Gas Pipeline Integrity Management
The Department of Transportation’s Research & Special Programs Administration (RSPA) and the Office of Pipeline Safety (OPS) in 2004 adopted a rule requiring gas pipeline operators to develop Integrity Management Programs for transmission pipelines that could affect high consequence areas in the event of pipeline failure (Covered Segment). The rule incorporates the requirements of the Pipeline Safety Improvement Act of 2002 that was enacted on December 17, 2002 (2002 Pipeline Safety Act).
The rule requires owners and operators of gas transmission lines to:
- Implement comprehensive Integrity Management Plans;
- Conduct baseline assessments and periodic reassessments to identify and evaluate potential threats to pipelines;
- Remediate significant defects discovered during these processes; and
- Continually monitor program effectiveness so that modifications can be recognized and implemented.
The rule requires pipeline operators to develop written Integrity Management Programs that address risks to each covered pipeline segment.
Covered Segments are identified by densely populated locations, or areas where a pipeline is located within a specified distance from an “identified site” (e.g., facilities with persons who are mobility-impaired, confined, or hard to evacuate, such as hospitals, churches, schools, or prisons, and places where people gather for recreational purposes). Such distances are based on the pipeline’s diameter and operating pressure.
The rule requires pipeline operators to develop, implement and follow written Integrity Management Programs that address the risks on each Covered Segment. The Integrity Management Programs, which must be kept on site for OPS inspection, must comply with extensive requirements set forth in the rule. The rule further requires appropriate training for an operator’s personnel involved in the Integrity Management Program.
WGP Integrity Management Program
Williams Gas Pipeline (WGP) is committed to operating its facilities in a safe and reliable manner to protect the public, the environment and employees. WGP has developed an Integrity Management Program to add integrity value to its system in accordance with 49 CFR Part 192 Subpart O.
WGP’s Integrity Management Program does the following:
- Identifies all Covered Segments covered in the new rule
- Addresses the 14 required elements identified by OPS, including:
- Identification of all Covered Segments;
- A baseline assessment plan for Covered Segments;
- Identification of potential threats to Covered Segments;
- A direct assessment plan;
- Provisions for remediating conditions found during an integrity assessment;
- A process for continual evaluation and assessment;
- Preventative and mitigative measures to protect Covered Segments;
- Performance measures to assess whether the integrity management program is effective;
- Record keeping requirements;
- A management of change process;
- A quality assurance process;
- A communication plan;
- A process for providing a copy of an operator’s integrity management program to a State authority where OPS has an interstate agreement; and
- A process for ensuring that each integrity assessment is conducted in a manner that minimizes environmental and safety risks.
- Creates a baseline assessment plan which identifies:
- Segments to be assessed;
- Methods selected to assess each pipeline segment;
- The basis for selecting each assessment method; and
- A priority-based schedule for completing the assessment.
WGP will use a combination of four assessment methods. WGP will select the method or methods best suited to address the threats identified in each segment. They include:
- Internal inspection tools – inline and pig testing;
- Pressure tests;
- Direct assessments – a process that includes data gathering, indirect examination, direct examination, and post-assessment evaluation; or
- Other proven technologies.
- WGP has developed a program for continual integrity assessment and evaluation once the baseline assessment has been completed.
- WGP has developed processes for continually improving and developing its framework into an ongoing Integrity Management Program. This includes methods to measure whether the program is effective in assessing and evaluating the integrity of each Covered Segment.
The hazards or threats considered below represent the nine categories of related failure type identified in ASME B31.8S and include:
- External corrosion
- Internal corrosion
- Stress corrosion cracking (SCC)
- Manufacturing Related Defects (Fatigue Cracking due to pre-existing ERW defects)
- Off-Pipe equipment
- Wrinkle bends
- Girth weld defects
- Coupling failure
- Third-party mechanical damage
- Ground movement/ loss of soil support due to weather and outside forces
- Incorrect Operations considered to be not segment specific and therefore addressed in WGP procedures and not included directly into the risk ranking.
The consequences considered included:
- Societal impact (safety and customer interruption)
- Environmental impact
- Customer impact
- Financial impact
WGP has prioritized the assessment of these segments. These timeframes, which are consistent with those mandated in the 2002 Pipeline Safety Act, are as follows:
|Method||Completion Date||Date by which 50% of a pipeline Covered Segment must be assessed|
|Pressure test or internal inspection tool||12/17/2012||12/17/2007 (completed)|
|Direct Assessment||12/17/2009 (completed)||12/17/2006 (completed)|
When a new location that must be assessed is identified, WGP will include it in its baseline assessment within one year from the date of identification. The baseline assessment of any newly identified location must be completed within 10 years (seven years if direct assessment is used) from that date.
WGP’s Integrity Management Program dictates that it will take prompt action to address and remediate all anomalous conditions discovered through the assessment process. All conditions that could reduce a pipeline’s integrity will be remediated. WGP will determine the existence of a condition within 180 days of conducting an integrity assessment. Except in the cases where a condition must be repaired immediately (in which case operating pressure must be temporarily reduced or the pipeline shut down until WGP completes repair of such conditions), and those conditions that require remediation within 180 days, WGP will complete remediation of conditions pursuant to the schedule ASME/ANSI B31.8S.