RV Articles

Understanding Fire Extinguishers

Most people know it's wise to keep several fire extinguishers in an RV, car, boat and house. However, going through the process of choosing which fire extinguisher is the best for each situation can be difficult. There are a variety of fire extinguishers on the market and a number of factors that affect each individual's buying decision.

There are a few questions that lots of travelers ask when looking for a fire extinguisher:

    • What do the numbers and letters on the fire extinguisher mean?
    • Is my extinguisher safe to use around my children and animals?
    • How much clean-up is required when the contents of my fire extinguisher are expelled?
    • How much does a good fire extinguisher cost?

Knowing the answers to these questions will help you determine which extinguisher is right for your needs.

What do the letters and numbers on the fire extinguisher mean?

Fire extinguishers may have one or more letters on the label-A, B, C, D, or K-and a number from 1 to 120. The letters A, B, C, D and K represent the types of fire the extinguisher can extinguish.

Class A

Involves common combustibles like paper, fiberglass, wood, 12-volt wiring and many other items commonly found in a home, RV or boat.

Class B

Involves flammable and combustible liquids and gases like gasoline, diesel fuel, and propane.

Class C

Involves energized 120-volt electrical equipment, including wiring, fuse boxes, circuit breakers, machinery and appliances.

Class D

Involves combustible metals like magnesium, sodium, potassium, sodium-potassium alloy uranium and powdered aluminum.

Class K

Involves restaurant grease. If any of these symbols are missing on a portable fire extinguisher, it has not been rated for this class of fire.

The numbers on the label represent the area the extinguisher will cover. Class A is measured in cubic feet (1A equals 8 cubic feet.) Class B fires are measured in square feet (10B equals 10 square feet). There is no area measurement for Class C.

Types of Fire Extinguishers

There are a variety of fire extinguishers on the market. Some are designed for personal use and some for professional use. The following is a list of all fire extinguishers available today.

Dry Types

    ABC Dry Chemical

The material used in this type of extinguisher is monoammonium phosphate, a hazardous material that can be toxic. It has a very limited Class A fire-fighting ability. With this type, a very large ABC dry chemical extinguisher is required to handle a small Class A fire. Once the contents are expelled, the ABC dry chemical extinguisher is very expensive to clean up. The cost of this type of extinguisher is $10-$150, depending on its size.

    Purple K (PKP) BC Dry Chemical

The material used in this type of extinguisher is potassium bicarbonate-a hazardous material. The military and airports are the main users of the PKP. It is available on a limited basis and is expensive, $20-$50 each, depending on size.

    BC Dry Powder

This is the most common and least expensive extinguisher. It's made of non-toxic, sodium bicarbonate. In a non-motorized RV trailer, regardless of size or type of construction, only one 5BC extinguisher is required by the National Fire Protection Association. For a motorized Class A, B or C motor home, no matter the size, a 10BC extinguisher is required. This extinguisher is messy to clean up but is popular because of its low price. A BC Dry Powder extinguisher can be purchased for as low as $6. The price can go up to approximately $60 for a larger size. It's important to note that the BC Dry Powder extinguisher is not designed to fight Class A fires, fires involving common RV components like fiberglass, wood, and fabric.


No longer available to the general public, these extinguishers are very hazardous when used on a fire because of a chemical change that takes place during the heat phase of the fire. The Halon changes to hydrogen fluoride, hydrogen chloride, and hydrogen sulfide, according to the material safety data sheets. During the cooldown phase, it changes one more time into phosgene gas. Although Halon was initially thought to absorb oxygen, it actually displaces oxygen in the area of the fire. Halon is clean and requires little clean-up; unfortunately, t's highly toxic. It costs an average of $150/pound.


This extinguisher is a popular replacement for Halon. It is environmentally-friendly but still has some of the same hazards as Halon during the heating and cooling process. Halatron is very expensive for the average RVer, boater or homeowner. A 23-pound 1A 10BC extinguisher costs about $250, and a 2A 10BC costs about $350.

