UG-6(c) - Body Flange

[marty007]

Hello,

In the 2013 edition of ASME VIII-1, some additional restrictions were placed on forgings in paragraph UG-6(c).

The wording that I have a question on is:

"Forgings certified to SA-105... may be used as tubesheets and hollow cylindrical forgings for pressure vessel shells that otherwise meet all the rules of this Division, provided that the following additional requirements are met:"

Would you typically consider an Appendix 2 weld-neck flange as a part of a pressure vessel shell and be subject to the restrictions of this paragraph, or would it not be considered a part of the shell and be exempt from UG-6(c)?

Up to now we considered it part of the shell (was thinking of the hub on a weldneck in particular), but our AI is questioning our interpretation. We have been on the conservative side of things, but it would be nice to relax our forging requirements if possible.

Cheers,

 

[SnTMan]

marty007, SA-105 was used for hub flanges forever with no special requirements prior to the recent UG-6(c) changes. It appears to me this change was made to permit some uses of SA-105 that were previously not permitted by the SA-105 Scope. I would not consider a hub flange as "hollow cylindrical forgings for pressure vessel shells".

I do not think the provisions of UG-6(c) need be applied to hub flanges.

Regards,

Mike