ASME B16.5 versus AWWA C207 Flanges
ASME B16.5 versus AWWA C207 Flanges
(OP)
Application: Treated chlorinated water about 100 psi working pressure.
I would like to know the correct application of flanges when joining a 4 inch steel flanged nozzle to a flanged steel butterfly valve. The butterfly valve would probably have a raised face. Is a ASME B16.5 identical to a AWWA C207 flange or does one have a raised face and the other not? What is the difference? Is a raised face necessary or is a flat face more desireable? I would be using a EPDM gasket material. Previously a flat faced flange has been specified for the nozzle flange but I want to know if this is optimum. Is a serrated surface needed in both at flat face and raised face application. I realize a flat face should be used with a cast iron flange. Also, what type of serrations, concentric or spiral, is best for this application.
I would like to know the correct application of flanges when joining a 4 inch steel flanged nozzle to a flanged steel butterfly valve. The butterfly valve would probably have a raised face. Is a ASME B16.5 identical to a AWWA C207 flange or does one have a raised face and the other not? What is the difference? Is a raised face necessary or is a flat face more desireable? I would be using a EPDM gasket material. Previously a flat faced flange has been specified for the nozzle flange but I want to know if this is optimum. Is a serrated surface needed in both at flat face and raised face application. I realize a flat face should be used with a cast iron flange. Also, what type of serrations, concentric or spiral, is best for this application.





RE: ASME B16.5 versus AWWA C207 Flanges
The bolt patterns of the C207 Cl. B and D flanges are the same as the 150# B16.5 flanges, and you can bolt one to the other. The AWWA flanges are thinner (for Cl. B and Cl. D) and may require slightly shorter bolts. The AWWA flanges are commonly made as plate flanges, without a hub. The main motivation to use AWWA flanges is that they are cheaper in larger sizes. In 4" size, it may be easier to just use a forged flange. Either FF or RF should work there. I don't know about that gasket specifically, but with normal rubber gaskets, the flange finish is not critical under those conditions.
RE: ASME B16.5 versus AWWA C207 Flanges
RE: ASME B16.5 versus AWWA C207 Flanges
This is a generalization only. This is not always the case. It really depends upon the sizes and pressures.
Regards,
EJL