Sect VIII UG-34 vs. B16.5 blind thickness 1

[BigTank]

should one expect to see a correlation here? will a blind that is usable in the code ever fail UG-34 required thickness calculations?

likewise, will a flange as calc'ed by appendix 2 ever be thicker than a usable (by code) b16.5 flange?

thoughts?

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[TomBarsh]

I see you've seen the related thread:

http://www.eng-tips.com/viewthread.cfm?qid=261110&page=1

I'm not sure about blind flanges, I have never run numbers on them to compare the two methods (well, I guess I have but I don't remember the outcome).

But certainly there is little correlation between flange thickness per Appendix 2 and B16.5. Many B16.5 flanges when analyzed by Appendix 2 will have an MAWP that is much less than their standard pressure-temperature rating. But then, some such flanges will have an MAWP that is far greater than their pressure-temperature rating.

Having looked at this in the past, I observed that "stocky" flanges, say a 6" Class 1500 flange, will have Appendix 2 MAWP values possibly far exceeding their pressure-temperature rating. But "wimpy" flanges, like a 24" class 150", will likely have an MAWP nowhere near their pressure rating.