Once a structure is commissioned information on the condition of the structure and the performance of the CP system is obtained by surveying the structure to obtain data on the potentials and in some cases field gradients. The number of locations where data is collected and the frequency of such surveys are very much dependent upon the operator and can vary significantly. Data is typically provided in tabular form and has to be assessed by the CP engineer along with other integrity data to identify anomalies (i.e. where the potential is outside the expected range) and to identify trends which may indicate that the design is not performing as expected.
A new development in the services offered by BEASY is to enable the survey potentials to be visualized in 3D on the model of the structure as shown in the figure. Similarly the consumption data for all the anodes and their remaining life can be visualized on the model as well as Excel tables. The presentation and visualization of survey data in this way provides significant benefits by:
- Clearly indicating anomalies where there is questionable measurement data as well as where the CP system is not performing as expected
- Quantifying the degradation of coatings to enable better prediction of the performance of the CP system over the whole life of the structure
- Providing 3D visualization of the potential survey data
- Extending the survey data to visualize the protection provided to areas where measurements cannot be made
Therefore this type of study can substantially add value to the information obtained from the survey and enable the operator to optimize the cost, planning and extent of future surveys.
Finally where the computer model has been used to validate the peformance of initial design or retrofit, this type of study can play an integral part of the integrity management to compare the model predictions with the data obtained from the survey to check if the structure is being protected as expected. The model can then be used to make updated predictions of the performance at the end of the design life based on the actual coating degradation rates for example.