Understand extinguisher ratings
If your truck ever catches fire, you want to make sure you’re ready to act. Hesitation can lead to property loss, injury, or even death. Understanding how fire extinguishers are rated can help you ensure you have the right extinguisher available in case you ever need it.
An extinguisher rating includes a letter and a number, or a combination of letters and numbers, such as 1A:10B:C.
The letter tells you what class of fire the extinguisher can be used on:
- Class A extinguishers are for use on everyday items like wood or paper.
- Class B extinguishers are for use on flammable liquids such as oil, paint, or gasoline.
- Class C extinguishers are for use on electrical fires.
The number means different things based on the class:
- For a Class A extinguisher, the number shows how many water-equivalent units it holds. A unit is 1.25 gallons, so a 4A holds the equivalent of 5 gallons (4 units x 1.25 gallons per unit = 5 gallons).
- For a Class B extinguisher, the number tells you the size of the fire in square feet that the extinguisher can put out. For example, a 5B extinguisher will cover approximately 5 square feet.
- A Class C extinguisher does not have a number. Once the electrical source is no longer energized, the fire is treated according to the fuel source, e.g., oil, wood, etc.
Some extinguishers can be used on Class A, B, or C fires. An extinguisher with a rating of 1A:10B:C holds the equivalent of 1.25 gallons of water and can extinguish 10 square feet of flammable liquid. It is safe to use on ordinary wood or paper fires, flammable liquids, and electrical fires.