ASME B16.9

ANSI B16.9 Standard covers overall dimensions, tolerances, ratings, testing, and markings for factory-made wrought buttwelding fittings in sizes NPS 1/2 through NPS 48 (DN 15 through DN 1200).

B16.9 is to be used in conjunction with equipment described in other volumes of the ASME B16 series of standards as well as with other ASME standards, such as the Boiler and Pressure Vessel Code and the B31 Piping Codes.

Fittings may be made to special dimensions, sizes, shapes, and tolerances by agreement between the manufacturer and the purchaser. 

The design of fittings shall be established by mathematical analyses (e.g., ASME B16.49 for bends) contained in nationally recognized pressure vessel or piping codes, or at the manufacturer's option by proof testing. In order to meet
design or manufacturing requirements, it is expected that some portion of formed fittings may have to be thicker than the pipe wall with which the fitting is intended to be used. The mathematical analyses, if used, may take into account such thicker sections. Records of mathematical analysis and/ or successful proof test data shall be available at the manufacturer's facility for inspection by the purchaser.