The ability to understand what the UL ratings are and what they mean for the fire extinguisher you are using is just as important as knowing how to use the fire extinguisher.

1. FIRE EXTINGUISHER
UL RATING:
WHAT IT MEANS
OnlineSafetyDepot.com

2. UL Ratings Apply to both Portable and
Wheeled Fire Extinguishers
Portable Fire Extinguisher Wheeled Fire Extinguisher

3. Universal UL Rating Symbol

4. What does UL Stand for?
■ UL stands for Underwriters Laboratories,
■ Underwriters Laboratories is a nonprofit organization dedicated to public safety.
■ Underwriters Laboratories (UL) performs product testing for evaluation of safety
risk and performance values on a vast variety of products.
■ Additionally, UL offers third-party certification when certain standards are met.
■ A UL listing on a product means that the product has been tested and determined
that it meets UL’s requirements which are based on nationally recognized safety
standards.

5. ANSI/UL 771: Rating and Fire Testing
of Fire Extinguishers
■ The ratings are described using numbers preceding the class (Class of fire) letter.
■ Fire extinguishers are labeled to identify the classes/types of fire (Class A, B, C, D,
or K) on which the extinguisher will be effective and the relative fire extinguishing
effectiveness or capacity.
■ The UL rating is commonly broken down into Class A and Class B:C ratings. For
example, if an extinguisher’s label has the following rating 6A:30B:C. it provides
the following information:

6. Classes of Fires - A Quick Review
Class of Fire Fuel source for the Fire
Class A: Wood, paper, cloth, plastics, trash
Class B: Flammable liquids – gasoline, grease, oil, acetone, and flammable gases
Class C: Electrical fires, energized electrical equipment fires
Class D: Metal fires involving magnesium, sodium, potassium and sodium-potassium
alloys
Class K: Cooking oil fires

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9. UL Rating Explained-
■ If an extinguisher’s label has the following rating 6A:30B:C. it provides the following
information:
■ A = Class A fire and the amount of chemicals/agent in the extinguisher equivalent to
the amount of water the extinguisher holds equal to 1.25 gallons of water. The number
4 that precedes the class fire letter A is the number of equivalents. Therefore, the 6A
equates to 7.5 gallons of water extinguishing capability (6 x 1.25 = 7.5).
■ B = the amount of square footage that the extinguisher can cover or able to extinguish.
The number 30 that precedes the letters B:C is the number of equivalents. Therefore, a
30B equates to being able to extinguish 30 square feet of a Class B fire.
■ C = means agent is non-conductive and could also be used on a Class C fire.

10. Additional Reading Sources
■ What Kind of Extinguisher Do I Need?
■ The Importance of Fire Extinguisher Tamper Seals
■ Understanding Portable Fire Extinguishers- Use and Limitations
■ Specifications For Wheeled Fire Extinguishers
■ Fire Extinguisher UL Ratings: What It Means
■ Fire Safety – Prevention, Early Warning & Emergency Plan Execution
■ How To Operate A Fire Extinguisher
■ Offshore Fire Extinguisher Placement & Protection