What type of protection provides the highest degree of protection for the exterior of a coated steel pipe?

Cathodic protection is recognized for providing the highest degree of protection for the exterior of a coated steel pipe. This method involves the use of an electrical current to mitigate corrosion processes that can attack the steel surface, effectively reducing the electrochemical reactions that lead to rust and degradation.

In cathodic protection, either sacrificial anodes or impressed current systems are employed to create a negative charge on the pipe, ensuring that it remains protected from corrosion that would typically occur when the pipe is exposed to moisture, soil, and other corrosive environments. By doing so, it significantly enhances the durability and longevity of the pipe beyond what is achievable through merely applying protective coatings or barriers.

Other protection methods, while useful, do not offer the same level of active corrosion prevention. For example, galvanic protection relies on the use of anodic materials that corrode preferentially to the protected metal, but this is limited in its application and effectiveness depending on environmental factors. Corrosion resistance can describe inherent properties of materials or coatings, but without additional protective measures, it cannot provide the same active defense as cathodic protection. Finally, epoxy coating serves as a barrier to corrosion but can wear away over time, ultimately reducing its effectiveness if not complemented with cathodic protection