What are the classes of fire and their suppression agents?

Fire classes determine the appropriate suppression agent. Class A fires involve ordinary combustibles like wood and paper, suppressed by water. Class B fires involve flammable liquids and gases, suppressed by carbon dioxide, dry chemical, or foam. Class C fires involve energized electrical equipment, suppressed by carbon dioxide or clean agents like FM-200 that do not conduct electricity. Class D fires involve combustible metals, suppressed by dry powder agents specific to the metal. Class K fires involve cooking oils, suppressed by wet chemical agents.