ASME-U stamped Vessel

[coatingcontrol]

We have an ASME-U stamped Vessel where we cut a nozzole and re-weld it .The weld NDT teseted and found acceptable and the whole vessel hydrotested and passed the test . Vessel is back to service. Does this vessel still maintain U-Stamp ? .If not what is require to reinstate it ? Regards

 

[JStephen]

The U-stamp relates to the original construction, not to the condition or modification or repairs of the vessel, so you don't "lose" a U-stamp. There is an "R" stamp pertaining to repairs or modifications per the National Board Inspection Code.

 

[vesselfab]

were the nozzle repairs made by a holder of a valid "R" stamp as issued by NBIC?

 

[pflow]

Is the hydrotest requirement after the repairs at the discretion of the holder of the "R" stamp?

 

[Duwe6]

pflow, The requirement for post-repair hydro rests in the hands of the "R"-stamp holder's Authorized Inspector. Can't recall ever seeing an A.I. require a re-hydro for a repair this minor. But requiring one is within the A.I.'s prerogative.

Ordinarily, a re-hydro is only specified for a significant Alteration, as opposed to a Repair.

 

[bernoullies123]

Interpretation: VIII 89-5
Section VIII-l Interpretations No. 24

In summary: Vessel hydro completed. Prior to shipment an arc strike noted and grinded below t minimum. Buttered back per approved WPS and NDT all clear. Question: Hydro to be performed again?
Reply: Yes.

 

[Vinch]

I will try to clear things up. Test requirements for a reparation is often misunderstood.

Duwe6, a hydro test ,as per ASME sect. VII, of a repaired item is never required nor is it allowed. What the NBIC part 3 call for is a leak test and that is mandatory for any repairs on the pressure boundary. The leak test can take many form: hydro pressure, pneumatic pressure, soap bubble test... It could look like an hydro-test but the difference is that pressure shall not exceed MAWP.

Bernouillie, ASME sect. VII only applies to new construction.

For the original question, the U-stamp is maintained. Keeping records of repairs made on a vessel is a good practice and that is one thing the R-stamp program is for.

 

[Bocephus50]

Was nozzle a RFWN Flg which was cut-off and replaced or rewelded? Or was the nozzle cut-out of the vessel shell and replaced with new fabricated nozzle?

Vessel was originally ASME Code U stamped (code of construction). Repairs and alterations (after inservice) must be made by an R stamp holder in order for the vessel to maintain its code integrity. R stamp holder will apply R stamp after completion and approval by their Commissioned Inspector (equivalent to Authorized Inspector for new construction).

Completed Repair requires pressure test unless NDE alternative is approved by Inspector and possibly jurisdiction.

 

[GenB]

oatingcontrol,
answer: no.
reinstate: Get an R stamp holder right away and see if he/she can save your vessel.
If it was done w/o proper inspection. you may have the R
Contractor cut and re-weld it to keep the certification.
regards. er