scope:

This specification covers materials and dimensions for cast and forged, carbon-steel and alloy-steel ring-joint flanges intended for use in accordance with the service pressure ratings given in Sect. III. These flanges are intended for use in water, oil, or gas service, and are suitable for use with valves covered by API Std 6C and 6D, and with wellhead fittings covered by API Std GE. Series 2900, 10,000-lb. flanges covered by Table 10 are the proper flanges for use with 10,OOO-lb. valves for well control service, as given in API Std GC. Because of threading and other dimensional requirements, casing and tubing flanges are peculiar to oil-field service.

The types of flanges covered include threaded flanges (line pipe, casing and tubing), slip-on welding flanges (line pipe and casing), welding-neck flanges (line pipe), blind flanges, and also integral flanges (facing dimensions only) for valves and fittings.

This standard also covers ring-joint gaskets and flange bolting, but neither is to be furnished unless the purchase order so states. 

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.