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

[nichols7007]

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!

 

[jte]

Why not follow the guidance in ASME PCC-2?

http://catalog.asme.org/Codes/PrintBook/PCC2_2008_Repair_Pressure.cfm

jt

 

[bernoullies123]

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

 

[stanweld]

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.

 

[nichols7007]

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

 

[jte]

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

 

[bernoullies123]

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.

 

[metengr]

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.