Oil SPCC Tank Integrity Testing
The most recent changes governing inspections pertaining to Aboveground Storage Tanks (ASTs), as part of the U.S. Environmental Protection Agency’s rule for Spill Prevention Control and Countermeasure (SPCC), occurred in 2008 (40 CFR 112). Today, 10 years later, many plants are facing the need to conduct the mandatory integrity testing of ASTs which contain oils, and which have a capacity of 55 gallons or more. (Bulk containers are defined as aboveground storage tanks made of plastic, steel, or fiberglass-reinforced plastic, or simply a portable container (e.g., drums, totes), with the capacity to hold 55 gallons or more.) These inspections, which must be performed by a certified inspector, are required in order to prevent oil leaks and spills due to tank integrity or structural issues, and they must be conducted by a specific date dictated within each plant’s site-specific Oil SPCC plan.
Not all ASTs are equal though, and therefore, the type and scope of the inspection will vary for each site, and each tank at that site. For example, a 6,000 gallon tank containing vegetable oil which can be inspected all around is different from a 2,000 gallon oil tank partially buried in the ground.
Also complicating the matter is that U.S. Environmental Protection Agency (USEPA) guidance on this matter is somewhat vague, i.e., there is no “golden” specified standard that USEPA requires to be followed. However, as indicated in this fact sheet, USEPA suggests one of two known and frequently used standards that can be used as a guide. Those standards are the Steel Tank Institute (STI) SP001 Standard for the Inspection of Aboveground Storage Tanks and the American Petroleum Institute (API) Standard 653 for Tank Inspection, Repair, Alteration, and Reconstruction. Generally speaking the API is the “appropriate” standard for field-erected tanks that are greater than 50 feet in height and greater than 30 feet in diameter. Conversely, while the STI standard is written specifically for steel tanks, it is better suited for smaller, shop-built tanks and thus, in most cases, is the appropriate standard to use for tank integrity testing.
It should be noted that for poly and fiberglass reinforced plastic (FRP) tanks, select individual state guidance documents exists and there are recommended practices developed by the Fiberglass Tank & Pipe Institute. However, Hixson has found these to be more of general guidelines and provide somewhat arbitrary certified inspection intervals. Conversely, the STI standard provides a more regimented approach that gives credit for the specific tank setup, size, and secondary containment; all of which ultimately dictate the intervals and levels of required inspections, be it by plant personnel or a certified inspector.
It is Hixson’s experience that, in certain situations, it is possible to implement strategies to minimize testing intervals, e.g., secondary containment structures and double-walled tanks. Regardless, recordkeeping of all equipment inspection activities is key to maintaining compliance with Oil SPCC regulations.
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