There are a ton of different types of fire extinguishers and they’re all tailored to fighting different classes of fires. What are the classes of fires, exactly? Well, a fire’s class has to do with what sort of fuel the fire is burning to keep going. Some classes of fire are much easier to put out than others, whereas some require very specialized tools to take care of.
The Classes of Fire
- Class A – These are fires burning solid materials such as wood, paper or cloth.
- Class B – These are fires burning flammable liquids or gasses.
- Class C – These are fires from live electrical equipment.
- Class D – These are fires burning flammable metals such as potassium or magnesium.
- Class K – These are fires burning cooking oils like those used in fryers.
Types of Extinguishers
The most cost-effective way to fight Class A fires is to use a water based extinguisher. These come in four different types: water jet, water with additives, water spray, and water fog. Water jets work by spraying a jet of water at the burning materials to drown the fire and prevent another ignition. Water extinguishers with additives have special foaming chemicals added. They make the water lose its surface tension so that it can seep into the fire’s fuel more effectively. Water spray extinguishers use a very fine spray of water droplets. Water fog extinguishers use water in the form of mist, or fog. The droplets here are much smaller than those from other water-based extinguishers
Foam based extinguishers can be used to quelch both Class A and B fires. They are more versatile than water jet extinguishers because they can put out liquid-based fires but can also be used on solids such as wood and paper. The foam extinguishes liquid fires by suffocating the surface of the fuel, preventing flammable vapors from reaching the air and starving the fire.
Powder-based extinguishers are a solid multi-purpose extinguisher because they can be used on Class A and some Class B fires. Unfortunately, they do not cool the fire, so it can re-ignite if you’re not careful. They can also create a loss of visibility and impact oxygen levels. They are not typically used inside unless there is no alternative option.
Carbon Dioxide based extinguishers are ideal for places with a lot of electrical equipment such as offices or server rooms because they are safe to use on Class C electrical fires. Carbon dioxide extinguishers do not leave any residue, unlike a foam extinguisher. They can also be used on some Class B fires. CO2 extinguishers work by smothering the fire and cutting off the supply of flammable oxygen.
Wet chemical extinguishers are suitable for use on Class K fires involving cooking oils. They are extremely effective when used correctly. The chemical cools the burning oil and reacts to form a slippery soap-like solution, cutting off the surface and preventing another ignition. They’re mainly designed for Class K fires, but they can also be used on Class A and B fires.
Class D fires are tricky because different metals require different kinds of extinguishers. Some class D extinguishers handle a large number of common metal fires, whereas others are made specifically for the kind of metal you’re dealing with. Most of these extinguishers operate by using certain chemicals that neutralize the flammability and volatility of the burning metal through chemical reactions.
Do you know the right type of fire extinguisher for the types of fires your building is as risk for? Don’t worry! The fire protection specialists at A Total Solution, Inc. are here to help! Contact us today for your FREE estimate!