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UG-44(b) ASME VIII-1.Control of final loads at the nozzle flange face, for the B16.5 rating

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BickVess

Mechanical
Jan 13, 2023
2
thread292-493724
I say keep the 'may' in UG-44(b)
There may be time/opportunely in some industries on high end work for feedback loops to have the vessels and piping systems design optimised in glorious unison. My experience says the piping analysis is usually detailed much later.

Gasket leaks at a flange piping termination, have to be the final responsibility of the piping engineer as they have control of the overall forces & flexibility.
The customers piping designers specify the system flange ratings; so they can adjust their piping/supports to make it work for the flange ratings.
Overly stringent mission creep of UG-44(b) responsibility at the flange face back to the vessel designer, should be avoided.
As a vessel code designer it feels reasonable to get the build going with a generous predefined set of loads at the shell to nozzle junction. Then advise that no other significant loads are allowed beyond the ones quantified on our approved drawing, so it's clear what's been covered. The piping/system designer can take it from there; the vessel designer having safely given them parameters
Significant is a useful & safe word in engineering.

Any other vessel manufacturer's tips for getting by between this particular rock & a hard place would be welcome.
 
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Thanks
I did see that one.

I'm interested in how other vessel engineers decide what's reasonable, and communicate significant loads allowed that the piping engineers must keep within.
That's specific to a termination nozzle flange. In the common instance where system flange rating is specified, but the piping engineers not yet ready to engage in precise load calculations.

A key point being that the 'may' means that when the piping engineer gets to it; they can use any reasonable method to assess loads on the flange joint are not excessive, and discuss with the vessel designer if not clear cut.
 
Just as an update to that older thread - no changes to UG-44(b) are forthcoming in the 2023 Edition. Hopefully for 2025...
 
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