Munitions Firefighting Test 2025 – 400 Free Practice Questions to Pass the Exam

Class D fires involve combustible metals such as magnesium, titanium, or sodium, which have unique burning characteristics and require specific extinguishing agents. The correct extinguishing agent for Class D fires is dry powder agents. These agents are specifically formulated to smother and cool the burning metal without reacting adversely, as water and other agents might do.

Using water on Class D fires can exacerbate the situation, as it may react violently with the burning metal, potentially causing explosions or spreading the fire. Similarly, carbon dioxide is ineffective for these types of fires; while it can displace oxygen, it does not have the capacity to adequately control metal fires. AFFF foam is also unsuitable, as it is designed for class B fires involving flammable liquids and may not effectively extinguish metal fires, and in some cases, can also react with certain metals.

Dry powder agents, on the other hand, work by isolating the fuel from the oxygen and have an effective cooling capability for high-temperature metal fires. This makes them the safe and reliable choice for combating Class D fires.