Welding of Attachment after hydro-static Test
Welding of Attachment after hydro-static Test
(OP)
Dear Experts,
Are we allowed to attach some clips after Hydro-static Test on pads which are previously welded on P.V's shell as per ASME code?
Please share your thoughts
Thanks
Are we allowed to attach some clips after Hydro-static Test on pads which are previously welded on P.V's shell as per ASME code?
Please share your thoughts
Thanks





RE: Welding of Attachment after hydro-static Test
After hydro test, I thought it was considered finished and as such, you would need to get an R-stamp in order to do anything further?
RE: Welding of Attachment after hydro-static Test
(a) A hydrostatic test shall be conducted on all vessels
after
(1) all fabrication has been completed, except for operations
which could not be performed prior to the test
such as weld end preparation [see U-1(e)(1)(-a)], cosmetic
grinding on the base material which does not affect
the required thickness; and
(2) all examinations have been performed, except
those required after the test.
The completed vessels, except those tested in accordance
with the requirements of UG-100 and UG-101, shall
have satisfactorily passed the hydrostatic test prescribed
in this paragraph.
ALSO, and this could depend on the AI's interpretation, it falls under the scope of ASME until the data report is signed. I.E.: you could re-hydro the vessel prior to signing the data report and it's still under ASME. Once the data report is signed, to modify the vessel, an R-stamp is required.
RE: Welding of Attachment after hydro-static Test
RE: Welding of Attachment after hydro-static Test
ahmadire: Yes, you can
U-1 (e)(2) where nonpressure parts are welded directly to either the internal or external pressure retaining surface
of a pressure vessel, this scope shall include the design,fabrication, testing, and material requirements established
for nonpressure part attachments by the applicable paragraphs of this Division;3
ENDNOTES
3 These requirements for design, fabrication, testing, and material for nonpressure part attachments do not establish
the length, size, or shape of the attachment material. Pads and standoffs are permitted and the scope can terminate
at the next welded or mechanical joint
Regards
r6155
RE: Welding of Attachment after hydro-static Test
"(e) In relation to the geometry of pressure containing
parts, the scope of this Division shall include the
following:
...(2) where nonpressure parts are welded directly to
either the internal or external pressure retaining surface
of a pressure vessel, this scope shall include the design,
fabrication, testing, and material requirements established
for nonpressure part attachments by the applicable
paragraphs of this Division;3"
So all that is saying is that non-pressure parts welded directly to the pressure retaining surface are included in the scope of this section (VIII). How does that say that you don't have to test the vessel in accordance with the requirements of the scope of section 8?
EndNote 3 is saying that you could have a 1"x1" clip or a 1milex1mile clip and it's still under the scope of the section (size doesn't matter) and that the boundary of the attachment needing to be within the scope of the section ends with the next welded joint past the welded connection to the pressure vessel
r/
RE: Welding of Attachment after hydro-static Test
Sorry, I just re-read the original question: Clips attached to pads attached to the pressure vessel.
RTFQ, huh?
r1655 is correct.
r/
RE: Welding of Attachment after hydro-static Test
And yes, I would not be concerned about any type of rehydrotest for a typical structural attachment weld onto a typical repad in a post-construction environment.
RE: Welding of Attachment after hydro-static Test
You are free to weld to components which are NOT part of the pressure boundary, but which were welded to the pressure boundary before the hydrotest. An example would be a repad, a poison pad, a leg or support bracket, and presumably a lifting lug. That would of course assume that the welding you're doing would be entirely limited to the non-pressure retaining component and would not result in depositing weld material on the pressure retaining boundary.
Yes, the scope of the vessel can terminate in a nozzle, i.e. a piece of pipe, to which piping will later be welded. The weld between the vessel and the piping becomes subject to the piping code and its NDE requirements.
Once the vessel is in service, post-fabrication codes apply and sometimes specific NDE can be performed instead of repeating the hydrotest.
RE: Welding of Attachment after hydro-static Test