ASME Pipe Repair to Elbow by full encirclement sleeve PCC-2

[mechengr12]

I have a 26" elbow that is in an extremely difficult place to remove and no pipe supports for the rest of the hanging pipe. Thickness was measured at .205" with a required thickness of .06" but typically we want a thickness of 0.100" for structural purposes. I do not want to run into a issue in the near future for a pinhole or further thinning. Can I use a full encirclement steel reinforcing sleeve for the elbow as depicted in ASME PCC-2 Article 2.6. What is the best way to fabricate a sleeve? Is this allowed for an elbow?

 

[Duwe6]

If that ell is not installed yet, buy a STD wall one and have it counterbored to match the connecting piping.
I doubt if a full encirclement clamp can be made for an ell, too many compound curves to match. One of the engineering assumptions for Full Encirclement is that there is a high percentage of contact surface between the clamp and the existing fitting/pipe.
If the ell is installed, I would beef up the heel of the ell [done that, successfully]. Use an ell of the same size, cut out an oval and press the oval until it has opened up enough to fit the installed ell 'like a glove'. That oval should cover from a couple of inches short of the pipe welds, and at least 120° of the heel of the ell - extrados. Further, since the Flow-Accelerated-Corrosion FAC of pipes at ells tends to be on the pipe, just past the ell, I would also put a 120° - 175° encirclement on the downstream pipe, about 1½ to 2 pipe diameters long. Saw / torch some 1 to 1½" diameter plugweld holes in these patches, to give them structural strength. The perimeter fillets really only handle pressure.

Buy the fab crew another, new 26" ell to test-fit against in the shop, before they take the patch to the field.

ps - if you use this bit of experience, a star would be nice.

 

[keyen]

Have you considered a non-metallic repair as described in Article 4.1 and 4.2? These types of repairs lend themselves well to large diameter piping with troublesome geometry. PM me if you need a contractor that's capable of doing this kind of repair (with the backup engineering) in the US or Canada.

 

[LittleInch]

There has also been a lot of work done to install two half shells bolted or re-welded together with some gap between them (20-50mm) (30" elbow?) which is then carefully injected with epoxy grout to provide the link between the original pipe and the reinforcement shell. Of course you then need to re-analyse your pipe with all this extra weight on it. NO good for through wall defects, but supplies all the require reinforcing for all the other stresses.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way