Water Jacketed Vessel Code Boundary 1

[Speckworm]

Hello,
An ongoing debate between fabricators of ours is whether a continuous 1" water jacket on an ASME coded vessel should be included in the code boundary of U-1 stamped vessel. The jacket pressure relief device is set for 20psi. We consider the exception under U-1(c)(2)(f), however the inner wall of the jacket is a furnace wall that is rated in the documentation for up to 300F. Does this disqualify the water jacket from the exception of being within the code boundary or is the design temperature limit of 210F only for the outer jacket wall?
Thanks.

 

[david339933]

Did you look at the scope of jacketed vessels in Appendix 9? Specifically 9-1(c)?

 

[Speckworm]

I did and to me it conflicted with the exception and is not clear if one overrules the other - leaving possible room for debate.
BUT, by bringing my attention to 9-1 again (thank you by the way) I re-read it very closely and I think I found the final verdict in 9-1(a): "The jacketed portion of the vessel is defined as the INNER and outer walls..." with the inner wall at a design temp of 300F it clearly disqualifies the exception in U-1.
You have been most helpful. Thank you very much for your reply.