Use of CP Coupons and Soil Corrosion Probes inApplication of Pipeline Cathodic Protection Criteria

摘要

Cathodic protection (CP) coupons and soil corrosion probes (SCPs) can be effective tools in applying CP criteria under challenging operating environments. These: ituations include measuring off-potentials using coupons in cross-bonded systems or structures influenced by interference from CP systems not controlled by the main protected system operator, or Where CP potentials cannot be reliably measured and corrosion rate measurements using electrical resistance (ER) soil corrosion probes are used as an alternative to conventional CP criteria for buried pipelines.This paper looks at the various scenarios where CP coupons and SCPs can be used, using field data from installations on buried pipelines, and also with reference to the requirements of the new ISO standard ISO/FDIS 15589-1 on different CP criteria for varying soil resistivities. Information is also given on the recent work by the NACE International Technical Committee TG-321 draft report on soil corrosion probes.