BowTie Analysis for Hazardous Facilities

Overview

BowTie Analysis is a structured Major Accident Hazard (MAH) management technique used to identify, assess, and control high-consequence risks within tolerable limits. It visually links hazards, credible threats, preventive barriers, mitigative measures, and consequences, providing a clear and auditable framework for BowTie risk assessment in complex oil & gas and energy facilities.

This approach supports effective ALARP demonstration, improves risk visibility, and ensures safety-critical risks are managed throughout the asset lifecycle.

Methodology

The BowTie Analysis methodology is applied during the engineering phase and integrated with upstream safety studies such as HAZID and HAZOP. The study followed a structured and workshop-based approach:

• Identification of MAH scenarios for process and construction activities
• Definition of hazards, top events, credible threats, and worst-case consequences
• Development of detailed BowTie diagrams using specialist BowTie software
• Identification and categorisation of preventive and mitigative barriers
• Evaluation of barrier effectiveness, independence, and criticality
• Identification of Safety Critical Elements (SCEs) and Safety Critical Tasks (SCTs)
• Assessment of escalation factors and escalation controls
• Qualitative ALARP demonstration through barrier adequacy verification
• Multidisciplinary BowTie workshops involving engineering, operations, maintenance, and HSE teams

Outcomes

The BowTie Analysis delivered measurable improvements in MAH risk management, including:

• Clear visualisation of major accident risk pathways
• Improved understanding of hazard escalation during construction and operations
• Identification of safety-critical equipment and safety-critical human actions
• Strengthened design, construction, and operational controls
• Practical recommendations to improve system reliability
• A structured basis for ongoing barrier management across the asset lifecycle

BowTie Analysis for Gas System Modification – QatarEnergy (FEED Stage)

Introduction

A BowTie Analysis was performed for QatarEnergy during the Front-End Engineering Design (FEED) stage of a gas system modification project covering multiple gas distribution stations and downstream power plant interfaces across Qatar, including Ras Laffan Industrial City, Mesaieed Industrial City, Al Wakrah, and Ras Abu Fontas.

The study addressed Major Accident Hazards (MAHs) associated with modifications to live operating gas facilities, where uninterrupted gas supply to critical power generation assets and personnel safety were key requirements. The analysis considered risks arising from construction activities, pipeline tie-ins, station bypass installations, and temporary operating conditions.

The BowTie methodology was applied as part of a broader HSE risk management framework, ensuring that MAH controls and associated preventive and mitigative safety barriers were systematically identified and embedded into design development, and operational philosophy, in line with QatarEnergy corporate safety standards.

Project Insights

Loss of containment of fuel gas was identified as the primary top event across all credible Major Accident Hazard (MAH) scenarios. The BowTie Analysis evaluated hazards associated with live system modifications, including:

• Construction activities
• Hot tapping and pipeline tie-ins
• Pipeline reconfiguration
• Pressure control changes
• Temporary operating conditions

Credible threats contributing to these scenarios included:

• Mechanical damage during construction
• Over-pressurisation
• Isolation and valve failures
• Corrosion and degradation mechanisms
• Dropped objects
• Vehicle movements and lifting operations

Preventive safety barriers were systematically reviewed to confirm adequacy and effectiveness, including:

• Design verification and compliance with engineering standards
• Permit-to-work and isolation management systems
• Contractor competency, training, and authorization controls
• Inspection, testing, and maintenance regimes

Mitigative safety barriers were assessed to limit consequences in the event of a loss of containment, including:

• Gas detection and alarm systems
• Emergency Shutdown (ESD) functions
• Pressure protection systems
• Fire and gas detection and suppression systems
• Emergency response arrangements

Escalation factors that could degrade barrier performance during construction and temporary operations were identified, leading to targeted improvements in:

• Work sequencing and planning
• Supervision and real-time monitoring
• Asset integrity management

A qualitative ALARP demonstration confirmed that risks associated with the modifications can be reduced to tolerable levels through appropriate engineering and operational measures.

Conclusion

The BowTie Analysis provided QatarEnergy with a clear and defensible HSI framework for managing Major Accident Hazards during gas system modifications at the FEED stage.

By defining hazards, safety-critical barriers, and escalation controls, the study supported safer execution of live system works while reducing reliance on procedural controls alone.

The outcome enhanced confidence in maintaining uninterrupted gas supply, improved visibility of safety-critical elements and tasks, and embedded MAH management into design decision-making supporting safe project delivery and long-term operational resilience.

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