Weld of lifting appurtenances after hydrostatic test.

[rikywere]

Hello everybody,
I am facing a unexpected problem and do not know how to solve it in a quick and economical way.
I work for an EPC company and one of our tanks vendors has designed and fabricated a 4.3m diameter and 8m high SS shop fabricated tank. The problem comes because they assumed that tank was going to be transported in vertical conditions but due to it svelteness we find it dangerous and unstable, so we want to do it in horizontal position . They provided lifting lugs made from plates welded perpendicular to the tank shell, so that are not designed to withstand the horizontal loads that would appear during tilting the tank, additionally, there is not provision for tailing lug. The thing is now, that the tank is already hidrotested so that welding is not allowed. Am I right? Or can we weld trunions and tailing lugs? If not.. any suggestion to lift and tilt the tank?
Many thanks in advance.

 

[rikywere]

Sorry, I forgot to mention something. Of course, we can weld if we rehydrotest the tank. This is what we are trying to skip, a second hydrotest.
regards,

 

[Duwe6]

Actually, welding on appurtanances to the surface may be allowed. It's stainless, so no PWHT issues. If I was your API-650/653 Inspector, I would allow adding lugs. Who is the Inspector of record for this tank? Go grovel, admit your omission, and ask permission. Rehydro is only mandatory for major alterations, that involve full-penetration shell welds.

 

[rikywere]

Hello,
I am getting a bit confused now, I am more into pressure vessels world and some lost in API650 world. As far as I knew, there will not be any API-650 inspector, I mean, there is not any inspector from API similar to the one from ASME to stamp the vessel. The only inspectors would be our inspector and the inspector hired for the final client. None of them are API representatives.
Regards,

 

[Duwe6]

The client's inspector is the person to ask. For API work, Inspector [with a capital 'I'] is the person representing the client. With a little luck, he will be either a certified API-653 or a Tank Engineer.

You will find that API allows Inspectors a lot more freedom of action than ASME does. That, I presume, is why there are a bunch of things that are not as clearly delineated in API Codes, that are in ASME. Gives the Inspector quite a bit of discretion as to how 'oddball' items, like your forgotten lugs, are handled.

 

[IFRs]

Are you building an API 650 tank?
API 650 7.3.6.1 clarifies what can be welded to the shell after a hydrotest

 

[rikywere]

Yes, it is an API650 tank.
7.3.6.1 Leads us to 7.2.1.1 where allow welding of “Non-structural small attachments”. Is a lifting trunnion a “Non-structural small attachments”? During service, this will not be anything but an ornament.

 

[IFRs]

Personally, I would consider it such.
Using the tail and to lugs should not impact the structural integrity of the tank.
My opinion only, certainly up to individual interpretation.