Final answer:
Class K fires are fires that involve combustible metals, which require specific extinguishing methods different from other fire classes.
Step-by-step explanation:
Class K fires involve combustible metals such as potassium, sodium, aluminum, and magnesium. These types of fires can occur in environments where metals that can burn are processed or used. They are distinct from other classes of fires, such as Class A (wood and paper fires), Class B (flammable gases and liquids), and Class C (electrical fires). Since combustible metals can react violently with water and certain chemicals, specific extinguishing agents designed for Class K fires are necessary, often in the form of dry powder agents that can smother the fire without causing a reaction.