Ebook: API Standard 650 Welded Tanks for Oil Storage

This Standard is based on the accumulated knowledge and experience of Purchasers and Manufacturers of welded
oil storage tanks of various sizes and capacities for internal pressures not more than 17.2 kPa (21/2 pounds per
square inch) gauge. This Standard is meant to be a purchase specification to facilitate the manufacture and
procurement of storage tanks for the petroleum industry.
If the tanks are purchased in accordance with this Standard, the Purchaser is required to specify certain basic
requirements. The Purchaser may want to modify, delete, or amplify sections of this Standard, but reference to this
Standard shall not be made on the nameplates of or on the Manufacturer’s certification for tanks that do not fulfill the
minimum requirements of this Standard or that exceed its limitations. It is strongly recommended that any
modifications, deletions, or amplifications be made by supplementing this Standard rather than by rewriting or
incorporating sections of it into another complete standard.
The design rules given in this Standard are minimum requirements. More stringent design rules specified by the
Purchaser or furnished by the Manufacturer are acceptable when mutually agreed upon by the Purchaser and the
Manufacturer. This Standard is not to be interpreted as approving, recommending, or endorsing any specific design or
as limiting the method of design or construction.
The verbal forms used to express the provisions in this document are as follows.
Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the standard.
Should: As used in a standard, “should” denotes a recommendation or that which is advised but not required in order
to conform to the standard.
May: As used in a standard, “may” denotes a course of action permissible within the limits of a standard.
Can: As used in a standard, “can” denotes a statement of possibility or capability.