A close interval survey (CIS) is a preventive action that canhelp prevent this corrosion before it starts. CIS is one part of asuite of tools used to identify conditions that cause corrosion,allowing you to assess the effectiveness of the cathodicprotection (CP) system protecting your pipeline – ensuring it isoperating to NACE SP0169 specified standards.
Prevent corrosionbefore it starts.
Once corrosion is detected in a pipeline, extensive (andcostly) remediation programs must be implemented toensure ongoing safety of your assets, employees, neighborsand the environment. These may include costly replacementor repair of corroded sections of pipeline, a reduction inmaximum allowable operating pressure (MAOP) and throughputor an increase in required assessments of your pipeline.
Pipeline operators estimate that the total cost of maintenanceof CP systems can be up as much as 15 times lower comparedto monitoring and repairing corrosion. A proactive, preventiveclose interval survey program – including those that conductannual pipeline surveys – can be a fraction of the cost of aprogram to survey and remediate corroded pipe.
Regulations prescribe how often pipeline operatorsmust perform an assessment of their transmissionpipelines. In the U.S., it is a minimum of every sevenyears for transmission lines and every five years if thepipe carries hazardous liquids.
Many operators, however, perform CIS assessmentsmore frequently so they can take action to preventcorrosion. Once corrosion is detected, costly repairsor a reduction in MAOP is required which leads toreduced throughput and lower revenue for operators.