In Service leak test after repair

[demsha]

Hello All;

We had an average size of repair completed on an internal attachment to shell of a pressure vessel. The defect area was ground smoothly and filled with proper weld procedure.
Subsequently, the area was examined by 100% MPI. No defects were found. Hydro test was not done due to process contamination and other reasons. I understand that In-service inspection can be done instead of Hydro.
Can anyone tell me where I can find information regards to how to conduct the in-service inspection?

Thanks in advance.

 

[jte]

demsha-

In your case, one good - and that's probably more "mandatory" - source will be ABSA

http://www.absa.ca/.

But take a look at ASME PCC-2 Article 5.1 and particularly Fig. 1. Also take a look at NB-23, aka the NBIC or National Board Inspection Code or perhaps API-510.

 

[metengr]

NBIC Part 3 under repairs. This is done nearly routinely.

 

[pradipgoswami]

demsha,

Please look at NBIC-23, Part-3, Sec-4, Clause,4.4.1.
All weld repair are to be subjected to liquid pressure test.

In service leak test is allowed only, when this test is accepted by Original Code of Constriction.The extract from NBIC-23 is below:-

"When an initial service leak test is permitted by the original code of construction, such testing may also be used to verify the leak tightness integrity of repairs".

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[r6155]

NDE must have done BEFORE welding with proper welding procedure.
See PCC-2 Article 2.11
5.1.1 Nondestructive Examination Before Welding.
Consideration should be given to the need for nondestructive
examination of surfaces to be welded.............

Regards
r6155

 

[metengr]

pradipgoswami
The original post mentioned an in-service inspection using NDT, and not a leak test. In lieu of a pressure test, which can be any pressure up to a code hydrostatic test, NDT is permitted by Part 3 of the NBIC under repairs and as I said, is routinely performed.

 

[DekDee]

r6155,
There is a big difference between "NDE must have done" and "Consideration should be given"
Regards,
Shane

 

[r6155]

DekDee
I know the difference, but in this case PCC-2 Article 2.11 5.1.1 appear not to be considered.
“Good engineering practice” always must be applied.

Regards
r6155

 

[demsha]

Thanks a lot for all of your feedback. My question is if the original code doesn't mention in-service leak test at all, how we can verify the integrity of the vessel?
We did 100% MPI after the repair. Is this good enough?

 

[metengr]

demsha
Yes, as I said, refer to the Part 3 of the NBIC. Post repair NDT, like MT, is permitted and used in lieu of post repair pressure testing. Seek concurrence from the Inspector.

 

[r6155]

integrity of repairs is not equal to integrity of pressure vessel
Integrity of pressure vessel is 100% volumetric examination by Acoustic Emission (AE) testing.

Regards
r6155

 

[metengr]

demsha;
In-service inspection, in-service leak test are comparing apples to oranges. First, an in-service leak test does nothing to establish the integrity of a pressure vessel. It only means you don't have any gross leaks at the time the test was conducted.

You need to understand what in-service damage mechanisms exist and implement a fitness for service evaluation under API 579.