WW-U-531F, FEDERAL SPECIFICATION: UNIONS, PIPE, STEEL OR MALLEABLE IRON: THREADED CONNECTION, 150 LB, 250 LB, 300 LB WSP (16-APR-1984) [S/S BY ASME-B16.39]

WW-U-531F, FEDERAL SPECIFICATION: UNIONS, PIPE, STEEL OR MALLEABLE IRON: THREADED CONNECTION, 150 LB, 250 LB, 300 LB WSP (16-APR-1984) [S/S BY ASME-B16.39]., This specification covers pipe unions with threaded connections, for 450psig (pounds per square inch gauge) WSP (working steam pressure), 250 psig WSP, and 300 pound WSP unions joining standard weight and extra heavy pipe.