Underground Storage Tank Testing for US Operators: Compare Scope

Compare underground storage tank testing bids as four separate scopes: complete-tank tightness, underground-piping tightness, release-detection-equipment operability and containment-component testing. A passing result in one scope does not establish coverage of the others.[1][3][5]

Divide the request into four testing scopes

EPA’s release-detection booklet, hosted by West Virginia DEP, says regulated USTs need a method or combination capable of detecting releases from each tank and every connected underground-piping portion that routinely contains product. Confirm applicability and accepted procedures with the implementing agency.[5]

• Complete-tank tightness. Coverage: Define whether the method tests both the liquid-filled and vapor spaces. New York requires both, while Minnesota’s guidance says an ullage-only test covers only the headspace.[3][7] Procedure: Require the bidder to identify any untested space. Output: A separate result for each tank.
• Underground-piping tightness. Coverage: New York requires testing of every underground-piping portion that routinely contains petroleum.[3] Procedure: Identify every included and excluded run. Output: Line-specific results rather than a tank result presented as evidence for piping.
• Annual release-detection-equipment operability. Coverage: Applicable gauges, probes, sensors, controllers and handheld devices. Procedure: EPA’s release-detection page includes checks of configuration, alarms, battery backup, buildup, float movement, cables, communication and operability.[1] Output: Component-level findings.
• Containment-component testing. Coverage: List spill buckets or catchment basins, overfill devices and other applicable components separately.[4] Procedure: Require the bidder to identify the controlling agency, manufacturer or code basis for each proposed test and frequency. Output: A separate result for each scheduled asset.

Build the asset inventory before requesting bids

Use an asset-level bid schedule so every bidder prices the same equipment.

• Tanks: Record each tank’s capacity, product, installation or replacement date and release-detection method. If probes are used, identify one for each tank, as EPA specifies.[1]
• Piping: Record whether each run is pressurized or suction, its installation date, route and secondary-containment status. Identify each automatic line-leak detector and secondary monitoring method.[4][5]
• Associated equipment: List spill buckets or catchment basins, overfill devices, tank and piping corrosion protection, probes, sensors, consoles, alarms, battery backup and handheld detection equipment.[1][4]

Flag any claimed suction-piping exemption. An archived EPA page identifies operating pressure, slope back to the tank, a check valve directly beneath the pump and readily determinable installation characteristics as relevant conditions.[2] Also flag potentially excluded tanks for agency confirmation. Arkansas guidance lists examples such as certain small farm or residential tanks, on-premises heating-oil tanks and tanks holding 110 gallons or less, but those examples should not be generalized nationwide.[4]

Compare tank methods by coverage, interruption and limits

Compare the proposed procedure, not just its method name. EPA’s release-detection guidance and Minnesota’s guidance support requiring a performance claim and written operating limits showing what a passing result covers.[5][7] The cited EPA and Minnesota pages do not state shutdown conditions for SIR, vacuum/acoustic or tracer testing, so bidders should specify them.[1][7]

Static ATG

Coverage: Minnesota’s guidance says some certified automatic tank gauges can perform tank tightness testing, but a tank result does not cover connected piping or separate components.[5][7]

Interruption: EPA says static testing requires a shutdown or period with no product movement.[1]

Constraints: Each tank needs its own probe. EPA says solely in-tank ATG cannot serve as primary release detection for tanks installed or replaced after April 11, 2016.[1]

Continuous ATG

Coverage: EPA describes continuous ATG as in-tank release detection that collects data during short inactive periods.[1]

Interruption: It collects data without taking the tank out of service.[1]

Constraints: Each tank requires a probe. EPA’s release-detection guidance says tanks installed or replaced after April 11, 2016 require secondary containment with interstitial monitoring rather than solely in-tank ATG.[1][5]

Statistical inventory reconciliation

Coverage: EPA says SIR analyzes inventory, delivery and dispensing data and produces a report. Monthly monitoring must detect at least 0.2 gallons per hour or 150 gallons within a month; a tank-tightness equivalent must detect at least 0.1 gallons per hour.[1]

Interruption: Bidder-specified; require the proposal to state any shutdown and product-movement restrictions.

Constraints: EPA says few product or site restrictions apply to SIR and that it has been used primarily on tanks of no more than 18,000 gallons; the up-to-1,000-gallon, 1,001–2,000-gallon and over-2,000-gallon limits on EPA’s page apply to manual tank gauging, not SIR.[1] An inconclusive result requires another method or other steps that produce a conclusive finding.[1]

Volumetric testing

Coverage: Minnesota’s guidance says volumetric testing measures a change in product volume or mass. The proposal should specify whether the procedure covers both the liquid-filled area and vapor space.[3][7]

Interruption: EPA’s current and archived pages say tank tightness testing generally requires a shutdown or no product movement.[1][2]

Constraints: Minnesota’s guidance says volumetric testing may require a partially full or overfilled tank, while product temperature affects volume measurements.[7]

Vacuum/acoustic testing

Coverage: Minnesota’s guidance classifies vacuum/acoustic testing as non-volumetric. Require the proposed procedure to define whether it covers the complete tank.[7]

Interruption: Bidder-specified; require the proposal to state operating and product-movement conditions.

Constraints: Require written tank-size, product, access and system limits. EPA’s release-detection guidance says documented limitations govern use, and Minnesota’s guidance says some methods exclude larger tanks.[5][7]

Chemical-tracer testing

Coverage: Minnesota’s guidance classifies chemical-tracer testing as non-volumetric, so the proposal should identify the tank portions tested.[7]

Interruption: Bidder-specified; require the proposal to state shutdown and product-movement conditions.

