Major Hazard Facilities
Hazard Identification
Overview
This seminar has been split into two sections
1.
Hazard Identification
2.
Major Accident Identification and Risk Assessment
The
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seminar has been developed to provide
Context with MHF Regulations
An overview of what is required
An overview of the steps required
Examples of hazards identified
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Some Abbreviations and Terms
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AFAP - As far as (reasonably) practicable
DG - Dangerous goods
Employer - Employer who has management control of the
facility
Facility - any building or structure at which Schedule 1
materials are present or likely to be present for any purpose
FMEA/FMECA - Failure modes and effects analysis/ Failure
modes and effects criticality analysis
FTA - Fault tree analysis
HAZID - Hazard identification
HAZOP - Hazard and operability study
HSR - Health and safety representative
LOC - Loss of containment
LOPA – Layers of protection analysis
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Some Abbreviations and Terms
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MHF - Major hazard facility
MA - Major accident
OHS - Occupational health & safety
PFD – Process Flow Diagram
P&ID – Piping and Instrumentation Diagram
PSV – Pressure safety valve
SMS - Safety management system
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Topics Covered In This Presentation
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Regulations
Definition – Hazard
Introduction
HAZID Requirements
HAZID Approach
Consultation
Conducting the HAZID
Overview of HAZID techniques
Review and Revision
Sources of Additional Information
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Regulations
Basic outline
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Hazard identification (R9.43)
Risk assessment (R9.44)
Risk control (i.e. control measures) (R9.45, S9A 210)
Safety Management System (R9.46)
Safety report (R9.47, S9A 212, 213)
Emergency plan (R9.53)
Consultation
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Regulations
Regulation 9.43 (Hazard identification) states:
The employer must identify, in consultation with employees,
contractors (as far as is practicable) and HSRs:
a) All reasonably foreseeable hazards at the MHF that may cause
a major accident; and
b) The kinds of major accidents that may occur at the MHF, the
likelihood of a major accident occurring and the likely
consequences of a major accident.
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Definition
Hazard
Regulatory definition per Part 20 of the Occupational Health
and Safety (Safety Standards) Regulations 1994 :
“A hazard means the potential to cause injury or illness”
Interpreted: Any activity, procedure, plant, process, substance,
situation or other circumstance that has the potential to cause
harm.
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Introduction
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HAZID is critical to safety duties and the safety report
Employer must identify all major accidents and their related
causes using a systematic and documented HAZID approach
The process must be transparent
HAZID results must be reflected in risk assessment, SMS,
adoption of control measures and safety report
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Introduction
An example - Gramercy Alumina Refinery, US Department of
Labor Report ID No. 16-00352, 5 July 1999 at 5am
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Introduction
Were the hazards identified?
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Introduction
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HAZID process must be ongoing to ensure existing hazards are
known, and
New hazards recognised before they are introduced:
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Prior to modification of facility
Prior to change in SMS or workforce
Before and during abnormal operations, troubleshooting
Plant condition monitoring, early warning signals
Employee feedback from routine participation in work
After an incident
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Introduction
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Information from accident investigations can be useful as input to
determine contributing causes
Emergency Preparation
7%
5%
2%
12%
Quality Assurance
4%
1%
Other Training
Industry Guidance
5%
1%
4%
4%
8%
Incident Investigation
Employee Participation
Facility Siting
Internal Auditing and Oversight
Safe Work Practices
Management of Change
7%
4%
Engineering Design & Review
Maintenance Procedures
5%
HAZCOM
8%
Operator Training
Operating Procedures
13%
10%
Process Hazard Analysis
Process Safety Information
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HAZID Requirements
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A systematic, transparent and comprehensive HAZID process
should be used based on a comprehensive and accurate
description of the facility
MAs and the underlying hazards should not be disregarded
simply because:
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They appear to be very unlikely
They have not happened previously
They are considered to be adequately controlled by existing
measures
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HAZID Requirements
The risk diagram can be useful for illustrating this aspect, as
shown below
Relative Frequency of Occurrence
Increasing risk
Breakdowns
Public criticism
Staff
Protest pickets
complaints
Personal injury
Industrial
stoppage
Maintenance OH&S
Safety Report Influence
High technology and high
hazard system failures
Class actions
Market collapse
Fatality (fatalities)
Fire &
Catastrophic
Explosion
Consequence Severity
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HAZID Requirements
Exclusions
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The HAZID process (for MHF compliance) is not intended to
identify all personnel safety concerns
Many industrial incidents are caused by personnel safety
breaches, such as the following:
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Person falls from height
Electrocution
Trips/slips
Contact with moving machinery
etc
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HAZID Requirements
Exclusions
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These are generally incidents that do not relate to the storage
or processing of Schedule 9 materials and are covered by
other parts of an Employer’s safety management system for a
facility such as:
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Permit to work
Confined space entry and management
Working at heights
Work place safety assessments
etc
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HAZID Approach
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What can go wrong?
