Use of RFSO flanges over 24 inches for Section VIII

[Jordan123]

I'm trying to use a 30 inch 304L RFSO flange under Section VIII. I understand B16.5 covers these up to 24 inches and B16.47 for larger diameters does not include slip-ons. Section VIII UG-11 allows for use of prefabricated pressure parts made to an ASME (i.e.; UG-44) or manufacturers standard (footnote 6). I have seen references to both B16.1 and AWWA Standard C207-07 but neither covers this material of construction so it would seem to preclude use under UG-11. On top of that, we don't know how to derive the temp-pressure rating from what's given in these. We have tried to verify use using Appendix 2 calcs but it is failing thickness significantly for seating condition. Our conclusion at this point is that we can't use based on either UG-11 or Appendix 2. Short of alternate calcs such as finite element analysis, is there any way to use this under VIII? FYI design pressure is 60 lbs and temp is 340F.

 

[DSB123]

You can always perform calculations to ASME to prove the design of the flange you want to use.

 

[prex]

If you fail the gasket seating condition per App.2, you won't be able to prove the conformance to Div.1 with any other method, including FEA.
If you reduce the number of bolts, will your flange satisfy App.2?

prex

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[Jordan123]

Thanks DSB123 and prex for your responses. Subsequent to my post we were able to work out the calcs per Appendix 2.
It would seem the conclusion that there is no prequalifying standard is correct and turning to App 2 is the right route.
I would have rescinded the post, but I didn't see a way to do so.

 

[jte]

I would have rescinded the post, but I didn't see a way to do so.

Just click on the Red Flag link in the middle of your post. Write a sentence or two requesting that your post be pulled. Chances are pretty good that the site management will delete the thread on your request.