SPCC Tank Integrity Testing: What 40 CFR 112 Requires

Short answer: 40 CFR 112.8(c)(6) requires you to test or inspect each aboveground bulk storage container for integrity on a regular schedule and whenever you make material repairs. The rule sets no fixed interval or method. You choose them by following industry standards, usually API 653 for field-erected tanks and STI SP001 for shop-built tanks. You document the programme in an SPCC Plan certified by a Professional Engineer and keep comparison records.

This guide explains what the rule text actually says and how EPA interprets it. It covers how the industry standards plug in, which NDE methods count as integrity testing and what each one finds, and the record set an EPA inspector expects to see. It is written for terminal and tank-farm operators, facility managers, EHS staff and the engineers who certify SPCC Plans in the USA. Regulatory citations come from the current eCFR text of 40 CFR Part 112 and EPA's published SPCC guidance. Confirm the current text and any state requirements before you change a Plan.

What 40 CFR 112.8(c)(6) says

Direct answer: The paragraph has five working parts: test or inspect each container on a regular schedule and after material repairs; set personnel qualifications, frequency and type of testing in line with industry standards; keep comparison records; inspect supports and foundations; and frequently inspect the container exterior for deterioration, discharges and oil in diked areas.

In the rule's own terms, the owner or operator must determine, in accordance with industry standards, three things: the appropriate qualifications for people performing tests and inspections, and the frequency and type of testing and inspection. Those choices must take into account container size, configuration and design. The rule lists examples of designs that change the answer: shop-built, field-erected, skid-mounted, elevated, equipped with a liner, double-walled or partially buried.

The rule also gives examples of integrity tests and says the list is not exhaustive: visual inspection, hydrostatic testing, radiographic testing, ultrasonic testing, acoustic emissions testing, or other systems of non-destructive testing. Records of inspections and tests kept under usual and customary business practices satisfy the recordkeeping requirement of the paragraph.

The same integrity-testing language appears at 112.12(c)(6) for animal fats and vegetable oils, with one carve-out. Bulk containers subject to 21 CFR part 110 that are elevated, made of austenitic stainless steel, have no external insulation and are shop-fabricated may use formal visual inspection on a regular schedule. Oil production facilities follow 112.9 instead. EPA's fact sheet notes that the integrity testing requirement applies to aboveground bulk containers at onshore facilities other than oil production facilities.

Which containers need integrity testing

Direct answer: Aboveground bulk storage containers of 55 U.S. gallons or more at an SPCC-regulated facility, whether shop-built or field-erected, on or partly in the ground, or elevated. Double-walled containers are included. Oil-filled operational equipment, such as transformers, is not a bulk storage container and is not subject to integrity testing.

A facility is in the SPCC programme in the first place when it could reasonably discharge oil to navigable waters or adjoining shorelines and exceeds the storage thresholds in 112.1. For aboveground storage, the facility is exempt if aggregate capacity is 1,320 U.S. gallons or less, counting only containers of 55 gallons or more. EPA's 2013 Bulk Storage Container Inspection Fact Sheet lists the containers in scope. They include large field-erected tanks and small shop-built ones, containers on the ground, partially buried, bunkered or vaulted, or off the ground, and double-walled containers. The fact sheet also states plainly that oil-filled equipment is outside the integrity-testing requirement.

Ask whether a container is in scope before you ask how to test it. Portable containers such as drums and totes are in scope, but industry standards treat them very differently from a large tank. STI SP001, for example, allows visual inspection of portable containers that have adequate secondary containment, and EPA accepts that as meeting the rule.

Performance-based: who sets the frequency and method

Direct answer: EPA says the SPCC rule is performance-based. It does not prescribe a frequency or methodology. The owner or operator, and the certifying Professional Engineer (PE), select an industry standard and follow it. Once the Plan says a standard will be used, the relevant parts of that standard become mandatory for the facility.

EPA's page on SPCC inspection schedules states that the rule "does not prescribe a specific frequency or methodology" and relies on good engineering practice and industry standards, naming API and STI. Under 112.3(d), the PE who certifies the Plan attests to several things: that the Plan follows good engineering practice, including consideration of applicable industry standards, and that procedures for the required inspections and tests have been established. EPA's fact sheet adds the point that bites in enforcement. When an owner says in the Plan that a standard will be used to meet integrity testing, implementing the relevant portions of that standard becomes mandatory.

EPA's fact sheet defines a "regular schedule" as testing per industry standards, or at a frequency sufficient to prevent discharges. Industry standards set scope and frequency from the container's age, service history, construction (shop-built or field-erected, welded or riveted), prior inspection results and current condition. They may also weigh discharge risk, such as a tank near saltwater where faster corrosion would be expected. Intervals can therefore change over a container's life as corrosion rates and settlement data come in. The Plan should document the schedule and the container conditions behind it.

