On June 15, 2016, the Pipeline and Hazardous Materials Safety Administration (PHMSA) issued an advisory bulletin to pipeline operators related to the effectiveness of coating and corrosion control measures on buried, insulated pipelines. PHMSA’s advisory bulletin responds to a recent pipeline failure and oil spill in California. The failure involved a buried oil pipeline coated with coal tar urethane and covered with tape wrapped foam insulation. The pipeline was insulated because it carried high-viscosity crude that required heat in order to transport. PHMSA found that the pipeline ruptured because of external corrosion that occurred under the pipeline’s coating system. PHMSA also found that this corrosion was facilitated by wet dry cycling. PHMSA’s Failure Investigation Report is here
PHMSA indicates that corrosion under insulation (CUI) is an integrity threat that is difficult to address through conventional cathodic protection systems and can lead to accelerated corrosion and stress corrosion cracking. PHMSA recommends that operators review their operating, maintenance, and integrity management activities to ensure that their buried, insulated pipelines have effective coating and corrosion control systems. PHMSA recommends that operator procedures consider the need for corrosion control systems that prevent moisture buildup, coatings that avoid cathodic protection “shielding,” advanced ILI data analysis to account for CUI, ILI data analysis and excavations to accurately assess corrosion as outlined in API Standard 1163, and additional or more frequent reassessment intervals for pipelines with known susceptibility to moisture retention.
For more information please contact Jim Curry, Keith Coyle or Brianne Kurdock of our Pipeline and HazMat Safety Practice.