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What incidents or scenarios could
arise as a result of things going
wrong?
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What could cause or could
contribute to these incidents?
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HAZID Approach
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Considers all operating modes of the facility, and all activities
that are expected to occur
Human and system interfaces together with engineering issues
Dynamic process to stay ahead of any changes in the facility
that could erode the safe operating envelope or could introduce
new hazards
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HAZID Approach
The HAZID approach is required to:
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Be team-based
Use a a process that is systematic
Be pro-active in searching for hazards
Assess all hazards
Analyse existing controls and barriers - preventative and
mitigative
Consider size and complexity in selecting approach to use
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HAZID Approach
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Consideration needs to be given in selecting the HAZID
technique
Some issues to take into account are:
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Life cycle phase of plant
Complexity and size
Type of Process or activity covering:
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Engineering or procedural
Mechanical, process, or activity focussed
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HAZID Approach
Life Cycle Phases of a Project
Concept
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Design
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Construction
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Commission
The HAZID approach can be used in
the first stages of the life cycle
phase of a project
Prior to design phase, little
information will be available and the
HAZID approach will need to be
undertaken on flow diagrams
Assumptions will need to be
transparent and documented
Production
Decommission
Disposal
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HAZID Approach
Complexity and Size
• The complexity and size of a facility includes the number of
activities or systems, the number of pieces of equipment, the
type of process, and the range of potential outcomes
• Some HAZID techniques may get bogged down when they are
applied to complex processes
• For example, event tree and fault tree analyses can become
time consuming and difficult to structure effectively
• However, simple techniques may not provide sufficient focus to
reach consensus, or confidence in the identification of hazards
 Conclusion: Start with simple techniques and build
in complexity as required
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HAZID Approach
Type of Process or Activity
• Where activities are procedural or human error is dominant
then task analysis may be appropriate (e.g. task analysis,
procedural HAZOP, etc)
• Where knowledge of the failure modes of equipment is critical
(e.g. control equipment, etc) then FMEA may be appropriate
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HAZID Approach
Type of Process or Activity
• Where the facility is readily shown on a process flow diagram
or a process and instrumentation diagram, then HAZOP may
be used
• Where multiple failures need to be combined to cause an
accident, or multiple outcomes are possible then fault tree
analysis and event tree analysis may be beneficial
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Consultation
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The MHF Regulations require Employers to consult with
employees in relation to:
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Identification of major hazards and potential major accidents
Risk assessment
Adoption of control measures
Establishment and implementation of a safety management
system
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Development of the safety report
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Consultation
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Consultation is also required in relation to the roles that the
Employer defines for employees
The adequacy of the consultation process is a key step in
decision-making with regards to the granting of licences
A teamwork approach between the Employer, HSRs and
employees is strongly advocated for the safety report
development process as a whole
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Consultation
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Employees have a significant effect on the safety of
operations, as a result of their behaviour, attitude and
competence in the conduct of their safety-related roles
The involvement of the employees in the identification of
hazards and control measures enhances:
Their awareness of these issues
and
Is critical to the achievement of safe operation in practice
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Conducting the HAZID
HAZID Team Selection
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The team selection for the area or plant is critical to the whole
hazard identification process
Personnel with suitable skills and experience should be
available to cover all issues for discussion within the HAZID
process
A well managed, formalised approach with appropriate
documentation is required
Team selection and training in methodology used is to be
provided
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Conducting the HAZID
HAZID Team Selection
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Facilitated multi-disciplinary team based approach
Suitably qualified and experienced independent person to
facilitate
Suitably experienced and qualified personnel for the process,
operations and equipment involved
