Impact of IR Drops on the-850 mVCSE Cathodic Protection Criterion for Coated Steel Pipes in Soil

By means of numerical modeling and experimental measurements, this work addresses the longstanding controversy of whether or not IR (ohmic) drops need to be considered in on-potential cathodic protection criteria. The results suggest that the IR drop is of little importance in many situations of practical relevance, and that its adverse influence on assessing the effectiveness of corrosion protection is generally overrated. This suggests that on-potentials are in principle suitable to be directly used for determining if a cathodic protection (CP) system offers adequate corrosion protection. This is considered a relevant finding because on-potentials are straightforward to measure, and their interpretation is free of many of the difficulties associated with instant-off potentials. Irrespective of the parameter used, however, a number of issues are discussed that need to be addressed in further work in order to provide the knowledge required to settle on threshold values. (C) 2017 American Society of Civil Engineers.