This Standard covers threaded malleable iron unions, Classes 150, 250, and 300. It also contains provisions for using steel for NPS 1⁄8 unions. This Standard includes
(b) pressure–temperature ratings
(f) joints and seats
(h) hydrostatic strength
(i) tensile strength
(j) air pressure test
Mandatory Appendix I provides tables in U.S. Customary units.