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Up Topic Welding Industry / Technical Discussions / Root repair
- - By fit.to.a.flange (*) Date 05-05-2008 11:42
Can the qualified welder repair the root pass directly inside the pipe if the defects are found to be in the root? Assuming the pipe is large enough for the welder to perform his repairing work using the same WPS and welding process. Construction code is B31.3 and didn't address such manner.

Appreciate feedbacks. Thanks.

John Boy..
Parent - - By jon20013 (*****) Date 05-05-2008 11:58
I think this will mostly depend on your inspector and how the WPS is written.  My knee-jerk response would be "heck yes" but I've had my QA people come back to me (as the welding engineer) and rightly state that my WPS didn't address welding from 2 sides; only showed a Vee-groove with no back welding for example.
Parent - - By Shane Feder (****) Date 05-05-2008 12:24
Hi Jon/John,
As a welder of many years on plain old carbon steel pipe we have done many internal repairs (touch ups) on the root run and as far as I am aware there is no metallurgical reason why it would be detrimental.
However, as my Welding Engineer boss rightly pointed out is is a definite no-no with exotics unless a qualified repair procedure for the touch ups has been done.
Jon, I think with the WPS, if it was qualified single-sided there should be no reason why it couldn't be welded double sided, as long as the repair or rewelding was reflected on the WPS,
Regards,
Shane
Parent - - By jon20013 (*****) Date 05-05-2008 12:34
Shane, I definately agree and would gladly endorse the practice but like I said, if the QA/QC Inspector points out that the WPS is a one-sided joint configuration, it's hard to argue.  In any case, this is a non-essential variable and can be changed by a simple swipe of the pen!  In almost all cases now, when I write a WPS, I include the provisional statement!
Parent - By fit.to.a.flange (*) Date 05-05-2008 13:15
Shane/Jon,

Yes, agree with you guys that this can be done and supplemented into the existing WPS without re-qualification of the PQR!

Thanks.

John boy...
Parent - - By Kix (****) Date 05-05-2008 19:55 Edited 05-05-2008 20:27
I can't get the picture to work.  Anyway, since you brought up the subject, it was a picture of me repairing a root that the shop did with lack of fusion inside a 14" Hydrogen flare line @ Conoco Phillips Wood River Refinery.  Sucks to be skinny sometimes.;-)

[IMG]http://i11.photobucket.com/albums/a189/vdubin474/indapipe2.jpg[/IMG]  There we go, that was me going in.  I had to lay lengthwise in the pipe.  Can you say confined space.;-)
Parent - - By swsweld (****) Date 05-05-2008 22:24
Kix, did you use tig or stick for the repair? If tig, did you use ventilation? I always hated the depth perception when welding with arms extended like that. But it's a good feeling successfully doing the trick welding that most others can't do. At least that's what I've been told :)
Parent - By Kix (****) Date 05-06-2008 12:32
I had to stick weld the repair with 5P.  The roots were originally put in with 5P so the repair was to be the same.  The flare tower was laying on it's side (this was new gravy construction ;-)) so I was able to put a fan in the end of the tower sucking outward drawing fresh air in through the T and all the sockolet weld openings in the bottom of the flare.  There were 2 sockolet roots that didn't go in either so I had to crawl in a good ways further to get them.  My fitter could grab my ankles and pull me out quick if I had probs.  I really miss those days and that feeling, it's enough to make me want to head south and hit up all this new construction thats gettin ready to kick off.  I just don't get that rewarding feeling with this job up here and I hate going to the same place every morning.  I'm starting to think I was put on this earth to make arcs and sparks.:-)
Parent - - By fit.to.a.flange (*) Date 05-06-2008 04:59
Kix,

The pipe shown in your attachment appeared to be a thin wall, I supposed. Doesn't that much more practical and better chances of getting the work done minimizing another repair from outside? I could really imagine the tiny space you had in there!

John boy...
Parent - By Kix (****) Date 05-06-2008 12:59
If I had to guess the wall thickness on that pipe I'd have to go with 14" sched 80. If you can get to the root and know what the prob is, then I'd say get it from the inside.  Then have it NDT'd in a cost affective manner.  It was funny watching the mag man crawl in that pipe I repaired to MT the roots.  He had Iron powder all over him when he came out.
Up Topic Welding Industry / Technical Discussions / Root repair

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