TYPE B SURVEY WITH A CLOSE INTERVAL POTENTIAL SURVEY (CIPS) TO ASSESS THE EFFECTIVENESS OF THE CATHODIC PROTECTION

In this survey package, the DCVG and Soil Resistivity surveys of Type B are accompanied by a CIPS survey to investigate the effectiveness of the cathodic protection system. PIM Ltd recommends a modified CIPS technique whereby ON/OFF Pipe-to-Soil Potentials are recorded at the epicentre of coating faults located by DCVG. This is the least protected position on the pipeline. Instant OFF Potentials provide an estimation of the level of protection at a fault. The standard continuous CIPS technique can be used, if required.

The client receives a report, which summarises the condition of the pipeline and includes tabulated information on severity, corrosion status, Soil Resistivity and Pipe-to-Soil Potentials for each coating fault. In addition, a pipeline coating rehabilitation program is recommended; coating faults requiring repair are listed and, if required, allocated to Rehabilitation Packages of Work. During surveying an audit of all CP hardware and other pipeline right-of-way furniture is conducted. The effectiveness of the cathodic protection system is also reviewed and recommendations are made for adjustment or improvement. More inputs significantly improve confidence in the rehabilitation decision process.