API 653 and STI SP001: the two standards most Plans use

Direct answer: EPA's fact sheet names API Standard 653 and STI SP001 as the two commonly used inspection standards. API 653 is typically used for field-erected tanks built to API 650 or its predecessor API 12C. SP001 focuses on welded, metal, shop-fabricated and small field-erected tanks, plus portable containers.

The inspector qualification for SP001 formal inspections comes from STI's published material and industry summaries. Confirm it against the current SP001 edition; the seventh edition was released in early 2024. For the comparison in depth, read STI SP001 vs API 653. For the field-erected side, see our API 653 interval explainer and API 653 inspection checklist.

EPA's fact sheet describes an API 653 programme in terms that show why NDE contractors are needed. A formal in-service external inspection involves visual inspection and UT of the shell. A formal out-of-service internal inspection looks at the floor, walls and structure, and should also cover the shell, roof, nozzles and appurtenances. It typically includes MFL scanning of the floor, vacuum box testing of floor welds, helium leak testing, UT measurements and bottom settlement measurements.

Integrity test methods and what each one actually finds

Direct answer: The methods named in 112.8(c)(6) do different jobs. UT measures remaining wall thickness. MFL screens floor plates for corrosion. Radiography images welds and wall loss. Acoustic emission detects active leaks. Hydrostatic testing proves tightness and strength after construction or major repair. Visual inspection finds what is on the surface. A programme picks the mix that its industry standard requires.

For floor scanning specifically, see our MFL vs UT floor scanning comparison and our MFL testing page.

Baselines, comparison records and the three-year rule

Direct answer: 112.8(c)(6) requires comparison records, meaning records that let you see change over time. 112.7(e) requires written inspection procedures and signed inspection and test records to be kept with the Plan for three years. EPA recommends keeping formal test reports for the life of the container.

EPA's fact sheet explains baselines. For most NDE protocols, a baseline is needed because the corrosion rate drives the next interval. Where no baseline exists, the programme may need two data-collection rounds: one to establish existing shell and bottom thickness, and a second to establish corrosion rates and set the next interval. Where the chosen standard requires only visual inspection for a container type, no thickness baseline is needed.

The fact sheet gives a worked example. A facility owner buys a site with a 10,000-gallon aboveground container that has no inspection records and no known in-service date. Since the Plan must be reviewed every five years under 112.5(b), EPA suggests scheduling the baseline inspection within that five-year review window. It also suggests prioritising containers with unknown history, older containers and those in demanding service. If an integrity testing programme is not yet running, the introductory paragraph of 112.7 lets the Plan describe it as not yet operational. The Plan must then give the details and an implementation schedule.

A comparison-ready NDE record should carry the container ID, the date, the inspector's name and qualification, the standard and edition followed, and the method and equipment. It also needs each reading's location against a fixed grid or CML map, the prior reading at the same location, and a plain statement of anything outside the acceptance criteria the inspector applies. The 112.7(e) record must be signed by the appropriate supervisor or inspector.

Deviating from a standard: environmental equivalence and hybrid programmes

Direct answer: You may depart from an industry standard's integrity testing requirements only by documenting an environmentally equivalent alternative under 112.7(a)(2), certified by a PE. Tier II qualified facilities need a PE to certify each such alternative. Tier I qualified facilities following the 112.6(a) template cannot deviate at all.

EPA's fact sheet describes a site-specific or "hybrid" inspection programme. It combines elements of standards and good engineering practice to minimise the risk of container failure and to detect leaks before oil reaches navigable waters. The Plan must give the reason for the deviation, describe the alternative in detail and explain how it achieves equivalent protection. EPA also explains the history. Older guidance described a visual-plus-leak-containment approach as potentially equivalent for shop-built containers up to 30,000 gallons. That approach still exists as an engineering choice, but EPA notes that STI SP001 was later revised to set out good engineering practice for shop-built containers. For tanks larger than 5,000 gallons, most industry standards require more than a visual inspection by the owner.

Qualified facilities are defined in 112.3(g). A Tier II qualified facility has aggregate aboveground oil storage of 10,000 U.S. gallons or less and a clean discharge history: no single discharge over 1,000 gallons, and no two discharges each over 42 gallons within any twelve-month period, in the three years before self-certification. A Tier I facility meets those criteria and has no individual aboveground container larger than 5,000 gallons. Qualified facilities may self-certify, but the limits on deviations above still apply.

