Class K extinguishers are mandatory in commercial kitchens and they are designed to deal with the kinds of threats posed by cooking appliances and greases etc. The active extinguishing agent is aqueous film-forming foam (AFFF.) It quickly destroys the flames and forms a vapor-securing blanket to prevent reignition.

Class K fires are fires with substances such as the animal and vegetable fats present in commercial cooking oils and greases. These types of fires can only be effectively quenched with a Class K fire extinguisher.

Commercial kitchens are often the site of high-volume cooking activities which produce large amounts of grease or oil. A class K fire extinguisher is necessary to have close by in order to effectively suppress and defeat the fires that are most likely to occur in these locations. A class K fire extinguisher should also be used in conjunction with a fire suppression system. These fires may only be defeated efficiently with a Class K fire extinguisher.

A Class K fire extinguisher uses a fine wet mist consisting of an alkaline mixture, such as potassium acetate, potassium carbonate, or potassium citrate that forms a soapy foam as it is applied to the cooking oil or other substance, quenching the steam, vapors, and the fire’s risk of re-ignition.


If you run a commercial kitchen, concession stand, food truck, or food service of any kind, then a class K fire extinguisher is a mandatory requirement. Class K fires occur in cooking appliances that use flammable cooking substances like vegetable or animal oils and fats. Our class K fire extinguishers contain a blend of potassium acetate and potassium citrate that is ideal for combating high temperature fires that contain oils and grease. They can also be used on class A fires.

What the A B C K ratings mean on K Fire Extinguishers


Fire extinguishers with a Class A rating are effective against fires involving paper, wood, textiles, and plastics. The primary chemical used to fight these fires is monoammonium phosphate, because of its ability to smother fires in these types of materials.


Fire extinguishers with a Class B rating are effective against flammable liquid fires. These can be fires where cooking liquids, oil, gasoline, kerosene, or paint have become ignited. Two commonly used chemicals are effective in fighting these types of fires. Monoammonium phosphate effectively smothers the fire, while sodium bicarbonate induces a chemical reaction which extinguishes the fire.


Fire extinguishers with a Class C rating are suitable for fires in “live” electrical equipment. Both monoammonium phosphate and sodium bicarbonate are commonly used to fight this type of fire because of their nonconductive properties.


Fire extinguishers with a Class K rating are on fires involving cooking media (fats, grease, and oils) in commercial cooking sites such as restaurants.  The alkaline mixture combined with the fatty acid creates a soapy foam on the surface that holds in the vapors and steam and extinguishes the fire. These extinguishers are identified by the letter K.

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