Historical
ASME B16.4-2016
Gray Iron Threaded Fittings Classes 125 and 250
This Standard for gray iron threaded fittings, Classes 125 and 250, covers (a) pressure–temperature ratings (b) sizes and method of designating openings of reducing fittings (c) marking (d) material (e) dimensions and tolerances (f) threading (g) coatings Mandatory Appendix I provides table values in U.S. Customary units.
American Society of Mechanical Engineers [asme]