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HAZARD AND OPERABILITY STUDY

SECTION 01

PERSONAL AND PROCESS SAFETY

MANAGEMENT

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Accident Ratio Study

Tye and Pearson [1974]

Personal Safety Management

• Concerns the safety and wellbeing of people you are
responsible for- employees, contractors, visitors.
• What types of accidents are involved?
– Sprains, cuts, contusions, slips, trips, falls, burns (heat and
chemical), poisoning, broken limbs, hospitalization, death.
• What are the consequences?
– Employee not fully fit to work / absent, overtime payments,
additional contractors, liability claims, litigation, some poor/ bad
publicity.

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Measuring Personal Safety performance

• What are the metrics?
– First Aid injury (FAI)
– Medical treatment case (MTC) Restricted work injury (RWI)
– Lost Time injury frequency - LTI (per million m/H worked)
– Intervals between LTI - months, years
– Fatal accident frequency - fatalities per 100 million m/H.
– All Accident frequency - total accidents per million m/H worked

High visibility, high profile, target driven, industry wide metrics and
comparison data

Managing Personal Safety performance

• Site rules and induction process
• Personnel protective equipment (PPE)
• Safe Working practices e.g Manual Handling Regulations
• Control of Hazardous substances
• Permit to work systems
• Job/task risk assessments
• Workplace audits
• etc.

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Process Safety Management (1)

• Concerns the ability of the process, the equipment and
those operating it to overcome non normal conditions
without giving rise to a hazardous outcome.
• What types of accident are involved?
• Mechanical damage, process material contamination, loss
of containment (spillage, leak, release), fire, explosion,
detonation.

Process Safety Management (2)

• What are the consequences ?
– Loss of production (profit)
– Cost to repair or renew plant and equipment
– Investigation(s) by regulatory authorities
– Prosecution, class actions, fines, damage claims
– Bad publicity, loss of reputation, loss of business
• May or may not include personal injuries/multiple fatalities.

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Measuring Process Safety performance

• What are the metrics?
• Hazardous release reporting to regulatory authorities…
• Number of fires (?)
• Insurance claims (?)
• ……… (?)

Low visibility, often low profile (individual incidents can be VERY high
profile), absence of industry wide measurement or comparison data

Managing Process Safety performance

• Hazard identification (Hazard ID) at design stage
• Design, maintenance and operating standards
• Standing instructions
• Operating procedures
• Emergency procedures
• Operator training
• Audit
• Mitigation (firefighting, blast protection, plant layout)
• Reporting systems (including near misses) with incident severity
ranking

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Responsibility for PSM

• Design office?
• Plant change procedure?
• Plant managers?
• Safety department?
• Technical department?

 specialist understanding (rarely including management) and diffuse

responsibility

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Process Safety vs. Personal Safety

• A common assumption is that successful management of
personal safety implies successful management of process
safety…
• Process safety lapses can destroy your business, personal
safety lapses are unlikely to.
• Successful management of process safety requires
focused application of higher quality resources than
managing personal safety.

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Process Safety vs. Personal Safety

“BP mistakenly interpreted improving personal injury rates as
an indication of acceptable process safety performance at its
U.S. refineries.“

Baker Panel Report - BP's US Refineries Independent Review Panel

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Process Safety Management (PSM)

• Energy Institute (UK) EI-PSM
• High level management framework:
– Process Safety Leadership (5 elements)
– Risk identification assessment (2 elements)
• Hazard Identification and risk assessment
• Documentation, records and knowledge management.
– Risk management (11 elements)
– Review & improvement (2 elements)

• OSHA 3132
• API 754

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Process Safety Management

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SECTION 02

SPIRAL TO DISASTER – PIPER

ALPHA

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Spiral to Disaster - the story of Piper Alpha (1)

• Piper Alpha was an oil and gas production platform in the UK
sector of the North Sea operated by Occidental Oil.
• The platform was located 110 miles form the north east UK
coast.
• The platform produced 30,000 t/d of oil and accounted for some
10% of UK oil and gas production.
• Piper Alpha was part of the Piper, Claymore and Tartan oil
production system pumping oil to the Flotta onshore
terminal.
• On the evening of 6th July 1988 there was a release of gas
when a standby condensate oil pump was brought into service.

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Spiral to Disaster - the story of Piper Alpha (2)

• Piper Alpha platform was completely destroyed

• 167 lives were lost in the incident.
• There were 59 survivors
• The blaze on what little remained of the platform was
extinguished 3 weeks later

• An enquiry headed by Lord Cullen on behalf of the by the

UK Heath and Safety Executive found numerous safety
management failings.

