Corrosion is a natural process, which converts a metal to oxide. It is the gradual degradation of materials by reaction with its environment. To protect pipelines from corrosion, both external and atmospheric, we use pipeline coatings and cathodic protection (CP).
- Pipeline coatings are the most common anti-corrosion treatments. They work by providing a barrier of corrosion-resistant material between the damaging environment and the steel.
- CP is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded "sacrificial metal" to act as the anode. The sacrificial metal then corrodes instead of the protected metal. For structures such as long pipelines, where passive galvanic cathodic protection is not adequate, an external DC electrical power source is used to provide sufficient current.
NMGC monitors all cathodically protected steel pipe on an annual basis to verify the cathodic protection system is functioning properly.