Pipeline integrity management is a process for assessing and mitigating pipeline risks in order to reduce both the likelihood and consequences of incidents. The Pipeline Safety Improvement Act of 2002 is federal legislation that addresses risk analysis and integrity management programs for pipeline operators and directs the U.S. Department of Transportation (DOT) to adopt regulations on integrity management. DOT finalized these regulations in 2004. Natural gas transmission pipeline operators are required to have written programs in place by December, 2004, and to complete baseline assessments of pipe in high consequence areas by 2012.
Citizens Gas has implemented an integrity management program for pipelines in its high consequence areas according to the DOT regulations. It is a systematic, comprehensive process designed to provide information to effectively allocate resources for appropriate prevention, detection and mitigation activities. The program builds on an existing foundation of pipeline safety regulations covering design, construction, testing, operation and maintenance that has been in place for many years.
These are the basic steps in the integrity management process.
- High consequence area (HCA) identification - Locations along the pipeline system meeting the criteria for High Consequence Areas are identified. Generally, these are high population density areas, difficult to evacuate facilities (such as hospitals or schools), and locations where people congregate (such as churches, office buildings, or ball fields).
- Threat identification and risk assessment -Information about the pipeline segments is evaluated to identify threats to the pipe and assess risk.
- Baseline assessment plan- A schedule for performing pipe integrity assessments over the 10-year baseline period is developed. Risk assessment results are used to prioritize the projects. The method of integrity assessment is also selected for each segment and becomes part of the plan along with the schedule. More than one method may be required depending on the threats identified.
- Integrity assessment - The pipe segments are assessed according to the schedule and methods identified in the Baseline Assessment Plan. There are three primary assessment methods:
- Inline inspection - an inspection tool (often called a "smart pig") is run internally through the pipeline to evaluate the pipe condition.
- Pressure test - the pipe is pressured above its normal operating limit to test the strength of the pipe. Water is usually used to pressure the pipe during the test.
- Direct Assessment - a structured, multi-step evaluation is conducted to identify potential problem areas. Pipe at these locations is excavated and examined.
- Remediation - Potential integrity concerns identified during the integrity assessment are evaluated and actions are taken to eliminate the problems.
- Preventive and mitigating measures -Along with performing the integrity assessments on pipe segments, the process calls for implementing additional measures to prevent or mitigate problems before they occur.
- Continual evaluation and assessment - A continuing plan to evaluate the integrity of the pipeline after completing the baseline assessment is also part of the process. The ongoing plan includes reviewing updated information about the pipe, analyzing risk, and performing reassessments at regular intervals.
Safe and reliable delivery of natural gas is Citizens Gas’ primary concern. The integrity management program is an important part of our efforts toward achieving that goal.