What You Need to Know About Aboveground Storage Tank Integrity Inspections and Testing


Tanks - Tanklager - IndustrieanlageWhat You Need to Know About Aboveground Storage Tank Integrity Inspections and Testing

An aboveground storage tank (AST) inspection program is more than just looking for oil leaks. Does your staff know what to look for or do they just check the box on the checklist? Furthermore, are they correcting deficiencies to prevent potential releases of oil from the AST? We want to provide you with a better understanding of what is required for tank inspections and testing, common pitfalls with implementing a tank inspection and testing program, and how we can help.

What is Required?

Regularly scheduled inspections, evaluations, and testing of bulk oil storage containers by qualified personnel are critical parts of discharge prevention measures covered in the SPCC Plan. A container integrity inspection and/or testing program may involve one or more of the following:

  • External visual inspection of containers, foundations, and supports
  • Non-destructive testing (examination) to evaluate integrity of certain containers
  • Additional evaluations, as needed, to assess the containers’ fitness for continued service.

The type of inspection program and its scope will depend on site-specific conditions and the application of good engineering practices, which can be accomplished by following applicable industry standards.

Aboveground bulk storage containers with a capacity of 55 gallons or more must be included in the inspection and testing program, such as large (field-constructed or field-erected) and small (shop-built) bulk storage containers; containers located on, partially in (partially buried, bunkered, or vaulted tanks), and off the ground wherever located; and double-walled containers. Each of these containers must be tested or inspected for integrity on a regular schedule and whenever you make material repairs. Integrity testing is required for all aboveground bulk storage containers located at onshore facilities (except oil production facilities). Integrity testing is necessary to determine if the container (e.g. a tank) is suitable for continued use until the next formal inspection.

What is the Industry Standard?

Industry standards are technical guidelines created by experts in a particular industry for use throughout that industry and adopted by standards-developing organizations. These organizations use a consensus process to establish the minimum accepted industry practice. The American Petroleum Institute (API) Standard 653 “Tank Inspection, Repair, Alteration, and Reconstruction” and the Steel Tank Institute (STI) “SP001 Standard for the Inspection of Aboveground Storage Tanks” (STI SP001) are two commonly used inspection standards for aboveground bulk storage tanks.

What Should You Be Doing?

All companies employing ASTs must conduct periodic inspections as part of the overall tank integrity testing program.  The certified tank integrity testing is one component, which must be done by a certified inspector; however, facility personnel have the responsibility of the monthly and annual periodic inspections spelled out in STI SP001.

Obtaining a copy of the STI SP001 standard from the Steel Tank Institute website[1] is a necessary first step. With the initial development of SP001 in 2003, the standard has improved significantly and now STI has published its fifth edition. The sixth edition will be published in 2016.

STI SP001 Section 6.0 identifies the components involved in properly performing the monthly and annual inspections.  Example inspection checklists are included in Appendix C of the standard.  These checklists are guidelines and can be tailored to your site to facilitate performing the inspections and recordkeeping.  Monthly inspection items include checking the following:

  • Secondary containment system for the presence of water and debris
  • Secondary containment system for cracks
  • Primary tank for water
  • Containment drain valves for operable condition and ensure valve is in closed position
  • Visible leaks from the tank
  • Leaks in surrounding area
  • Leaks in interstice for double-wall tanks
  • Leaks in valves
  • Tank drain valves are locked
  • Spill bucket (if equipped) on fill pipe for debris, residue, and water. If present, remove.
  • Drain valve in spill bucket is operable and closed
  • Liquid level equipment (visual and mechanical) for physical damage
  • Level equipment is legible
  • Overfill equipment for proper operation.  If equipped with test button activate the audible horn and/or light to confirm proper operation.  Check batteries.
  • If overfill valve is equipped with a mechanical test mechanism, activate to ensure proper operation.
  • Piping for leaks, corrosion and damage
  • Attachments (e.g., ladder or steps) for secure installation and evidence of corrosion or damage.
  • Record other conditions that should be corrected to ensure safe operation or that may affect the SPCC Plan.

Annual inspections have additional items to be checked by facility personnel, as follows:

  • Tank containment
  • Tank foundation and supports, including water drainage and grounding
  • Cathodic protection
  • Tank shell, heads and roof
  • Tank equipment such as venting, valves (anti-siphon, check, gate, expansion relief, fire, and shear valves)
  • Interstitial leak detection equipment
  • Spill buckets on fill pipes
  • Strainer
  • Filters
  • Flame arrestors
  • Liquid level equipment
  • Overfill equipment
  • Insulation if present
  • Electrical wiring and boxes
  • Labels and tags

Remember that inspections entail a lot more than merely looking for oil leaks. Make sure facility personnel know how to properly inspect a tank, fill out the checklist properly, and correct any deficiencies in a timely manner.

What are the Common Pitfalls with Implementing Tank Inspections and Testing?

In EHS Support’s experience, many companies simply are unaware of how to properly implement a tank inspection program.  Companies want to do the right thing, but they are unaware that their current inspection procedures do not satisfy the latest regulatory requirements of 40 C.F.R. §112, the Oil Pollution Prevention regulations

There is also confusion about the definition of an industry standard, and whether an inspection procedure satisfies industry standards. USEPA clarified[2] through the regulatory process and with issuance of guidance documents that casual visual inspection of tanks is not enough to meet the standard. Sites must follow industry standards such as STI SP001 and API 653.  SP001 is the best standard to inspect shop-built tanks (less than 50,000 gallons).  The API 653 standard is best for the large, field-constructed tanks.

How Can EHS Support Help?

EHS Support can identify the appropriate and necessary tank inspection and testing requirements for each facility and provide training for facility personnel to conduct periodic inspections (monthly and annually).  We recommend a training program that is a combination of classroom training and field inspections of shop-built tanks at each location. Depending on the number of tanks and desired amount of field experience, training can take as little as four hours and EHS Support personnel will come to you.  We will review how to properly complete checklists, identify deficiencies, and initiate the corrective action process to comply with regulations and your company’s policies and procedures. EHS Support can also tailor the monthly and annual checklists to minimize the effort while complying with the requirements.


Above and beyond your internal inspection program, EHS Support can establish a tank management program, prepare and update SPCC Plans, conduct spill prevention audits, update tank inventories, and conduct certified tank inspections and testing. To find out more information about all of our aboveground storage services, please contact Mike Arozarena.

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[1] http://www.steeltank.com/Publications/STISPFAStore/tabid/487/Default.aspx

[2] USEPA’s SPCC Guidance for Regional Inspectors, August 2013



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