This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for pipe flanges in sizes NPS 26 through NPS 60 and in ratings Classes 75, 150, 0300, 400, 600, and 900. Flanges may be cast, forged, or plate (for blind flanges only) materials, as listed in Table 1A. Requirements and recommendations regarding bolting and gaskets are also included.