People’s lives depend on quality control for hazard and operability (HAZOP) studies. These tips will help to improve the quality of your studies.

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TEN TIPS ON HAZOP
QUALITY CONTROL
by Dr. Paul Baybutt
www.primatech.com

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TIP 1 – Define the study purpose,
scope and objectives
• A statement of purpose, scope and objectives is
essential to ensure studies are focused and complete
• The statement defines what must be addressed
– Also constrains studies to appropriate content
• Helps to ensure studies are conducted effectively and
efficiently
• For more information:
– The importance of defining the purpose, scope, and
objectives for process hazard analysis studies, Process
Safety Progress, Volume 34, Issue 1, pages 84 - 88, March,
2015

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TIP 2 – Use selection criteria for
practitioners
• A competency management system should be used
to ensure HAZOP practitioners are appropriately
qualified
• Selection criteria for facilitators and team members
should cover technical and personal attributes
• For more information:
Competency requirements for process hazard analysis teams,
Journal of Loss Prevention in the Process Industries, Volume
33, pages 151-158, January 2015

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TIP 3 – Validate safeguards separately
• Validation of the installation, functionality, and integrity
of safeguards should be performed before
commencing studies
– Inclusion would cause a serious distraction
• Studies should focus on the qualification of safeguards
for individual hazard scenarios
• For more information:
On the validation of safeguards for process hazard analysis,
Process Safety Progress, Volume 32, Issue 2, pages 165–169,
June 2013

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TIP 4 - Address all process phases
• Processes experience various phases of operation during
their lifecycle
– Startup, normal operation, shutdown, etc.
• Hazard scenarios may occur during any of these phases
– May vary by phase
• Studies must address all phases of process operation
• For more information:
Process hazard analysis for phases of operation in the process life
cycle, Process Safety Progress, Vol. 31, Issue 3, pages 279–281,
September, 2012

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TIP 5 – Do not pre-complete
worksheets
• Some HAZOP facilitators enter scenarios into the
study worksheets in advance of team sessions
– To reduce the time and effort required by the team
• The practice is poor technically and may violate
regulatory requirements
– Can lead to incomplete identification of scenarios
• For more information:
Pre-work and pre-completion of worksheets for process hazard
analysis, Process Safety Progress, Vol. 31, Issue 3, pages
275–278, September, 2012

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TIP 6 – Manage human factors
• HAZOP studies are subject to possible human failures
by the people who perform them
• Studies are difficult and time-consuming activities that
place significant demands on participants
– Increases the chance that errors will be made
• Human factors that influence study performance must
be recognized and addressed
• For more information:
The role of people and human factors in performing process
hazard analysis, J. of Loss Prevention in the Process Industries,
Vol. 26 pages1352-1365, 2013

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TIP 7 – Do not use super nodes
• Some companies use super nodes or combinations of
lines and major vessels to speed up studies
• The practice complicates the analysis and may result
in missed scenarios
• The line-by-line approach should be used instead
• For more information:
– Analytical Methods in Process Safety Management and
System Safety Engineering – Process Hazards Analysis, in
Handbook of Loss Prevention Engineering, Wiley, 2013

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TIP 8 - Fully address design intent
• Deviations from design intent are used to identify
hazard and operability scenarios
• Often, a short checklist of process parameters is
used
• This practice likely results in missed scenarios
• A full consideration of design intent is needed
– Ensure scenarios are identified as completely as possible
• For more information:
Design intent for hazard and operability studies, Process
Safety Progress, DOI: 10.1002/prs.11718

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TIP 9 – Identify basic causes
• Causes of hazard scenarios can be defined at
various levels
– Immediate, basic, underlying, and root
• HAZOP practitioners must decide at what level
causes will be identified
• Generally, at least basic causes should be recorded
• For more information:
Initiating events, levels of causality, and process hazard
analysis, Process Safety Progress, Vol. 33, Issue 3, pages
217–220, September 2014

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TIP 10 – Address multiple failures
• Hazard scenarios may involve multiple failures
– Initiating events may be single or multiple failures
– Safeguards are subject to multiple failures
– Enabling events may combine with other scenario events to
produce multiple failures
• Important scenarios will be missed if multiple failures
are not addressed
– Risks will be underestimated
• For more information:
Treatment of multiple failures in process hazard analysis,
Process Safety Progress, Vol. 32, Issue 4, pages 361–364,
December 2013

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For free materials on process safety,
click here:
notes.primatech.com/ss3