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Flush Patch Repair on B31.3 Process Piping???
2

Flush Patch Repair on B31.3 Process Piping???

Flush Patch Repair on B31.3 Process Piping???

(OP)
I was trying to find somewhere in ASME B31.3 Process Piping Code that would cover a flush patch insert (full penetration groove weld)on piping.

One of our clients has requested we remove an existing o-let (where the attachment weld has failed) on a line and replace it with a flush patch cut from the same diameter pipe.  The Code of Construction is B31.3 "Normal Fluid Service".  This a hydrocarbon system and operates around 200 PSI.  The flush patch will be examined 100% by the RT method.

My concern is that B31.3 does not cover this type repair, as opposed to just maybe welding in a new joint.  We have written authorization to proceed but I'm still a little concerned with liability and also prefer to know for myself.

Please Advise!

RE: Flush Patch Repair on B31.3 Process Piping???

The scope of ASME-PCC-2 is repair after it has been in service.  I'm assuming yours has not been in service.  

I had a similar issue, when we received a spool piece onsite it had a flush piece installed for some unknown reason. We cut it out and put in a branch connection and blinded it.  Gave the site an extra connection for the future smile  
 

RE: Flush Patch Repair on B31.3 Process Piping???

Review Section 8 of API 570. Flush patches are permitted for making permanent repairs. One should ask oneself whether replacement of the pipe containing the branch might be easier; cutting and fitting the patch may be more time consuming depending on the diameter of the pipe to be repaired.

RE: Flush Patch Repair on B31.3 Process Piping???

(OP)
Thanks for the input guys.  In response to bernoulies 123, the piping was inservice and taken out of service temporarely.  
Upon further review, the bottom line is that a "flush patch" on process piping is not covered under B31.3 as a repair method.  The correct fix , as we know would to replace a section of the pipe, removing the defected area. It might look bad,but not as bad a flush patch.

Thanks

RE: Flush Patch Repair on B31.3 Process Piping???

nichols-

I'll disagree a bit with the statement that the "correct fix" is replacement of the section of pipe. It is one acceptable method, but not the only one. Article 2.1 in PCC-2 specifically covers this; Figure 1 in that article is for pipe or tube.

jt

 

RE: Flush Patch Repair on B31.3 Process Piping???

http://dictionary.reference.com/browse/correct

verb (used with object):      
Mathematics, Physics. to alter or adjust so as to bring into accordance with a standard or with a required condition.

verb (used without object):
in accordance with an acknowledged or accepted standard; proper: correct behavior.

http://www.merriam-webster.com/netdict/correct
to make or set right

without getting into semantics I would have to concur with nich that 'correct fix' is pretty close to the meaning as described by the experts of the language.

I reckon this is one of the real problems with codes/standards etc. is how one interprets the exact meaning, and as engineers we all exploit this when we write specs...

Cheers.

 

RE: Flush Patch Repair on B31.3 Process Piping???

Quote:

My concern is that B31.3 does not cover this type repair, as opposed to just maybe welding in a new joint.  We have written authorization to proceed but I'm still a little concerned with liability and also prefer to know for myself.

Simply put, B31.3 is a construction code not a repair code. As mentioned above, you need to use in-service repair code books like NBIC, API or ASME PCC.
 

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