Fire extinguishers are important tools to have on hand in case of a fire, and can be especially helpful for snuffing out smaller flames before they spread. They’re also an essential part of your safety plan to ensure everyone has a clear path out of the building if it does become engulfed.
While fire extinguishers are useful, it’s important to understand their limitations. They should only be used on small, contained fires in their early stages. If they’re not enough to put out the fire or if it is spreading quickly, evacuate and call emergency services.
There are several types of fire extinguishers, and each one has its own unique properties. Knowing what each one is rated for can help you decide which ones to have in your workplace and which one is the best fit for your needs.
Dry chemical fire extinguishers are the most common type, and can be used on a variety of classes of fire. They consist of a mix of chemicals that creates a vaporized barrier over the fire, stopping oxygen flow and thus extinguishing the fire. They’re often used on electrical or paper fires, but can also be effective on Class A, Class B and Class C fires.
Water-based fire extinguishers are typically made of metal with a steel cylinder that holds up to 9 liters (2+1/2 US gal) of liquid. They work by cooling the burning materials, which stops the fire’s chemical reaction and halts its growth. They’re effective on class A and class B fires and can be used on some class D fires as well.
Sodium bicarbonate fire extinguishers (also known as baking soda) are effective on flammable liquids and gasses like gasoline, oil, grease and paint. They’re commonly used in offices, restaurants and auto body shops, and are safe to use on class A and class B fires. They can also be used on class C fires as they don’t leave a residue.
Foam fire extinguishers are blue or red in color and can be applied as aspirated or nonaspirated foam. When sprayed on a fire, it creates a frothy blanket or seal over the fuel that stops oxygen from reaching the flames, extinguishing the fire and helping to prevent flashback. Foam can be used on class A, class B and class C fires.
Halon fire extinguishers are a popular choice in the past, but have been banned from new production under the Montreal Protocol due to their ozone depletion and long atmospheric lifetime. However, they’re still being used to refill some newer fire extinguishers as well as older ones.
The most effective way to keep fire extinguishers in working order is to perform regular inspections. These should be done by a qualified fire protection service to make sure the extinguisher is in its designated location, the pressure gauge is within the acceptable range and the pin and handle are intact.