John, we did some field work today preparing for fixing this wire on Feyrer Park Road at the new Cathodic device, but we are a little confused: we hooked a clean copper wire to the nearest water meter, which is copper, and the other end to the junction box side of the blue wire (that is supposed to have it’s other end thermo welded onto the 14” steel line), and got continuity (116k-ohms). I uploaded a 24 second video of that test. Can you confirm this is the right thing to do? Or educate me a little bit on what my goal is? Because from what I can tell there is no broken wire between the junction box and the 14” line.
Thanks for being patient with me as I learn.
https://www.youtube.com/watch?v=wcV8SkK31cM
Andy Peters
City of Molalla
Public Works Operations Supervisor
(503) 829-6855 x220
Cell: 503-793-0507
117 N Molalla Ave
Molalla, OR 97038
From: John Keppler <jkeppler@farwestcorrosion.com>
Sent: Thursday, June 27, 2019 3:33 PM
To: Andy Peters <apeters@cityofmolalla.com>
Cc: Alexa Karmil <akarmil@farwestcorrosion.com>; Brandon LaVerne <blaverne@farwestcorrosion.com>
Subject: Pipeline CP Cable Repair
Andy, Farwest Job No. W-127
On June 20, 2019, Farwest corrosion performed a native potential survey of the pipeline, then attempted to commission the new rectifier. The rectifier had no output. Troubleshooting indicated one of the two output leads was bad. Further testing using the electrical ground as a structure indicated the anode bed had current output and appeared functional. This is indicative that the negative connection to the pipeline was broken in the accident. I have photos of the site on file should you require them.
The only way to have determined the cable was broken would have been to perform an initial site visit prior to ordering the rectifier. In that regard, a third trip is not an additional cost, but one delayed from the onset.
Farwest recommends the negative connection be replaced. Two No. 6 AWG wires should be thermite welded to the pipeline below grade, then routed to the existing below grade junction box, where they may be connected to the new rectifier negative lead. This is likely work your crew can complete. Alternatively, Farwest may assist the day of excavation, followed by commissioning of the CP system. A hand sketch and typical weld details are provided. A material quote is also attached. Materials are in stock here in Mukilteo, WA.
There are numerous cables buried between the road and fence, and potentially other utilities. I suggest you request permission from the adjacent farm to connect to your pipeline (within your easement) on the north side of the fence. Excavating from the north side of the fence will likely be safer for your crew and the public. Restoration should be minimal. Two new cables should be thermite welded to the pipeline, with the connections connected 12” apart. Each weld shall be coated with a mastic coating patch. The cables should then be routed with 24” minimum cover in to the existing below grade junction box. Provide 24” of slack wire at the pipe connection and slack to at least 24” above grade at the junction box. I have attached a typical weld detail and a sketch of the site.
Once the pipeline is exposed, a quick condition assessment should be made as to the condition of the coating and the pipe. Note the percentage of coating damage if any, coating type and adhesion where removed for wire connections (3” x 3” square). If pitting exists, note the size and depth of pitting. If the equipment is available, record ultrasonic thickness (UT) measurements on the pipe wall. Take photos. Including the installation, this should take no more than 2 hours in the excavation one open.
If you require assistance, please let me know your intended schedule. I know I cannot travel the week of July 15. I believe Wednesday, July 10 would work well for me should you desire assistance.
Regards,
| John Keppler - Principal Corrosion Engineer
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T: (425) 290-8832 | F: (425) 290-8773 | M: (425) 501-3401
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4640 Campus Place, Suite 105, Mukilteo, WA 98275
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