I'm a bit stumped as to how to design the weld joint for a nozzle penetration through a jacket wall under Section III Part ND. Under Section VIII, this would be straightforward: Appendix 9, preamble to 9-4 gives you exemptions from the basic code, and Figure 9-6(a) is pretty close to what I would like to do.

But since Section III doesn't have an analogous appendix, I take it that jacket penetrations are treated like any other category D weld? If so, then the ND-4244 figures would appear to require a fillet or radius on both sides of the jacket wall. That inside fillet is not absolutely impossible, but kinda tough. Is there an exemption somewhere that I'm missing?

Another caveat is that Appendix 9 seems to assume a thin and flexible jacket wall. In my case, my jacket wall is a flat plate at that point, so it's 1/2" thick, about as thick as my nozzle wall. Does that make the inside fillet more advisable?