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5 Classes of Fire

Do You Know The Class of Fire That’s Damaging Your Commercial Building?

Knowing what materials are more likely to cause fires is the first defense against potential fire damage in a commercial property. Whether you’re in the construction phase or looking at a building that’s been finished for some time, it’s always a good idea to review the property for any signs of potential fire hazards.

First, it’s important to distinguish between the different types of fires to get an idea of how fires start and what ignites them.

What are the Different Classes of Fire?

There are five (or six) different classes of fires depending on where you live. These classifications group flammable materials by physical characteristics and by similarities in combustion. 

This is an important distinction; you never want to treat an electrical fire the same way you’d treat a gas fire. Knowing the different classes of fires and how to prevent/put out each will enable you and your tenants to make smarter decisions when it comes to your commercial properties.

  • Class A
  • Class B
  • Class C
  • Class D
  • Class K

Class A Fires

Class A fires are your typical fire starters, think: generally flammable materials such as paper, wood, clothing and furniture fabrics, most trash, etc.

The best way to extinguish Class A fires is by dousing the ignited material with water, smothering with wet, non-gasoline material, or by using a dry chemical powder.

Class B Fires

Class B fires are fires that are caused by flammable liquids and combustible liquids, including combustible gasses in the US classification system. 

You should never fight Class B fires with water, as this will likely only aggravate the flames to possibly spread and cause more damage. Instead, knowing how to use a Halon fire extinguisher will be your best bet to quickly extinguishing Class B fires. 

Commercial building owners should have Halon fire extinguishers in every tenable unit, every floor’s egress, and every floor’s emergency exits. This ensures access to an appropriate fire fighting agent within reach in most areas of the building.

Class C Fires

Electrical fires are classified as Class C in the US classification system. These types of fires are at an elevated risk of causing electrical shock if faulty wiring is exposed to water during the fire. Most electrical fires are caused by shorted circuits, faulty wiring, or when an electrified circuit is exposed to an element like water.

Electrical fires need to be fought with a chemical compound-type firefighting agent, like Halon or Carbon Dioxide. Class C fires can be prevented by inspecting your commercial property’s wiring and ground power supply. Ensure all power is grounded and wired correctly and to code.

Class D Fires

Class D fires are caused by combustible metals. Remember how airport gate agents ask passengers if they have any lithium batteries in their checked bags before they check them under the plane? This is because lithium, a type of metal, is prone to combustion under extreme pressure and high temperatures and if often found in laptop battery packs. 

In air travel, this is one of the highest safety risks posed, but it is also worth considering in your commercial building. Review any structures of the building that contain a high amount of combustible metals to see if Class D fires pose a risk to your property.

Class K Fires

Class K (or Class F in the EU/AU), are also known as kitchen fires/grease fires. These fires are technically a subclass to Class B fires, but they take their own category due to the much higher flashpoint than Class B flammable liquids and gasses. 

Kitchen fires are most likely going to be caused by user error from a tenant or visitor mishandling kitchen equipment and foods on your property. Tenants should always be reminded to never use water on a grease fire, as that will likely only make the flames worse. 

Ensure Halon fire extinguishers are available in each unit of your commercial building to stop any fire damage from becoming worse.

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Closing: Classes of Fires

Fire damage and the threat of fire is nothing to scoff at, and can easily cost you thousands of dollars in damage. By understanding what materials are more likely to ignite into a fire and how to fight those fires, you can make better decisions about protective measures to take towards your commercial building.

U&S Companies provides residential and commercial fire restoration in Michigan, providing emergency 24/7 service. Request a quote today.

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