Metal fires are regarded as one of the most significant industrial fire hazards and need to be contained and suppressed using special approaches. Metal fires are a bit different from regular fires because they’re caused by materials such as magnesium, sodium, and titanium, which can burn really easily. The material burns at extremely high temperatures and may react explosively with water or foam.
In this article, we have provided in-depth knowledge about class D fire extinguishers. After reading this you will be able to use a class D fire extinguisher without any difficulty.
What are Class D Fire Extinguishers?
Class D fire extinguishers are meant for fires caused by the burning of metals. In such an instance, do not use water foam or a CO2 extinguisher since these might fuel the fire more.
For example, sodium or potassium can experience an actually violent reaction leading to increasing in size when water is used.
The dry powder in Class D extinguishers absorbs heat and forms a crust over the burning material. In this way, it isolates the fire from Oxygen. This is a key aspect in stopping combustion. Most industries using metals like magnesium, aluminium, and lithium commonly use Class D extinguishers because of their precise efficiency.
How Class D Fire Extinguishers Work
Class D fire extinguishers use certain materials to stop fires. This covers the following.
| Dry Powders | Working |
| Sodium chloride powder | This is the fire extinguishing agent that operates by creating a crust that helps to smother the flames for magnesium and titanium fires. |
| Copper-based powder | In Lithium fires, copper conducts heat away from the fire and lowers the temperature. |
These extinguishers work on a principle that creates a heat-resistant barrier that will not allow oxygen to hit the fire. The bigger the Class D extinguisher, the faster it will work in extinguishing the fire, which might be only in a few minutes.
This would be an important part of industrial safety for instance in smothering a magnesium fire producing temperatures over 4,000°F (2,200°C) much faster than other methods.
When to Use a Class D Fire Extinguisher
Class D fire extinguishers are mandatory in some environments.
| Places | Reasons |
| Industrial Factories | Processes that machine metals, such as aluminum and magnesium, create fine powders or shavings that might spontaneously ignite. |
| Workshops | These places often keep or process reactive metals like titanium and sodium, which require special care. |
| Laboratories | Any educational or research laboratory dealing with alkali metals such as Sodium and Potassium finds useful Class D extinguishers. |
NFPA estimated that more than 20% of the industrial fires involved combustible metals. Hence, Class D fire extinguishers must always be on hand on the premises.
Commonly Combustible Metals and Materials That Require Class D Fire Extinguishers
Some metals are very flammable and difficult to be controlled while burning. Some materials that require Class D fire extinguishers are:
Magnesium
It can flare up at temperatures as high as 3,000 degrees Fahrenheit if magnesium ever contact with water. It is quite commonly used in various automobile and aerospace industries.
Sodium and Potassium
Given the activity of alkali metals, these ignite readily in environmental conditions or upon reacting with water. Fire hazards include flammable products of fire with sodium hydroxide produced.
As defined by NFPA, using improper extinguishers causes reactions and contributes to the fire’s extension due to these metals.
Why Class D Fire Extinguishers are Important To Industrial Safety
The risk of destructive fires in industries handling reactive metals is high. Between 2010 and 2020, the United States had over 1,500 cases of metal fires per year. The property damage was in millions of dollars, and it was also a threat to life.
For example, in an automobile manufacturing plant, a magnesium fire occurred in 2019, and the damage was $2 million mainly because the right extinguishing equipment was not available. Class D extinguishers eliminate such risks as the fires are contained within a short time and do not spread to other areas.
Class D Fire Extinguisher proper usage and safety tips
Working with Class D fire extinguishers involves extensive knowledge. Some common things that need to be known are the following.
- Verification of the fire: Verify that you are dealing with a combustible metal. Failure to determine what type of fire it is may result in using an extinguisher for something you don’t want to use. It will make things worse.
- Use the Extinguisher Correctly: Aim the snout at the lowest part of the fire, totally covering the fire with the dry medium. Unlike other extinguishers, you are not “sweeping” through the agent, but create a full layer around the fire.
- Do not Use Water or Foam Extinguishers: These agents on a metal fire cause violent chemical activity and thus increase the danger.
Class D Fire Extinguishers: Maintenance and Care
Routine sweep and preservation are important to ensure that Class D extinguishers are reliable. The NFPA advises monthly visual checks for damage and evidence of tampering, and yearly professional servicing for their functionality.
After any use, extinguishers must be recharged immediately. Keeping them in easily accessible, well-marked locations in industrial facilities will improve response time during emergencies. A maintained extinguisher can last as long as 15 years, making it a great investment in safety.
Conclusion
Metal fires are one of the most dangerous types of industrial fires, and they can only be suppressed with proper tools. Class D fire extinguishers are a must in dealing with these unique issues, preventing catastrophic damage and lives lost. Through proper training as well as maintenance, and readiness, an industry can definitely make sure that it has a safer work environment.