A fuel storage site concentrates its fire risk at a few predictable points: the dispenser nozzle, the tank fill pipe, the loading rack and the delivery truck. Codes treat each one differently. The International Fire Code sets a minimum at every pump, NFPA 10 sets the rating and spacing for areas where flammable liquid can pool or spray, NFPA 30 covers indoor storage rooms, and the federal motor carrier rules cover the trucks. This guide sets out what each requires and compares the agents and unit sizes used at bulk plants, tank farms and fleet fueling sites.
The standards that apply
| Standard | Covers | Key extinguisher provisions |
|---|---|---|
| International Fire Code, motor fuel-dispensing | Retail and fleet fueling | At least 2-A:20-B:C within 75 ft of pumps, dispensers and tank fill-pipe openings |
| NFPA 10 | Portable extinguishers in all occupancies | Class B rating and travel distance by hazard level; high-flow units for pressurized and three-dimensional fires |
| NFPA 30 | Flammable and combustible liquids | At least 40-B outside an indoor liquid storage room, within 10 ft of the door |
| State bulk plant rules | Loading racks and tanks | Example: Pennsylvania requires at least two 20-B:C units within 75 ft of each loading rack |
| 49 CFR 393.95 | Trucks and tractors | 10-B:C or more on any power unit carrying placarded hazardous materials |
Most states and cities adopt the International Fire Code, sometimes with local amendments, and section numbers change between editions. The requirement itself, a 2-A:20-B:C unit within 75 feet of each dispenser, has been stable.
How NFPA 10 sizes Class B protection
NFPA 10 classifies an area by the amount of flammable liquid that could be involved in a fire, then sets a minimum rating tied to how far a person must walk to reach an extinguisher.
| Hazard level | Flammable liquid present | Minimum rating and maximum travel distance |
|---|---|---|
| Light | Up to 1 gallon | 5-B within 30 ft, or 10-B within 50 ft |
| Ordinary | 1 to 5 gallons | 10-B within 30 ft, or 20-B within 50 ft |
| Extra | 5 gallons or more | 40-B within 30 ft, or 80-B within 50 ft |
Tank farms, loading racks and bulk plants fall in the extra hazard row. Travel distance is measured along the path a person actually walks, around tanks, piping and vehicles, not as a straight line.
The B rating describes a still pool of fuel, which is how listing laboratories test. NFPA 10 recognizes that fuel spraying from a ruptured hose, running down a tank wall, or burning around obstacles behaves differently. For pressurized liquid and gas fires, three-dimensional fires and obstacle fires, it requires dry chemical extinguishers of at least 10 lb with a discharge rate of at least one pound per second. These are sold as high-flow extinguishers.
Requirements by area
| Area | Governing rule | What to install |
|---|---|---|
| Pump islands and dispensers | IFC | 2-A:20-B:C within 75 ft of every pump, dispenser and fill pipe |
| Tank rows and bulk storage | NFPA 10 extra hazard | 40-B within 30 ft or 80-B within 50 ft; wheeled units for large areas |
| Loading racks | State rules, NFPA 10 | Example minimum: two 20-B:C within 75 ft (Pennsylvania); high-flow or wheeled units for spray fires |
| Indoor liquid storage room | NFPA 30 | 40-B outside, within 10 ft of the door |
| Fuel delivery trucks | 49 CFR 393.95 | 10-B:C or more, securely mounted and within easy reach |
Pennsylvania's rule also allows the fire marshal to require more protection where a single tank holds over 50,000 gallons of Class I liquid. Other states have comparable provisions, so the local rule should always be checked.
Comparing agents
| Agent | Classes | Fit at fuel sites | Limitation |
|---|---|---|---|
| ABC (monoammonium phosphate) | A, B, C | The only common dry chemical that meets the IFC's 2-A requirement at pumps; covers buildings and vehicles too | Lower B performance per pound than Purple K |
| Purple K (potassium bicarbonate) | B, C | More than twice as effective as sodium bicarbonate on flammable liquid fires; first choice at tanks and racks | No A rating, so it cannot satisfy the pump rule alone |
| Regular BC (sodium bicarbonate) | B, C | Lower cost B:C protection | Less effective on fuel than Purple K |
| Carbon dioxide | B, C | No residue, for electrical rooms | Short range, poor outdoors in wind |
Because ABC and Purple K powders react with each other, a unit must only ever be recharged with the agent it was built for.
Comparing unit sizes
| Unit | Agent | UL rating | Hose |
|---|---|---|---|
| Badger 50 lb wheeled | ABC | 20-A:160-B:C | 25 ft |
| Badger 125 lb wheeled | ABC | 40-A:240-B:C | 50 ft |
| Buckeye K-50-SP, 50 lb wheeled | Purple K | 160-B:C | 25 ft |
| Badger 125 lb wheeled | Purple K | 240-B:C | 50 ft |
A single wheeled unit rated 160-B:C exceeds the extra hazard minimum of 80-B, and its hose lets one operator work a tank or rack fire from a distance. For pressurized and running fuel, a hand-portable high-flow unit is the faster tool; Badger's Extra High-Flow models are rated by the manufacturer to exceed the one-pound-per-second minimum. Our fuel storage fire extinguishers category groups wheeled, high-flow and pump-island units in one place, and the wheeled fire extinguishers page compares all wheeled models.
Delivery and service vehicles
Federal motor carrier rules require every truck and tractor to carry an extinguisher with a UL rating marked on it, a visual indicator showing whether it is charged, and a mount that keeps it from sliding or rolling. A truck carrying placarded quantities of hazardous materials, which includes fuel tank wagons, needs 10-B:C or more. Other power units need 5-B:C, or two units of 4-B:C each. A 5 lb Purple K unit with a vehicle bracket is a common choice for fuel and lube trucks.
Inspection and service
OSHA requires a monthly visual inspection and an annual maintenance check, with records kept. NFPA 10 adds a six-year internal examination and a 12-year hydrostatic test for stored-pressure dry chemical units. Outdoor units at fuel sites see more weather and grime than indoor ones, so a weather cover pays for itself on wheeled units.
Common mistakes
- Putting a Purple K unit at the pump island. Purple K is the better fuel agent, but the IFC's 2-A:20-B:C rule needs an A rating, so the pump unit should be ABC.
- Measuring distance as a straight line. Travel distance follows the walking path around tanks and vehicles.
- Relying on standard units at a loading rack. A spraying, running fire calls for high-flow or wheeled units.
References
- International Fire Code, motor fuel-dispensing facilities (2015 edition section 2305.5, as adopted in the Seattle Fire Code).
- NFPA 10, Standard for Portable Fire Extinguishers, sections 5.4 and 5.5.4, as summarized in Amerex Corporation Tech Tip 47.
- NFPA 30, Flammable and Combustible Liquids Code, section 9.10.2.2, as cited in Amerex Tech Tip 47.
- 34 Pa. Code § 14a.108, bulk plants.
- 49 CFR 393.95, emergency equipment on power units.
- Buckeye Fire Equipment, Model K-50-SP specification sheet.
For gloves, eye protection, spill control and the rest of the equipment these sites need, see our guide to fuel storage safety equipment.
This guide is educational. Requirements vary by state and code edition, and selection and compliance remain the operator's responsibility. Confirm ratings, quantities and placement with your fire marshal.
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