UG-46 interpretation - 28" vessel

[HowJoh]

Greetings all,

I'm designing a small S/S vessel: 28" OD, toriconical bottom head, 17" SWL, and stands vertically. I wish to use the drain, which is a 2" Sch40S WN flange that has be welded into the lower head, as one of the two inspection openings. The other inspection opening is a flanged 4" nozzle in the top head. My fabricator is insisting that to qualify as an inspection port it either has to be a 2" threaded & plugged port or be at least as large the the minimum handhole size meaning that it would have to be a 3" nozzle. I'd rather not do this as my drain line is a 1" NPS.

Opinions, ASME interpretations, experiences, & humorous ramblings all appreciated.

Cheers,

 

[bpv66]

Take a look at UG-46(f)(7). Flanged/threaded connections from which piping can be removed may be used in place of the required inspection openings provided:

1) The connections are at least equal in size of the required opening
2) The connections are sized and located to afford at least an equal view of the interior as the required inspection openings.

As long as the 4" nozzle piping and 2" drain line piping can be removed I see no Code requirement for having the plugged/threaded openings.

 

[HowJoh]

Thanks for your comments bpv66. Where I'm running into trouble is that the fabricator is saying that any opening under UG-46(f)(7) has to be at least the same size has the minimum handhole size. They're interpreting the statement "in size of the required opening" to mean the handhole size (2"x3") and not a 2" NPS opening. So far we've not heard back from the AI.