API Spec 12K:2008 pdf download
API Spec 12K:2008 pdf download.Specification for Indirect Type Oilfield Heaters.
62.3 WeldIng Procedure Qualifications
Each manufacturer shall quality the procedures they intend to use in production by producing weidments and having mechanical tests perfomied as required by Section IX of the ASME Code Where controlled hardness is required by NACE MR 0175. the maximum hardness of the base materials, the weld metal, and the heat affected zone may be detem’iined on the procedure qualification. The results of all tests shall be recorded and certified on procedure qualification records (PORs) by the manufacturer to support each WPS. Qualification by one manufacturer shall not qualify a WPS for any other manufacturer.
62.4 Welder Qualifications
Each manufacturer shall qualify all welders and welding operators employed en coil welding in accordance with the requirements of Section IX of the ASME Code. The results of all tests shall be recorded and certified on a welder performance qualification (WPQ) by the manufacturer for each welder and welding operator. Qualification of individuals employed by one manufacturer shall not qualify them for employment by any other manufacturer without requalification.
62.5 Pipe Bends
Pipe may be bent by any hot or cold method which wl result en arc surfaces free of cracks and substantially free of buckles. The minimum center-line racus of bends shall be 1 ½ times the nominal pipe size.
Flattening of a bend as measured by the difference between the maximum and minimum diameter at any cross section shall not exceed 8% of the nominal outside diameter. The mininum wall thickness of a bend after bending stial not be less than the minimum wall thickness (‘m) as defined in 5.1.1.
After cold bending, stress relieving iS required when the extreme fiber elongation of the outside periphery of the bend exceeds 15%. Stress relieving, when required, wil be done m accordance with the provisions for heat treatment as desaibed in ANSI/ASME B31 .3.
6.2.6 Nondestructive Examination
All components and welds shall as a minimum be visualy examined during and after fabrication. Visual examination is the observation of the portion of components. joints and other pçing elements that are exposed to view before, during, or after manufacture, fabrication, assembly, or testing to assure compliance with this specification and the manufacturer’s drawings.
In addition, coils fabricated from extra strong (XS) pipe through double-extra strong (XXS) pipe inclusive shall have 10% of the circumferential butt welds radiographed. The weld selection is to be random and each weld selected is to be radiographically examined over its entire length, The method of radiography shall be in accordance with the latest edition of the ASME Code, Section V. Article 2. The limits of wnperfections are given in Table 5.
6.2.8 Post Weld Heat Treatment
When the nominal wall thickness of a welded joint is equal to or greater than 3/4 in., the welded joints shall be stress relieved in accordance with the provisions for heat treatment as desaibed in ANSI/ASME B31 .3.
6.2.9 Hydrostatic Test
Heater coils shel be hydrostatically tested to one and one-half tries the maximum internal working pressure as calculated by Equation (2) of 5.1.1 with no allowance for corrosion or erosion, or the limiting maximum working pressure as determined by 5.1.4. Where test pressures hiier than specified above are required. the maximum coil working pressure shall be reduced if required to assure that the test pressure will not cause any material to be stressed above 90% of the minimum specified yield strength. Following the application of the hydrostatic test pressure. a visual inspection shall be made of all welded joints, This inspection shall be made at a pressure not less than two-thirds of the test pressure Any leaks revealed during this visual inspection will be repaired by welding after the water is drned, The coil shall be retested. It is recommended that the liquid temperature dtiing hydrostatic test be not less than 60°F.
6.3 Shell, Firetube, Stack and Accessories
Shell, firetube, stack and accessories shall be faodcated and assembled Using good workmanship to assure compliance with the manufacturer’s drawings and this specification. The completed heater shell shall be leak tested after the coil(s) and firetube(s) have been installed, examined for excessive distortion of flat sections. and any deficiencies repaired.
6.4 PaInting
Before shipment, heaters shall be mechanically cleaned of rust, grease, loose scale, and weld spatter, and the outside of the shell coated with one application of a good grade of commercial metal primer. Finish coats or special painting systems shall be applied if so agreed upon between the purchaser and the manufacturer.
