This Standard is based on the accumulated knowledge and experience of owners, operators, manufacturers, and repairers of steel storage tanks. The object of this publication is to provide guidance in the inspection, repair, alteration, and reconstruction of steel storage tanks used in the petroleum and chemical industries.

If tanks are inspected, repaired altered or reconstructed in accordance with this standard, the owner/operator may elect to modify, delete, or amplify sections of this standard. It is strongly recommended that such modifications, deletions, or amplifications be made by supplementing this standard rather than rewriting or incorporating sections into another complete standard.

The rules given in this standard are minimum requirements. This standard is not to be interpreted as approving, recommending, or endorsing any specific design nor limiting the methods of inspection, repair, alteration or reconstruction.

Each edition, revision, or addenda to this API may be used beginning with the date of issuance shown on the cover page for that edition, revision or addenda. Each edition, revision or addenda to this API standard becomes effective six months after the date of issuance for equipment that is certified as being rated, reconstructed, relocated, repaired modified, inspected, and tested per this standard. During the six-month time between the date of issuance of the edition, revision or addenda, and the effective date, the purchaser and manufacturer shall specify to which edition, revision or addenda the equipment is to be rated, reconstructed, relocated, repaired, modified, inspected, and tested. 254pp.