Direct assessment technology of pipeline external corrosion

External corrosion direct assessment (ECDA) is an important method for inspection and assessment of the degree of external corrosion and status of pipeline anticorrosion system. ECDA adopts the widely applied external inspection technology to determine the maintenance priority of pipeline and refrain from blindfold maintenance. The detailed procedure of ECDA including pre-assessment, indirect inspection, direct examination and post assessment is specified. Based on the advantages of ECDA and the domestic status of inspection technology and assessment methods, the international application status of ECDA is introduced, and the fact indicates that domestic inspection corporations follow behind the foreign inspection corporations in the aspect of indirect inspection method and data accumulation. An ECDA system suitable for the actual condition of China and in line with international practice should be built after learning from the oversea ECDA experiences to explore the inspection method applied for domestic pipelines, accumulate and fully use inspection data with the help of database technology.