Safety Assurance of LOPC MAH Scenarios That Have Potential to Result in Fatality

Abstract Enbridge operates the world’s longest and most complex crude oil and liquids transportation system, with approximately 28,000 kilometers of active pipeline across North America. The system transports a wide variety of crude oil and liquid products ranging from heavy crude to Natural Gas Liquid (NGL) via various sizes and lengths of pipeline that traverse populated areas such as city, town and sensitive public places. An ignition of a hypothetical hydrocarbon releases from the pipeline system in populated areas represents a hazard to health and safety with potential to lead to fatalities and/or injuries. Such scenarios with catastrophic consequence are often referred to as Major Accident Hazards (MAH) and a focus on MAH is common in Safety Case regimes (e.g. UK HSE). Enbridge’s liquid pipeline system executes systematic, comprehensive, and proactive approaches to achieve safety and reliability objectives across the lifecycle of assets. As part of integrity assurance, Safety Case assessments include a focus on MAH. The Safety Case assessment of MAH is comprehensive and considers process and non-process LoPC scenarios that have potential to lead to MAH and includes assessment of the controls relied on to manage risk. The assessment methodology is scalable and utilizes qualitative and quantitative risk methods. The results of the Safety Case assessment bring visibility to the information useful for establishing confidence in the systems relied on to achieve the safety and reliability objectives. This paper provides a high-level description of the Safety Case assurance methodology deployed by Enbridge specific to LoPC MAH scenario related to Health & Safety impact in a facility setting. The methodology is compared to best practice from other regulatory regimes. Enbridge has continued to develop the integrity Safety Case program over the past years and this paper discusses observations, including benefits and challenges, from applying the Safety Case assurance methodology within a large operating company.