What is a common agent used for kitchen fires (Class K)?

Class K fires are specifically related to cooking oils and fats, often found in commercial kitchen environments. The correct answer is Purple K, which is a type of dry chemical fire extinguisher that contains potassium bicarbonate. This agent is particularly effective for putting out Class K fires because it is designed to smother the flames and interrupt the chemical reaction that fuels the fire.

In contrast, water is not suitable for Class K fires, as it can evaporate and spread the burning oil, making the situation worse. Carbon dioxide is typically not effective for deep-fat fryers, as it may not adequately cool the burning oil. Other dry chemicals, while useful for other classes of fire, are not as specialized for the unique properties of cooking oils and fats as Purple K is. Thus, Purple K is specifically recognized for its effectiveness in extinguishing kitchen fires due to its ability to handle the high-temperature and chemical behavior of these types of fires.