treemkr
Mechanical
- Oct 3, 2006
- 18
I have a project where we need to increase the size of an existing nozzle in a column. This nozzle with be larger than any nozzle originally supplied with the column so it will be an alteration rather than a repair. The plant had done this previously approx. 15 years ago and at that time they cut out the existing nozzle, enlarged an opening, welded in the new nozzle, and then welded in a pipe cap to inner shell so they could do a 'local' hydrotest.
The contractor is offering to do this alteration by making a patch plate with the new nozzle installed where they would do a similar hydrotest, but in the shop vs. the field.
It should be noted that the original vessel shell used SA 212 B material, which has been disconntinued 30 or more years ago. I believe SA 515 70 is the replacement material for this. They want to use SA 516 70.
The nozzle will require a reinforcment pad.
My questions:
Is this 'patch plate' alteration procedure allowed by code? If so, should they do full radiography of the shell welds?
What are the issues, if any, of using the different shell plate material?
Would they need to follow the same weld procedures as original?
Any comments / clarifications would be helpful.
The contractor is offering to do this alteration by making a patch plate with the new nozzle installed where they would do a similar hydrotest, but in the shop vs. the field.
It should be noted that the original vessel shell used SA 212 B material, which has been disconntinued 30 or more years ago. I believe SA 515 70 is the replacement material for this. They want to use SA 516 70.
The nozzle will require a reinforcment pad.
My questions:
Is this 'patch plate' alteration procedure allowed by code? If so, should they do full radiography of the shell welds?
What are the issues, if any, of using the different shell plate material?
Would they need to follow the same weld procedures as original?
Any comments / clarifications would be helpful.