Aboveground fuel tanks
An aboveground storage tank (AST) is any fuel tank that sits on or above the ground instead of buried: a farm tank on a stand, a skid tank at a job site, a generator's base tank, or a fleet's fueling tank. Here's how they're built, the rules that apply, and the equipment that goes on them.
Types of aboveground tanks
Most steel aboveground fuel tanks are built to UL 142. Protected tanks are built to UL 2085, which adds insulation between the walls for fire protection (Western Global).
| Type | What it is | Typical use |
|---|---|---|
| Single-wall (UL 142) | One steel wall | Needs a separate dike or containment area to meet spill rules (40 CFR 112.8(c)(2)) |
| Double-wall (UL 142) | A tank inside a tank; the outer wall catches a leak from the inner one | Can help meet the containment requirement, but still counts toward your SPCC capacity (see the SPCC guide) |
| Protected (UL 2085) | Double-wall with insulation between the walls, built to limit heat to the inner tank during a 2-hour fire; can also be tested for ballistics and vehicle impact (Western Global) | Permanent installations with higher fire risk, such as gasoline dispensing; some states require it for aboveground gasoline dispensing tanks (NC State Fire Marshal) |
| Transfer and auxiliary tanks | Small tanks in a pickup bed | See diesel transfer tanks |
Field note: On the farm and fleet sites I service, most tanks are UL 142, and double-wall tanks are more common than single-wall tanks in a dike. Protected tanks are heavier and harder to move than standard tanks (Western Global).
The rules at a glance
Three sets of rules can apply to an aboveground tank: the federal SPCC rule, your fire code, and your state's tank rules.
| Rule | Who it covers | Guide |
|---|---|---|
| SPCC (40 CFR 112) | Sites with more than 1,320 gallons of aboveground oil storage that could spill to water; farms have higher thresholds | Do I need an SPCC plan? |
| Fire code (IFC or NFPA 30/30A, as adopted locally) | Tank construction, spacing, and equipment such as anti-siphon valves | Anti-siphon valves |
| State tank rules | Varies by state; some register or inspect aboveground tanks | Check with your state fire marshal or environmental agency |
Equipment on an aboveground tank
The fittings on top of the tank keep it filled safely, vented, and from leaking out through the piping. Guides for the rest are in the works.
| Equipment | What it does | Guide |
|---|---|---|
| Anti-siphon valve | Keeps fuel from draining out if a line breaks | Anti-siphon valves |
| Transfer pump | Moves fuel from the tank to equipment | 12V transfer pumps |
| Vents (normal and emergency) | Let air in and out as fuel moves; relieve pressure in a fire | Coming soon |
| Fill and spill containment | Catch drips at the fill when the delivery hose comes off | Coming soon |
| Overfill prevention | Stops or warns before the tank is overfilled | Coming soon |
| Gauges | Show how much fuel is in the tank | Coming soon |
All aboveground tank guides
- Do I need an SPCC plan?
The 1,320-gallon rule, the farm thresholds, which plan type you need, and a one-minute checker.
- Anti-siphon valves
Why elevated tanks siphon, what the fire code requires, picking the head setting, and pump troubleshooting.
- Diesel transfer tanks
Why 119 gallons matters, the rules for gasoline, payload math for your pickup, and setup.
- How to choose a 12V fuel transfer pump
Flow rate, duty cycle, and wiring explained, and Fill-Rite and GPI models compared.
For the fuel inside the tank, see the fuel quality guides.