API STD 598:1994 pdf download.Metal Plug Valves‑Flanged and Welding End
1.1 Scope
1.1.1 This standard covers metal plug valves with flanged or butt-welding ends and ductile iron plug valves with flanged ends in sizes NPS 1 through NPS 24, which correC- spond to nominal pipe sizes in ASME B36.10M. Valve bodies conforming to ASME B16.34 may have one flanged end and one butt-welding end. 1.1.2 This standard covers additional requirements for plug valves that are otherwise in full conformance to the requirements of ASME B16.34 for Standard Class 150 through 2500 or ASME B 16.42 for Class 150 and 300. 1.1.3 This standard covers both lubricated and nonlubricated valves that have two- way coaxial ports; three way and four- way plug valves are not discussed in this standard. This stan- dard includes requirements for valves ftted with intermal body, plug, or port linings or applied hard facings on the body, body ports, plug, or plug port. The extent of linings and the materials of which they are made are not covered in this standard. 1.1.4 Plug valves covered in this standard belong to one of four general design groups that in many cases have different face-to-face and end-to-end dimensions. Some types of plug valves are not made to all patterns. The four groups are described in 1.1.4.1 through 1.1.4.4. 1.1.4.1 The short-pattern design is found only in Class 150 and 300 where flanged plug valves match the face-to- face dimensions of steel flanged gate valves in NPS 1% through NPS 12. 1.1.4.2 The regular patterm design has a plug port area that is greater than the venturi pattem.
2.2.2 Face-to-face dimensions for raised-face and ring- joint flanged-end valves and end-to-end dimensions for butt- welding-end valves shall conform to ASME B16.10. 2.2.3 End flanges of steel valves shall be integrally cast or forged with the body; however, flanges may be attached by full-penetration butt welding if this method is specified in the purchase order. End flanges attached by welding shall be cast or forged butt-welding ends. Welds shall conform to ASME B31.3, as shall qualifications for the welding proce- dure and the welder or welding operator. The finished weld thickness shall not be less than the minimum body-wall thickness (see 2.2.1). No welding or brazing shall be permitted on ductile iron. 2.2.4 The dimensions and finish of steel end flanges shall be as specified in ASME B16.5 for the type of facing speci- fied in the purchase order. Flat- face flanges not covered by a lining material shall be finished as specified in ASME B16.5 for raised-face flanges.
API STD 598:1994 pdf download
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