scope:

General 

This standard establishes minimum requirements for material, design, fabrication, erection, and inspection for vertical, cylindrical, aboveground, closed- and open-top, welded storage tanks in various sizes and capacities for internal pressures approximating atmospheric pressure (internal pressures not exceeding the weight of the roof plates), but a higher internal pressure is permitted when additional requirements are met (see 1.1.13). This standard applies only to tanks whose entire bottom is uniformly supported and to tanks in non-refrigerated service that have a maximum design temperature of 93 °C (200 °F) or less (see 1.1.20). 

This standard provides industry with tanks of adequate safety and reasonable economy for use in the storage of petroleum, petroleum products, and other liquid products. This standard does not present or establish a fixed series of allowable tank sizes; instead, it is intended to permit the Purchaser to select whatever size tank may best meet his or her needs. This standard is intended to help Purchasers and Manufacturers in ordering, fabricating, and erecting tanks; it is not intended to prohibit Purchasers and Manufacturers from purchasing or fabricating tanks that meet specifications other than those contained in this standard.

NOTE A bullet (•) at the beginning of a paragraph indicates that there is an expressed decision or action required of the Purchaser. The Purchaser's responsibility is not limited to these decisions or actions alone. When such decisions and actions are taken, they are to be specified in documents such as requisitions, change orders, data sheets, and drawings.

This standard has requirements given in two alternate systems of units. The Manufacturer shall comply with either:

1) all of the requirements given in this standard in SI units; or

2) all of the requirements given in this standard in US Customary units. The selection of which set of requirements (SI or US Customary) to apply shall be a matter of mutual agreement between the Manufacturer and Purchaser and indicated on the Data Sheet, Page 1. 

All tanks and appurtenances shall comply with the Data Sheet and all attachments. 

Field-erected tanks shall be furnished completely erected, inspected, and ready for service connections, unless specified otherwise. Shop-fabricated tanks shall be furnished inspected and ready for installation. 

The annexes of this standard provide a number of design options requiring decisions by the Purchaser, standard requirements, recommendations, and information that supplements the basic standard. Except for Annex L, an Annex becomes a requirement only when the Purchaser specifies an option covered by that Annex or specifies the entire Annex. The designation "Normative" shall be understood to mean mandatory. The designation "informative" shall be understood to mean non-mandatory (i.e. informational data, recommendations, suggestions, commentary, samples, and examples). The contents of the annexes to this standard are either "normative" or "informative."

"Normative" is further divided into the following.

- Always required (L).

- Required if specified by the Purchaser (A, E, J, Y, U, W).

- Required if special materials are specified by the Purchaser (AL, N, S, SC, X).

- Required if pressure, vacuum, and high temperature are specified by the Purchaser (F, V, M).

- Required if special components or methods of design or construction are specified by the Purchaser (C, G, H, I, O, P).

All other annexes are "informative" (B, D, EC, K, R, T).