What is the Meaning of the Ratings for Fire Extinguishers?

When it’s time to purchase fire extinguishers for your business, you may be confused by the different letters and numbers on the label. To ensure you buy the right type and size for the application you have in mind, learn more about fire extinguisher classes and size ratings.

Before you can understand the ratings of fire extinguishers, you’ll first need to understand the different classifications of fire.

Fire Extinguisher Classes

  • Class A – Combustible materials
  • Class B – Flammable liquids
  • Class C – Flammable gases
  • Class D – Burning metals
  • Class E – Electrical fires
  • Class F – Cooking oils and fats

Since Class A, B, and C fires are all found in conventional homes and businesses, ABC fire extinguishers are designed to put out all three types of fires.

Fire Extinguisher Ratings

A fire extinguisher’s rating consists of 2 parts: a number and a letter.

The letter part of the rating denotes what class of blaze this fire extinguisher is suitable for.

The number part of the rating simply describes the size of the fire that the fire extinguisher can extinguish. The larger the number before the fire type letter, the larger the fire that extinguisher can tackle.

Each fire class rating is measured differently. Class A fire ratings are calculated by how many stacks of burning material the extinguisher can put out and Class B ratings are established by the number of litres of flammable liquid that can be extinguished. There is no size rating for Class C and Class D.

Why are Fire Extinguisher Ratings Important?

These ratings help us to establish whether the given risk is properly accounted for during Fire Risk Assessments and gives us the ability to estimate the type and number of fire extinguishers required when hiring them for events.

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