Integrity Management: A risk-based approach to improving pipeline safety
Objectives of Integrity Management
Pipeline safety regulations include requirements for operators of hazardous liquid and gas transmission pipelines to develop and implement comprehensive integrity management programs.
Codified in Title 49 of the Code of Regulations Part 195.452 and 192, Subpart O, these rules have four basic objectives:
- To perform integrity assessments of pipelines in locations where a pipeline failure could have significant adverse consequences (referred to as High Consequence Areas or HCAs).
- To improve operator management, analytical, and operational processes to manage pipeline integrity.
- To increase government’s role in the oversight of operator integrity management programs and activities.
- To improve public confidence in pipeline safety.
High Consequence Areas
While there are differences between the integrity management rules for gas and hazardous liquid pipelines, the basic requirements are very similar.
Both rules require operators to identify locations along their pipelines where a failure might affect an HCA. The regulations specify what conditions constitute an HCA for each type of pipeline. For natural gas transmission lines, an HCA is based on the population density near the pipeline. The specific definition of an HCA is in 49CFR192.905. For hazardous liquid pipelines, HCAs include:
- Urban areas and other populated places as designated by the U.S. Census Bureau.
- Commercially navigable waterways.
- Drinking water and ecological resources that are unusually sensitive to a pipeline failure. Detailed definitions are provided in 49CFR195.6.
Operators are also required to monitor conditions along their pipelines, and identify new HCAs when changes such as population expansion near the pipeline rights-of-way occur.
Integrity Management Programs
Both the natural gas and hazardous liquid integrity management rules require operators to develop and implement a formal integrity management program.
An integrity management program is a set of safety management, analytical, operations, and maintenance processes that are implemented in an integrated and rigorous manner to assure operators provide protection for HCAs. While the rules provide some flexibility for an operator to develop a program best suited for its pipeline system(s) and operations, there are certain required features – called “program elements” – which each integrity management program must have. The core integrity management program elements include:
- Identifying all locations where a pipeline failure might impact an HCA.
- Developing a risk-based plan (known as the Baseline Assessment Plan) to conduct integrity assessments on those portions of the pipeline. Integrity assessments are performed by in-line inspection (also referred to as “smart pigging”), hydrostatic pressure testing, direct assessment or other technology that the operator demonstrates can provide an equivalent understanding of the condition of the line pipe.
- Integrating the assessment results with other relevant information to improve the understanding of the pipe’s condition.
- Repairing pipeline defects identified through the integrated analysis of the assessment results.
- Conducting a risk analysis to identify the most significant pipeline threats in segments that can affect HCAs. Examples of pipeline threats include corrosion, excavation-induced damage, material defects, and operator errors.
- Identifying additional measures to address the most significant pipeline threats. These measures include actions to prevent and mitigate releases that go beyond repairing the defects discovered through integrity assessment.
- Regularly evaluating all information about the pipeline and its location-specific integrity threats to determine when future assessments should be performed and what methods should be selected to conduct those assessments.
- Periodically evaluating the effectiveness of the integrity management program and identifying improvements to enhance the level of protection.
The Baseline Assessment Plan must identify the specific integrity assessment method(s) for each segment that can affect an HCA. These methods must be based on the identification of the most significant integrity threats for the specific segment. The Plan must also include a schedule indicating when the assessments of each segment will be performed. The schedule must be risk-based, meaning that higher-risk segments are scheduled before lower-risk segments. Operators must document the technical basis for the assessment methods they select and the risk analysis performed to establish the schedule.
Time is of the Essence
The integrity management rules provide deadlines by which baseline assessments must be completed.
For example, at least 50% of natural gas pipeline mileage that can affect HCAs must be assessed by December 17, 2007, with higher-risk segments being addressed first. Assessments for all gas pipeline segments that can affect HCAs must be completed by December 17, 2012. Similar deadlines exist for hazardous liquid pipelines, with all segments that can affect HCAs being assessed by February 17, 2009.
Once baseline assessments are completed, operators must conduct periodic assessments on identified pipeline segments. The frequency of reassessment depends on the risk presented by each segment. Risk is determined based on many factors, including the pipe condition as learned from the integrity assessment; leak history; pipeline design features; operating and maintenance practices; and factors outside the pipeline such as population density or the presence of drinking water sources. The regulations provide time limits within which these future assessments must be performed.
The regulations also establish deadlines by which certain potentially serious defects identified by integrity assessments should be repaired. Both the gas and liquid pipeline rules identify certain defects which must be repaired immediately after they have been identified. For example, if inline inspection results identify a dent in the pipe that has any indication of metal loss, the operator must immediately reduce pressure or shut down the pipeline until the defect is repaired.
The Value of a Risk Analysis Approach
Although integrity assessment and repairing of identified piping defects is a very important part of the rules, integrity assessments are not capable of addressing all known pipeline failure causes.
This is Where the Risk Analysis Program Element Comes In
Comprehensive and systematic risk analysis is a valuable tool to help operators identify and determine the significance of previously unrecognized threats. Through rigorous analysis of all available data, pipeline operators are required to identify and evaluate all potential precursors to pipeline failure and the risks that they pose. Operators must also identify and implement additional preventive or mitigative measures to address the most significant threats identified by the risk analysis. These measures would be dependent on the nature of the threat and the specifics of the operator’s pipeline system and its operation. Some examples include: enhancing damage prevention programs; improving corrosion control monitoring; enhancing control center operator training; improving leak detection system capability; conducting emergency drills with local emergency responders; and installing remotely operated valves to expedite the isolation of a leak or failure when one is discovered.
Accountability and Continual Program Improvement
OPS expects operators to refine and improve their integrity management programs in an ongoing fashion.
The rules specify that operators must periodically evaluate the effectiveness of their integrity management program activities and processes. Program improvements could come from lessons learned following failures or leaks; internal audits of the program; and the introduction of new technologies. As part of their program evaluation, operators are required to identify specific performance measures that reflect program effectiveness. Those measures will be reviewed by OPS as part of its assessment of operator and industry-wide performance.