Pin hole leak in H2 pipe. How to repair? 3

[lithography]

I have a pin hole leak in a hydrogen pipe. The pipe passed near a HCL tank and has corroded. The pipe is 1" steel and the H2 is pressurised to 60psi. I want to make a temporay repair to this pipe and was looking for some ideas from engineers that may have had similar experiences in this type of repair situation. Needles to say this will only be temporay measure while we plan and schedule replacement of old pipe and re-routing.

 

[sshep]

We have have had a pipe clamping company make temporary repairs to small bore H2 and CH4 vapor lines in our ethylene plant. This is obviously not the most desirable situation, but if you can't reasonably shutdown or isolate then there are few good alternatives. Best wishes, sshep

 

[JStephen]

In the water works industry, they make repair couplings that consist of a rubber gasket and steel sleeve that clamp over the pipe for just such a purpose- I assume they would work here if the conditions weren't too severe.

 

[zdas04]

1" is tough. So is hydrogen at 60 psig. For tough problems I go to TD Williamson

http://www.tdwilliamson.com/hottaptdw/Rehab_Products/clamp_repair_sleeve.html

. This link takes you to their standard product for 2-30" leak repairs. I would contact them for the possibility of their having a smaller version that isn't on their web page.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[unclesyd]

Here are two different approaches to leak repair. We use the “box” technique with injected sealant on 3/4" and up Therminol vapor lines all the time. The boxes and sealant are expensive, real expensive if you require a special. Usually there is a local company that can box and shot a steam leak that will be able to do the job. The big companies mobilization fees are huge.

Here is what’s available.

http://www.teamindustrialservices.com/prp/default.html

http://www.jerman.com/pipeclamps.html

 

[rastademenace]

We have used a product called Stop-It by Indumar products. Their technical support is very well capable of handling various pipe leak solutions. I would recommend that you give them a call.

http://www.indumar.com

 

[unclesyd]

Leaks in UHP (Ultra High Purity) gas systems are a major problem and have to be addressed everyday. We use UHP N2 and O2 incursion was a bear. I just wish I had the money we spent keeping the N2, O2 free.
Here is site that discusses the problem in general way. We use both the analytical method and the He Mass Spectrophotometer approach to our system.

http://www.delta-f.com/AppNotes/apnote6.htm

 

[corrosionman]

lithography, We have often done emergency leak sealing for 1 inch pipes - - -put a small pad of rubber over the hole and use a Jubilee clip to tighten it.
Better still is to also have a small steel plate on top of the pad so it applies greater force on the rubber (the pressure in rubber must be greater than pressure of h2 trying to escape)
Ideally the clip buckle must be on the pad too (If its at the opposite side of pipe then a lot of the tension in the clip gets lost in overcoming friction with the pipe wall - - this phenomena is more significant at larger pipe diameters)
If it looks too "temporary" then wrap the whole lot in a couple of layers of GRP.
Cheers DW

 

[sshep]

On the basis that temporary often means an extended period of time (i.e. to the next turnaround), some of these rubber pad and clamp type assemblies described above sound pretty flaky in my opinion for industrial repair of an H2 leak.

When I said above that we clamp these things, I mean we use bolt together, sealant injected clamps of the type identified by unclesyd and zdas04 and installed by a professional repair service. H2 can leak very easy and burns invisibly (during the day anyway) which can creates a hazard not easily recognized to personnel working nearby. A do-it-yourself home water pipe style repair job is not a good idea. -sshep

 

[esimmons682]

lithography,

I agree with sshep. The cheap way out may work, but why take a chance. Products that I have had great success with in the past are Plidco split sleave clamps (

http://www.plidco.com)

and clockspring (

http://www.clockspring.com).

Clockspring is a permanant repair in most applications. Plidco is not, (are wasn't in the past) but easy to install. Hope this helps.