Guest blog by David Hatch from Process Safety Integrity
The outputs from PHA/HAZOP studies are stale, static and forgettable. The passage of time quickly erodes the memories of those who contributed, and those who did not attend but have to manage the risks are unlikely to correctly & consistently interpret the findings from masses of technical text.
Visualizing PHA/HAZOP Safeguards as bowtie barriers, means they can be monitored and managed using tools such as AuditXP and IncidentXP. A key benefit is a confirmation that predicted or assumed safeguards are actually installed, operating and performing appropriately.
This is the difference between ‘Belief’ & ‘Faith’ and genuine ‘Knowledge’. When we perform analysis, we believe that safeguards are or will be in place, we have faith that they will work as required, when required. But we don’t really know they do without planned challenges from audits, surveys, inspections etc. and learning from & acting upon incidents, including near misses/hits.
Enhancing PHA with graphical power
CGE Value Added Partners David Hatch (Process Safety Integrity), Ian Travers (Ian Travers Ltd) and CGE Implementation Specialist Paul McCulloch have co-authored an article “Enhancing PHAs: The Power of Bowties” in the February 2018 edition of the AIChE Chemical Engineering Progress (CEP) magazine.
This magazine was the first to publish H.G. Lawleys “Operability Studies and Hazard Analysis” in April 1974 which summarised ICI’s experience and evolution of a technique of ‘critical examination’ which would become the internationally adopted best practice of HAZOP (Hazard and Operability) also known as PHA (Process Hazard Analysis).
The current article proposes an approach which utilizes the systematic rigor of conventional PHA studies with the graphical power of bowtie analysis to:
- Ensure Safeguards (Barriers) are assigned to the appropriate Causes (Threats) and Consequences.
- Provide scalable views from the big picture (Node) down to sharp focus (Scenarios)
- Categorize components to highlight dependence (negative relationships) between Threats & Barriers and Barrier & Barriers
- Provide a framework for subsequent risk assessment (e.g. LOPA) and ongoing Safeguard (Barrier) assurance.
- Retain worksheet information and gain/enhance hazardous scenario knowledge
Responsible jurisdictions who oversee Major Accident Hazards, Highly Hazardous Chemicals, Major Hazard Facilities or Major Hazard Installations require PHA/HAZOP to be reviewed at regular intervals and/or following a major incident or modification, including significant change of personnel. Such reviews can be a significant drain on resources and can be better managed by having live oversight of hazards and the barriers that prevent and/or mitigate the risks associated with them.
Visual information is understood quicker and retained far longer than text. By migrating wordy worksheets into graphical scenarios, we aim to reduce situations where Threats are either ignored or underestimated, Safeguards are presumed to be present or their performance overestimated, and Consequences not considered or miscalculated.
Using Scrapbook & Advanced Filtering features of BowTieXP, we can migrate existing PHA/HAZOP worksheet data from commercial PHA software and conventional Office tools. We encourage you to read the article and welcome any questions you have on enhancing your existing studies.
PHA visualization and bowtie quantification training
Learn more about PHA visualization? On the 11th of April David Hatch and CGE will be conducting a 1-day training course to help you visualize HAZOP’s with the help of bowties. During the training, you will be working with bowtie guidelines in line with the recent publication of the CCPS (Center for Chemical Process Safety)/EI (Energy Institute) book ‘Bow Ties in Risk Management: A Concept Book for Process Safety’. Learn more about this event or register here.