18 " weld neck flange weld joint repair

[mariolucas75]

Gents,

What is a an option to repair 18" weld neck flange weld joint to pipe? There is a water seepage pin-hole in the weld.

Temporary / permanent repairs options ?

 

[LittleInch]

Grind it out and reweld.

Drill a hole, tap it and put a tapered bolt in it

Look at this https://www.epri.com/research/products/TR-108132

Did you do any searching?

 

[mariolucas75]

Thank you LittleInch,

I did some searching - some proposals were - wrap / clamp as temporary repairs ... but i am not sure whether the clamp / wraps will work in this case,
since it is a weld (weld cap) and flange neck - therefore how tight the wrap or clamp will sit ... (what would you think ?)

Another thing - weld repair - excavate the pin-hole area and put weld in excavation?

 

[LittleInch]

To be fair, weldneck / flange etc gets difficult as it's not a straight pipe. Most wraps don't work with a through hole failure.

You can get pin type clamps like this which should fit over your pipe to flange https://plidco.com/pipeline-repair-products/repair-maintenance/smith-clamp/

Or you can get whole flange sealing kits - see https://www.sealxpert.com/different-type-of-pipe-leak-repair-clamps-and-their-effectiveness

What is this flange connected to? Another flange or something big like a valve?

Proper repair when you can take out of service is a full weld repair so similar to what you do when you find a defect in a weld when you originally build it.

 

[mariolucas75]

Yes it is connected to a valve ....
What would be a difference - valve or another flange ?

 

[LittleInch]

You can encapsulate flange pairs, but not a valve

 

[r6155]

Any photo?

 

[mariolucas75]

Belzona 1111 for example ?

 

[mariolucas75]

Photos is scanned from B&W document ... the black stain is where is the pin-hole leak

 

[LittleInch]

I forgot to ask what the operating pressure was.... They look like pretty mighty bolts so is this a class 900 or more?

As with any repair or plugging, removal of rust and "gunk" can increase the leakage rate a lot or result in a jet of liquid, so shutdown or drain down should be the first action before going anywhere near this.

Of course a weld leak can be a crack or weld failure and is generally a bad thing.

 

[NovaStark]

If it is actually water seeping out, there are wraps like A+ that can be verified via ASME PCC-2 that an experienced leak sealing company can install for you.

Of course these tend to require some degree of surface preparation and as LI says, you can run the risk of making the leak worse.

In any event, you may be eventually tasked to determine the cause of the leak which may further guide what type of repair can be done or if you need to shutdown, etc.

 

[r6155]

Stop service before performing any repairs.