The new NACE Standard SP21424-2018 provides a set of simple criteria for assessing the risk of AC corrosion on existing collocations between powerlines and cathodically protected pipelines. However, the task of developing design criteria for new collocations is left to the pipeline operators.
This paper covers a number of challenges related both to developing design criteria for new collocations and applying the new Standard to existing collocations.
Topics like selection of the AC current density limit for mitigating AC corrosion on a new pipeline, recording AC and DC currents on 1 cm2 coupons and dealing with high AC and DC average current densities at low AC voltages are discussed in detail in this paper.
