What is a Class D Fire – the best suited Fire Extinguisher?

Class D fires occur from combustible metals, such as aluminium, titanium, magnesium, lithium, zirconium, sodium, and potassium. 

These types of fires usually occur in industrial, manufacturing, or laboratory settings when the metal fines – tiny, thin pieces of metal, often shavings or dust generated during the machining process ignite. Class D fires can cause significant damage and are not simple to put out. 

What Type of Extinguishers are Rated as Class D Fire Extinguishers?

Unfortunately, Class D fires cannot simply be extinguished with water or just any extinguishing agent. When water interacts with the combustible metal it intensifies the fire, increasing the heat and spreading molten metal. 

Because of this, it is vital that only a Class D fire extinguisher is used to extinguish a combustible metal fire. The best way to extinguish these fires is by smothering them & eliminating the oxygen element. The agent also helps to absorb the heat from the fuel.

The only type of Class D fire extinguisher is the Dry Powder extinguisher. The powder agent used is either powdered graphite, granular sodium chloride or copper based, all of which are effective at separating the fuel from the oxygen. 

While dry powder extinguishers are effective for Class D fires, they are not effective for any other class of fire.