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CP Interferance Audit of Cross Country Lines
Posted: 13 Oct 2010, 05:50
by Nabeel Ahmed Qureshi
Can any body share the procedure of conducting CP current Interference Audit of cross country lines crossing over each other & connected to different CP systems. What are the checks to be made during the audit & the rectifications of vulnerable observations during the audit.
Regards
NAQ
Re: CP Interferance Audit of Cross Country Lines
Posted: 13 Oct 2010, 18:47
by Nabeel Ahmed Qureshi
Any body have something to say about this?
Re: CP Interferance Audit of Cross Country Lines
Posted: 13 Oct 2010, 21:11
by mechcolor
Qureshi,
Now a days, such interferences due to neighboring pipelines, steel structure and electrical cables are simulated through computer aided programs which provide you not only the accurate results but also the ways to mitigate the upcoming issues.
Some weeks ago, I came across such a software and that was indeed a useful one. Let me see if I can trace that for you.
Re: CP Interferance Audit of Cross Country Lines
Posted: 14 Oct 2010, 08:46
by Nabeel Ahmed Qureshi
We have observed severe pitting on an above ground portion of an underground line & it does not seem the piiting occuring due to normal corrosion phenomena. (Pics attached below)
The line is inside well where we have maany other lines connected to different CP systems. Can any body let us know that what type of Pitting is this either due to CP current Interference or due to environment.
Re: CP Interferance Audit of Cross Country Lines
Posted: 15 Oct 2010, 04:21
by mechcolor
Yes this can be due to stray currents due to other systems running nearby.
Is pipe coated? If yes what's the type of coating?
It would be good if you can attach some bigger pictures.
Re: CP Interferance Audit of Cross Country Lines
Posted: 15 Oct 2010, 13:20
by Nabeel Ahmed Qureshi
Mechcolor,
This is above ground portion of the line on which we noticed this issue & the above ground portion of line is not coated. However, we do have applied coating on the underground portion which is Polyken primer & Tape.
Does stray currents effect the above ground portions of piping also?
Re: CP Interferance Audit of Cross Country Lines
Posted: 16 Oct 2010, 04:26
by ben
Are there insulation flanges installed when the line comes aboveground?
There would not be any impact of cathodic protection system on the aboveground portion of piping if insulation flanges have been installed.
Re: CP Interferance Audit of Cross Country Lines
Posted: 16 Oct 2010, 06:22
by Nabeel Ahmed Qureshi
Ben,
No isolation flanges exist b/w underground & above ground portion.
Now, can we say these pits are because of interference.
Regards
NAQ