Did you know there is more than one type of fire extinguisher, and each one is classified by its contents? Burn and Reconstructive Centers of America (BRCA) is helping keep our communities safe by breaking down fire extinguisher classifications into an easy-to-follow guide so that you know which fire safety device is right for your individual needs.
Types of Fire Extinguishers
Water-Based Extinguishers (recommended for use on flammable material fires)
This fire extinguisher is recommended for putting out ordinary fires consisting of flammable materials such as wood, plastic, paper, cloth and rubber. Flammable materials are classified as Type A fires. When buying a fire extinguisher for Class A fires, the extinguisher should explicitly have an “A” on it if it is intended to put out these types of fires. Things to be aware of about water-based extinguishers:
- Not suitable for freezing conditions (since the water inside will freeze)
- If expecting freezing conditions, check to see if the water-based extinguisher contains anti-freeze
- Not suitable for kitchen fires
- Will last a minimum of five years before it needs to be replaced
Film-Forming Foam Extinguishers (recommended for use on flammable material or combustible liquid fires)
Film-forming foam extinguishers discharge a foaming material rather than a liquid, similar to water-based extinguishers. This type of extinguisher is recommended for fires consisting of flammable materials (wood, plastic, paper, cloth and rubber) and combustible liquids (petroleum, oils, flammable gases, alcohols, etc.). Combustible liquids are classified as Type B fires. When buying these extinguishers, the containers should explicitly have an “A” or a “B” on the outside to indicate their ability to put out flammable material or combustible liquid fires. Things to be aware of about film-forming foam extinguishers:
- Not suitable for freezing conditions
- Forms a film on liquid surfaces to cover the combustible agent and prevent reignition
- Two types are: Aqueous Film-Forming Foam (AFFF) and Film-Forming Fluoroprotein (FFF)
- Expiration may vary. The expiration date should be printed on the canister
Carbon Dioxide-Based Extinguishers (recommended for use on combustible liquid or electrical fires)
These extinguishers contain gaseous Carbon Dioxide (CO2), meaning they do not leave a residue when discharged, making them preferable to use on electrical devices or equipment. This type of extinguisher is recommended for combustible liquid fires (Class B) and electrical fires (Class C). When buying these extinguishers, the containers should explicitly have a letter “B” or “C” in plain letters on the outside, indicating its use for putting out Class B and C fires. Things to be aware of about Carbon Dioxide-based extinguishers:
- Have a shorter range of 3 – 8 feet
- Suitable for cold weather
- Not recommended for windy, outdoor conditions because the gas may blow away or become less effective
- Not recommended for use in drafty or breezy indoor areas because the gas may blow away or become less effective
- Must be used with caution in confined spaces as it may limit the oxygen available
- Will last a minimum of five years before it needs to be replaced
Halogenated Agent-Type Extinguishers (recommended for use on flammable material, combustible liquid and electrical fires)
These extinguishers aren’t as common as they used to be due to the damaging effects Halon 1211 has on the earth’s ozone layer. Halon 1211 alternative agents are environmentally friendly and perform the same way. These extinguishers are recommended for use on flammable material fires (Class A), combustible liquid fires (Class B) and electrical fires (Class C). They discharge in a gas/mist state that dissipates quickly and leaves no residue. Things to be aware of about Halogenated agent-type fire extinguishers:
- Have twice the range of Carbon Dioxide-based extinguishers
- Not recommended for windy or drafty conditions as the extinguisher may become less effective
- Suitable for cold weather
- Expiration may vary. The expiration date should be printed on the canister
Multipurpose Dry Chemical-Type Extinguishers (recommended for use on flammable material and combustible liquid fires)
Most multipurpose dry chemical-type extinguishers have an ammonium phosphate base. These extinguishers are recommended for flammable material fires (Class A) and combustible liquid fires (Class B). Things to be aware of about multipurpose dry chemical fire extinguishers:
- Recommended for shallow fires. Efficacy may decrease with deeper-seated fires
- Works by sticking to the surface of burning materials and coating them, smothering the flames
- Little cooling effect
- Will last a minimum of twelve years before it needs to be replaced
Wet Chemical-Type Extinguishers (recommended for use on kitchen fires)
These extinguishers may contain water, potassium acetate, potassium carbonate, potassium citrate or any combination. This liquid discharge extinguisher is recommended for use on kitchen fires (Class K fires) that involve electrical kitchen appliances and flammable materials such as cooking oils or animal fats. Things to know about wet chemical-type fire extinguishers:
- Work by coating the fire in foam and cooling it so the fire cannot reignite
- Prevent splashing from hot oils or fats
- Reduce the hazard of electrical shock
- Reduces the amount of cleanup once the fire is out
- Will last a minimum of five years before it needs to be replaced
Dry Powder-Type Extinguishers (Recommended for use on combustible metal fires)
People using this type of extinguisher should closely follow the techniques and recommendations. This type of extinguisher can be applied to Class D fires by extinguisher discharge or by being shoveled onto the flames. Class D fires include combustible metals such as titanium, magnesium, zirconium, sodium, lithium and potassium. Expiration dates may vary depending on contents. The expiration date should be printed on the outside of the canister.
How to Properly Use and Discharge a Fire Extinguisher:
Pull, Aim, Squeeze, Sweep (PASS)
- Step One: Pull the safety pin.
- Step Two: Aim the extinguisher’s nozzle at the base of the flames.
- Step Three: Squeeze the handle.
- Step Four: Sweep the nozzle from side to side while ensuring you are still aiming at the base of the flames.
*Keep a distance of between six-to-eight feet away from the flames. Only use a portable fire extinguisher when the fire is small, contained and not actively growing. For fires that are actively growing and out of control, do not attempt to put it out. Instead, get your and your loved ones to safety and call 911.
How to Maintain a Fire Extinguisher
Fire extinguishers work by keeping their contents pressurized. This is shown via a little meter that typically can be found near the handle. If the needle is in the green zone, then the can is well pressurized. If the needle begins to slowly fall below the green zone, that means the pressure is leaking. Fire extinguishers can lose pressure naturally over time. Whether the extinguisher has been discharged or not, if it passes the hydrostatic test and there are no flaws or pressure leaks, then you can have the canister refilled. However, an extinguisher that is leaking pressure and does not pass the hydrostatic test must be disposed of either by taking it to a fire safety company or by recycling it through a steel plant. It is recommended not to throw away the extinguisher in the garbage as the contents are still highly pressurized.
Even if the extinguisher is holding its pressure, every twelve years your extinguishers should be taken to someone certified to check them and conduct a hydrostatic test. This test checks the pressure in the can and ensures there are no leaks or other flaws. You can find someone certified to check your fire safety equipment through your local fire department. Always pay attention to the expiration date on the canister and be sure to have it inspected or properly disposed of once that date has passed.
Further Information
For more information on fire extinguishers in your home or at work, please contact your local fire department.
