Corrosion Monitoring

This is usually applied to fixed plant containing aggressive materials and is intended to monitor the rates of internal corrosion of the walls of the plant. This may be done by drilling sentinel holes part away, through the wall, which can be plugged when they leak or by inserting readily removable coupons of material of which the corrosion rate is assumed to relate to that of plant.

In the case of the first four techniques of monitoring which are applied primarily to various forms of rotating plant, the way in which they are used is that the existence of a problem is usually detected from the general level of the measurement, and its rate of change, while the nature of the problem can generally be determined from a more detailed analysis of the measurements obtained. This is outlined in Table.

              Table: Application of Monitoring Methods
         (For Detection and Analysis of Problem)

The techniques/methods of monitoring described in Table are in fact a mechanism of communication between a machine and a monitoring engineer. It will be observed that the visual method of monitoring in relation to the others requires negligible technological backup. This is because the necessary analytical facilities already exist with the human observer. The lack of these natural analytical facilities in the other three methods of monitoring is the main reason why more complex technological facilities and methods need to be applied.