API 650-2005 pdf download.Welded Steel Tanks for Oil Storage.
Scope 1.1 GENERAL 1.1.1 This standard covers material, design, fabrication, erection, and testing requirements for vertical, cylindrical, aboveground, closed- and open-top, welded steel 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 1.1.10). This standard applies only to tanks whose entire bottom is uniformly supported and to tanks in nonrefrigerated service that have a maximum design temperature of 93°C (200°F) (see 1.1.17) or less. 1.1.2 This standard is designed to provide the petroleum industry with tanks of adequate safety and reasonable econ- omy for use in the storage of petroleum, petroleum products, and other liquid products commonly handled and stored by the various branches of the industry. This standard does not present or establish a fixed series of allowable tank sizes; instead, it is intended to permit the purchaser to select what- ever size tank may best meet his 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 pur- chaser’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. 1.1.3 This standard has requirements given in two alternate systems of units. The requirements are similar but not identi- cal. These minor differences are due to issues such as numeri- cal rounding and material supply. 2.2 PLATES 2.2.1 General 18.104.22.168 Except as otherwise provided for in 2.1, plates shall conform to one of the specifications listed in 2.2.2 through 2.2.5, subject to the modifications and limitations in this standard. 22.214.171.124 Plate for shells, roofs, and bottoms may be ordered on an edge-thickness basis or on a weight [kg/m 2 (lb/ft 2 )] basis, as specified in 126.96.36.199.1 through 188.8.131.52.3. 184.108.40.206.1 The edge thickness ordered shall not be less than the computed design thickness or the minimum permitted thickness. 220.127.116.11.2 The weight ordered shall be great enough to pro- vide an edge thickness not less than the computed design thickness or the minimum permitted thickness. 18.104.22.168.3 Whether an edge-thickness or a weight basis is used, an underrun not more than 0.25 mm (0.01 in.) from the computed design thickness or the minimum permitted thick- ness is acceptable. 22.214.171.124 All plates shall be manufactured by the open- hearth, electric-furnace, or basic oxygen process. Steels pro- duced by the thermo-mechanical control process (TMCP) may be used, provided that the combination of chemical com- position and integrated controls of the steel manufacturing is mutually acceptable to the purchaser and the manufacturer, and provided that the specified mechanical properties in the required plate thicknesses are achieved. Copper-bearing steel shall be used if specified by the purchaser. 126.96.36.199 Shell plates are limited to a maximum thickness of 45 mm (1.75 in.) unless a lesser thickness is stated in this standard or in the plate specification. Plates used as inserts or flanges may be thicker than 45 mm (1.75 in.). Plates thicker than 40 mm (1.5 in.) shall be normalized or quench tempered, killed, made to fine-grain practice, and impact tested.