In addition to the well-known fire classes A, B, and C—which classify fires involving solid, liquid, or liquefying substances and gaseous substances—there is also fire class D. This class includes fires involving metals, which pose particular hazards and require the use of special extinguishing agents and techniques.
Metal fires often occur as a result of overheating or flying sparks in industrial processes. Improper extinguishing can trigger violent reactions, and in extreme cases even explosions. This makes it all the more important to be familiar with the characteristics of this fire class and to take appropriate protective measures at an early stage.
Typical substances in fire class D include:
These metals can self-ignite at high temperatures and burn with enormous heat—sometimes over 2,000°C. Particularly dangerous: Reaction with water or conventional extinguishing agents can lead to explosions or the release of flammable gases. It is therefore essential to take targeted and professional action in the event of metal fires.
Class D fires occur primarily in areas where highly flammable metals are used. Typical areas of application are:
Finely dispersed substances such as metal dust or chips are particularly dangerous, as they ignite more easily and can accelerate the development of a fire.
Metal fires must not be fought with water, foam, or CO₂ extinguishers. These agents are not only ineffective, but can also trigger dangerous chemical reactions.
Instead, special metal fire extinguishing agents are used, including:
These extinguishing agents work by binding heat and forming a barrier layer that shields the source of the fire from oxygen. It is important to select the appropriate extinguishing agent for the metal that is burning.
Special D fire extinguishers can be used to fight metal fires. These are filled with suitable metal fire powders.
Class D fires are rare, but potentially extremely dangerous. Without the right expertise and equipment, a minor incident can quickly escalate. This makes it all the more important to be prepared.
CWS Fire Safety is your reliable partner for preventive fire protection. We offer individual consultation and practical training courses – for greater safety when dealing with metal fires.