ASME BPVC Section VIII Division 1 UG-34

[DMay121]

Hey there,

I am currently analyzing a vessel that uses an unstayed flat head that is bolted down with thirty two 1-1/8-8 bolts. The gasket is a full-face typed elastomer gasket that follows sketch (p) of Fig. UG-34. Generally, Appendix 2 is used to carry out calculations for the bolts and the flange or cover, but in the first line of Appendix 2 it states it can only be used when the gasket material is contained completely within the bolt diameter. Seeing that this vessel utilizes a full-face gasket that has bolt holes machined out it, Appendix 2 can't be used.

I know that I can use equation 1 in UG-34 to calculate the thickness of the flat head, but how should I go about calculating bolt stresses and the required thickness of the flat head because of the compression stress of the bolts? Is there a standard I can reference or do I need to use FEA or some textbook equations?

Thanks,
David

 

[SnTMan]

XL83NL, you're welcome

DMay121, I doubt you are going to find it written in the Code. I frankly don't believe I have run into a situation where tr has been so small that UG-16 thickness is a consideration, not that it couldn't happen. As well, re-reading UG-16, it would appear to not apply to nozzles, where trn below UG-16 thickness could be more commom.

Common sense? I dunno. Common practice? I'd say yeah.

Of course, if tr is set at UG-16 thickness and reinforcement makes without adverse economical effects on the design, I suppose the practice is not wrong. I'm thinking of a situation where, say, shell / head thickness is 1/4", tr is 0.050", tr is then set to 0.063" and reinforcement is adequate. No harm in a little extra conservatism.

This is the kind of thing that makes checking / reviewing other's work such a joy. I have myself found it necessary to adopt the philosophy "If it ain't wrong, it's right."

Good luck,

Mike

 

[jg9731]

Thank you SnTMan, I've been looking for a copy of TF Bulletin 45 for hours!