What is a Class B Fire Extinguisher Used For?

Since not all flames are created equal, nor are all fire extinguishers. Using a suitable fire extinguisher during a fire can affect life and property. This is particularly true for Class B fires, which include flammable liquids and more typical combustible materials (such as wood, paper, etc.).

Liquids that are flammable and combustible, like gasoline, alcohol, oil-based paints, and lacquers, are involved in class B fires. Therefore, extinguishers with a B grade are made to put out flames involving flammable and combustible liquids.

What Are Class B Fires?

As previously mentioned, Class B fires involve flammable liquids and gasses. In the fire triangle (fuel, heat, oxygen, and chemical reaction), they serve as the fuel source.

Examples of flammable liquids are gasoline, diesel fuel, oils, tars, petroleum oils, solvents, alcohols, and oil-based paints. Gasses that can catch fire include butane, hydrogen, and propane.

Water cannot put out the fuel sources of class B fires (gasses and liquids), which can be highly volatile. Instead, water will just spread the fuel source, which will spread the fire. Because of this, it’s crucial only to employ extinguishing substances and techniques meant to put out Class B flames.

What Types of Extinguishers are Rated as Class B Fire Extinguishers?

The best technique to put out a Class B fire is to cut off the fuel’s oxygen supply or stop the fire triangle’s chemical reaction because of the fuel’s unique properties.

Different types of fire extinguishers are available that are specifically made to do this job on Class B fires:

CO2: When used on a Class B fire, a carbon dioxide fire extinguisher suffocates the fire by releasing CO2, which deprives it of the oxygen it needs to continue burning. Due to the discharge’s extreme coldness, it also aids in heat removal.

However, keep in mind that this extinguisher is only efficient at a very short distance from the fire—between 3 and 8 feet—due to how quickly the CO2 gas scatters.

Foam: These extinguishers are effective against Class A and B flames. In Class B fires, the foaming agent operates by sealing off the surface of the flammable liquid to separate the fuel and oxygen. These extinguishers, however, only work when the flammable liquid is not flowing freely.

Dry Chemical: Dry chemical extinguishers, whether standard or multipurpose types are categorized for class B fires because their agent puts out a fire by stopping the fire triangle’s chemical reaction. Because they use a pressurized, non-flammable gas to propel the dry extinguishing chemical further, these extinguishers have a greater range.
Clean Agent: Clean agent extinguishers put out Class B and C fires, as well as occasionally Class A flames, by using an extinguishing agent that stops the chemical reaction of a fire and removes heat (depending on the size of the extinguisher).

They are known as “clean” agents because they contain halogen and halocarbon substances, which are less harmful to humans and the environment and don’t need to be cleaned up as thoroughly after usage.

Most of the extinguishers listed above can be used on fires other than Class B ones, but it’s always a good idea to read the label on any extinguisher you use.

Furthermore, while certain Class B extinguisher types spread better than others and differ in other ways, they might still need to be more efficient for the particular sort of Class B fire that poses the most risk to your home or place of employment.

What Are Combustible Gasses and Liquids?

Combustible refers to a substance that burns or ignites easily; incombustible or non-combustible refers to a substance that does not burn. The fuel that determines the class B designation is comprised of the following liquids and gasses:

Gasoline and diesel
Ethanol and methanol

Acetylene
Methane
Butane

Isopropanol
Acetone
Propane

Class B flames have the same fundamental components as their class A counterparts; specifically, fuel, oxygen, heat, and a sustained chemical reaction collectively referred to as the “fire tetrahedron” are required for a fire to burn.

Suppose the fuel source is removed, as in the case of a BBQ grill, this type of fire can be confined and frequently goes out fast. The flames can, however, ignite quickly after the last portion of the tetrahedron is introduced when most elements are present but inactive.

Preventing a Class B Fire

It pays to take precautions to stop a class B fire from starting because it can be pretty dangerous.

Never store more flammable liquid than is necessary, and keep it far from ignition sources.

Consider keeping liquid in steel cabinets constructed specifically for flammable storage. Then, for around 30 minutes, they act as a barrier between a possible fire outside and the combustible liquid inside.

So keep in mind to avoid using water and to keep suitable fire extinguishers nearby just in case.

FAQs

Can you use water on a Class B fire?

Water does not put out Class B fires and makes them worse by spreading the flammable substance. Only use powder, foam, or carbon dioxide extinguishers on these fires to snuff out the oxygen source.

How do you recognize a Class B fire?

What causes a Class B fire?

What is the extinguishing material used for class ABC?

Monoammonium phosphate, a dry chemical, is used in ABC Fire Extinguishers to quickly put out various fires by covering the flames. All three types of fire can be extinguished using this light yellow powder: Paper, wood, and rubbish are all in Class A. Gasses, and liquids fall under class B.

What is the most effective approach to stop a Class B fire?

Never refuel gasoline-powered machinery while it is still warm. Keep flammable substances in tightly sealed, spill-proof containers that close on their own. Pour only the amount you’ll need from the storage drums. Keep flammable substances away from anything that could spark.