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Conducting the HAZID
HAZID Team Selection
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These employees MAY BE the HSRs but DO NOT HAVE TO BE
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However, the HSRs should be consulted in selection of
appropriate persons - this process must be documented and be
transparent
No single person can conduct a HAZID
A team approach will be most effective
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Conducting the HAZID
HAZID Study Team
The typical study team would comprise:
• Study facilitator
• Technical secretary
• Operations management
• HSR/Operations representative
• Project engineer or project design engineer for new projects
• Process engineer
• Maintenance representative
• Instrument electrical representative
Note: the above team make up is indicative only
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Conducting the HAZID
HAZID Planning
The following steps are required:
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Planning and preparation
Defining the boundaries and provide system description
Divide plant into logical groups
Review P&IDs and process schematics to ensure accuracy
Optimise HAZID process by means of preplanning work
involving relevant stakeholders (operations, maintenance,
technical and safety personnel)
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Conducting the HAZID – Consider the Past, Present and Future
Historical
conditions
Existing
conditions
What has gone wrong in the past?
Root Cause
Historical Records
Process Experience
Near Misses
What could go wrong currently?
HAZID Workshop
HAZOP Study
Scenario Definitions
Checklists
Identified
Hazards
What could go wrong due to change?
Future
conditions
Change Management
What-If Judgement
Prediction
unforeseeable
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Conducting the HAZID
It is tempting to disregard “Non-Credible” Scenarios BUT
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“Non-credible” scenarios have happened to others
Worst cases are important to emergency planning
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It happened to someone else …
Aftermath of an explosion
(U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD, SIERRA
CHEMICAL COMPANY REPORT NO. 98-001-I-NV, January 1988)
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Conducting the HAZID
Issues for consideration
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Equipment can be off-line
Safety devices can be disabled or fail to operate
Several tasks may be concurrent
Procedures are not always followed
People are not always available
How we act is not always how we plan to act
Things can take twice as long as planned
Abnormal conditions can cross section limits
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Power failure
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Conducting the HAZID – HAZID Process
System description
Define boundary
Divide system into sections
Analyse each section
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asset or equipment failure
external events
process operational deviations
hazards associated with all materials
human activities which could contribute to incidents
interactions with other sections of the facility
Existing studies
Selected methods
Systematically record all hazards
Independent check
Hazard Register
Revisit after risk assessment
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Conducting the HAZID
Meeting Venue
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Hold on site if possible
Avoid interruptions if possible
Schedule within the normal work pattern, or within the safety
report activities
Meetings less than 3 hours are not effective
Meetings that last all day are also not effective, however
practicalities may require all day meetings
Don’t underestimate the time required
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Conducting the HAZID
Recording Detail
• The level of detail is important for:
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Clarity
Transparency and
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Traceability
A system (hazard register) is required for keeping track of the
process for each analysed section of the facility
The items to be recorded are:
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Study team
System being evaluated
Identified hazard scenario
Consequences of the hazard being realised
Controls in place to prevent hazard being realised and their
adequacy
Opportunity for additional controls
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HAZID Techniques - Overview
Increasing effort required
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Checklists - questions to assist in hazard identification
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Brainstorming - whatever anyone can think of
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What If Analysis - possible outcomes of change
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HAZOP - identifies “process plant” type incidents
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FMEA/FMECA - equipment failure causes
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Task Analysis – maintenance activities, procedures
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Fault Tree Analysis - combinations of failures
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Checklists
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Simple set of prompts or checklist questions to assist in hazard
identification
Can be used in combination with any other techniques, such as
“What If”
Can be developed progressively to capture corporate learning of
organisation
Particularly useful in early analysis of change within projects
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Checklists
