API Spec 12F-2008 pdf download.Specification for Shop Welded Tanks for Storage of Production Liquids.
3 Definitions 3.1 butt weld A weld placed in a groove between abutting members. Grooves may be square, V (single or double), or U (single or double). 3.2 double-welded butt joint A joint between two abutting parts lying in approximately the same plane and welded from both sides. NOTE A joint with filler metal added from one side only is considered equivalent to a double-welded butt joint when means are provided for accomplishing complete penetration and reinforcement on both sides of the joint. 3.3 double-welded lap joint A joint between two overlapping members in which the overlapped edges of both members are welded with fillet welds. 3.4 fillet weld A weld of approximately triangular cross-section joining two surfaces approximately at right angles to each other, as in a lap joint, tee joint, or corner joint. 3.5 full-fillet weld A fillet weld whose size is equal to the thickness of the thinner member joined. 3.6 tack weld A weld made to hold parts of a weldment in proper alignment until the final welds are made.
4 Material 4.1 General Materials listed in this section have been selected to provide adequate strength and reasonable service life. Other materials having mechanical properties equal to or greater than these listed may be used by agreement between the purchaser and the manufacturer. Where higher strength materials are used, the minimum thicknesses called for in this specification shall not be reduced. 4.2 Plates Plates shall conform to the latest edition of one of the following ASTM standards: ASTM A36, ASTM A283 (Grade C or D), and ASTM A285 (Grade C). Shell plates for which minimum thicknesses have been fixed for practical reasons (greater than required by computation) and which will not under run the required computed thickness by more than 0.01 in., as well as all roof and bottom plates, may be purchased on a weight basis. The plate thicknesses or weights, as stipulated herein, are minimums; thicker or heavier material may be required on the order at the option of the purchaser. 4.3 Sheets Sheets shall conform to the latest revision of ASTM A1011, Grade C or D, open-hearth process and basic oxygen process. Sheets may be ordered on a weight or thickness basis, at the option of the tank manufacturer. 4.4 Welding Electrodes Manual arc-welding electrodes shall conform to the E60 and E70 Series of Classification (suitable for the electric current characteristics, the position of welding, and other conditions of intended use) in the latest edition of AWS A 5.1. 4.5 Structural Shapes Structural shapes shall be of open-hearth, electric-furnace, or basic oxygen process and shall conform to the latest edition of ASTM A36.
4.6 Piping Pipe shall conform to Grade A or B of the latest edition of API 5L, ASTM A53, or ASTM A106. 4.7 Flanges Hub slip-on welding and welding-neck flanges shall conform to the material requirements for forged carbon steel flanges as specified in ASME B16.5. 4.8 Couplings Couplings for threaded connections may be supplied with or without recess, complying with the dimensional, physical and chemical requirements of the latest edition of API 5L, Grade B. Alternatively, couplings may comply with the latest edition of ASME B16.11. 4.9 Bolting Tank bolting 1 / 2 in. in diameter to and including 1 / 2 in. in length shall conform to the requirements given in Annex A. All other bolting shall conform to the latest revision of ASTM A307, Grade A or B. Unless otherwise specified on the purchase order, black-finish bolts and nuts shall be furnished. When specified to be galvanized, bolts and nuts shall be zinc-coated in accordance with Annex A or the applicable ASTM specification. Alternative materials and/or finish conforming to recognized standards for bolting may be furnished by agreement between the purchaser and the manufacturer. 5 Design 5.1 General Tanks covered by this specification have been designed using established engineering calculations to determine minimum metal thickness and bolting specifications for each size tank filled with water (62.37 lb/ft 3 @ 60°F) and at the internal pressure specified in Table 1, Column 2. In order to assure structural stability and integrity, additional metal thickness has been added to that determined by calculation. The minimum metal thickness specified in this standard shall in no case be decreased. 5.2 Joint Design Definitions Definitions in Section 3 shall apply to tank-joint designs.