Statement on Class K Extinguishers

Fire extinguishers for the protection of cooking media fires (vegetable or animal oils and fats) traditionally required a minimum 40-B rated sodium bicarbonate or potassium bicarbonate dry chemical extinguisher as specified for extra (high) hazard requirements of Table 3-3.1 of NFPA 10. The evolution of high-efficiency cooking appliances and the change to hotter-burning vegetable shortening has created a more severe fire hazard and has prompted the creation of a new classification of fire, Class K. Testing by Underwriters Laboratories has shown that wet chemical extinguishers with a K classification have several times the extinguishing capability of a 40-B rated sodium bicarbonate or potassium bicarbonate extinguisher in controlling cooking fires.

The Class K extinguisher offers improved fire control for this type of hazard by:

• Creating a foam blanket by saponifying the hot cooking oils.
• Cooling both the appliance and the hot cooking oils.
• Offering improved visibility during fire fighting.
• Minimizing splash hazard.
• Providing easier clean-up than when using dry chemical agents.

Accordingly, the Fire Equipment Manufacturers’ Association, Inc. [FEMA] recommends that all Class B extinguishers used to protect cooking appliances/kitchens be replaced by the owners with Class K extinguishers as soon as possible. The travel distance of 30 feet as previously described in NFPA 10 is still recommended.

Prepared by the members of FEMA’s Portable Division