(a) This Standard covers pressureûtemperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings. Included are (1) flanges with rating class designations 150, 300, 400, 600, 900, and 1500 in sizes NPS 1?2 through NPS 24 and flanges with rating class designation 2500 in sizes NPS 1?2 through NPS 12, with requirements given in both metric and U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units (2) flanged fittings with rating class designation 150 and 300 in sizes NPS 1?2 through NPS 24, with requirements given in both metric and U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units (3) flanged fittings with rating class designation 400, 600, 900, and 1500 in sizes NPS 1?2 through NPS 24 and flanged fittings with rating class designation 2500 in sizes 1?2 through NPS 12 that are acknowledged in Nonmandatory Appendix E in which only U.S. Customary units are provided (b) This Standard is limited to (1) flanges and flanged fittings made from cast or forged materials (2) blind flanges and certain reducing flanges made from cast, forged, or plate materials Also included in this Standard are requirements and recommendations regarding flange bolting, gaskets, and joints.