Aboveground fuel storage terms, translated into buyer language

AHJ (Authority Having Jurisdiction)

The agency or official with authority to approve a specific installation. Depending on location and project type, that may be a state fire marshal, local fire department, building official, environmental agency, or more than one reviewer.

AST (Aboveground Storage Tank)

A storage tank installed aboveground. The exact regulatory definition can vary by program; do not assume every rule uses the same definition.

Aggregate capacity

The combined capacity of relevant tanks or containers at a facility when a rule uses a facility-wide threshold. SPCC, for example, is analyzed at the facility level rather than one tank at a time.

APSA

California's Aboveground Petroleum Storage Act, administered locally through Unified Program Agencies/CUPAs and distinct from federal SPCC.

Berm / dike

External secondary containment surrounding a primary tank. Its required capacity and freeboard depend on the governing rule and site conditions.

CUPA

Certified Unified Program Agency. In California, the local agency that administers multiple environmental programs, including APSA in many jurisdictions.

Double-wall tank

A tank with a primary shell and a secondary outer shell, creating an interstitial space that can provide integral containment and a place to detect primary-shell leakage.

Emergency vent

A vent sized for abnormal pressure relief, such as fire exposure, distinct from normal venting used during filling, withdrawal, and thermal breathing.

Freeboard

Additional containment volume above the stored-liquid displacement needed to account for precipitation or other site-specific conditions where required.

IFC (International Fire Code)

A model fire code adopted by many U.S. states and local jurisdictions, often with amendments. The adopted edition matters.

Interstitial monitoring

Checking the space between primary and secondary walls for evidence of leakage. The method may be visual, electronic, hydrostatic, vacuum-based, or another approved approach depending on the tank/system.

NFPA 30

NFPA's Flammable and Combustible Liquids Code. It addresses storage and handling of flammable and combustible liquids and is often referenced through an adopted fire code.

NFPA 30A

NFPA's Code for Motor Fuel Dispensing Facilities and Repair Garages. It becomes especially relevant when a tank is part of vehicle/equipment fueling.

Normal vent

The tank venting path used to manage ordinary pressure/vacuum changes from filling, withdrawal, and temperature change.

Protected AST

An aboveground tank system with additional fire-resistance/protection evaluated under an applicable standard such as UL 2085. It is not synonymous with every double-wall tank.

Secondary containment

A method of controlling a release from the primary container. Double-wall construction, dikes, berms, remote impoundment, and other approaches can serve this function depending on the rule and installation.

SPCC

EPA's Spill Prevention, Control, and Countermeasure rule under 40 CFR Part 112. Applicability depends on facility type, oil-storage capacity, and the reasonable expectation of a discharge to navigable waters or adjoining shorelines; 1,320 gallons alone is not the full test.

STI SP001

An industry standard for inspection of aboveground storage tanks. Whether and how it applies depends on the facility's program, tank configuration, and inspection plan.

UL 142

UL's standard for steel aboveground tanks for flammable and combustible liquids. A UL 142 listing is a product certification, not approval of the complete site installation.

UL 2085

UL's standard for protected aboveground tanks for flammable and combustible liquids. It is distinct from UL 142 and should not be described as automatically including a separate UL 142 listing.

ULC / CAN/ULC

Canadian standards and certification references used in the National Fire Code/provincial code environment. U.S. UL and Canadian ULC requirements are not automatically interchangeable.

UST (Underground Storage Tank)

A regulated underground storage system can be defined differently by program. Under EPA's federal UST program, the system generally falls within the definition when at least 10% of the combined tank-and-connected-piping volume is underground.

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