Abriox

AT SACRIFICIAL ANODES

Galvanic systems are generally self-regulating with a fixed, and relatively low, current output. Once they have been installed and checked they do not need such regular monitoring as an impressed current system. However, because the current output is not controllable, changes in the structure that cause an increase in protection current demand, such as the deterioration of the pipeline coating, may necessitate replacement of the anode or the installation of additional anodes.

For these reasons monitoring may be considered for:

• Pipe-to-soil potential

• Instant OFF potential (if a coupon is fitted)

• Anode current output

• Anode current density.

A practical consideration is that anode systems are often accessed from surface boxes in roadways. Clearly measurements at these points need to be carefully undertaken and may require road closure in compliance with Street Works and other safety regulations.

The MERLIN Test Post Monitor is sufficiently flexible to be able to monitor the above parameters and is now being deployed for monitoring sacrificial anodes.