Practical Application of
Bowtie Analysis
Enhancing Traditional PHA
James Sneddon
Principal Consultant, Risktec Solutions (Canada) Ltd.
Purpose of Presentation
Introduce bowtie methodology and its use as a risk assessment tool
Discuss the practical application and benefits of bowtie analysis, as observed
cross-industry
Compare and contrast bowtie methodology, and its ‘place’ within the risk
management process, with the more established HAZOP process
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Bowtie Diagram
Basic Structure
Impacts
Causes
Preventive Business Recovery
controls upset preparedness
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Bowtie Methodology
A short History…
Exact origins of bow-tie methodology are hazy – believed to originate from ICI in the late 1970’s
Royal Dutch/Shell Group first major company to integrate bow-ties fully into business practices
Use of bow-ties now widely spread between companies, industries, countries and from industry
to regulator, e.g.:
Abu Dhabi National Oil Company (ADNOC)
UK Health and Safety Executive
French Government
Australian State Regulator
Land Transport Safety Authority of New Zealand
International standards (e.g. ISO 17776:2000)
International Association of Drilling Contractors (IADC)
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Typical Risk Management Process; Where do Bowties fit in?
Identify Develop Risk Assess Risk Bowtie
Hazards Scenario Analysis
Risk Management Process
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Bowtie Diagram
An Overview…
Identify Assess
Consequence
Consequence 1
Hazard and Hazard Source 1
Threat 1
Recovery
Threat Measure
Control Recovery
Threat Measure
Control Top Consequence
Consequence 2
Threat 2
Threat Threat Event Recovery Recovery
1
Control Control Measure Measure
Threat 3 Threat
Threat Recovery
Control
Control Measure Consequence
Recovery
Consequence 3
1
Measure
Control Recover
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Practical Uses of Bowtie
Communication How do we engage non-risk specialists?
Formal demonstration Can we really demonstrate control of our risks?
Specific risks Are these non-routine activities/ problematic
areas, and their inherent risks properly
understood and controlled?
Critical roles Do our people know what is expected of them?
Competencies Are competence and control requirements
aligned?
Procedures Are they complete and effective?
Auditing How can we focus audits on what really
matters?
Critical systems and What are they?
performance standards
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Bowtie and the HSE Management System
HSE / Safety Critical Equipment HSE Critical Tasks
Operator Competencies Training and Development
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Total Hazard Control
In the end you must have all connections in place for effective hazard control
Location/
operation
Hazard Performance
Activity to measures
Standards & control risk
Procedures
Competence
Threat
Task
People
Threat
control
Release
of hazard Recovery Consequence
Risk Evaluation & measure
Management
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Benefits of Bowtie Analysis
Goes beyond usual risk assessment ‘snapshot’ and highlights links between risk controls and
management system
Helps to ensure that risks are managed rather than just analysed
Forces a comprehensive and structured approach to risk assessment
Excellent for communicating risk issues to non-specialists
Ownership – involves people, gains buy-in, practical approach
Operations – assigns responsibility for hazard controls and links to asset integrity
All risks – not just HSE
Risk reduction - identifies where resources should be focussed for risk reduction, i.e. prevention
or mitigation
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Limitations of Bowtie Analysis
Qualitative – does not replace QRA
Does not replace techniques like or HAZOP or FMECA
Depends on experience of personnel and active participation
Ensure controls in bowtie are truly independent
Not obvious which controls are most important
Use as a communication tool (simple bowtie) vs complete demonstration of hazard management
(detailed bowtie) – potential conflict
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HAZOP vs. Bowtie
In General……
HAZOP excels at performing a detailed, structured review of
the operation of a process, identifying the possible causes
of a deviation from the design intent, the consequences and
the engineering safeguards present.
Bowties are a very flexible, graphical risk analysis method,
that allow for visualization of the relationship between
Cause – Loss of Control – Consequence and the barriers in
place to manage the sequence.
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HAZOP vs. Bowtie; Key Differences
Graphical Representation : Allows for a much clearer, easier to understand representation of
the risks and how they are managed.
Flexibility: Bowties are a very flexible method, and in addition to looking at process risks (which
is generally where HAZOPs are employed), are also applied to a far wider range of risks
including logistics, construction, security, etc.
Barrier Identification: HAZOPs tend to concentrate on the engineered safeguards in place ,
whereas Bowties will consider a wider range of safeguards e.g. training & competency, external
protection, inspection & maintenance, etc.
Internal vs. External: HAZOPs tend to concentrate on what is happening inside the process,
whereas Bowties allow for consideration of external events as well e.g. external impact, weather,
human error etc.
Preventative vs. Mitigative: HAZOPs end to concentrate on the preventative safeguards
employed to stop a sequence from happening; Bowties allow for a more thorough consideration
also of the mitigative controls.
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HAZOP vs. Bowtie; Key Differences
Representation of Risk: HAZOPs tend to stop with the static representation of risk. Bowties
allow for a deeper interrogation of the safeguards, to ask not only what is there, but why it will still
work in the future.
Demonstration through HSE MS: Bowtie barriers can be hot-linked to external information e.g.
operating procedures, to allow for personnel to interrogate further if required
‘Live’ Risk: Bowties can be linked to ‘live’ information from maintenance management systems
e.g. SAP, to show a live picture of the risk management status indicating barrier status (on- or off-
line).
None of this is intended to say the Bowties should replace HAZOP. They are
complementary tools. There is nothing better than HAZOP for ensuring that
process systems are designed fit for purpose. Bowties follow on from this to
allow for a through life picture, applicable to all levels of personnel, that can be
applied to all risks.
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Questions?
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