ASME VIII: Appendix Y or Appendix 2

[pastyl]

At a beu heat exchanger the tubesheet is fixed and gasketed on both sides by channel flange and the shell flange.
In case o-ring gasket is used (m=y=0) there is a contact surface between channel flange and tubesheet and the same valids for shell flange and tubesheet.
However the contact surface is not extended beyond bolt diameter.
My question is if ASME VIII App.2 or App. Y is suitable for flanges & bolts stress calculation.

 

[SnTMan]

pastyl, what I'm going to say is based on kind of a quick read of Appendix Y, work with Part UHX, and what I can get from your description of the configuration:

To satisfy Part UHX and Appendix 2 requirements for consideration of mating flange loads, pass partition area, heat exchanger (including tubesheet) design per UHX, I believe I would design such that no metal-metal contact occurs outside the bolt circle (as your configuration seems) and design per Appendix 2.

It appears to me that Appendix Y does not explicitly cover mating flange loads, as your HX will have if tube and shell are at different pressures, although you could probably design similar to the Appendix 2 approach to address this.

As I said, I would not call the above definitive, but this approach might be the easiest to defend if required.

Regards,

Mike