Deep Groundbed For Cathodic Protection Systems used for Pipeline prote

[Vinzzzz]

Hi to all,

I'm studing a cathodic protection system done by others, in which is considered the use of an impressed current system with deepwell groundbed with Fe-Si anodes to reach a 100 ohm per metyer.

Now constructor say that to a depth of 5 m he have found water and wants to know if is possible the use of a deep groundbed in presence of water. it is possible the use of a deep groundbed if water is present? If yes, do someone give me referencies about norms and an example of design (DWG's) in presence of water?

In case of is not possible to use a Deep groundbed i want to consider the possibility to use an horizonantal shallow anode groundbed above 5 m ( 2.5 m in depth, the same pipeline depth). it is the rigth solution?

Thanks
Vincenzo

 

[SJones]

NACE SP0572
Peabody's Control Of Pipeline Corrosion
ISO 15589-1

Steve Jones
Materials & Corrosion Engineer

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

 

[rustbuster]

Yes,

Typically deep well ground beds are watered to ensure there is adequate electrolyte for the system to operate.

A very basic question from your contactor, are the C.P. people? If not I would look to a reputable contractor for system installations.

 

[Vinzzzz]

ok thanks to all for responses,

but let me other 2 questions

1- is real that tipically deep groundbeds are washed in order to decrease the resistivity but i know also (as i understand oon NACE RP 572)that if water goes into the vent pipe, gases developed by anodic reactions could not be vented trough the vent pipe causing the non functioning of the anode.

2- in presence of water i know that backfill is not necessary due to the fact that could be washed out by water.

Could you please give me your opinions on these matters?

regards Vincenzo

 

[rustbuster]

Hydrogen gas will difuse through the water and vent.
Backfill (coke) is typically used.

 

[Vinzzzz]

Ok thanks,

i have read in an accurate way the peabody book and also Nace RP 572 and now i can say that water is necessary to reduce soil resistivity (as exoplainde from you before) infact during the summer season could be necessary to inroduce water in the well.

thanks a lot for your replies

Regards

Vincenzo