Corrosion Monitoring System
1. Monitoring
Routine monitoring is recommended for all Cathodic Protection installations. The purpose of monitoring is to ensure the system is operating efficiently. Monitoring is comprised of both a visual inspection and electrical testing. The general monitoring schedule will be:
Activity
|
Time Period
|
| Transformer rectifier |
Twice in a month/owner requirement |
| Junction boxes |
Once in a month/owner requirement |
| Structure to soil potential measurement. |
Once in a month/owner requirement |
| Instant OFF potentialmeasurement through Interrupting the current. |
Quarterly/owner requirement |
| Close interval potential logging/survey |
Once in 3 years/Owner requirement |
| Current attenuation test |
Once in 3 years/Owner requirement |
| Direct current voltage gradient |
Once in 3 years/Owner requirement |
2. Maintenance
The major causes of Cathodic Protection failure are due to negligence in effective maintenance. Maintenance for Cathodic Protection systems include the following:-
- Clean and tighten all bolted current – carrying connections.
- Checking the indicating meters for accuracy.
- Replace damaged and faulty spare parts.
- Cleaning and Lubricating of Screws and terminals of the junction boxes and covers, and Repair any broken test post and reposition if necessary.
- Record the readings for all test points along the pipeline.
- Adjust the rectifier output according to the required protection level value.