5. Corrosion monitoring and treatment control

5.1 Corrosion rate measurement

When we speak of "corrosion control", we must always remember that the techniques used were developed with a view to determining a corrosion rate in the presence of uniform corrosion. Assessing the risk of a circuit being perforated by a localized corrosion process is much more uncertain. However, in water systems, uniform corrosion is very rarely the cause of system malfunctions. Caution should therefore be exercised before choosing any of the techniques described below.

In industrial circuits, the aim is generally to achieve a steel corrosion rate of 50 µm/year or less. In some cases, 50 to 100 µm/year may be acceptable.