Magnesium Fires – Understanding Class D Fire Risks

What Is a Magnesium Fire?

Magnesium fires are classified as Class D fires because they involve combustible metals. These fires behave very differently from ordinary combustible fires and can reach extremely high temperatures.

Magnesium is used in a range of industries, including aerospace, automotive engineering and manufacturing, where its lightweight properties make it a valuable material. However, if it ignites, it requires specialist firefighting techniques.

The Dangers of Magnesium Fires

One of the greatest hazards of a magnesium fire is that using the wrong extinguishing method can make the situation significantly worse.

Applying water or other unsuitable extinguishing agents to burning magnesium can cause violent reactions, produce flammable hydrogen gas and increase the intensity of the fire. For this reason, only extinguishing agents suitable for Class D combustible metal fires should be used.

Magnesium Fire Demonstration

In this demonstration, a magnesium fire was used to illustrate the challenges associated with extinguishing burning metals.

The demonstration showed how a Zenova FX500 aerosol fire extinguisher was used to tackle the fire under controlled conditions.

Using the Zenova FX500

The Zenova FX500 is an aerosol fire extinguisher that can be operated in a 360-degree orientation. This makes it suitable for use in awkward or confined locations where accessing the seat of the fire may be difficult.

During the demonstration, the extinguishing agent was applied directly to the burning magnesium. Under the controlled demonstration conditions, the fire was extinguished rapidly, within approximately five seconds.

Working in Difficult Locations

The compact design of the FX500 allows it to be used in locations where larger portable extinguishers may be difficult to position. The ability to operate the aerosol from any angle provides greater flexibility when access is restricted.

Important Safety Considerations

Magnesium fires are specialist fires. Anyone dealing with combustible metal fires should receive appropriate training and ensure the correct extinguishing media is available.

If there is any doubt about the type of fire or the correct extinguishing method, evacuate the area immediately and contact the fire and rescue service.

Key Learning Points

• Magnesium fires are Class D combustible metal fires.
• They burn at extremely high temperatures.
• Using water or another unsuitable extinguishing agent can make the fire more dangerous.
• Only use extinguishing media suitable for combustible metal fires.
• Always prioritise personal safety and maintain a safe escape route.