Additional welding after hydrostatic test
Additional welding after hydrostatic test
(OP)
I have a queries on whether it is permissible to do welding of small of pipe support clip on vessel with only fillet welding after completion of shop hydrostatic test.





RE: Additional welding after hydrostatic test
RE: Additional welding after hydrostatic test
You don't specify if your question is per Code rules or other, nor other pertinent specifics such as material type, etc, so, a second hydrotest may or may not be required. If your question centers around Code rules, talk to your AI. If we're talking carbon steel, chances are good that you won't have to re hydro. Customer requirements may differ, but, we have done welding after hydro many times without a second hydrotest.
RE: Additional welding after hydrostatic test
RE: Additional welding after hydrostatic test
RE: Additional welding after hydrostatic test
This is one of those areas where internal conflicts arise with Code bodies. Section I permits welding of P-No 1 pressure retaining materials after hydrostatic testing under restrictive conditions. See PG-54.3.2
My counterparts in the SG and SC of Section VIII don't see it this way. Philosophical differences I suppose. Anyway, do the clip welding after the vessel is commissioned into service. The NBIC or API provide rules for this activity.
RE: Additional welding after hydrostatic test
Regards,
Mike
RE: Additional welding after hydrostatic test
Metengr, if you disagree please let me know.
RE: Additional welding after hydrostatic test
Is the clip welded to a pressure retaining boundary. If not, I don't see where you have any concern. If it is welded to a pressure boundary, can you change to detail?
Joe Tank
RE: Additional welding after hydrostatic test
I also tend to agree with the Section I criteria. I suspect that you also meant to reference PW, not PG.
Regards,
RLS
RE: Additional welding after hydrostatic test
In the first place, NOT EVEN A SINGLE TOUCH OF WELDING ROD SHOULD BE DONE ON THE PRESSURE VESSEL AFTER HYDROTEST. Even then, if you have to weld, there are 2 possiblities.
1. Welding is allowed, if you do a second hydrotest after welding.
2. Welding is allowed on the repad, if the repad is already welded to the vessel before hydrotest.
Regards,
Aravind Sujay
RE: Additional welding after hydrostatic test
As some of the previous responders have pointed out, life exists after the hydrotest. Real world issues include things like weld buildup to repair corroded areas, adding clips for various reasons, adding nozzles, etc etc. Many times the AI will not call for a hydrotest for these situations. Each situation is individual and needs to be assessed individually. Making absolute statements in a nonabsolute world is not realistic. Yes, I'd rather see things done perfectly. Yes, I've seen "R" stamps go on vessels before they were ever placed into service (no second hydro for the "R" stamp). Yes, I've seen "R" stamp nameplates inadverdently switched on major process vessels (in this case for rerates). Yes, believe it or not, I've seen a single vessel with two adjacent U stamp nameplates (long story there, and I don't agree with the logic).
It ain't a perfect world.
jt
RE: Additional welding after hydrostatic test
When I review this case in details, we have to consider why we have to hydro test after welding.
The purpose is to verify leakage on surface of vessel.
However, when we need additiona welding Vessel Long or Cir or nozzle as penetrated welding,
Absolutely, in this case, this carbon vessel should be performed Hydro test once again.
But this vessel is subject to addition welding on surface of vessel of course, this is on pressure boundry but Not direct wleding into pressure boundry like as pipe support clip or Internal support clip ( Demister support ring)
Consequently, this kind of welding is not necessary for mandatory requirement of Hydro test. regardless of ASME rule.
Anyone opinion, pls let me know.
RE: Additional welding after hydrostatic test
I believe we are attempting to split hairs with words regarding pressure boundary definitions. Your AI has the final call on this. There are Code rules established that unfortunately one size fits all does not work.
I don't necessarily agree with my counterparts that are involved with Section VIII, and sometimes they don't agree with me. So, follow what your AI requires and move on.
As I stated earlier, weld the clip to the vessel using an R-Certificate under the NBIC, as a repair.