An overview of major methods for inspecting and monitoring external corrosion of on-shore transportation pipelines

Abstract

Corrosion can occur on underground pipelines especially at coating defects, where metal can be considered directly exposed to the soil, or under disbonded coatings, where the occluded geometry significantly affects the efficiency of cathodic protection (CP). In order to ensure the effectiveness of corrosion mitigation measures such as CP and protective coatings, inspection and monitoring of pipeline corrosion are required. This paper provides an overview of major methods that are used for inspecting and monitoring external corrosion of on-shore pipelines subjected to CP. Particular focus is on discussing the advantages and limitations of major inspection tools that are used to ensure pipeline integrity, and electrochemical corrosion sensors that are designed to monitor pipeline corrosion processes and rates. It is shown that there is a need for expanding the capabilities of corrosion monitoring methods suitable for the pipeline industry.