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Other major disasters 1966 - 2010 incurring fatalities

• Refinery fire at Feyzin, France January 1966 - 18 fatalities

• Flixborough (Nypro UK) Explosion June 1974 - 18 fatalities
• Pemex LPG Terminal, Mexico City November 1984 - 500+ fatalities
• Union Carbide, Bhopal, India December 1984 - 2153 fatalities.
• BP Texas City Refinery, Texas, USA March 2005 - 15 fatalities
• Deepwater Horizon, Gulf of Mexico, USA April 20th 2010 - 11
fatalities

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Not all major disasters result in fatalities

• Icmesa Chemical Co., Seveso, June 1976 - release of toxic cloud.
• Grangemouth Refinery, March 1987 - explosion of Hydrocracker LP
separator.
• Marathon Petroleum, Texas, October 1987 - accidental release of 37
tons of Hydrofluoric Acid (HF)
• Fire and Explosions at Texaco Milford Haven Refinery, UK, July
1994.
• Buncefield, UK explosions and fire December 2005

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SECTION 03

HAZOP BACKGROUND AND

TERMINOLOGY

21

Background to HAZOP and terminology

• HAZOP - a Hazard and Operability study
• Hazard - a situation or condition arising from a deviation
that could cause damage, injury, or other form of loss
• Operability - the ease or difficulty with which a task may be
undertaken within a given set of circumstances and
environment.

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Hazop Studies
• Initial HAZOP methodology developed by ICI in 1950's
• a series of serious incidents in the early 1960's convinced
management that a more formalised technique for identifying
plant design shortcomings was
required
• Formal Hazop methodology was developed
• Codified by Chemical Industries Association (CIA) in 1977
• Adopted and prescribed by regulatory bodies (HSE, OSHA) as
evidence of hazard assessment.
• Subsequently extended and applied in other industries,
activities e.g. railways, ship mooring systems, heavy lift
operations.

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HAZOP Definition
• The application of a formal, systematic and critical
examination of the process and engineering intentions of
the facilities to assess the hazard potential of mal operation
or malfunction of individual items of equipment and the
consequential effects on the facility as a whole.

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What Hazop does NOT do

• Hazop will not verify that a design will perform (capacities,
yields, product qualities)
• does not generate the opportunity to redesign the plant
• Takes only 1 deviation at a time into account (not double
jeopardy)
• Can be limited by its boundaries.

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Hazop Terminology (1)

• Node - the section of the plant under study
• Node description - verbal description of where the node
starts, where it ends including all included equipment.
• Design intent - what the designer intends for this node
expressed as flow rate, pressures, temperatures, phase,
etc

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Hazop Terminology (2)

• Guideword - a word applied to Parameters to generate
deviations
• Parameters - flow, temperature, pressure, level, etc
• Deviation - a condition that deviates from the design intent.

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Generating Hazop Deviations

Deviation = Guideword + Parameter

No Flow

More Flow

Less Flow

Reverse Flow

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Basic Hazop Guideword and Parameter

Guideword Parameter
• No • Flow
• More • Temperature
• Less • Pressure
• Reverse • Level
• Part of
• Other than
• As well as

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Basic Hazop Deviations

• No flow, more flow, less flow, reverse flow
• More temperature, less temperature
• More pressure, less pressure
• More level, less level

10 deviations

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Some Additional Basic Deviations

• Level - no level i.e. complete loss of liquid or interface level
• Pressure - No pressure means vacuum

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SECTION 04

MECHANIC OF THE HAZOP

PROCESS

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Mechanics of the Hazop process (1)

• Select the node
• Establish the design intent / process conditions
• Select the first deviation to be applied
• 'Brainstorm' all credible causes giving rise to the deviation.
List them.

Note - causes MUST be within the Node being studied (exception is study boundaries)

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Mechanics of the Hazop process (2)

• Return to the first cause, logically develop the
consequences
Note - consequences can be anywhere in the node, plant, site or the
local environment

• Take consequences to their natural conclusion(s)

WITHOUT taking into account any safeguards
• Record the consequences
• Examine all (active and passive) safeguards and record

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Mechanics of the Hazop process (3)

• Using the team's judgement decide:
– are the safeguards adequate for the consequences developed by
the team?
• Based on the outcome of the team's deliberations arrive at
a consensus to:
Accept
– The safeguards result in the hazard being tolerable – no action
required
Mitigate
– Recommend that the cause or consequences be made less likely
or less extreme

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Mechanics of the Hazop process (4)

Protect
– accept cause and / or consequences but make recommendations
to protect people and equipment from the hazard
Correct
– recommend the cause and / or consequences be designed out.

• Record the teams' decision.

