DNV—GL — CATHODIC PROTECTION OF SUBMARINE PIPELINES

Another DNV GL publication providing guidance on cathodic protection - this one may be used together with the cathodic protection design related recommended practice and is devoted to the protection of submarine pipelines. Subject pipelines are normally designed using the external coating as primary corrosion control system. However, a CP, standing for the cathodic protection, is still provided serving as back-up for any deficiency that may be there in the primary coating.

These deficiencies usually include damages to the coating occurring in the course of the transportation of the pipe and its installation, mechanical damage, coating degradation etc. The detailed and thorough design of the coating systems and due control of the quality are, in turn, primary factors. The cathodic protection is normally achieved by means of galvanic anodes or impressed current from rectifier. The galvanic anodes are often referred to as sacrificial anodes and they are mainly used for the protection of submarine pipelines.

These systems are traditionally self-supporting and all anodes comprising the system are installed directly on the pipe using the bracelet type anodes that clamp around the line and electrically connect to the pipe in an individual manner. The design of the cathodic protection systems applied for protection of the submarine pipelines is carried out in two stages, namely conceptual and detailed design...