This standard is intended to cover API ring-joint dimensions for American Standard (ASA)1 steel flanges@ (threaded with API standard line pipe threads2 or American Standard thread)@ other sizes of flanges as required@ and rolled@ and slip-on welding and welding neck flanges. These ring-joint dimensions are also to be used on steel flanged valves and fittings where connected to ring-joint flanges@ or where ring joints are required in piping connections. If flanges of larger size than those covered herein are required@ the flange diameters@ thicknesses@ drilling@ and ring-joint dimensions shall be in accordance with ASA standards. This standard also covers ring-joint flange unions for use with API tubular goods@ (line pipe@ casing@ drill pipe@ and tubing). 2-a. Nothing contained in this specification is to be construed as granting any right@ by implication or otherwise@ for manufacture@ sale@ or use in connection with any method@ apparatus@ or product covered by letters patent@ nor as insuring anyone against liability for infringement of letters patent. 1 ASA Standards mentioned herein may be secured from the American Stanards Association@70 West 45th St.@ NewYork 17@ N. Y. 2See API Std. 5-F: Threads in Fittings.
API STD 5-G-3-1945 history
1945API STD 5-G-3-1945 STANDARD ON RING JOINTS FOR STEEL FLANGES AND FLANGE UNIONS (Third Edition; Incorporates Supplement 1: August 1946)
1940API STD 5-G-3-1940 RING JOINTS FOR STEEL FLANGES AND FLANGE UNIONS (Second Edition; Incorporating Supplement: January 1941)
1937API STD 5-G-3-1937 RING JOINTS for STEEL FLANGES AND FLANGE UNIONS (FIRST EDITION)