What Is a Class D Fire Extinguisher?

inspecting fire extinguisher

As you may already know, different types of fires need to be extinguished in different ways. This is why firefighters and fire experts use a classification system to identify different fires so that they can be put out more effectively.

The classification system used to differentiate fires is determined by the fire’s primary fuel source. Each type of fire then corresponds to a specific type of extinguishing agent. This is where different types of fire extinguishers, like the Class D fire extinguisher, come into play.

If you run a business or manage an industrial facility, you should familiarize yourself with the different types of fire extinguishers, as this knowledge could save lives and untold amounts of property damage. We have provided this straightforward guide to Class D fire extinguishers.

We will explain what they are, how they work, and what types of locations require them. From there, we will even provide a brief overview of the other types of fire extinguishers and other tools you can use to protect your business from fire damage.

What Is a Class D Fire?

A Class D fire is a type of fire that involves combustible metals, such as magnesium, titanium, sodium, and others. Unfortunately, fires that are fueled by combustible metals are challenging to put out.

Types of Metals that Can Fuel Type D Fires

While most metals are not combustible or flammable, the following can all fuel Class D fires:

  • Magnesium
  • Sodium
  • Potassium
  • Sodium-potassium alloys
  • Zirconium
  • Lithium
  • Titanium

Certain types of plastics contain small fragments of combustible metals, so fires fueled by these plastics are also considered Class D fires.

d class extinguisher caution

What Is a Class D Fire Extinguisher?

As you may suspect, Class D fire extinguishers are designed to put out Class D fires. Class D fire extinguishers are the only safe option for putting out Class D fires, as other types of fire extinguishers can be completely ineffective.

Certain fire extinguishers can do more damage than good if used on a Class D fire, as the extinguishing agents within them can react with a combustible metal fire. Not only can this add to the severity of the fire by spreading the flames, but it can also further reduce air quality for those attempting to put the fire out.

Water can also react to flammable and combustible metals in a negative way. Simply spraying a Class D fire with water could increase the heat generated by the fire and spread molten metal to other areas.

Since Class D fires are notoriously difficult to extinguish, facilities with abundant combustible metals should have numerous Class D fire extinguishers distributed in easy-to-reach locations.

How Do Class D Fire Extinguishers Work?

Class D fire extinguishers work the same way as other types of fire extinguishers, but they use unique extinguishing agents. Like any type of fire extinguisher, a Class D fire extinguisher puts out a fire by smothering the flames and preventing oxygen from fueling the fire.

The extinguishing agent in Class D fire extinguishers also helps to absorb some of the heat from the metal fire, which can quickly reduce the intensity of the fire.

Class D fire extinguishers achieve this by using a unique type of dry powder, a blend of powdered graphite, granular sodium chloride, and fragments of copper. When sprayed on top of a Class D fire, these powder extinguishers form a barrier between the ignited metal and the oxygen surrounding it. This can put the fire out almost immediately.

Where Are Class D Fire Extinguishers Required?

Since Class D fires can only be safely extinguished with a Class D fire extinguisher, they are required in any facility that houses or works with the combustible metals and plastics highlighted above.

Therefore, these dry powder Class D extinguishers should be in various industrial facilities, manufacturing factories, laboratories, and warehouses. There is an even higher risk of a Class D fire breaking out if the metals mentioned above are cut and shaved in a facility, as the smaller pieces and metal dusts are much easier to ignite.

Not only can these unique types of fires cause significant damage to a structure and everything stored within it, but they can also pose a serious risk of injury and death.

This is especially true if those within the facility need access to working Class D powder fire extinguishers. All personnel spending a significant amount of time around these materials should also have proper training on using a Class D powder fire extinguisher.

For a basic understanding of how to operate a fire extinguisher, we recommend reading How to Use a Fire Extinguisher Properly.

What Are Other Types of Fires and Fire Extinguishers?

fire extinguisher types

Including Class D fires, there are five main categories of fires and fire extinguishers. If you are unsure which of the following you need, we recommend reading Different Fire Extinguisher Types & Which One You Need.

Class A Fires

These fires involve ordinary combustible materials, like wood and paper. They can be put out with a basic Class A fire extinguisher or foam fire extinguisher.

Class B Fires

Class B fires are fueled by flammable liquids, such as gasoline, oil-based paints, alcohol, and even some types of flammable gas. Some Class B fire extinguishers are foam fire extinguishers, but most use a dry powder, like ammonium phosphate.

Class C Fires

These fires involve energized electrical equipment, so they are very tricky. Since water and most other types of liquid will only make an electrical fire worse, Class C fire extinguishers use a non-conductive extinguishing agent that smothers the fire without increasing the chances of electrical shock for the user.

Class K Fires

Class K fires are those involving cooking oils and fats, usually within a cooking appliance. Class K extinguishers are typically found in large-scale kitchens. They use a soapy foam that smothers the fire and helps to cool the appliance.

Other Classes to Know

In Australia and Europe, there are some minor differences in fire classes. In Europe, electrical fires are Class K; in Australia, electrical fires are Class E. In the UK, a fire involving cooking oils and fats is a Class F fire.

Other Important Fire Safety Tools

Fire sprinkler systems are also critical for fire safety, as they can automatically detect a fire and smother it before it has a chance to create too much damage.

If you want to know more about these systems, we recommend reading Different Types of Fire Sprinkler Heads.

While we are on the topic of fire sprinkler systems, we also recommend taking a look at the Shutgun. This affordable and straightforward tool can allow users to deactivate a misfiring sprinkler head quickly so it does not have the opportunity to cause significant water damage. Given that fire sprinklers cause an average of $35,000 in water damage, the Shutgun is a wise investment.

To learn more about the Shutgun and place an order for your own, we recommend visiting the Shutgun information page.

Like this post? Share it!