CP not protect the internal

[cytech]

Hi All

We have an old cp system protection those buried pipe, there are few buried pipe internally is corroded, please advise whether the cp system only protecting the external surface of the pipe and not internal or probably need to maintain the system?

Regards
Cy

[ashcoft]

the CP system for underground steel pipe has two type those are for internal and external. CP for internal cannot protect the internal pipe and external CP cannot protect the internal.

[ahmadlie]

are the external pipeline is corroded??the pipe carry what fluid?

[scipion]

the CP protect only the surface in direct contact of the electrolyte in your case the external surface of the pipe from external corrosion (soil corrosion)

[rexomen]

cp system only protect the surface of the material in contact with the electrolyte. lining system can be applied to the internal protection by inserting a corrosion resistant materials made ​​of filament wound composite or extruded thermoplastic inside the pipe.

[rexomen]

sorry double post...