Insulated Coatings Advisory

TUESDAY, JUNE 28, 2016

With an eye toward its mission to protect people and the environment through the safe transportation of hazardous materials, the U.S. Department of Transportation’s pipeline safety bureau has issued an advisory bulletin on corrosion related to insulated coatings on buried pipelines.

The Pipeline and Hazardous Materials Safety Administration (PHMSA) uses advisory bulletins to inform pipeline operators and federal and state pipeline safety personnel of matters that have the potential of becoming safety or environmental risks.

The newest advisory bulletin, published in the Federal Register and announced Friday (June 24), urges pipeline owners and operators to review their operating, maintenance and integrity management activities to ensure that their insulated and buried pipelines have effective coating and corrosion control systems in place.

Teaching By Example

PHMSA released “Pipeline Safety: Ineffective Protection, Detection, and Mitigation of Corrosion Resulting From Insulated Coatings on Buried Pipelines” in response to the failure of Plains All American Pipeline LP Line 901 in Santa Barbara, CA.

The final investigation report into the Line 901 crude oil spill indicated that the buried pipeline failed due to extensive external corrosion that occurred under the insulated coating.

As a result, the PHMSA advisory advises operators to become familiar with the circumstances that contributed to the Line 901 accident (summarized in the advisory bulletin), as well as to consider the preventative and mitigative actions the advisory recommends for minimizing failures.

Procedural Recommendations

In addition to having effective cathodic protection (CP) systems in place, personnel are reminded to conduct in-line inspections for all threats and to ensure in-line inspection tool findings are accurate, verified and conducted for all pipeline threats.

Plains Line 901 section 1

PHMSA urges operators and other pipeline personnel to consider preventative and mitigative actions, as outlined in its advisory, to minimize failures, protect the environment and ensure the safety of the public.

Specifically, PHMSA advises owners and personnel to consider procedures for insulated and buried pipelines that include:

  • Coatings and CP systems that are designed, installed and maintained in a manner that does not promote shielding and moisture that can lead to excessive external corrosion growth rates and pipe steel cracking such as stress corrosion cracking;
  • Addressing inadequate corrosion prevention by replacing lines with compromised coatings or inadequate CP systems, repairing or recoating compromised portions of coatings on insulated or buried pipelines, taking additional precautions (specified in the bulletin) if it is found that adequate CP is not possible because insulated coatings have disbanded;
  • Advanced in-line inspection (ILI) data analysis techniques to account for the potential growth of CUI and addresses anomaly assessment; and
  • Analysis of data and excavations and reassessments that measure and mitigate threats.


The mission of the Pipeline and Hazardous Materials Safety Administration is to protect people and the environment by advancing the safe transportation of energy and other hazardous materials that are essential to our daily lives. 

Founded in 2004, PHMSA develops and enforces regulations for the safe operation of the nation's 2.6 million mile pipeline transportation system and the nearly 1 million daily shipments of hazardous materials by land, sea and air.


Tagged categories: Cathodic disbondment; Cathodic protection; Coating Materials; Coatings under insulation; Corrosion; Corrosion protection; Corrosion Under Insulation (CUI); Disbondment; Insulating coatings; North America; Oil and Gas; PHMSA; Pipeline; Pipes

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