Which extinguishing agent is approved for use in a class K system?

The correct answer, wet chemical, is specifically formulated for use in Class K fire suppression systems. Class K fires involve cooking oils and fats commonly found in commercial kitchens. Wet chemical agents work by both cooling the burning oil and creating a barrier that helps to prevent reignition.

This is achieved through the use of a potassium-based agent that reacts with the hot oil, forming a soap-like solution which suffocates the fire and prevents oxygen from reaching the fuel. The effectiveness of wet chemical systems in managing this type of fire makes them essential in environments where cooking equipment is used, such as restaurants and cafeterias.

Other options like dry chemical, foam, and carbon dioxide are not suitable for Class K fires. Dry chemical agents may be effective on some types of fires, but they do not adequately address the unique challenges posed by cooking oils. Foam tends to work well with flammable liquids but is ineffective against grease fires. Carbon dioxide, while useful for certain classes of fires, does not provide the cooling or protective benefits necessary for cooking oils, and it does not prevent the risk of reignition, which is critical in these scenarios.