Tank Categorization

Tank Categorization

Tank Categorization is a critical prerequisite to the development or updating of a compliant and useful SPCC plan. Regulations require an owner to use the AST type, capacity, installation characteristics, and previous inspection history, if any, to develop a schedule of applicable types of inspections for each AST, per Table 5.5 of the STI SP001 standard.

  • Category 1: ASTs with spill control and Continuous Release Detection Method (CDRM)
  • Category 2: ASTs with spill control and without CRDM
  • Category 3: ASTs without spill control and without CRDM


Inspection and integrity examination

The frequency and type of inspection to be performed is a result of the category the tank is placed.

Required inspection intervals are set individually for every tank as part of the design of the SPCC (Spill Prevention Countermeasure and Containment) Program, that every facility storing regulated product must have in place (CFR 40 Part 112).

The US EPA has divided regulated facilities into four size categories based upon an aggregate of oil storage capacity.



Size Category Aggregate Capacity

Non-farm facilities:1,321 to 10,000 gallons

Farm facilities: 2,501to19,999 gallons

Non-farm facilities: 10,001 to 42,000 gallons

Farm facilities: 20,000 to 42,000 gallons
III All facilities: 42,001 to 1 million gallons
IV All facilities: greater than 1 million gallons

Qi2 Elements inspectors and engineering team are experts in the regulatory definitions, and highly experienced in tank categorization, and determining inspection sequencing. 

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