Hai,
Can anybody suggest what is the limit of UG-45 nozzle wall requirement.
I will explain the case. Suppose I have a drain nozzle at bottom head of the vessel of 6" NPS. As per nozzle internal pressure calculation the required thickness is 5 mm including corrosion allowance and as per UG-45 the minimum required thickness for 6" pipe is 6.22+3 (C.A) = 9.22 mm.
Now my question is whether we need to keep this 9.22 mm thickness up to the entire length of the nozzle? (i.e., from vessel surface to flange end) or this UG-45 thickness requirement is limited to only up to the nozzle reinforcement limit normal to the vessel wall (2.5T)?.
Please advise on this.
Regards
Anil Kumar.

Hello Anilkumar

The UG-45 requirement is there to ensure the nozzles subject to external loads from piping thrusts is thick enough to accommodate those loads, without doing a detailed analysis. For example, in the code, that requirement is not required for manways, because piping is not attached to manways. Now, if you have a nozzle serving the purpose of drainage, it too might not have attached pipework. In which case you could probably treat in the same way as one would do with a manway. In the PV Elite nozzle dialogue screen, there a check box asking if the nozzle is a manway. If that box is checked, the UG-45 analysis will not be done by PV Elite.

As to you question about having part of the nozzle satisfying UG-45, I see not reason why you cannot do that. The pressure vessel envelope terminates at the first joint in the nozzle, so presumably it is not a code violation.