HYDRO-TEST AFTER REPAIR TO NEW VESSEL
HYDRO-TEST AFTER REPAIR TO NEW VESSEL
(OP)
I have a an ASME VIII Divison 1 vessel which is now finished, tested and sitting at site.
However one nozzle is of an incorrect size. We need to replace this nozzle with a larger one.
Welding will be done with an approved weld procedure at site.
Welds wll be 100% Dye Penetrant tested.
My question is - do we need to re do the ASME code hydrotest as we have cut into the vessel pressure envelope.
If I were just welding a an external pipe support clip to the vessel without cutting the shell / ends then I would not apply another hydro-test
Any comments / help will be most helpful
However one nozzle is of an incorrect size. We need to replace this nozzle with a larger one.
Welding will be done with an approved weld procedure at site.
Welds wll be 100% Dye Penetrant tested.
My question is - do we need to re do the ASME code hydrotest as we have cut into the vessel pressure envelope.
If I were just welding a an external pipe support clip to the vessel without cutting the shell / ends then I would not apply another hydro-test
Any comments / help will be most helpful





RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
The accomplishment of this alteration should be under the control of a company in possession of a NB “R” stamp qualified for field alterations. At a minimum this job requires a review of Sec VIII DI, UG-36 openings in pressure vessels and UG-37 reinforcement requirements. The alteration requirements are based on the nozzle size and location, the design pressure and temperature parameters of the pressure vessel, the nozzle and shell material types. In addition to the required hydrostatic test upon completion of the alternation, there are many other factors that need to be checked prior to commencement of this job.
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
An R-2 form must be issued and registered with National Board.
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
If you wind up requiring a hydrotest, you might want to consider (and discuss with the AI) welding a pipe end cap or 2:1 head (if the nozzle is really big) on the inside of the shell at the nozzle. Use fillet welds - size them right for the longitudinal pressure and keep them below VIII-1 minimums for PWHT. If I recall correctly, a 7/16" fillet is the max you can put on without requiring a PWHT vessel to be re-PWHT.
This head on the inside of the shell at the nozzle will allow you to hydro the nozzle and its connection to the shell without having to hydro the entire vessel. After the hydrotest cut off the head and grind flush. Many AI's will accept this. Again, check with yours first.
jt
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
One thing I didn't mention and perhaps should have done is that the vessel is not ASME - 'U' Stamped - only designed and fabricated in accordance with Division 1 rules. The vessel is located in a gas plant in Pakistan where there is no Authority Inspectors.
My main question is where in the ASME VIII Division 1 code does it state that when a nozzle is added to new finished and tested vessel that a new hydrotest has to be applied to it?
In my opinion we have to hydrotest however my superiors are trying to get around this. It may be that our client / end user will have the final say on this.
Thanks again
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
NDE as a minimum if you have no other choice.
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
For the sake of discussion, the nozzle in question could be classified as a repair, pending the nozzle size is not larger than any nozzle included in the original design NBIC appendix 6 B. 10. This must be evaluated to determine if this is deemed an alteration/repair. If considered as a repair, hydrotesting would be a optional testing method, however would not be required by the NB.
Your example of addition of a bracket could be considered an alteration in regards to loading, and could require a hydrotest if deemed an alteration.
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
Regards
joe
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
I have the following problem.
My Client (I am a contractor) has just received a new pressure vessel (Instrument air receiver) with MAWP 8 bar. The vessel manufacturer did not wanted to weld a few attachements for sustaining a ladder but we still need these.
The vessel is primed, has 10mm thickness and was tested in the manufacturer's yard. The vessel is not ASME stamped but is
Can I weld 4 attachements for sustaining a vertical ladder ?
Where in ASME 8 can I find the rules concerning welds on vessels after delivery ? Please, can you help ?
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
TO ADD A LADDER TO THE TANK, THE MANUFACTURER SHOULD HAVE TAKEN INTO ACCOUNT THE ADDITIONAL STRESES NECESSITATING A THICKER WALL OR REINFORCEMENT PADS AS IS PROVIDED FOR LEG SUPPORT.
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
material of shell, location of the new nozzle, size of the nozzle, temperature of the process, thickness of the shell,is the pressure cyclic, what is the process is it Lethal, what NDT has been done for the rest of the fabrication ...dye pen mentioned indicates not much ..if a new nozzle was added with 100% NDT it may be better than any of the others have had.
ASME are preparing a series of Post Construction codes which should prove helpfull in cases like this
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
Many replies in this thread are correct when they state that the ASME does not discuss changes or repairs to vessels that have already received final ASME acceptance as evidenced by a signed data report. The cases presented add the wrinkle that they meet the ASME but are not stamped however that wrinkle has no bearing on the final answer. Many responders have suggested that the NBIC applies. They are only correct if the vessel is operated in a location where the jurisdiction has a pressure vessel law that imposes the NBIC as the directed means of repairs and alterations. To be clear, the NBIC only has Repair and Alteration authority where its rules are imposed by the political authority. Most (but not all) States here in the US have similar statements in there laws. It is clear that these cases require repairs and/or alterations to a previously fabricated unit. It should also be clear the the means of performing the work is under the total control of the local Jurisdictional authority only.
Lane Baker
Baker Quality Services
LaneBQS@att.net
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
RE: HYDRO-TEST AFTER REPAIR TO NEW VESSEL
The equipment has now been modified, NDE applied, has been hydro-tested and the client is happy too.
For the record the vessel details were :-
Amine Drain Tank
DP 3.5 barg / FV @ 120°C
I.Dia = 2100
Thk = 9 mm
6" NB Nozzle replaced with a 10" NB
Contents - Amine Solution + Hydrocarbons
Thanks for all the replies