CP structure( tank bottom plate ) -to-soil potential is minimum -850 mv at 25C (77F). But if the tank is steam coiled to maintain a crude at 90C what could be the minimum protection potential ? regards

dear krish, thanks do you mean to say if T> 80C the minimum CP potential should be -1.1V ( i.e. - 1100 mv ? ) ? or U mean to say that the maximum CP potential should nt exceed -1.1V ( i.e. -1100mV) in case T> 80C ? Pl. clarify . My question is if bottom plate T >80C what is the minimum level of CP potential ? >Even though you maintain 90 C inside the tank but actual >temperature experienced by the bottom plate is still lower >due to heat dissipation. Further it depends on whether the >underside of bottom plate is coated or not. > >Up to 80 C the -850mv protection is holds good and if it is >exceeds to 80 C then the safe limit would be around -1.1 mv >.If you keep more than this value there is a chance of >excess hydrogen evolvation which may damage the system.