Within the past year, the American Petroleum Institute (API) published the first edition of API RP 1176, a recommended practice for assessment and management of cracking in pipelines. While the API guidance typically focuses on pipelines that transport liquids, this document specifically states that the recommended practice is applicable to any pipeline system used to transport hazardous liquid or natural gas, including those defined in U.S. Title 49 CFR Parts 195 and 192.
Crack management programs can be built following a Plan-Do-Check-Act process, an iterative four-step management method used in business for the control and continual improvement of processes and products. This process was incorporated in API 1173: Pipeline Safety Management Systems. Crack management should:
- [Plan] Identify the extent to which cracking could affect pipeline integrity
- [Do] Provide for timely assessment of the integrity of each segment with respect to the possibility of cracking on a prioritized basis that is informed by an assessment of risk
- [Check] Establish reassessment frequencies, as applicable
- [Act] Define preventive and mitigative measures to address relevant threats including those not covered by integrity assessments
Pipeline operators now have access to a recommended practice document can provide guidance in developing or making improvements to their crack management programs. The challenges that they face are lack of expertise in all the topics covered by API 1176, limited resources to develop and implement a major addition their integrity management plans, and incomplete knowledge concerning threats that potentially exist on their pipeline systems.
Environmental cracking including stress corrosion cracking, long seam defects and mechanical damage are the primary cracking threats mechanisms that need to be understood for each pipeline segment. Assessment and modeling of these threats requires the appropriate selection of detection and measurement technologies. If threats are identified they will require the correct repair method. If the threats can change due to pipeline operational practices or by third part damage mitigation and prevention strategies must be implemented for the pipeline. Finally the crack management program’s performance must be evaluated and possibly modified to address deficiencies in the program.
Kiefner subject matter experts participated in the development of API RP 1176 as contributors and technical editors and are well qualified to apply the content of this document. There are eight basic elements of crack management to incorporate into integrity management plans. These are:
- Data Gathering, Review, and Integration
- Incorporation of Crack Management Elements
- Inspection, Mitigation, and/or Remediation
- Continue to Assess for Cracks Periodically
- Establish and Implement Preventive and Mitigative Measures
- Evaluate Crack Management Elements
- Manage Change
- Update, Integrate, and Review Data
Each of these elements will be discussed in upcoming posts.