Basic Engineering Common Core (BECC) 3 Practice Test 2026 - Free Engineering Core Practice Questions and Study Guide

Magnesium fires are classified as Class D fires, which involve combustible metals that can burn at extremely high temperatures. For these types of fires, the appropriate fire extinguisher is a Class D extinguisher, specifically designed to control fires involving flammable metal substances like magnesium. Class D extinguishers often use specific dry powders, such as sodium chloride or copper powder, that work by smothering the fire without reacting with the burning metal.

Using water-based extinguishers or AFFF-type extinguishers is not suitable for magnesium fires because these can react violently with burning magnesium, potentially worsening the situation by spreading the fire or causing an explosion. CO2 extinguishers are ineffective since they are typically used for flammable liquids and electrical fires and do not address the unique challenges posed by metal fires.