How to read fire extinguishers |

How to read fire extinguishers


No matter what kind of commercial or industrial space you have, you’ll need fire extinguishers on hand in case of a fire. However, understanding what kind of extinguisher you’ll need can be challenging for most and takes some research and advice from fire safety professionals who can identify the kinds of fires that occur in businesses like yours and what kind of chemical will do the best job of putting out that specific kind of fire.

That being said, there’s something to be said for gathering some information of your own on fire extinguishers so you can have a better idea of what classes of extinguisher are out there and generally speaking – what the use is for each kind of fire extinguisher.

Here is a quick post on how to read the numbers on a fire extinguisher so you can have an idea of what you’re looking at. Let’s jump right in!

Fire extinguisher classes

Letters on a fire extinguisher exist to help identify the classification of a fire extinguisher. Long story short – what kinds of fires that specific extinguisher will put out. Here’s the cheat sheet:

• Class A- puts our your run of the mill combustible fires like wood, paper, plastic and the like.

• Class-B is used to put out fires caused by combustible liquids like gas, oil, petroleum and any other kind of liquid that can grow and start a fire.

• Class-C is electrical fires. So anything near an outlet, fires caused by sparks, wires that are on fire, etc.

• Class-D extinguishers are used for combustible metals and are found in more industrial settings. These substances include magnesium, potassium and sodium)

• Class k extinguishers are basically kitchen extinguishers that can put out grease and oil fires.

A, B and C extinguishers are commonly found in homes, while D and K are more common in commercial and industrial settings.

Size ratings

So you’ll frequently come across extinguishers with labels that might look like 4A:20B:C or something that looks close to it. Long story, short – these numbers will tell you the size rating of the extinguishing agent inside the extinguisher. Here’s the quick breakdown:

• Class A size ratings tell you the water equivalency of the solution. Each number represents 1 ¼ gallons of water. So for example if you had 2A on the extinguisher – then the extinguisher will have the same effect as 2 ½ gallons of water. 4A would be the highest rating – which means it’d have the effectiveness of 5 gallons of water.

• Class B ratings simply tell you the square footage or area the spray will cover. So if we took our example; ‘20B’ would means if you blew the agent side to side you could cover an area of about 20 square feet.

• The last letter is basically what kind of fire (like we talked about above) the extinguisher puts out. So if it’s a Class C or a letter C at the end of that code – then it’s used to put out Class C fires.

If you need help in purchasing code-compliant extinguishers, give our team a call today and we’ll be happy to help! Hopefully though – this will help make it a little easier for you to identify what kind of extinguishers are at your disposal and perhaps even let you know what else you need to get. Good luck!

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