Class K Fire Extinguishers
Class K fire extinguishers are built for the one fire that most extinguishers handle poorly: burning cooking oil in a commercial kitchen. Each unit discharges a wet chemical agent as a fine mist that cools the oil and reacts with it to form a soapy foam blanket, sealing the surface so the fire cannot flash back.
Modern deep fryers hold large volumes of vegetable oil at high temperatures, and those fires burn hotter than the animal fats older extinguishers were designed for. Spraying them with a standard dry chemical or water extinguisher can splash burning oil across the kitchen. NFPA 10 requires a Class K extinguisher near cooking appliances that use vegetable or animal oils and fats, and fire inspectors check for one in every commercial kitchen.
We stock Class K wet chemical fire extinguishers from Badger and Buckeye in the two standard sizes:
- 6 liter units for food trucks, small cafés and kitchens with one or two fryers
- 2.5 gallon units for restaurants, cafeterias, hotels and high-volume kitchens
Every model is rechargeable, mounts on the included wall hook, and has a wand that lets the operator apply the agent gently from a safe distance. Most carry an A rating as well, so they also cover wood, paper and cloth fires in the kitchen.
Compare the models below, or read our Class K fire extinguisher guide further down the page for placement rules and how to use one on a fryer fire.
What Is a Class K Fire Extinguisher?
A Class K fire extinguisher contains a wet chemical solution, typically based on potassium acetate or potassium citrate. When it hits burning cooking oil, it cools the oil and triggers saponification, a reaction that turns the surface of the oil into a layer of soap-like foam. That layer cuts off oxygen and holds in vapor while the oil cools below its ignition point.
Why a Kitchen Fire Extinguisher Must Be Class K
Cooking oil fires are deep-seated and hot. A dry chemical extinguisher can knock the flames down, but the oil stays hot enough to reignite. Water is worse, because it sinks, flashes to steam and throws burning oil out of the fryer. A Class K kitchen fire extinguisher is the only portable type listed for this hazard. Do not confuse it with purple K, a dry chemical for fuel fires.
Class K Fire Extinguisher Requirements
Placement
NFPA 10 requires Class K extinguishers within 30 feet of cooking appliances that use combustible cooking media. One 6 liter Class K unit covers up to four fryers holding up to 80 lb of oil each, and larger fryer lines need additional extinguishers. Mount the extinguisher along an exit path, not right beside the fryer, so staff can reach it without passing through the fire.
Use with a hood suppression system
A Class K fire extinguisher does not replace the automatic suppression system in your hood. Activate the hood system first, then use the extinguisher as a backup. NFPA 10 calls for a placard near the extinguisher stating this order of use.
Class K Fire Extinguishers for Food Trucks and Concessions
Food trucks, trailers and concession stands with fryers fall under the same rules as restaurant kitchens. A 6 liter Class K fire extinguisher fits the tight space. Most also need an ABC unit, commonly 2-A:10-B:C or larger, for the generator, propane and electrical systems. Mount both near the service door so they can be reached quickly.
Choosing a 6 Liter or 2.5 Gallon Class K Extinguisher
The 6 liter size is lighter and easier for any staff member to handle, which suits food trucks, coffee shops and kitchens with one or two fryers. The 2.5 gallon size carries more agent for longer discharge, which suits full-service restaurants, institutional kitchens and large fryer lines.
How to Use a Kitchen Fire Extinguisher on a Fryer Fire
Turn off the heat source if it is safe to do so. Pull the pin, hold the wand level, and apply the agent in a gentle sweeping motion from at least 6 feet away so the mist falls onto the oil instead of splashing it. Discharge the full contents, then leave the fryer alone until it cools.
Class K Fire Extinguisher Maintenance
Inspect monthly and have the unit serviced annually. Wet chemical extinguishers need a five-year hydrostatic test, and grease can clog the nozzle, so keep it clean. Recharge wet chemical units with the matching agent and a proper adapter, available in our extinguisher accessories department.