Class K extinguishers

Class K of fires include cooking fats & oils made from vegetables and animals, such as a fryer. It uses an black background hexagon, with a K. A cooking pan on fire is used as the symbol.

Class K wet chemical (potassium acetate, potassium carbonate, or potassium citrate) extinguishes the fire by forming an air-excluding soapy foam blanket over the burning oil through the chemical process of saponification and by the water content cooling the oil below its ignition temperature.