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Figuring Out the Numbers and Letters on Your Fire Extinguisher

There is a sense of safety in having a fire extinguisher in your commercial building.  On the other hand, few things are more confusing than the numbers and letters on the side of the tube. What do they mean? Why are they important? You know some extinguishers put out certain types of fires but not others. The last thing you want to do in case of an emergency is to use the wrong device.

Why It Is Important to Know the Distinctions

Rather than using a professional fire service and supply company—which is a wise, safe way to proceed—business and property owners sometimes purchase extinguishers off the shelf. This means they are potentially utilizing extinguishers that are improper for the materials in their buildings. For instance, any warehouse that stores paper goods should have type A extinguishers on hand at a minimum. Another issue is having the proper size and quantity of extinguishers. You should also be familiar with how likely the materials in your building are to ignite.

Deciphering Those Letters and Numbers

Here is a basic guide to understanding the code on the side of your extinguishers. First, the numerical part of the inscription is giving you the equivalence of the fire retardant compared to gallons of water. So if the code reads “2A,” it is telling you that what is contained in the tube is equivalent to two gallons of water. As for the letters:

  • A is for ordinary fires (paper, wood, plastics)
  • B is for flammable liquids
  • C is for electrical fires
  • D is for flammable metals
  • K is for cooking fires started by oil or grease

You can take the guesswork out of trying to choose the right extinguishers. We provide DC/Baltimore commercial buildings with the necessary schedule for having them checked regularly.  Contact us at Castle Sprinkler & Alarm, (301) 927-7300.