Conductivity on a buried pipeline
Conductivity on a buried pipeline
(OP)
We have applied an insulator to a buried pipeline and are in the process of validating the effectiveness of the insulator. The insulator isolates a bolt-on sleeve from the pipline. One engineer used an ohm meter and measures resistance. Any resistance reading is considered a failed validation test. Another engineer uses the connectivity setting on the ohm meter and hears a beep if a connection is located. The latter engineer is using the setting normally used to check if a wire has a short.
Which method is accurate? Which method provided the true answer if a component is checked for contact to the steel pipe? Is there a threshold ohm value that defines connectivity or is any resistance measured a bad thing?
Thanks, AWOL
Which method is accurate? Which method provided the true answer if a component is checked for contact to the steel pipe? Is there a threshold ohm value that defines connectivity or is any resistance measured a bad thing?
Thanks, AWOL





RE: Conductivity on a buried pipeline
RE: Conductivity on a buried pipeline
Do you need 200 ohms isolation or 2 megohms isolation?
Once you know the requirement, the correct test method will be obvious.
TTFN
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RE: Conductivity on a buried pipeline
RE: Conductivity on a buried pipeline
*Our final application will be on buried liquid and gas pipeline under pressure. Our test is on empty pipes in a lab (not buried). Our goal is to provide a steel repair clamp that is isolated from the pipe as not to affect any induced current or other corrosion protection systems that the pipeline already has in place. The purpose of our insulating material is to isolate the clamp from the pipe and avoid a location of corrosion.
*Knowing the requirements is one of our biggest issues. Company xyz that supplies Flange Isolation Kits to pipeline operators use a 500 ohm plus guideline. If the flange-to-pipe measures greater than 500 ohms, is is considered to be isolated. We cannot use this value for our application but I am looking for guidance, such as a NACE standard.
*The RF isolation meters are great tools for this project as suggested. I will look into a service to have this done. Again, if I cannot validate a go/ no go answer, I will be back to measuring an ohm value and have to determine if it is high enough per industry standards.
Here is some information a NACE engineer in CA shared. Set up the Wavetek (we have the 85XT) to measure ohms. Even if it reads ohm values, the meter must stabilize to a value. If the ohm value jumps around and does not stabilize, there is no connectivity. Period. In trying this, I cannot get a stable reading; it jumps around.
I plan to pursue the model 601 to get thrid-party opinion.
Any more ideas? Thanks for the great responses.-awol
RE: Conductivity on a buried pipeline
RE: Conductivity on a buried pipeline
I'd hope you would at least coat and wrap the device and put a small mag anode on it, if it is indeed isolated from the pipeline.
RE: Conductivity on a buried pipeline
RE: Conductivity on a buried pipeline
However, you might also want to check the requirements of regulators/laws etc. in the application/locales you are dealing with (even though you " don't anticipate a stand-alone corrosion issue with it).
RE: Conductivity on a buried pipeline
RE: Conductivity on a buried pipeline