Fires involving certain combustible metals would be classified as:

Fires involving certain combustible metals are classified as Class D fires. This classification specifically pertains to fires that involve metals such as magnesium, titanium, sodium, and potassium. Unlike other classes of fires, Class D fires require special extinguishing agents due to the unique properties of the metals involved, which can react violently to water and some other common extinguishing agents.

Class D fire extinguishers typically use dry powder agents specifically designed to smother the combustion process and interrupt the reaction between the metal and oxygen or the metal and water. Understanding Class D fires is crucial for fire safety and prevention, especially in industries that handle or utilize combustible metals. Other classes, such as Class A (ordinary combustibles), Class B (flammable liquids), and Class C (electrical fires), have different characteristics and extinguishing methods, underscoring the importance of proper classification in effective fire response and safety measures.