Loading… ASME B16.47 Large Diameter Steel Flange Standard In November of 1980, Subcommittee C of the American Society of Mechanical Engineers (ASME) B16 began work on the B16.47 Large Diameter Steel Flange Standard to standardize dimensions, tolerances, markings, and materials for Nominal Pipe Sizes 26” to 60”. Prior to this in July of 1952, MSS-SP44…