Constraints: Minnesota’s guidance says tracer methods may suit some temperature- or volume-sensitive products, but clay-like soil may preclude their use.[7]

An ullage test can avoid filling the tank, but Minnesota’s guidance says it tests only the headspace. Do not treat it as complete-tank testing unless an accepted complementary procedure covers the remaining area.[3][7]

Match piping scope to pressure, layout and exemption status

Pressurized piping

Compliance basis: The archived EPA page says pressurized piping installed before April 12, 2016 needs an automatic line-leak detector and either annual line-tightness testing or an allowed monthly monitoring method.[2] EPA’s release-detection guidance says newer piping requires secondary containment with interstitial monitoring, while all pressurized underground piping requires an automatic line-leak detector.[5]

Proposal detail: Require the detectable leak rate and test pressure. The archived EPA page gives the federal baseline as 0.1 gallons per hour at 1.5 times normal operating pressure; a lower pressure requires a correspondingly lower detectable rate.[2]

Layout risk: Provide piping drawings and ask how the procedure addresses long or complicated runs, risers and dead ends. The archived EPA page warns that trapped vapor can invalidate a test.[2]

Suction piping

Compliance basis: Do not accept the label “safe suction” as proof of an exemption.

Proposal detail: The archived EPA page describes qualifying piping as operating below atmospheric pressure, draining back to the tank when suction is released, having one check valve directly beneath the pump and having installation characteristics that can be readily determined.[2]

Layout risk: Arkansas guidance describes an exempt system as operating “under atmospheric pressure,” while the archived EPA page says “less than atmospheric pressure.” Treat those phrases as a conflict requiring confirmation from the controlling implementing agency.[2][4]

Verify the method and tester before award

EPA’s release-detection guidance says requirements may differ in states with EPA-approved programs. Where a state program lacks approval, federal and state requirements both apply; federal requirements apply in Indian country.[5]

Send the implementing agency the asset type, installation date, proposed method and procedure, testing frequency, performance claim and tester qualifications. Retain its written response or its accepted-method and approved-tester information.[5]

For annual release-detection-equipment testing, EPA requires following manufacturer requirements, a nationally recognized code of practice or an implementing-agency procedure determined to be no less protective.[1] EPA’s release-detection guidance says agencies may prefer or require independent third-party method evaluation. Minnesota’s guidance requires an agency-approved tester and recommends checking experience and references.[5][7]

EPA’s release-detection guidance applies a benchmark of at least 95% probability of detection and no more than 5% probability of false alarm to applicable tank methods, automatic line-leak detectors and line tightness tests. It excludes secondary-containment/interstitial, groundwater and vapor monitoring from that benchmark.[5]

Normalize bids by access, disruption and exclusions

Give every bidder the same asset schedule and require each line item to be marked included, excluded, optional or not applicable.

• Operating conditions: State the required tank-fill condition, test duration, shutdown period and restrictions on product movement. EPA says continuous ATG can collect data during short inactive periods, while static ATG requires a shutdown or no product movement.[1]
• Method limits: Record access needs, tank-size limits, product restrictions and soil compatibility. Minnesota’s guidance says temperature-sensitive products, larger tanks and clay-like soils can limit method suitability; EPA’s release-detection guidance says documented duration and limitations govern use.[5][7]
• Exceptions: Require bidders to identify inaccessible piping and explain how trapped vapor will be addressed because the archived EPA page says it can invalidate piping tests.[2]

Require an asset-level handover package

Make final payment contingent on a signed result for every inventoried tank, piping run, monitoring device and containment component. Identify each asset by number or location.

The package should state the method and procedure, test date and duration, measured result, pass, fail or inconclusive status, performance claim, limitations, tester identity and qualifications, and applicable third-party evaluation.[1][5][7] Also require calibration and maintenance records and disclosure of untested portions, assumptions, deviations, invalid runs and required follow-up.[1][5]

Keep implementing-agency correspondence or accepted-method evidence with the report. Ask the agency to confirm applicable submission and record-retention requirements.

Define the response to inconclusive or failed results

An inconclusive SIR result is not a pass. EPA calls for another method or other steps that conclusively determine whether the tank leaks.[1] The contract should require prompt escalation, a written finding identifying the affected assets and a separate corrective-action proposal.

Follow the controlling agency’s reporting, shutdown, emptying and investigation instructions.[5] Minnesota’s guidance, for example, requires immediate notification to the Minnesota Duty Officer, emptying, investigation and resolution after a failed test. It also requires reporting a detected leak below 0.1 gallons per hour; these are Minnesota requirements, not nationwide rules.[7]

What to confirm with each provider

• Itemized prices for mobilization, tanks, piping runs, monitoring devices, containment components, retesting and corrective work
• Travel charges, taxes, minimum charges and payment terms
• Scheduling, cancellation and rescheduling terms
• Service area and tester eligibility in the controlling jurisdiction
• Report delivery deadline and submission responsibilities
• Retest policy, warranties and whether corrective repairs are included

References

1. Release Detection for Underground Storage Tanks – Internal Methods | US EPA (epa.gov, 2018)
2. Release Detection for Underground Storage Tanks (USTs) | Underground Storage Tanks (USTs) | US EPA (epa.gov, 2021)
3. Petroleum Bulk Storage Underground Tank Tightness Testing FAQ's – NYSDEC (ny.gov)
4. ADEQ Underground Storage Tank Operator Training Study Guide (ar.us)
5. Release Detection For Underground Storage Tanks And Piping: (wv.gov, 2016)
7. Tightness testing for underground storage tanks (mn.us)