What is an ABC Fire extinguisher?

Chris HuntAbout the Author: Hi! I'm Chris Hunt, and I wrote this article. With years of experience as a former firefighter and knowledge of combustible materials, I have personally researched and compiled the information presented here. Please note that the content provided is solely my opinion and should not be construed as professional advice. Additionally, I do not guarantee the quality or performance of any of the products featured. Please be sure to review the website's Disclaimer, Terms and Conditions before using the site. As an Amazon Associate I earn from qualifying purchases (without additional cost or expense to you).

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

A fire extinguisher usually has 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 standards 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 types of fires can ABC Extinguishers fight?

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

ABC Fire Extinguisher

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

Class A Fires – Common Combustibles

Combustible materials such as wood, paper, plastic, cloth, and rubber fuel Class A fires. Most objects will fit into this category when you look around your living room. For example, the coffee table, couch, desk, bookshelf, and books on the shelf will all be Class A combustible materials.

Several substances, including water, foam, and dry chemicals, can suppress Class A fires. For example, an ABC extinguisher uses dry chemicals to suppress fires.

Class B Fires – Combustible Liquids and Gases

Combustible liquids and gases can fuel Class B fires. In Europe and Australia, Class B is for beverages, and Class C is for gases.

Class B flammable 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.

Dry chemicals, halogen, and specialized foams can suppress Class B fires. Halogen was standard in household fire extinguishers until the 1990s when scientists discovered they were terrible for the Ozone layer. So now, we tend to use the dry chemical mono ammonium phosphate found in most ABC-grade extinguishers.

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

Class C Fires – Energized Electrical Fires

Energized electrical sources cause Class C fires. Examples include clothes dryers, space heaters, overloaded power boards, faulty wall wiring, and frayed extension cords. While electrical sparks cause the fire, the fuel for these fires is, in fact, Class A fire fuel. Thus, the fire might behave like a Class A fire once the electrical source stops.

Class C fires are classified because one should not use water to suppress energized electrical sources. Water is an electrical conduit, meaning you may electrify yourself if you attempt to fight a fire using water. The best way to stop a Class C fire is the dry chemical mono ammonium phosphate found in most ABC-grade extinguishers.

ABC Fire extinguisher in action

2. Where Should I use an ABC Fire Extinguisher?

You can use an ABC fire in homes, garages, workshops, cars, and boats. However, industrial settings such as commercial kitchens should use other extinguishers. Always check the rules and recommendations of your local jurisdiction.

ABC fire extinguishers are typically for 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 house. However, the NFPA recommends other non-ABC type extinguishers for domestic kitchens.

For example, the Kidde RESSP extinguisher is for domestic kitchens (with a BC rating and a different type of powder inside it). It is currently (at the time of first writing) the only extinguisher on the market with a UL rating for domestic kitchen use.

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

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

We’ve put together a guide that looks at quality certified extinguishers for more details about what sort of fire extinguisher you need on your boat.

In Cars and Trucks. Most jurisdictions don’t have rules that the average car needs an extinguisher (check-in your authority), but many people like to present them in their car anyway. Sports cars and racing cars are examples of cars that often require extinguishers. An ABC extinguisher is standard in a car because ABC extinguishers can suppress gasoline and other liquid fires. Some extinguishers are DOT (Department of Transport) approved. Check out our complete guide on car fire extinguishers for more.

In RVs, Caravans and Campers. Campers, RVs, and caravans often need fire extinguishers. In particular, this is the case of RVs, which have a kitchen. Nonetheless, any trailer with a campfire or propane fire pit by their vehicle might like an extinguisher as they’ll be working with open flames. We have a buyer guide for campers if you’re after a fire extinguisher for your RV or caravan.

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

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

A common misconception is that an ABC fire extinguisher contains a water-based substance. Unfortunately, this is not valid. 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. Therefore, the substance is most effective when the fire gets wholly smothered. However, an extinguisher may not be enough when the fire becomes too large. Fire extinguishers only have about 8 – 22 seconds of discharge, depending upon their size.

While mono ammonium phosphate is standard against household fires, this might not be the case in some instances because of its corrosive nature. For example, due to its corrosive properties, the aircraft industry does not use monoammonium phosphate as a standard.

Fire Extinguisher

3. What other types of Fire Extinguishers are There?

ABC extinguishers are the recommended solution 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 must carry Class D fire extinguishers. Class D fires 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 with these fires as combustible metals can burn at such high intensity that they separate water into hydrogen and oxygen atoms, increasing its ferocity.

Class D extinguishers contain a dry powder substance (not confused with a dry chemical in ABC extinguishers). This dry powder is sodium chloride. When it touches the burning metals, this substance forms a cake, which draws heat away from the fire and cuts off its fuel’s oxygen supply.

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

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

The primary Class K extinguishers available today are marked A-K extinguishers, which are usable for Class A fires. These extinguishers use a wet chemical compound with potassium acetate’s active agent. This damp 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 it “must be non-toxic to be safe for home and car use.” However, it can be irritable to inhale or swallow, particularly in large amounts. Therefore, it would be best to carefully clean it from surfaces and discard any food that comes into contact. However, the implication is that it is unlikely to cause severe damage if inhaled or consumed in small amounts (see source linked above). Nonetheless, if irritation does occur, you may require a visit to a doctor or ER 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 wash down through drains. However, it can negatively affect the local water table, carefully disposed of. The residue from a used fire extinguisher is not particularly toxic but avoids 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 usual.
  3. Use 98% hot water and 2% vinegar solution for stubborn residue. An explanation of baking soda and hot water paste may be adequate. 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 disposed of or recharged after discharge. Contact your local fire station for information on how to renew 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 you cannot control the fire or 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 for industrial flammable metal fires (Class D) or commercial kitchen fires (Class K).

As well as a fire extinguisher, it would be best if you had other essential fire safety equipment in your home, including: