When working with metals, things can go wrong very fast. A Class D fire is a metal fire. It happens with metals like magnesium or titanium. These fires are very hard to stop. They burn super hot and can keep burning even without any extra fuel.
It’s important to know what causes them and what to do if one starts. In this blog, you’ll learn what Class D fires are, how they begin, and what to do to stay safe if they happen.
What is a Class D Fire?
A Class D fire starts when metals that can burn—like magnesium, potassium, lithium, sodium, or titanium—catch fire. This can happen if the metal gets too hot, rubs too much, or gets hit by sparks from machines.
Once the metal starts burning, it can keep going on its own because it burns at very high heat. These fires are very dangerous. You can’t use water or normal fire extinguishers because they make the fire worse.
To stop this kind of fire, you need a dry powder extinguisher. The powder covers the fire, takes away the heat, and blocks the air so the fire can’t keep burning.
You’ll mostly see these fires in factories, workshops, and labs, where metal dust or tiny metal bits are common.
Causes of Class D Fires
A Class D fire often starts when a metal reacts with heat, rubbing, or sparks. Let’s see where and how this can happen, especially in places that work with metals.
In factories or workshops, fires can start when:
- Metal is cut, ground, or sanded, creating tiny pieces that can catch fire.
- Machines get too hot when used for a long time.
- Welding or cutting is done near metal dust or shavings.
- Metal waste is not stored or cleaned the right way.
- Metal powders are kept near heat or water.
All these things can turn normal work into a fire risk if people don’t follow safety steps.
Improper handling of combustible metals
Improper storage can turn safe metals into fire risks.
- Keeping metal dust in plastic or cardboard boxes
- Storing near fuel, oil, or chemicals
- Not checking containers for leaks.
- Moving metals roughly, causing friction.
- Ignoring temperature control during shipping
- Good storage and gentle transport help prevent accidents
Storage and transportation risks
A lot of Class D fires come from poor handling.
- Not wearing gloves or safety gear.
- Using broken or wrong tools
- Letting dust pile up
- Not cooling metals properly.
- Forgetting to inspect machines for heat buildup
Proper care and simple safety checks help avoid serious accidents.
How to Extinguish a Class D Fire
A Class D fire means burning metal. It gets very hot and reacts badly to water. So don’t use water at all.
First, keep yourself and others safe. Tell people to move back. Make sure you can run out if the fire grows. If it’s too big, call the fire station right away.
If you can, turn off any machines or power near the fire. This stops more sparks.
Use the right kind of extinguisher — one made for metal fires, called Class D dry powder. Don’t use water, foam, or any normal one. They will make the fire worse.
Put the powder slowly on the fire. Don’t throw it hard. Just cover the burning metal gently until you can’t see the flames. The powder will stop the fire and cool it.
Wait after it stops. The metal stays hot for a long time. Don’t touch it or move the powder.
When everything is calm, tell the fire team. Let them clean and take care of the area.
Why Water and Foam Should Not Be Used
Water and foam should never be used on a class D fire. These fires involve burning materials like magnesium, lithium, or titanium, which react very strongly with water. Then water touches these metals. It can split into hydrogen and oxygen. Causing an explosion makes the fire spread even faster.
Form doesn’t help either because it can not smother the fire or cool the metal properly. Instead of putting it out, it often makes things worse. The safest way to handle a metal fire is to use a class D dry powder extinguisher made for combustible metals only.
Dry powder extinguishers for Class D fires
For Class D fires, use only a dry powder extinguisher.
It is made for metal fires and keeps them under control.
The powder takes away the heat and covers the burning metal.
This stops the flames and keeps the fire from growing.
Water should never be used. It makes metal fires worse.
The powder works in a different way. It cuts off the air so the fire cannot breathe.
Different metals may need different kinds of powder.
Some fires need sodium chloride powder.
Others may use graphite powder.
When you use the extinguisher, do it slowly and softly.
Do not throw the powder fast or hard. It can spread the burning metal.
Keep adding the powder until the fire is fully covered.
When the flames go out, leave the powder there.
The metal stays hot for a long time even after the fire is gone.
