Crude oil and liquids pipeline systems integrity

Enbridge’s Liquids Pipelines integrity management program addresses aspects of evaluating and maintaining pipeline integrity to minimize the risks and consequences of having a pipeline failure that could impact populated areas and surrounding environments.

Federal and provincial/state pipeline regulations provide strict guidelines for pipeline companies such as Enbridge to develop, maintain, and continuously improve integrity management programs to protect high consequence areas (HCA). These regulations require pipeline operators to identify HCAs located along the pipeline – heavily populated, and unusually environmentally sensitive – that could be affected by an unintended release of the product transported inside the pipeline.

Our approach

Enbridge’s liquids integrity management (IM) plan is built around information and knowledge gathered through more than 50 years of pipeline operating experience. This includes technical and surrounding environment knowledge from repeated inside-the-pipeline inspection and testing data, as well as from information gathered outside the pipeline from thousands of excavations performed along our pipeline system.

This detailed knowledge of our pipeline system enables us to adopt a defect management approach to our pipeline monitoring and assessment. Using our extensive knowledge base, the IM plan is designed and implemented to assess and address, in a proactive manner, the risk associated with each potential defect that exceeds scientifically determined tolerances.

This approach involves identification and timely repair of those defects that affect the pipeline. We use established engineering guidelines for tolerances, specifications and procedures to guide our assessment.

The focus of our IM plan is to identify and correct low-level pipeline damage and deterioration before major repairs are required.

Our expertise

Enbridge’s pipeline integrity management team, including trained field personnel, provides expertise in managing the risks of pipeline operations. They manage the identification, assessment, and mitigation of risk as it relates to pipeline design and construction, system operations, and system integrity.

Our analysis

Enbridge’s emphasis is on prevention of pipeline failures, but we also focus on high consequence areas (HCAs). Each year we perform detailed potential consequence analysis along our pipelines to determine how a potential pipeline failure could affect an HCA. The areas around segments of our pipeline are evaluated to determine if the contents from a pipeline rupture have the potential to migrate to a nearby HCA. Scenario considerations are developed to determine how release profiles could affect HCAs both by moving over land or through water.

We estimate the severity of pipeline releases in terms of the potential volume of product that could be released, the physical pathways and dispersion mechanisms by which the product could move to a HCA, the amount of product that might actually reach the boundaries of the HCA, and the population and environmental resources that could be affected by such a release.

How we assess potential risks

Enbridge’s priority is to avoid accidents along the pipeline, but we take extra steps in assessing and preventing risks in high consequence areas (HCAs).

Our integrity management (IM) plan includes risk assessments that comprehensively evaluate the range of potential threats to our pipeline and consequences to any nearby HCAs. The types of potential threats include hazards or damage that, over time, deteriorate the pipeline. These threats generally fall into one or more of the following categories:

  • Metal loss or corrosion
  • Pipe deformation, such as denting caused by third-party digging near our pipeline
  • Cracking related to steel manufacturing or forming processes
  • Cracking related to exposure to natural environments
  • Incorrect operations

The risk analysis involves the use of data within an integrity assessment program in which data is gathered from, but is not limited to, the following sources:

  • Original construction records
  • Pipeline alignment sheet records
  • Personnel interviews
  • Digital elevation models
  • Historical data
  • Leak and incident data/reports
  • Operating characteristics
  • Corrosion monitoring
  • Cathodic protection surveys
  • Transported product information
  • Digital maps delineating HCAs

How we manage potential risks

In order to manage risks posed to our pipelines, preventative and mitigation measures are considered on a case-by-case basis. These measures either reduce specific threats to our pipeline or reduce the consequences of a leak or spill.

Management of risk relies on a program that meaningfully gathers and analyzes the data related to hazards that may affect the pipeline. Based on many factors — such as pipeline failure history, inside-the-pipeline inspection results, excavation/direct assessment, susceptibility studies, models, and data trending — potential risks are identified.

That data is then collected and analyzed to characterize these hazards. Integrity management strategies that will protect high-consequence areas above and beyond normal maintenance are then developed, documented and implemented to address the hazards. Our integrity management (IM) plan is continuously improved through ongoing data and performance analysis.

Our leak prevention measures

Preventative measures begin with the design and construction of our pipelines. These measures include design specifications, selection of suitable construction materials, development and selection of welding procedures, pipe coatings, and cathodic protection systems. Additionally, manufacturing controls are used to promote high-quality installation of the pipeline and to limit operating stress.

We have a comprehensive preventive maintenance program to inspect, maintain, and test facilities. We check and adjust our cathodic protection system, we routinely test our valves to verify they are operating correctly, and we calibrate electronic components.

We also monitor the pipeline 24 hours a day, 365 days a year from our control center and through regular aircraft and/or ground patrols that keep tabs on activity near our pipeline. Our gathering pipelines are monitored during operation, as some do not operate around the clock.

To prevent external damage to our pipeline from excavators, we participate in local one-call programs and Call/Click Before You Dig initiatives in Canada and the U.S. When we determine that anyone is planning to dig on or near our pipelines, our specially trained field personnel mark the location of the pipeline and monitor any digging that occurs near our pipe.

These are just a few of our normal operations and maintenance practices. As our neighbor you, too, can help by calling us or your local law enforcement agency if you see any unauthorized digging along our pipeline or unauthorized personnel in our facilities.


A communications component of Enbridge’s integrity management (IM) plan helps us apprise appropriate company personnel, jurisdictional authorities, and the public about our pipeline integrity management efforts.

Communications with affected public, emergency agencies, and public officials regarding our IM plans in high-consequence areas are carried out according to a written plan. Specific information regarding IM plans is included with our outreach along our pipeline system, and interested parties are invited to this website for an overview.