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What are Flanges

What are Flanges

Pipe flanges are a mechanical compression connection using bolts and gaskets for quick assembly and disassembly. Flanges are used both for structural and process applications connecting pipe to pipe, to valves, pumps and numerous other types of equipment. Pipe flanges are manufactured to standard specifications as well as custom designs. The ANSI B 16.5 spec covers 1/2″ thru 24″ nominal pipe size. The ASME B 16.47 Series A and B flanges are from 26″ thru 60″. TEMA Classifications for the Heat Exchanger Industries. The Industry Standard Flanges and AWWA for the Water Works Industry. Coastal Flange manufactures and stocks flanges to these specs. Contact us with any questions and to get your bid winning quote today.


Flange Pressure Ratings

All flange specifications are broken down by size and pressure classification. The ANSI B 16.5 has 7 pressure ratings. They are 150#, 300#, 400#, 600#, 900#, 1500# and 2500# pressure ratings. The ASME B 16.47 Series A and B flanges are supplied in 150#, 300#, 400#, 600# and 900# pound range. Please note in the 400#, 600# and 900# ratings sizes 38” thru 60” Series B are the same dimensions as Series A.
The Industry Standard are made to the following pressure ratings, Class 75, Class 125 Light Weight, Class 150/125, Class 175, Class 250, Class 300 and the Class 350.
The AWWA Classes for the Water Works Industries are Class B at 86 psi. Class D at 175 psi up to12” nominal pipe size. For 14” and above it is 150 psi. Class E flanges at 275 psi. The Class F are 300 psi.



The Material Test Report is the Quality Document that is first applied at the mill that pours the billet.It has the chemistry of the materials used in this process, the mechanical properties are added at the forge shop that forms the forgings. When Coastal receives in the forgings that heat number is applied and follows the flange thru the machining process and is hard stamped on the od of the flange along with the manufacturers name or logo as well as the pipe size, pressure rating, flange specification and the material grade and heat code.

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