi-purpose dry chemical”. It is distributed from the extinguisher as a dry powder.

It is a common misconception that an ABC fire extinguisher contains a water-based substance. This is not true. Water is not commonly used in fire extinguishers because it can spread fires, is often heavier than liquids (which means the liquids float to the surface and still have access to oxygen, and is an electrical conduit. 

Monoammonium phosphate is effective in suppressing fires by separating the fuel from oxygen. The substance is most effective when the fire is entirely smothered. However, when the fire becomes too large, an extinguisher may not be enough. Fire extinguishers only have about 8 – 22 seconds of discharge depending upon their size.

While monoammonium phosphate is often used for household fires, it is not used in some instances because of its corrosive nature. The aircraft industry does not use monoammonium phosphate as standard due to its corrosive properties.

3. What other Types of Fire Extinguishers are There?

ABC extinguishers are usually recommended for household use. But there are situations where you may need another type of extinguisher.

Class D “Dry Powder” Fire Extinguishers – For Combustible Metals

Many factories and labs that use combustible metals are required to carry Class D fire extinguishers. Class D fires are fires that have combustible metals such as sodium, lithium, aluminum, potassium, magnesium, titanium and zirconium as the fuels for the fire.

Combustible metal fires burn at extremely high temperatures, requiring specialized substances to suppress the fires. Water is particularly incompatible for these fires as combustible metals can burn at such high intensity that the separate water into hydrogen and oxygen atoms which actually increase the ferocity of the fire.

Class D Extinguishers contain dry powder substance (not to be confused with dry chemical substance in ABC extinguishers). This dry powder is usually made of sodium chloride. This substance forms a cake when it touches the burning metals which both draws heat away from the fire and cuts off the oxygen supply to the fire’s fuel.

Class A-K “Wet Chemical” Fire Extinguishers – For Commercial and Industrial Kitchens

Class K fires are fires that have cooking oils, food greases, lard and animal fats as their fire fuels. These fires often require specialist extinguishers. Many districts mandate that businesses working in food preparation have a Class K compatible extinguisher in proximity to their commercial kitchen.

The main Class K extinguishers available on the market today are marked A-K extinguishers, as they’re also usable for Class A fires. These extinguishes use a wet chemical compound with the active agent being potassium acetate. This wet chemical has enhanced heat reduction above and beyond ABC rated extinguishers.

4. Frequently Asked Questions

Is the powder in ABC fire extinguishers toxic?

According to this distributor, the substance in ABC fire extinguishers is usually non-toxic. They claim that it “must be non-toxic in order to be safe for home and car use.” However, it can be irritable to inhale or swallow, particularly in large amounts. It should be carefully cleaned from surfaces and foods that it comes in contact with are best disposed of. However, the implication is that it is unlikely to cause serious damage if inhaled or consumed in small amounts (see source linked above). Nonetheless, if irritation does occur, a visit to a doctor or ER may be required to get expert advice.

How do you Clean up Fire Extinguisher Powder?

The powder in ABC fire extinguishers is mostly phosphates and sulfates that should not be washed down drains. It can negatively affect the local water table, meaning it should be disposed of carefully. The residue from a used fire extinguisher is not particularly toxic, but avoid consumption. To clean off dry chemical ABC fire residue, Guardian Fire Protection Services recommends:

  1. Vacuum and sweep all loose powder.
  2. Wash all affected dishes as normal.
  3. For stubborn residue, use a 98% hot water and 2% vinegar solution. A solution of baking soda and hot water paste may also be effective. After scrubbing, use a damp rag to dab the area clean.
  4. Finally, wash the affected area with soap and water. Dry with a fan.

A fire extinguisher will need to be either disposed of or recharged after discharge. Contact your local fire station for information on how to recharge your rechargeable fire extinguisher. Some larger local fire stations may offer recharging services for a fee.

5. Conclusion

Most households will likely have (or be required to have) an ABC fire extinguisher readily available in case of fire. They can be effective in the early stages of a fire emergency, but cannot put out larger fires. If the fire cannot be controlled or you do not know how to use a fire extinguisher, evacuate the area and contact your fire emergency services.

ABC extinguishers are designed for regular combustibles (Class A), combustible gases and liquids (Class B), and energized electrical fires (Class C). They are not recommended for industrial combustible metal fires (Class D) or commercial kitchen fires (Class K).

As well as a fire extinguisher, you should also have other basic fire safety equipment in your home including a kitchen fire blanket, fire extinguisher cabinet, fire escape ladder for multi-story homes, fireproof document safe, and of course a smoke detector.