Repair in Fabrication Shop
Repair in Fabrication Shop
(OP)
We found incorrect elevation of nozzle during final dimension check. The fabricator proposed to repair by patching (double v-groove butt weld) at the shell. They confirm the quality by RT 100%.
Is this conformed to ASME Sec. VIII Div. 1? Please comment.
Is this conformed to ASME Sec. VIII Div. 1? Please comment.





RE: Repair in Fabrication Shop
RE: Repair in Fabrication Shop
If you can not alter the piping think about blanking the existing, incorrect nozzle off and adding a nozzle in correct location.
This is by far the most acceptable solution when the vessel integrity is concerned.
I assume that both nozzles meet the requirements for reinforcement and the material is available. You need to have a look at the price of alterations. The other thing to consider is the process the stagnant volume after this blanking off might be not acceptable in your application.
Please let me know what was your final solution.
Putting Human Factor Back in Engineering
RE: Repair in Fabrication Shop
The fabricator must get concurrence from the AI for this repair to the vessel wall because this is a new vessel. Make sure you have discussed this with their AI for all necessary QC hold points and NDT.
RE: Repair in Fabrication Shop
jonesey & VeryPicky,
The nozzle is for adsorbent unloading (size 6"). The elevation before repair is 10 cm above the required elevation. Therefore, We cannot blank or accept without repair. After repair, the reinforced pad will cover the entire of repair area.
metengr,
We will perform hydrostatic test after pass NDT. Thanks again for your comment.
RE: Repair in Fabrication Shop
RE: Repair in Fabrication Shop
Putting Human Factor Back in Engineering
RE: Repair in Fabrication Shop
Thanks for your comment. There are 2 unloading nozzle at the opposite site. The incorrect elevation was found only 1 nozzle. Therefore, I keep the orientation. You are right...The repair area and nozzle intersect. The fabricator fit up the upper moon cressent section with the removed lower moon cressent section.
Due to no deviation from ASME Sec. VIII Div. 1, I cannot refuse the proposed repair procedure from this fabricator. Any further comments will be appreciated.
RE: Repair in Fabrication Shop
You can reject any repair, within reason. I understand that you ordered a new vessel and getting a repaired one.
To me this is a reason enough for the client to be involved in the repair. You have to ask yourself if the repair is acceptable from technical point of view for your application.
I am just saying that I don't have enough data for welds intersecting at the tangent like in the patch described by you and the nozzle loading. I would expect that the fabricator did proper stress analysis in that particular corner.
If you happy there is nothing more to say.
Putting Human Factor Back in Engineering