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DIMENSIONS
Flange dimensions are determined by pipe size and pressure class required for the application. Most of these dimensions have been standardized and published as ASME, MSS, API or other standardization organization specifications. When conditions create a need for a flange to be made to special requirements, Boltex has the means for creating the design to meet the criteria specified by the customer for a nominal charge. See the ordering information section for details.
 
ASME DIMENSIONS
ASME B16.5 provides dimensions and tolerances for flanges in pipe sizes from ½" through 24" and in pressure classes from 150 through 2500. In addition, B16.5 provides pressure ratings for various temperature ranges and a listing of materials from which flanges can be produced. It is the most widely used flange specification in the world. The flanges covered by this specification include welding neck, slip-on, lap joint, threaded, socket welding, blind and reducing flanges.

 ASME B16.47 provides dimensions for flanges in pipe sizes from 26" through 60" in Classes 150 through 900 for Series A flanges and Classes 75 through 900 for Series B flanges. Series A flanges have the same bolt circle, outside diameter and flange thickness as MSS SP44 flanges while Series B flange dimensions are the same as those for API 605. API 605 has been discontinued since the publication of B16.47 Series B data. The user is advised that the B16.47 specification applies to welding neck and blind flanges only. Any other configuration is nonstandard and may not carry the B16.47 marking. This is also true for flanges designated as MSS SP44 or API 605.

 ASME B16.36 is the dimensional specification used for orifice flanges. This specification provides the specific information for Classes 300 through 2500 and in pipe sizes from 1" through 24". For materials, reference is made to B16.5. Orifice flanges covered by this specification include welding neck, slip-on, and threaded for class 300 flanges only. All other pressure classifications are for welding neck flanges only. Any other configuration is nonstandard and may not carry the B16.36 marking.

 In addition to the standards listed above, API provides its own dimensional requirements and pressure classes in specification API 6A for wellhead equipment. API flanges are special application flanges and are not covered by this web site. Cast iron flanges are covered by ASME B16.1. Some B16.5 flanges are manufactured as "flat faced" for the specific purpose of mating to the cast iron flange faces of valves, pumps and other devices.

 AWWA standards are for steel pipe flanges for waterworks service, sizes 4'' to 144''. These flanges are for attachment to steel water pipe and fittings.