Initiating
Events
General Causes
Initiating Causes
Overfills And
Spills
Improper
Operation
Operating Error
Inadequate / Incorrect Procedure
Failure To Follow Procedure
Outside Operating Envelope
Inadequate Training
Vessel/Tanker
Shell Failure
Corrosion
Wet H2S Cracking
General Process
Cooling Water
Steam / Condensate
Service Water
Mechanical
Impact
Missiles
Crane
Vehicles
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Checklists
Advantages
• Highly valuable as a cross check review tool following
application of other techniques
• Useful as a shop floor tool to review continued compliance
with SMS
Disadvantages
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Tends to stifle creative thinking
Used alone introduces the potential of limiting study to
already known hazards - no new hazard types are identified
Checklists on their own will rarely be able to satisfy regulatory
requirements
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Brainstorm
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Team based exercise
Based on the principle that several experts with different
backgrounds can interact and identify more problems when
working together
Can be applied with many other techniques to vary the
balance between free flowing thought and structure
Can be effective at identifying obscure hazards which other
techniques may miss
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Brainstorm
Advantages
• Useful starting point for many HAZID techniques to focus a
group’s ideas, especially at the project’s concept phase
• Facilitates active participation and input
• Allows employees experience to surface readily
• Enables “thinking outside the square”
• Very useful at early stages of a project or study
Disadvantages
• Less rigorous and systematic than other techniques
• High risk of missing hazards unless combined with other tools
• Caution required to avoid overlooking the detail
• Relies on experience and competency of facilitator
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What If
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What if analysis is an early method of identifying hazards
Brainstorming approach that uses broad, loosely structured
questioning to postulate potential upsets that may result in an
incident or system performance problems
It can be used for almost every type of analysis situation,
especially those dominated by relatively simple failure
scenarios
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What If
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Normally the study leader will develop a list of questions to
consider at the study session
This list needs to be developed before the study session
Further questions may be considered during the session
Checklists may be used to minimise the likelihood of omitting
some areas
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What If
Example of a What If report for a single assessed item
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What If
Advantages
• Useful for hazard identification early in the process, such as
when only PFDs are available
• What If studies may also be more beneficial than HAZOPs
where the project being examined is not a typical steady state
process, though HAZOP methodologies do exist for batch and
sequence processes
Disadvantages
• Inability to identify pre-release conditions
• Apparent lack of rigour
• Checklists are used extensively which can provide tunnel
vision, thereby running the risk of overlooking possible
initiating events
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HAZOP
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A HAZOP study is a widely used method for the identification
of hazards
A HAZOP is a rigorous and highly structured hazard
identification tool
It is normally applied when PFDs and P&IDs are available
The plant/process under investigation is split into study nodes
and lines and equipment are reviewed on a node by node
basis
Guideword and deviation lists are applied to process
parameters to develop possible deviations from the design
intent
HAZOP results in a very a systematic assessment of hazards
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HAZOP
Example of a HAZOP report for a single assessed item
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HAZOP
Advantages
• Will identify hazards, and events leading to an accident,
release or other undesired event
• Systematic and rigorous process
• The systematic approach goes some way to ensuring all
hazards are considered
Disadvantages
• HAZOPs are most effective when conducted using P&IDs,
though they can be done with PFDs
• Requires significant resource commitment
• HAZOPs are time consuming
• The HAZOP process is quite monotonous and maintaining
participant interest can be a challenge
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FMEA/FMECA
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Objective is to systematically address all possible failure
modes and the associated effects on a technical system
The underlying equipment and components of the system are
analysed in order to eliminate, mitigate or reduce the failure
or the failure effect
Best suited for mechanical and electrical hardware systems
evaluations
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FMEA/FMECA
Example of an FMEA/FMCEA report for a single assessed item
Potential
Failure
Mode
Potential
Effects of
Failure
Potential
Causes
of
Failure
Comments
Recommendations
Open
indicator
switch failed
Wrong
indication of
valve back to
control system
causing
possible
incorrect
controller
action to be
taken
Wear and
tear
Commissioning
and test
procedures
must ensure
that all diverter
equipment
indicators are
correctly wired
to the diverter
control system
The integrity of the
position indicators for
the Diverter system
equipment is critical to
the logic of the control
system.