Common mistakes EPA inspectors find

Direct answer: The usual gaps are Plans that name a standard but never implement it, containers missing from the testing schedule, no baseline data for old tanks, visual-only programmes for large tanks without a PE-certified equivalence, and records that cannot be compared year to year.

• Naming a standard without following it. Once the Plan cites API 653 or SP001 for integrity testing, the relevant portions are mandatory.
• Leaving containers out. Small shop-built tanks, elevated tanks and double-walled tanks are still bulk storage containers.
• No baseline. Without one, there is no corrosion rate and no defensible interval.
• Assuming visual is always enough. It may be, for some containers under the selected standard. For larger tanks, a visual-only approach usually needs a PE-certified environmental equivalence.
• Forgetting "material repairs". Integrity testing is also triggered whenever material repairs are made, not only by the calendar.
• Losing records. Three years is the minimum. Corrosion rates need older data, which is why EPA recommends keeping formal reports for the container's life.
• Ignoring supports and foundations. The rule names them explicitly.

State rules, pipeline tanks and Canada

Direct answer: SPCC is a federal floor. Several states run their own aboveground tank programmes with added inspection requirements, and pipeline breakout tanks fall under PHMSA's 49 CFR 195. Canadian facilities follow federal and provincial storage-tank rules instead of SPCC.

Check your state environmental agency's aboveground storage tank rules. Some states adopt or reference API 653 or SP001 directly or add registration and inspection requirements. California's Aboveground Petroleum Storage Act, for instance, is administered with local agencies. Breakout tanks on regulated hazardous-liquid pipelines must be inspected under 49 CFR 195.432, which incorporates API 653 by reference. That section bars the use of API 653's risk-based alternative internal inspection interval. See our PHMSA 49 CFR 195 page. In Canada, federal storage-tank regulations apply on federal lands and to federal undertakings, and provinces and territories set their own requirements. Confirm the applicable regime for each site.

How Atlantis supports this

Atlantis NDT performs the integrity testing methods the SPCC rule names and the industry standards call for. That covers shell UT thickness surveys, floor MFL scanning with UT prove-up, MT, PT and visual examination at welds and repairs, and corrosion mapping, by ASNT-certified technicians under ASNT Level III oversight. We record readings against a fixed grid so they become comparison records, and we report findings against the acceptance criteria your inspector applies. The certified API 653 or STI inspector signs the formal inspection, and your PE and Plan set scope and frequency. Atlantis does neither. See aboveground storage tank inspection and API 653 tank inspection support, or request a quote; we reply within 24 hours.

Frequently asked questions

What are the SPCC integrity testing requirements?

40 CFR 112.8(c)(6) requires testing or inspecting each aboveground bulk storage container for integrity on a regular schedule and after material repairs. Frequency, method and personnel qualifications are set by industry standards. You must also keep comparison records and inspect supports, foundations and the container exterior.

How often does SPCC require tank integrity testing?

The rule sets no fixed interval. The schedule comes from the industry standard in your Plan, such as API 653 or STI SP001, applied to the container's condition and history, and documented in the Plan.

What industry standard satisfies 40 CFR 112.8(c)(6)?

EPA names API 653 and STI SP001 as the commonly used standards. Other standards or a PE-certified environmentally equivalent programme can also be used.

Is visual inspection enough for SPCC integrity testing?

Sometimes. It depends on the standard and the container. SP001 allows visual inspection for some containers, such as portable containers with secondary containment. EPA notes that most standards require more than an owner's visual inspection for tanks above 5,000 gallons.

Who can perform SPCC tank integrity testing?

The person the selected standard qualifies. Formal API 653 inspections need an API 653 certified inspector. Formal SP001 inspections need an STI-certified inspector, or an API 653 inspector with STI's adjunct certification. NDE crews perform the testing under that inspector.

How long must SPCC inspection records be kept?

Three years under 112.7(e), signed by the appropriate supervisor or inspector and kept with the Plan. EPA recommends keeping formal reports for the life of the container.

Do double-walled tanks need SPCC integrity testing?

Yes. Double-walled containers are aboveground bulk storage containers. The rule lists double-walled design as a factor in choosing the testing approach.

Do transformers need SPCC integrity testing?

No. EPA states that oil-filled equipment is not a bulk storage container and is not subject to the integrity testing requirement. Other SPCC provisions may still apply.

Can a qualified facility skip integrity testing?

No. Tier I and Tier II facilities still test. Tier I facilities following the template cannot deviate from the industry standard. Tier II facilities need a PE to certify any environmentally equivalent alternative.

What triggers integrity testing besides the schedule?

Material repairs. The rule requires testing or inspection whenever material repairs are made.

Planning an SPCC testing round? Ask about baseline UT surveys, or send your tank list for MFL and shell UT scoping.