Frequently-Asked Question FAQ #126

FAQ-126: ICDA on Dry-Gas System that Previously Transported Wet Gas

Question: Can Internal Corrosion Direct Assessment (ICDA) be used on a dry-gas system that was used previously to transport wet gas?

Answer: The ICDA process is designed to locate portions of the pipeline in which electrolyte may be present (and corrosion may therefore be occuring) and to examine those areas to identify any degradation. The process is not applicable to wet gas systems, because electrolyte is present throughout and the ICDA screening process can not work.

Pipeline systems that formerly carried wet gas could potentially have suffered internal corrosion at any location. Application of ICDA, alone, may not identify such degradation, since it focuses on areas where electrolyte may be present under current conditions. Therefore, ICDA cannot be used as an assessment method for a pipeline system that formerly carried wet gas, unless a plan is developed as required by 192.927(b). An assessment conducted subsequent to conversion that would have found any significant areas of internal corrosion degradation and caused their remediation would support the acceptability of ICDA. Results from such an assessment should be considered in integrating data concerning pipeline condition.