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Overview of STI SP001

SP001 is a standard maintained by the Steel Tank Institute/Steel Plate Fabricators Association (STI/SPFA). It includes inspection requirements for welded metal, shop-fabricated and small field-erected tanks. Also included is the inspection of smaller, portable containers such as 55-gallon drums, intermediate bulk containers (IBCs), and other such containers that may be of metal or plastic construction.

Revision History

In September 2011, after nearly two years of study and revision by a broad-based committee of experts, the Steel Tank Institute published the 5th Edition: SP001 Standard for the Inspection of Aboveground Storage Tanks.

Changes were developed through the STI AST Inspection Standards Committee review process. The revised standard was unanimously approved by a 21-member committee balanced among STI tank fabricators, federal and state regulators, bulk storage tank owners, tank repair companies, and several other interested parties. Significant changes from the previous edition include:

  • Elevated tanks previously required a release prevention barrier (in addition to secondary containment) to qualify as a Category 1 tank. This requirement was deleted, as leaks from elevated tanks are visible.
  • Double-wall tanks must have overfill prevention in order to be considered to have secondary containment. In the revised standard, however, overfill prevention may simply be a person watching the fill.
  • The requirement for a release prevention barrier to be sufficiently impervious was deleted, to avoid confusion with EPA's definition of secondary containment.
  • Language was added to the schedule of inspections concerning the initial inspection date, which is now based on the initial service date of the tank.
  • Additional examples of tank configurations were added as examples of tank categories.
  • Inspection requirements for several types of valves, leak detection equipment, spill containers, etc. were added to the equipment checklists in the Appendix.

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