Wetting Agent

    AB type wetting agent from Cold Fire

The wetting agent is a chemical compound that, when added to water, materially reduces its surface tension. This increases its penetrating and spreading ability. Commonly used in the auto racing industry, it is non-corrosive, non-toxic and biodegradable. This extinguisher system is ideal for RVs and boats and is available for purchase at many RV rallies and auto races.

The Cold Fire product has been on the market for a little more than a decade. The Wetting Agent from Cold Fire is used in pre-installed extinguishing systems for RV engine compartments and may be used as a replacement for Halon systems in some boats. There is very little clean up once the Wetting Agent is released and it costs between $6-$450 to purchase, depending on its size.

Ultimate Foam

    ABC New Designer Foam

Available since 1999, and manufactured by Kidde, the material in this extinguisher is a non-toxic new generation of foam, popular because of its safeness around children and animals. It is effective on both vertical and horizontal surfaces and is easy to use. It requires very little clean-up. This extinguisher is ideal for RVs and, with the proper Coast Guard approved bracket, can be used in some boats. ABC New Designer Foam is not available in all states, so check for it at RV rallies. It costs about $40.00.

    ABCDK ALLFIRE Designer Foam

HAWK International has been offering this product since 1995. The material in this extinguisher is non-toxic, non-corrosive, biodegradable and friendly to children and animals. It is easy to use, even for someone who has limited use of his or her hands. It cleans up with little effort. It has the ability to hold vertically and flows easily into areas most extinguishers cannot reach. The ABCDK ALLFIRE Designer Foam extinguisher has the ability to cool even the hottest materials. Its biggest value is the ability to emulsify hydrocarbons, like gasoline, motor oil and diesel fuel, so they cannot re-ignite. This extinguisher is ideal for all applications. Small hand held units cost $20.00, larger refillable for $120.00, and 5gal or 55gal bulk at $20.00 per/gallon.

    Aqueous Film-Forming Foam (AFFF)

The fire service and military have used this type of foam for more than 40 years. It is slightly toxic and corrosive and has not been readily available to the public. There has been little or no education on this type of extinguisher for use in the RV or boat industry. The AFFF cools fuel and smothers a fire by forming a foam blanket. Firefighters must be careful not to disturb the foam blanket because vapors can re-ignite. This type of foam does not cling very well to a vertical surface. When AFFF is used, the foam requires clean-up and then the surface it covers requires clean-up. AFFF is sold only in 5-gallon to 55-gallon drums. It costs approximately $30/gallon.

Who's Looking Out for You?

An association called the National Fire Protection Association (NFPA) acts as an advocate for public fire safety. Among other things, the NFPA makes recommendations for the type, size, and location of fire extinguishers for businesses and industry. Fire departments and fire extinguisher companies that refill and service extinguishers are the watchdogs that insure the NFPA's standards are met. Thanks to their standards, fire extinguishers are in many public buildings and are required in RVs, boats, RV parks, and service stations. Although the NFPA standards are overall positive, the standards require the use of certain older style extinguishers such as the dry powder and dry chemical extinguishers. If you have ever used a dry powder or dry chemical fire extinguisher, you'll remember the mess it created. Moreover, it may not have put out the fire or kept it out. Some of the so-called clean agent Halon and CO2 extinguishers lose some of their effectiveness on a windy day and in a confined space, such as an RV or boat. They can also be heavy and expensive.

What's Best for My Situation?

The NFPA regulates fire extinguisher use in business and industry, but unfortunately, there is no national association promoting fire extinguisher safety and maintenance to the public. Due to this lack of information, the public is rarely informed when a new fire extinguisher is released onto the market, including some impressive advancements in extinguisher technology introduced in the last 10 years.


Disclaimer: The information in this article was obtained from various sources. This content is offered for educational purposes only and does not represent contractual agreements, nor is it intended to replace manuals or instructions provided by the manufacturer or the advice of a qualified professional. The definitions, terms and coverage in a given policy may be different than those suggested here and such policy will be governed by the language contained therein. No warranty or appropriateness for a specific purpose is expressed or implied.

You are leaving AIS Insurance and will be redirected to our partner site to complete your quote and purchase.