Class K Fire Extinguishers
Class K fire extinguishers are specifically designed and certified for use on fires involving combustible cooking media—the vegetable oils, animal fats, and greases used in commercial cooking appliances. The ‘K’ stands for kitchen.
These specialized fire extinguishers contain a low-pH potassium acetate, potassium carbonate, or potassium citrate solution that operates through a process called saponification. When the chemical agent is discharged onto the burning hot grease, it reacts to create a soapy, non-combustible foam blanket. This blanket rapidly cools the grease and seals off the oxygen supply, suppressing the fire and preventing reignition.
Common Usage Situations
Class K fire extinguishers are mandatory in any professional food preparation environment that uses deep-fat fryers or commercial woks:
- Restaurants and cafeterias. Required near all deep fryers, griddles, and broilers that use cooking oils.
- Commercial kitchens in institutions. Essential for kitchens within hospitals, schools, and corporate campuses.
- Food processing plants. Used in areas involving large-scale cooking operations with high-temperature oils.
- Food trucks and mobile cooking units. Necessary to meet safety codes for their specialized cooking appliances.
Due to the extremely high heat and specific chemical nature of modern cooking oils, only a Class K fire extinguisher is approved to effectively suppress these fires without risking serious injury or spreading the burning grease.