Long-Term Cathodic Protection Performance Data of Two off-Shore Structures

Cathodic protection of submerged steel marine structures is regularly used for their corrosion control. With the availability of large weight anodes and a high current capacity aluminium anode formulation, recent static uncoated marine structures regularly use sacrificial anode systems. Such systems are frequently designed for the sacrificial anode system to last for the design life of the structure. Codes of practice exist to help the designer chose the right combination of anode composition, weight and anode number appropriate for a specific location and structure size. These codes of practice were conceived and formulated early on in the lifetimes of many of the off-shore structures they were used to design. In most structures no extensive ongoing measurements have been made and so the correlation of these standards with real performance has not always been possible. Recently, in the Far East, monitoring data has been made available from structures in Japan and China which may well allow the standards to be assessed more critically. The presentation and analysis of these data will be the subject of this paper.