• Proceed to the next cause on the brainstormed list.

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HAZOP Mechanic

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Selection a Hazop Node

Factors to take into account:
• too small, few causes for deviations, slow progress
• too large, many causes in different parts of the node, difficulty in
keeping team on specific parameter and cause

Useful approach:
• follow logic of process starting with an incoming line
• include at least one item of equipment (pump, compressor, heat
exchanger, vessel, tank)
• start small to get team used to Hazop methodology

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Strengths and weaknesses of the Hazop process

• Strengths
– Immensely detailed, line by line examination of the process
– Deviations often overlapping e.g. No Flow  Less Level
– Thorough examination of what can go wrong
– Provides a permanent record of hazards and all safeguards
Provides a start point for any plant modifications
• Weakness
– Resource intensive (4-6 people for several weeks)
– Requires high quality individuals (experienced, knowledgeable,
team players, consensus oriented)
– Depends on diligent follow up and sign off for effect

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SECTION 05

CAUSE, CONSEQUENCES AND

SAFEGUARDS

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Causes in a Hazop study

• Use imagination ('brainstorming') to identify all possible and
credible causes of the deviation within the node boundary

• e.g. no flow: valve(s) closed

pump stopped
control valve closed
filter blocked
tank empty
line frozen (also less temp)
line broken

• Record all the causes before examining consequences

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Line broken
• Well designed, operated and maintained process or utility lines
do not just 'break'. If the team assumes that lines can just
'break', it will lead to unrealistic consequences and
recommendations.

• Lines can ( and do) 'break' due to:

– impact from falling object
– overpressure
– impact from vehicle
– internal or external corrosion
– thermal expansion
– brittle fracture
– other identifiable reasons…

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Consequences in a Hazop study

• Develop the consequences in a logical sequence from the cause
• Don't stop at the first consequence
• Pursue to the worst credible outcome
e.g.
Deviation Cause Consequences
No flow pump discharge pump deadheaded
valve closed pump contents heat up
mechanical seal damage
seal leaks
hot hydrocarbon release
possible ignition and fire

43

Safeguards in a Hazop study

• Safeguards either stop the cause from happening, or mitigate
the consequences
• Assess and evaluate all identified safeguards
– local flow indicator on pump discharge
– panel mounted low flow alarm
– hydrocarbon gas detection on pump seals
– CCTV on pump alley in control room
– operator training and vigilance
– first aid fire fighting facilities in the vicinity
– operator training in first aid firefighting
– full time company fire brigade
– external emergency services

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Consensus judgement of the team

• 4-6 discipline specialists having between them practical
knowledge and experience on:
– the process and what can happen
– individual equipment items, how they work, failure modes
– control systems and instrumentation
– process plant operations, operator training and routines, control room
operations, operating and standing instructions, plant emergency
procedures
– site emergency resources, facilities, equipment and organisation

Informed discussion enables the team to arrive at a consensus judgment on the

adequacy of the safeguards against the worst credible outcome

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Heat Exchanger

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Heat Exchanger

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SECTION 06

RECORDING THE STUDY

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Role of the Hazop Recorder

• Ensures that all essential information pertaining to the
study and the team's deliberations are recorded in pre
determined format
– Recorder normally uses a PC based system (proprietary or basic
word processor / spreadsheet)
– marks up node boundaries on the Hazop master drawings (A0)
as directed by the Hazop team leader

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Role of the Hazop Recorder (cont.)

• Enters the node number, node description, design intent,
process conditions, drawing number(s), team members on
the Hazop log sheet
• The Hazop log sheets (or electronic copy) with master
P&ID's provide permanent record of team's thinking
• Arranges for a print out of each days' log sheets to provide
a working hard copy for reference

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Recording format
• Written record on Hazop log sheets may be acceptable
• Word processor or spreadsheet on PC preferable
• Proprietary software available

• e.g:
– Lihou - Hazop Manager v.6.0 (www.lihoutech.com)
– Isograph - Hazop +2013 (www.isograph-software.com)
– PrimaTech - PHA Works 5.(www.primatech.com)
– IHS - PHA-Pro (www.ihs.com)

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Worksheet

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By-exception recording
• By-exception recording means that the recorder only
records deviations that result in an action item
• The Hazop report is more difficult to interpret as absence of
a deviation entry may be due to the team not considering it
or the team not considering action necessary.
• Does not save much as the recorder is there anyway

53

Full recording
• Full recording means that the recorder captures all salient
aspects of the team's deliberations
• Much easier to read and to assess quality of study
• Easy to quickly find if the team have missed/ ignored/
omitted deviations, causes, consequences and safeguards
• Easier to use for operating manual preparation, plant
modifications

