UL 711: Rating and Fire Testing
Performance testing and rating standards for UL Listed fire extinguishers
Last updated: March 14, 2026
Contents
Overview
UL 711 establishes the rating and fire testing requirements for portable fire extinguishers. This standard determines the fire-extinguishing potential of extinguishers through standardized fire tests, providing the basis for the familiar rating classifications (like 2-A:10-B:C) seen on UL Listed extinguishers.
Terminology Note: Technical specifications and building codes may reference "ANSI/UL 711" (the formal designation with ANSI approval), while fire extinguisher labels show "UL Listed" with the rating (e.g., "2-A:10-B:C"). Both refer to the same standard - the ANSI prefix simply confirms national recognition.
The current edition (Edition 8) was published August 6, 2018, and works in conjunction with NFPA 10 for installation requirements.
Fire Classifications
UL 711 covers testing for all major fire classifications:
Class A
Ordinary combustibles
Class B
Flammable liquids
Class C
Electrical equipment
Class D
Combustible metals
Class K
Cooking oils & fats
Each class requires specific test fires and performance criteria to achieve certification. Most commercial and industrial extinguishers carry an ABC combined rating — the numbers before each letter indicate relative extinguishing capacity.
Rating System
The UL 711 rating system uses numbers and letters to indicate extinguishing capability. Class A and B ratings are numerical — higher numbers mean greater capacity. Class C, D, and K ratings are pass/fail with no numerical scale.
| Class | Rating Format | What the Number Means | Example |
|---|---|---|---|
| A | 1-A to 40-A | Relative extinguishing potential (2-A = 2x capacity of 1-A) | 3-A |
| B | 1-B to 640-B | Square feet of flammable liquid fire | 40-B |
| C | Pass/fail | Safe for energized electrical equipment (no numerical scale) | C |
| D | Metal-specific | Tested on specific combustible metals (no numerical scale) | D |
| K | Pass/fail | Commercial cooking oil and fat fires | K |
Example: A 3-A:40-B:C rated extinguisher can handle Class A fires three times larger than 1-A, Class B fires up to 40 square feet, and is safe for electrical fires. This is the typical rating for a 5 lb ABC dry chemical unit.
Testing Procedures
UL 711 testing simulates real fire scenarios to verify extinguisher performance. Each test type targets a specific aspect of fire suppression capability.
| Test | Description |
|---|---|
| Class A | Wood crib and excelsior fires of varying sizes |
| Class B | Flammable liquid pan fires with specified areas |
| Discharge | Complete discharge time and throw range measurements |
| Operator safety | Heat exposure and visibility during use |
| Re-ignition | Monitoring for fire rekindling after extinguishment |
| Conductivity | Electrical conductivity limits for Class C qualification |
| Consistency | Tests repeated by multiple operators to verify reproducibility |
Performance Requirements
To earn a UL 711 rating, an extinguisher must successfully extinguish test fires within specified parameters and demonstrate consistent results across multiple tests conducted by different operators. Most portable units must maintain a minimum discharge duration of 8 seconds and achieve sufficient throw distance to keep the operator at a safe distance from the fire.
After extinguishment, the fire is monitored for re-ignition — the unit fails if the fire rekindles within the observation period. For Class C qualification, electrical conductivity must measure less than 1.00 milliampere. Supplemental tests cover special hazards such as deep-seated Class A fires.
The standard also includes UL 711A provisions for residential extinguishers, with specific requirements for cooking equipment fires.
Frequently Asked Questions
What is the difference between UL 299 and UL 711?
UL 299 covers construction and performance requirements — how the extinguisher is built, its materials, and mechanical testing. UL 711 covers fire testing and rating — how the extinguisher performs against actual test fires. An extinguisher must pass both standards to earn the "UL Listed" mark.
What do the numbers in a fire extinguisher rating mean?
The numbers indicate extinguishing capacity. For Class A, the number is a relative multiplier (2-A handles twice the fire of 1-A). For Class B, the number is the square feet of flammable liquid fire the unit can extinguish. Class C, D, and K ratings are pass/fail with no numerical scale.
Does my fire extinguisher need to be UL Listed?
Yes, in most cases. NFPA 10 requires portable fire extinguishers to be listed and labeled by a nationally recognized testing laboratory. UL is the most common listing organization in the United States. DOT also requires UL-listed extinguishers on commercial motor vehicles under 49 CFR §393.95.
How often is UL 711 updated?
UL standards are updated as needed rather than on a fixed cycle. The current edition (Edition 8) was published August 6, 2018. Updates typically address new agent types, testing methodology improvements, or alignment with international standards.
What is a Class K fire extinguisher rating?
Class K is a pass/fail rating for extinguishers designed to suppress fires in commercial cooking equipment — deep fryers, griddles, and other appliances that use cooking oils and fats. Class K extinguishers typically use wet chemical agents and are required in commercial kitchens alongside hood suppression systems.
UL 711 Rated Fire Extinguishers (5)
Buckeye ABC Dry Chemical Fire Extinguisher w/ Vehicle Bracket – 2.5 lb.
$48.00
Buckeye ABC Dry Chemical Fire Extinguisher w/ Wall Hook – 10 lb.
$84.00
Buckeye ABC Dry Chemical Fire Extinguisher w/ Wall Hook – 20 lb.
$155.00
Buckeye ABC Dry Chemical Fire Extinguisher w/ Wall Hook – 5 lb.
$55.00
Buckeye ABC Dry Chemical Fire Extinguisher w/ Vehicle Bracket – 5 lb.
$58.00