Cathodic Protection

[Metalmeister]

What is a reasonable or expected service life of an underground carbon steel pipe used in electric transmission that is cathodically protected? I recently observed a pipe segment that was in the ground for over 25 years that looked brand new. Much existing underground transmission pipe cable is 50 yrs old or more. Assuming an effective impressed current cathodic protection system, seems like the pipe could last forever with the transmission cable being the weak link. Your thoughts and experience would be much appreciated.

 

[strider6]

i think that, as you said, the expected life is a function of the expected life of the componenet of the cathodic protection systems (anodes, cable..). And if you don't have any stray current, interference effect with other cp system...and if a correct maintenance activity is performed then you can expect that your pipe will never corrode.



S.

Corrosion Prevention & Corrosion Control

 

[brimmer]

Service life could be infinite from a corrosion perspective. Most impressed current CP systems would be designed with a 25 year life, cathodic up keep/maintenance is vital. Coating type and coating degredation along with environment in relation will perhaps play the largest part in pipe lifespan.

 

[Metalmeister]

Strider6/Brimmer:

Thank you for your responses. They are helpful.

 

[fdac]

Under effective cathodic protection, external corrosion rates are negligible. You need to ensure the CP is appropriately monitored and maintained, of course.