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Simultaneous recording
• Study is recorded as it progresses
• PC screen is projected and is visible for team to read
• Team can promptly agree / check / change wording
• Once agreed log sheet is not revisited
• The log sheets form the basis of the Hazop report

55

Hazop recording shorthand

• No causes identified - NCI
• No hazardous consequences - NHC
• No credible causes - NCC
• Not applicable - N/A
• See More Flow Node XX - links causes, consequences and
safeguards to a previous node

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SECTION 07

ADDITIONAL HAZOP DEVIATIONS

AND OPERATIBILITY PARAMETERS

57

Additional Deviations
• No exhaustive list
• Common sense, judgement and experience
• Literature
• Nature and specifics of the process
• Role of the team in selecting what deviations to apply to the
study

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Additional Hazop Deviations

More, less, reverse - Phase

More, less, no, reverse - Reaction

As well as, other than, part of - Composition or contamination

More - Vibration More, less, no - Mixing.

More, less - Viscosity More - Corrosion

More - Static electricity More - Erosion

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Some Operability Parameters

• Health and Environment - Noise, toxicity, flammability

• Isolation for Maintenance

• Sampling

• Utility failure

• Temperature - Winterization, Personnel protection

• Ergonomics - Manual handling

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How many are required?

• Probably 10 Basic deviations as a minimum
• Nature of the process will include / exclude others
• The Hazop technique results in overlap between deviations
• Non process Hazop's introduce additional deviations
• Operability parameters may be fewer on existing plants
• From experience:
– minimum 12
– maximum 26

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SECTION 08

ROLES AND SELECTION OF THE

HAZOP TEAM

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The Hazop team (1)

• Multi-disciplinary team
• Usually 5 to 7 in total (beware large teams)
• Full time:
– Process engineer / chemist (process specialist)
– Operations representative (Senior technician, supervisor)
– Mechanical Engineer (maintenance background)
– Instrument / Control Engineer
– Hazop Recorder
– Hazop Team Leader

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The Hazop team (2)

• Part time:
– Electrical engineer
– Materials and Corrosion engineer
– Rotating Equipment engineer
– Civil engineer
– Safety specialist Other specialist(s)

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Roles of full time team members (1)

• Process Engineer / Chemist -
– familiar with details of how the process works
– knows process chemistry information
– confirms all design and operating data
– familiar with individual equipment design and operating data
– provides knowledge of process safeguarding philosophy and
detailed information on how each element operates

65

Roles of full time team members (2)

• Operations representative -
– knowledgeable and experienced in process plant field and control
room operations
– familiar with operation of the specific process
– knows the plant layout and location of equipment
– familiar with all operating procedures including start-up, shut¬
down and emergency procedures

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Roles of full time team members (3)

• Mechanical Engineer -
– experienced in the mechanical features of all individual
equipment items such as pumps, compressors, heat exchangers,
pressure vessels, valves, pipeline fittings, etc
– familiar with design standards for individual equipment items,
pipe class data, relief valve specification
– familiar with maintenance standards and procedures
– able to make general rotating equipment and metallurgy input

67

Roles of full time team members (4)

• Instrument / Control engineer -
– familiar with and able to explain the functioning of control systems
and safeguarding instrumentation (trips, alarms)
– familiar with system failure modes and individual item failure
modes
– knowledgeable on automatic start up and shut down systems,
interlock features and voting systems
– conversant with procedures for checking plant safeguarding
instrumentation

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Roles of full time team members (5)

• Hazop team leader -
– experienced in Hazop methodology
– manages the team (availability, absences)
– manages time
– ensures suitable environment (room, facilities, reference
documents, drawings)
– directs the study, produces Hazop report

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Roles of full time team members (6)

• Hazop study recorder -
– familiar with Hazop methodology
– possesses adequate IT and keyboard skills
– working knowledge of chemical engineering terms and units of
measurement

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Attributes of Hazop team members

• Willing contributor
• Competent, experienced, open minded
• Ability to visualise realistic situations beyond their own
experience
• Ability to give clear, concise and logical input
• Consensus oriented
• Team player

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Hazop team goals

• Primary
– Thorough
– Complete Full list of hazard cases
– Knowledge based
– Multi-disciplinary effort
• Secondary
– Auditable Guideword and parameter protocol followed
– Structured Study well documented
– Efficient

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SECTION 09

PREPARING FOR A HAZOP STUDY

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When to undertake a Hazop study

• Can be conducted at many stages within the life of a plant
– design freeze (new plant)
– plant modifications (projects)
– retrospective (existing plant)
– safety critical procedures
– non routine operations e.g. catalyst regeneration
– change of feedstock / process materials / products

