What is 100 mV criterion in CP?

[Tonysi12]

Does any one knows, how 100mV criterion works in CP system?
How do we know that pipe is stable per 100 mV criterion?

Thanks in advance

 

[brimmer]

It is the difference between the native soil potential (pipe completely depolarized), and the polarized (off) potential. To complete a survey, you need to make sure your system is completely off to get native readings, then energize the system let it polarize, and interrupt during survey to get off readings. The idea is there is at least 100 mV of difference between these readings, so you know the pipe more electronegative than the surrounding soil.

 

[SJones]

How do we know that pipe is stable per 100 mV criterion?

Achieving the 100 mV criterion is no guarantee that the buried pipe is totally free of corrosion, i.e. it does not remove the need for integrity verification activities. Consult ISO 15589-1 for situations where applying this criterion is prohibited.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[Tonysi12]

Thanks.