U stamp question

[ME231]

When does a "U" stamp vessel become certified?
Is it after the U stamp has been applied, or after the data report is submitted, or after the vessel has left manufacturing facility.
We have a U stamped vessel on which one of the openings needs to be modified. Vessel has not yet left the manufacturing facility so we have had full control over it since the U stamp was applied.
Would this warrant a "corrected copy" or an "R" stamp?
thanks in advance for your advice...

 

[ME231]

Clarification...the modification does not involved welding. Size of the opening was increased.
Thanks

 

[bcguy]

I would suggest discussing with your AI. If the vessel is still in your facility and under your control, it could be handled with an NCR. It would just be a matter of destroying the MDR and certifying a new one after the modification has been made.

If you have already sent in the MDR for registration with the National Board then a corrected copy would have to be submitted to the National Board.

In my opinion, an R stamp would not be required in either case, as the vessel is still in your facility and have never been put in service.

 

[gr2vessels]

The increase of opening size on a pressure vessel shell carries new design requirements. I'm not sure what opening is that can be increased without significant modification of the vessel design and doesn't involve welding. Can you please provide some more details, otherwise the replies might not be relevant.
gr2vessels