API 653, Tank Inspection, Repair, Alteration, and Reconstruction, is a standard developed and published by the American Petroleum Institute (API) and covers the inspection, repair, alteration, and reconstruction of steel aboveground storage tanks used in the petroleum and chemical industries. The first edition of API 653 was published in in January of 1991. The fifth and most recent edition of the standard was published in November of 2014.

The requirements put forth by API 653 are meant to cover those steel storage tanks that constructed under the standards of API 650 and it’s predecessor API 12C. If there are any conflicts found between this standard and those, API 653 is to take precedence. While it was specifically written to apply to those tanks constructed under API 650 and API 12C, it can be applied to tanks constructed under other standards as well at the owner’s discretion.

This standard provides the minimum requirements for maintaining the integrity of welded or riveted, non-refrigerated and refrigerated, atmospheric pressure, aboveground storage tanks after they have been placed into service. It only applies to maintaining the integrity of the foundation, bottom, shell, structure, roof, attached appurtenances, and nozzles to the face of the first flange, first threaded joint, or first welding-end connection of the tank.

The American Petroleum Institute offers API 653 certification training and exams for inspectors. To take the exam, a minimum amount of experience and education are required. It can vary, but in general the more highly educated one is, the less experience that is required of that person to qualify for the exam. Certification under API 653 is valid for a three year term at which point it needs to be renewed.