RISK OF INTERNAL CORROSION OF PIPES CAUSE D BY CELL-FORMATION OR ANODIC INTERFERENCE NEARBY INSULATING JOINTS

Insolating joints are used for pipes in the cases of cathodic protecti on or mixed installation. The length of these joints should be suffici ently high to decrease a risk of anodic interference, which can be inv estigated with the aid of a ring-column device. An investigation with different values of the lengths leads to a summarised polarisation par ameter which acts like an increase of the length of the insolating joi nts. The minimum value of these lengths can be calculated on basis of current measurements and a given tolerable limit of the cell current d ensity.