ASME B16. 28-1994 pdf download.Wrought Steel Buttwelding Short Radfus Elbows and Returns.
2.1 Design of Fittings
The design of the fttings shall be established bymathematical method analysis contained in nationally recognized pressure vessel or piping codes or at the manufacturer's option by proof testing in accordance with Section 9 of this Standard. In order to meet design requirements, it is expected that some portion of formed fittings may have to be thicker than the pipe wall with which the ftting is intended to be used.
2.2 Basis of Ratings
The allowable pressure ratings for fttings designed in accordance with this Standard shall be as for straight seamless pipe of equivalent size and material [nominal pipe size (NPS), wall thickness or schedule number, and including a comparison of chemical composition and mechanical properties of the respective material specification].
2.3 Record Maintenance
Records of mathematical analysis and/or successful proof test data shall be available at the manufacturer's facility for inspection by the purchaser.
Certified copies of this data shall be made available to the purchaser upon agreement with the manufacturer.
4 MARKING 4.1 Standard Marking (See Note) Each fitting shall be permanently marked to show the following: (a) manufacturer's name or trademark; (b) material grade and class (ASTM or ASME grade symbol) and the heat number or manufactur- er's heat identification; (c) conformance to this Standard, designated by the prefix“WP" in the grade symbol marking; (d) schedule number or nominal wall thickness designation; (e) NPS. NOTE: The pressure rating of the fiting is represented by the NPS, wall thickness (or schedule number), and material marked on the ftting. (See para. 2.2.)
4.2 Exceptions Where the size of the ftting does not permit com- plete marking, the identification marks may be omit- ted in reverse of the order presented above.
4.3 Depth of Stamping Where steel stamps are used, they shall be low stress and care should be taken so that the marking is not deep enough or sharp enough to cause cracks or to reduce the wall thickness of the fitting below the design minimum allowed. 5 MATERIAL Wrought fittings covered by this Standard shall be in accordance with ASTM A 234, A 403, A 420, or the corresponding ASME Boiler and Pressure Vessel Code, Section II specification.ASME B16. 28 pdf download.