"R" Stamp required or not? 4

[ET50]

We recently recieved a pressure vessel and installed it in our system. Before actually putting it into service we discovered a pinhole leak on one of the weld seams on the shell during a Nitrogen purge/leak test of other devices. We sent the vessel back for repair, and it arrived back without an "R" Stamp or other documentation. Is this legal given that the vessel never was commished into service in our system, or does it require an "R" stamp because it was initially inspected, hydrotested, and "U" stamped regardless of the fact it never officially went into service?

 

[mettamadhan]

Duwe6 there are cases that a crack may arise during the operation from a pinhole due to service conditions. You cannot compare a 2" nozzle addition with this case. Any code is sometimes generalised to cover all these service conditions.

 

[Duwe6]

Don't think many folks will want to hydro to verify a crack removal/repair. An unsuccessful repair will evidence itself with a catastrophic failure during hydro.

The NDT method performed to determine 'crack' vs. 'pinhole' will usually be deemed as adequate evidence of a successful repair. It is VERY imprudent to re-perform the original hydro on a used vessel.

 

[jtseng123]

Duwe6, technically, I disagree with you not performing original hydrotest again. There is nothing wrong to do it again to prove the repaired area will fit for service when the whole vessel is simulated in design condition. It is to check the gross integrity of the repaired area when the vessel is fully stressed, not just a pin hole. Also, NBIC states clearly re-ydrotest is required unless in certain conditions you can waive it, with consent from AI and end user.
Without re-hydrotest, end user must be willing to take the risk of failure during operation.
Practically from what I have seen, re-hydrotest is hardly done to save cost and to improve schedule. A day's down time is equal to million $$ for a plant.
If any of you are just an engineer like me, not an AI or end user, do not make any decision not to re-hydrotest. Read the NBIC, present the fact to AI and end user, let them make the call.

 

[PVinspector]

If the vessel is new, and has not been in service, when you send it back to the Certificate holder who built it they often check to see if the data report has been submitted to the National Board. If it has, R stamp should be the only option. If the Data Report has not been submitted, and the AI is OK with it, often the repair (or modification) is made, data report changed if needed (not needed in this case), vessel re-hydrotested, and the data report is signed and sent to the National Board. While this is not specifically permitted under new construction, it is not specifically prohibited. I think it is a common practice, and if documented properly in the Inspector's bound diary, nothing is being hidden and it avoids the addition of an "R" nameplate on an otherwise new vessel.

 

[metengr]

The above post is really a stretch. If the vessel has been hydrotested and CODE STAMPED it is COMPLETED, and is no longer under the construction code.

The Code does not permit one to simply go back and repair/alter a completed vessel and simply re-hydrotest the vessel and now say it is what, RE_COMPLETED?