Fire extinguishers are a vital component of any facility's safety plan. They are ideal for putting out and controlling fires caused by flammable liquids, combustibles, cooking, electrical malfunctions, and other incendiary situations. Learn about the different types of fire extinguishers, their UL ratings, and the environments they are best used in.
A Complete Guide to Fire Extinguishers
Compare fire extinguisher types, ratings, and uses to make informed decisions and be prepared for any type of fire emergency.
Fire Extinguishers
Types of Fire Extinguishers:
CO2 Fire Extinguishers
A carbon dioxide fire extinguisher is filled with highly pressurized carbon dioxide, which dissipates quickly without leaving residue. This makes this type of fire extinguisher ideal for environments like computer rooms, cleanrooms, and areas with electronic motors. However, CO2 extinguishers are not effective for Class A fires.
UL Rating: Class B and C.
Dry Chemical Fire Extinguishers
A dry chemical fire extinguisher is filled with mono-ammonium phosphate, sodium bicarbonate, or potassium bicarbonate, depending on the type.
UL Rating: Class A, B and C.
Halotron Fire Extinguishers
A Halotron fire extinguisher is filled with hydrochlorofluorocarbon (HCFC) blends of chlorine, fluorine, carbon, and hydrogen. It leaves no residue, is ozone-friendly, and will not cause thermal shock to electrical equipment.
UL Rating: Class A, B, and C.
Water Fire Extinguishers
A water fire extinguisher is filled with air-pressurized water and does not leave any chemical residue after use, making it best suited for tackling fires involving materials like wood, paper, and cloth.
UL Rating: Class A.
Wet Chemical Fire Extinguishers
A wet chemical extinguisher is filled with potassium acetate, carbonate, or citrate. It is recommended for use on cooking media, including vegetable or animal oils and fats.
UL Rating: Class K.
Fire Extinguishers Ratings:
UL Fire Extinguisher Ratings indicate fire-fighting capabilities, as tested by Underwriters Laboratories, Inc., can be seen on each extinguisher with a labeled number followed by a letter. The first number set in the rating is multiplied by 1.25, indicating the extinguishing agent in gallons. The second number set applies to the square feet the extinguisher covers.
For example, in "3-A", the number 3 indicates the relative power against a certain class A of fire (for class information please see below). The 3-A has triple the power against a common combustible fire compared to one rated 1-A. Class C fire extinguishers are not labeled with a relative power rating because these fires are a combination of Class A and Class B with live electrical equipment.
The ratings can be seen on each fire extinguisher with a labeled number followed by a letter.
Fire Extinguisher Classes:
Class A fire extinguishers are used for fires that involve common combustibles, such as wood, paper, cloth, rubber, trash, and plastics. These fires are common in a home or commercial setting and can occur anywhere these types of materials are found.
Class B fire extinguishers are used for fires that involve flammable liquids, gases, solvents, oil, gasoline, paint, lacquers, and other synthetic or oil-based products. Class B fires often spread rapidly and can reflash after the flames are extinguished.
Class C fire extinguishers are used for fires that involve electrical equipment, such as computers, wiring, controls, motors, data processing panels, or appliances. They can be caused by a spark, power surge, or short circuit.
Class D fire extinguishers are used for fires that involve combustible metals, such as magnesium, lithium, and sodium. Combustible metal fires, which are unique to industrial hazards, require special dry powder agents.
Class K fire extinguishers are used for fires that involve combustible cooking media, such as oils and grease commonly found in commercial kitchens. Modern cooking media formulations used in commercial food preparation require a special wet chemical extinguishing agent, which effectively suppresses these extremely hot fires and prevents them from reigniting.