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Liquids Systems Integrity

High Consequence Areas
Our Approach
Our Expertise
Our Analysis
How We Assess Potential Risks
Our Leak Prevention Measures


High Consequence Areas

For liquid petroleum pipelines, high consequence areas (HCAs) are defined as any of the following:

  • High population areas, defined by the Census Bureau as urbanized areas.
  • Other populated areas, defined by the Census Bureau as places that contain a concentrated population.
  • Unusually sensitive areas.
  • Commercially navigable waterways.

Unusually sensitive areas are defined as drinking water or ecological resource areas that are especially responsive to environmental damage from a hazardous liquid pipeline release. The federal government has applied this definition to identify HCAs and has made maps depicting these locations to pipeline operators. Operators are also responsible for independently evaluating information about the area around their pipeline to determine whether a pipeline accident could affect a nearby, but not adjacent, HCA.

Our Approach

Our liquids integrity management (IM) plan is built around information and knowledge gathered during 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

Our 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

Our 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 pipeline to determine how a potential pipeline failure could affect a 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

Our 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.
  • Quadrangle USGS maps.
  • 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, preventive 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

Preventive 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 their “Call Before You Dig” initiatives. 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 the 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.