It is recommended that
the position indicators
are discretely function
tested prior to
commencement of each
program
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FMEA/FMECA
Advantages
• Generally applied to solve a specific problem or set of
problems
• FMEA/FMECA was primarily considered to be a tool or process
to assist in designing a technical system to a higher level of
reliability
• Designed correction or mitigation techniques can be
implemented so that failure possibilities can be eliminated or
minimized
Disadvantages
• It is very time consuming and needs specialist skills from
different backgrounds to obtain maximum effect
• Very hard to assess operational risks within an FMEA/FMECA
(like they can be within a HAZOP or What if study)
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Task Analysis
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Technique which analyses human interactions with the tasks
they perform, the tools they use and the plant, process or
work environment
Approach breaks down a task into individual steps and
analyses each step for the presence of potential hazards
Used widely to manage known injury related tasks in
workplace
Excellent tool for hazard identification related to human tasks
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Task Analysis
Disadvantages
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Does not address plant process deviations which are not related
to human interaction
Caution
• Relies on multi-disciplined input with specific input of person
who normally carries out the task
• Often assumed to be the only tool of hazard identification or
risk assessment, as it is used generally at the shop floor
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Fault Tree Analysis
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Graphical technique approach
Provides a systematic description of the combinations of
possible occurrences in a system which can result in an
identified undesirable outcome (top event)
This method combines hardware failures and human failures
Uses logic gates to define modes of interaction (ANDs/ ORs)
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Fault Tree Analysis
Process
vessel over
pressured
AND
Pressure
rises
PSV does not
relieve
AND
Process
pressure
rises
OR
Control
fails high
Fouling inlet
or outlet
PSV too
small
Set point
too high
PSV stuck
closed
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Fault Tree Analysis
Advantages
• Quantitative - defines probabilities to each event which can be
used to calculate the probability of the top event
• Easy to read and understand hazard profile
• Easily expanded to bow tie diagram by addition of event tree
Disadvantages
• Need to have identified the top event first
• More difficult than other techniques to document
• Fault trees can become rather complex
• Time consuming approach
• Quantitative data needed to perform properly
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Review and Revision
The following are examples of when a HAZID revision should occur
Organizational
changes
New
projects
HAZID
Revision
Incident
investigation
results
Process or
condition
monitoring
changes
Abnormal conditions
through design envelope
changes
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Sources of Additional Information
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Loss Prevention In The Process Industries, Second Edition, Reed
Educational and Professional Publishing, F. P Lees,1996
Guidelines for Hazard Analysis, Hazardous Industry Planning
Advisory Paper No.6, NSW Department of Planning, June 1992
HAZOP and HAZANs, Notes on the Identification and Assessment
of Hazards, Second Edition, Trevor Kletz, The Institution of
Chemical Engineers, 1986
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Sources of Additional Information
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Guidelines for Hazard Evaluation Procedures, Second Edition,
Centre for Chemical Process Safety, American Institute of
Chemical Engineers, 1992
Layer of Protection Analysis, Simplified Process Risk Assessment,
Centre for Chemical Process Safety, American Institute of
Chemical Engineers, 2001
Hazard Identification and Risk Assessment, Geoff Wells, The
Institution of Chemical Engineers, 19.
MIL-STD-1629A, 1980
Failure Modes and Effects Analysis, J. Moubray, RCM II, 2000
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Questions?
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