When confronting a Class D fire, which option is the most effective control method?

When dealing with a Class D fire, which involves combustible metals such as magnesium, titanium, or sodium, the most effective control method is utilizing dry powder extinguishers. Dry powders, specifically designed for metal fires, work by smothering the flames and creating a barrier between the fuel and the oxygen, effectively extinguishing the fire. These extinguishers contain agents like sodium chloride or copper powder, which are formulated to react safely with burning metals.

Other methods, such as using foam, applying water, or employing sand, are not suitable for Class D fires. Foam and water can react violently with certain metals, potentially exacerbating the fire situation or causing hazardous reactions. While sand can help create a barrier, it doesn't provide the same level of fire suppression as dry powder and may not effectively extinguish the flames. Therefore, dry powder extinguishers are the safest and most effective means of controlling Class D fires.