Safety case is utilized within the Enbridge Pipeline Integrity Management Program as a means to provide evidence that the risks affecting the system have been effectively mitigated (LeBlanc, et al. 2016). The safety case is an independent, evidence-based assessment based on system integrity management processes applied across all pipelines. This paper describes the process in which safety case methodology was implemented to manage geohazard threats. The benefits of assessing geohazard and other integrity threats will also be discussed. The safety case report documents the opportunities to address the identified problems in addition to the relationship between hazards, implemented controls, and associated susceptibility.
To demonstrate that adequate safety controls for geohazard threats have been incorporated into the operational and maintenance phase of the pipeline system, the geohazard management component of the safety case was assessed using a bowtie diagram. The results gave visibility to the geohazard program and its effectiveness. Predefined safety performance metrics with probabilistic and deterministic criteria are evaluated to confirm the geohazard program’s continued effectiveness.
Results from the safety case assessment identify opportunities for improvement and provide a basis for revision to maintenance, assurance and verification programs. Ultimately the assessment demonstrates that geohazard threats in the pipeline system are being recognized and assessed. The assessment provides evidence that adequate resources and efforts are allocated to mitigate the risk and identifies continuous improvement activities where needed. The safety case report generated as the final portion of an integrity management framework demonstrates risk is as low as reasonably practicable (ALARP).