Do not touch it or move anything until it cools completely.
Once it is cool, it can be cleaned up safely.
This slow and careful way keeps the fire from starting again.
Specialised suppression agents
In some cases, industries use metal-specific agents, tailored to a certain element:
- Lithium fires: use copper-based dry powder
- Magnesium and sodium fires: Use sodium chloride powder
- Titanium fires: use graphite-based extinguishing agents
- These agents not only cool the burning metal but also prevent reignition
What is a Class D Fire Extinguisher?
Now that we have discussed everything about class D fires, let us understand everything about what class D fire extinguishers are in detail:
Features of a Class D extinguisher
- A class, the fire extinguisher is made only for combustible metal fires, like magnesium, titanium, and lithium, and not for other types
- It uses powder like sodium chloride, graphite, or copper to safely smother burning metals
- It has a gentle application nozzle that is designed to release the powder softly, so burning metal isn’t scattered
- The powder absorbs heat and forms a crust to cut off oxygen and cool the fire
Applications in Industrial Environments
|
Place |
Metal Type | Use of Class D Extinguisher |
| Metalworking factories | Magnesium, aluminium, titanium |
Used to stop fires during cutting or grinding metal. |
|
Aerospace and car plants |
Light metals and alloys | Helps control metal fires during welding or repair work. |
| Battery factories | Lithium |
Used when lithium catches fire in battery making or testing. |
|
Chemical labs |
Metal powders or alloys | Keeps lab workers safe from small metal fires. |
| Recycling centers | Metal scraps and dust |
Stops fires caused by sparks or heat during metal sorting. |
Limitations and Precautions
Not for other fires:
Class D extinguishers are only for metal fires. Don’t use them on wood, paper, or electrical fires.
Short range:
The powder works only when it touches the burning metal. It doesn’t spread far, so you have to be close.
Heavy to move:
Some Class D extinguishers are big and hard to carry fast during an emergency.
Needs training:
You should know how to aim and use it the right way. If you spray too hard, burning metal pieces can fly around.
Store it well:
Keep the extinguisher in a dry, clean spot near where you work with metal so you can grab it quickly.
Safety Tips for Preventing Class D Fires
Let us understand the safety precautions that one must follow while preventing class D fires in detail.
Proper storage of combustible metals
- Keep metals like titanium, magnesium, and aluminium in dry and cool places
- Store them in sealed containers to stop contact with air or moisture
- Avoid keeping them near oil, water, or any flammable material
- Put clear metal containers, so everyone knows what is inside
- Clean metal dust or straps often to prevent buildup and fire risk
Regular workplace safety training
- Train all staff on how to handle and store combustible metals safely
- Teach employees how to identify early signs of metal fires
- Conduct fire safety drills, so everyone knows how to handle emergencies
- Make sure everyone knows how to use a class D fire extinguisher
- Refresh training sessions regularly to keep everyone updated
Using non-sparking tools and equipment
- Always use tools that are made of non-sparking materials like brass or plastic.
- Avoid using steel tools that can cause sparks when hitting metal surfaces
- Keep the tool clean and well-maintained to reduce friction
- Use grounded equipment to prevent static electricity
- Replace our tools quickly to avoid any accidents or mishaps
Conclusion
Fires can be dangerous, but with the right attention, they can be prevented. Regular training, proper storage, and the use of safe tools. Make a big difference in dealing with class D fires. Always stay alert and follow safety rules to keep everyone in your workplace and the workplace safe.
FAQs
1. What materials are included in Class D fires?
These fires happen when metals like magnesium, titanium, sodium, or aluminium catch fire. They burn fast and get worse with water or air.
2. What fire extinguisher is used for Class D fires?
Use only a Class D extinguisher. It has a special powder that covers the fire and cools the metal.
3. Can water put out a Class D fire?
No, never. Water can make the fire blow up or spread.
4. Where are Class D fires most likely to occur?
They mostly happen in metal shops, factories, or labs where people work with metal pieces or dust.
5. What’s the difference between Class C and Class D fires?
Class C fires come from electric things. Class D fires come from burning metal. They need different extinguishers.
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