Monitoring & Maintenance
Monitoring and Maintenance of Cathodic Protection Systems
Cathodic protection is a well proven technique for the corrosion prevention of reinforced concrete and steel structures. Australian Standard AS 2832.5-2008, Cathodic protection of metals, Part 5: Steel in concrete structures, provides guidelines for the design, installation, commissioning and monitoring of cathodic protection systems.
Our extensive experience from audits and reviews of a large number of operating cathodic protection systems over the past 30 years reveals the importance of the correct monitoring and adjustment of CP systems. This task must be performed by experienced cathodic protection/corrosion engineers who can perform the work based on the applicable standards and the specific conditions of each structure. This will ensure that the optimum protection of the structure is maintained at all times, any side effects associated with the CP application are eliminated, and maintenance costs are maintained at a minimal level for the life of the CP system.
Key considerations for CP system monitoring:
Selecting the optimum protection criteria for each structure based on the requirements of the standard. The suitability of adopting one of the four criteria as detailed in AS 2832.5-2008 must be considered based on the specific condition of each structure. Considerations include anode type, extent of repair, exposure condition, tidal variation, potential grout acidification and system design.
Accurate measurement of the instant OFF potential, where applicable, the use of external datalogging equipment to calibrate the instant OFF measurements may be required.
Incorporation of yearly site inspections and assessment of the corrosion condition of the structure in conjunction with the CP system monitoring.
Incorporation of simple and efficient measures in the monitoring and maintenance program to ensure adequate regular functional checks of the CP system subject to individual system status.
Implementation of a management system for the CP system monitoring that will allow on-line access to all records associated with the CP systems including construction drawings, maintenance records and monitoring data. This will greatly assist in optimum system adjustment and long term performance.