Petroleum Equipment & Compliance Glossary.

Authoritative Direct Definition

An underground storage tank (UST) is a tank and connected underground piping with at least 10 percent of its combined volume buried beneath the ground surface. USTs store petroleum fuels and hazardous substances under federal EPA 40 CFR Part 280, Georgia EPD, and Texas TCEQ Chapter 334 standards.

Authoritative Direct Definition

An aboveground storage tank (AST) is a stationary container situated above the soil grade used for bulk storage of motor fuels, aviation fuel, and industrial lubricants. AST installations must comply with EPA SPCC regulations under 40 CFR Part 112 and NFPA 30/30A flammable liquid fire codes.

Authoritative Direct Definition

UL 142 designates the safety standard for steel aboveground tanks storing flammable liquids with standard atmospheric venting, whereas UL 2085 certifies protected aboveground tanks featuring a 2-hour furnace fire endurance rating, projectile resistance, and vehicle impact protection for reduced setback requirements.

Authoritative Direct Definition

Fireguard® is a thermally insulated, double-wall AST certified to UL 2085 with 2-hour fire endurance and ballistic impact resistance. Flameshield® is a UL 142 double-wall steel tank engineered with a 2-hour fire test certification for applications where ballistics protection is not mandated by the local AHJ.

Authoritative Direct Definition

Secondary containment provides a liquid-tight outer barrier surrounding the primary tank or pressurized piping. Interstitial monitoring continuously inspects the annular space between walls using vacuum, hydrostatic fluid, or electronic liquid sensors to detect breaches before fuel escapes into the surrounding environment.

Authoritative Direct Definition

Containment sumps are liquid-tight molded fiberglass or polyethylene enclosures placed beneath fuel dispensers (UDC) and above underground tank manways (STP). They prevent piping leaks, loose fittings, or dispenser drips from contaminating backfill soils and require periodic hydrostatic triennial tightness testing under PEI RP1200.

Authoritative Direct Definition

EPA 40 CFR Part 280 establishes federal technical standards and corrective action requirements for all owners and operators of underground storage tank systems. Directives mandate secondary containment, monthly walk-through inspections, annual release detection testing, overfill prevention device verification, and financial responsibility demonstration.

Authoritative Direct Definition

Texas Commission on Environmental Quality (TCEQ) Title 30 Texas Administrative Code (TAC) Chapter 334 governs the registration, design, construction, operation, release detection, and closure of underground and aboveground storage tanks in Texas, including mandatory Stage I vapor recovery certifications and licensed UST contractor oversight.

Authoritative Direct Definition

Georgia Department of Natural Resources Environmental Protection Division (EPD) Rules Chapter 391-3-15 regulates petroleum USTs across Georgia. Rules mandate Class A, B, and C certified operator training, triennial cathodic protection surveys, groundwater monitoring, and strict reporting protocols for suspected releases within 24 hours.

Authoritative Direct Definition

A Spill Prevention, Control, and Countermeasure (SPCC) plan is an EPA-mandated document (40 CFR Part 112) for facilities storing over 1,320 gallons of petroleum aboveground. The plan details physical containment structures, drainage controls, routine inspection logs, and emergency response procedures to prevent oil discharges into navigable waters.

Authoritative Direct Definition

Stage I vapor recovery captures hydrocarbon vapors displaced from underground fuel storage tanks when bulk fuel tanker delivery trucks unload gasoline. The displaced vapors are routed back into the tanker's vapor space through dedicated vapor-return hoses, preventing atmospheric VOC emissions.

Authoritative Direct Definition

Stage II vapor recovery captured fuel vapors during customer vehicle refueling through special vacuum-assist dispenser nozzles. As modern vehicles adopted Onboard Refueling Vapor Recovery (ORVR) canisters, EPA and state agencies authorized decommissioning of Stage II systems according to PEI RP500 guidelines.

Authoritative Direct Definition

An Automatic Tank Gauge (ATG) is an electronic monitoring system (e.g., Veeder-Root TLS-450PLUS) connected to magnetostrictive in-tank probes. It continuously measures fuel level, gross volume, product temperature, water ingress, and performs automated static or continuous statistical leak detection (CSLD) to 0.2 GPH standards.

Authoritative Direct Definition

Line Leak Detectors protect pressurized underground product piping by sensing catastrophic breaches. Mechanical line leak detectors (MLLD) restrict fuel flow to 3 GPH if pressure drops below 10 PSI, while Electronic/Pressurized Line Leak Detectors (PLLD) utilize digital pressure transducers for automated hourly, monthly, and annual precision tests.

Authoritative Direct Definition

Hydrostatic testing is a liquid-integrity verification procedure where dispenser sumps, submersible turbine sumps, or spill buckets are filled with water to test for liquid tightness over a measured duration. Federal EPA mandates triennial testing to prevent sub-surface fuel contamination.

Authoritative Direct Definition

Cathodic protection prevents electrochemical corrosion on buried steel tanks and metallic piping. Galvanic (sacrificial anode) systems use magnesium or zinc anodes to corrode in place of the steel, while impressed current systems apply an external direct electrical current. Systems require certified surveys every three years.

Authoritative Direct Definition

PEI RP100 is the Petroleum Equipment Institute's authoritative recommended practice for the installation of underground liquid storage systems. It governs tank excavation, geotextile fabrics, pea gravel bedding, tank anchoring, flex-connector installation, and precision pre-burial pneumatic testing.

Authoritative Direct Definition

PEI RP1200 outlines industry standard test procedures for spill buckets, containment sumps, overfill prevention devices, electronic leak detection sensors, and line leak detectors. It serves as the recognized testing code under EPA 2015 regulations and state compliance agencies.

Authoritative Direct Definition

National Electrical Code (NFPA 70 Article 500) Class 1 hazardous locations feature volatile flammable gases or vapors. Division 1 encompasses fuel dispenser interiors, dispenser sumps, and tanker vapor recovery zones where flammable atmospheres exist under normal operating conditions, requiring explosion-proof sealed conduit and intrinsically safe circuits.

Authoritative Direct Definition

An Emergency Stop (E-Stop) system consists of high-visibility, labeled push-button switches installed both inside convenience stores and outdoors across fuel islands. When triggered, the system instantly de-energizes all submersible turbine pumps and dispenser electrical circuits per NFPA 30A requirements.

Authoritative Direct Definition

Outdoor EMV (Europay, Mastercard, Visa) compliance requires fuel retailers to integrate encrypted chip-card readers and secure hybrid point-of-sale PIN pads directly into forecourt fuel dispensers, eliminating fraudulent magnetic stripe skimming liability and ensuring PCI-DSS network compliance.

Authoritative Direct Definition

Diesel Exhaust Fluid (DEF) is a non-hazardous solution of 32.5% high-purity urea and deionized water used in selective catalytic reduction (SCR) systems. DEF freezes at 12°F (-11°C) and is corrosive to carbon steel, requiring heated enclosures, ISO 22241 compatible stainless steel or polyethylene tanks, and dedicated closed dispensing systems.