“Class K” refers to fires involving cooking oils or fats such as vegetable or animal oils and fats. These types of fires are typically found in commercial kitchens, such as restaurants and cafeterias.
Class K fire extinguishers use wet chemical agents specifically designed to extinguish fires involving cooking oils and fats. These agents work by creating a barrier between the oil and the oxygen, which cuts off the fire’s oxygen supply, and by cooling down the oil to prevent reignition. They are labeled with a “K” on them, to indicate that they are safe to use on kitchen fires.