ASME B16.4

Description / Abstract: 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.