Insulation joints on tank nozzle for CP isolation
Insulation joints on tank nozzle for CP isolation
(OP)
Referencing the thread 172892.
Does not the HDPE lining provided under the tank pad make the CP galvanic cell independent of the rest of the ground, thereby not requiring the piping connection isloations. A tank has a static grounding also provided against static buildup, this ground connection may be going deeper than the HDPE lining.
Does not the HDPE lining provided under the tank pad make the CP galvanic cell independent of the rest of the ground, thereby not requiring the piping connection isloations. A tank has a static grounding also provided against static buildup, this ground connection may be going deeper than the HDPE lining.





RE: Insulation joints on tank nozzle for CP isolation
RE: Insulation joints on tank nozzle for CP isolation
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Insulation joints on tank nozzle for CP isolation
RE: Insulation joints on tank nozzle for CP isolation
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Insulation joints on tank nozzle for CP isolation
There is also the Tank equipment ground electrical earthing connection provided. This will be a leakage path. The CP vendor has proposed the use of a polarization device that will stop the DC CP impressed current from leaking to the outside ground through the earthing ground connection. With the use of this, I think it makes sense to have the insulation joints on the piping connection. The piping connections being the only leakage path. Though the insulation joints don't make effective sealing at the joints, they are vulnerable to failure, especially bolt sleeve of bakelite or other brittle material. Despite the cons on the inulation joint, I think I have to accept the use. I would not want the CP contractor to say that he has a problem make the system effective because of the leakage through the pipe flange.