CP GROUND BED REPLACEMENT

[09091960]

I'm new to the field of gas buried pipe industry.My company got a data base to monitor the ON/OFF CP serveys,which carried out twice per year.At the end of february 2008, as per the maintenance plan we have to decide on which ground beds to replaced/ repair. In general what are the main factors which one should look into before replacing cathodic protection ground beds.

 

[ErnieWise]

From an economical stand point I'd say that if your CP system is still meeting the protection criteria (-850mV instant off or 100mV shift according to NACE SP0169-2007) then there is no need to replace the ground bed. Usually the manufacturer will specify an expected life of the ground bed and of course if it's exceeded that then it's probably time to replace it.

 

[09091960]

Thanks for your reply.Can the 100mv shift occers for any other reasons, like changes in the soil resistivity, all the anodes in the bed are not working properly etc. If it for any oter reason, what are the steps to be carried out before replacement of anode beds?