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Planning a Hazop study (1)

• Establish the scope of the study (new plant, existing plant)
• Establish any 'ground rules'
• Identify team members
• Locate a suitable venue
• Estimate the duration of the study
• Draw up proposed working arrangements

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Planning a Hazop study (2)

'Ground rule' examples:
• Engineering philosophy
– If it works and is safe, don't change it
– No retrospective upgrades
• Engineering standards
– All control valves to be provided with isolation and bypasses
– All relief valves to be spared
– Field emergency shutdown facility for all fired equipment

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P & I Drawings
• P&ID shows all piping including physical sequence of
branches, reducers, valves, equipment, instrumentation and
control interlocks.
• It also shows line and equipment numbering, piping class
breaks, line sizes, permanent start up and flush lines, vendor
package interfaces, instrumentation inputs and outputs.
• Update status of P&ID's needs to be established (random
checks).
• Symbol list
• A0 masters for mark up, A3 working copies for team

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Supporting documents (1)

• An extensive range of supporting documents may include:
– Engineering codes and standards used in the design
– Material safety data sheets (MSDS) for all substances
– Plot plans showing equipment location and elevation
– Engineering design data sheets for all equipment items
– Piping specification summary
– Electrical single line diagrams

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Supporting documents (2)

• Line designation tables
• Process flow diagrams
• Local environmental conditions (max. & min temperatures,
rainfall, wind speed, earthquake, lightning strike)
• Utility supply design temperatures and pressures
• Cause and effect diagram for safeguarding instrumentation
• Trip and alarm set points
• Relief valve sizing criteria

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How long will the study take?

• Function of number of nodes x number of deviations

• Extent to which equipment / operations are replicated

• Team working hours

• Team member availability

• Quality / accuracy of drawings

• Initial progress will (usually) be slow

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Hazop study duration data

Continuous process plant

Type of
Hazop P&ID no Nodes/P&ID Working days Nodes/day

New 1 24 3.6 16 5.4

New 2 22 2.4 8.25 6.4

Exist. 1 12 2.0 6.5 3.7

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SECTION 10

WRITING HAZOP
RECOMMENDATIONS

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Writing Hazop recommendations

Several types of Hazop team recommendations:

Action
– describes what the team recommends is done
Check
– describes a check to be conducted
Operating note
– an item the team feel appropriate to include in Operating Procedures
Hazop note
– an item the team require to be recorded to explain some aspect of the
team's thinking

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Hazop action recommendations

• Action recommendations must be:
– clear - what, where ,why
– concise
– unambiguous
– relevant
– stand alone i.e. can be understood and acted on by others
– action party assigned (ideally)
• Don't redesign - the team does not have the time or
competence

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Hazop checks
• Often used when data or information is incomplete or
contradictory:
– check relief valve sizing case
– check spec, break location
– check static discharge head of pump
– check capacity to withstand vacuum
– check control valve action on air failure

85

Operating Notes
Intended for inclusion in:
• Operating Manuals, Operating Instructions, Operating
• Procedures, Standing Instructions,Emergency procedures
– valves to be locked open, shut
– local readout to be visible to operator
– PPE to be worn when undertaking this task
– composition to be verified by sample before action
– explosivity test to be undertaken prior to start of blower

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Hazop notes
• Explain team's thinking:
– Records assumptions / estimates / perceptions

– Elaborates on background to Recommendations, Checks

– Prompts review of node(s) if assumptions no longer valid

– Makes later reading of Hazop report easier to comprehend

87

Hazop recommendations
• For the study to be worthwhile and to have lasting value:
– Recommendations must be traceable to node

– An action party must be assigned to each recommendation

– Responsibility for follow up and sign off must be agreed.

– Regular review of status of all Hazop action items

– Progress reported

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SECTION 11

RISK RANKING HAZOP

RECOMMENDATIONS

89

Risk Ranking Hazop recommendations (1)

• A large Hazop study may generate many recommendations

• Risk Ranking provides:

– Guidance on priorities

– Ensures appropriate allocation of resources

– Makes action list manageable

– Enables realistic time scale to be set

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Risk Ranking Hazop recommendations (2)

• When to Risk Rank?
• Undertake by the team during the study
– Risks lack of “balance”
– Detracts from the hazop process

• Undertaken by the team after the study

– Overview of all action items achieve more balanced ranking
– A smaller team may be tasked to undertake ranking
– Ranking needs to ‘fit’ with other process safety priorities

91

Risk Ranking principles

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Qualitative Risk Ranking matrix example

93

Shell Group Risk Ranking Matrix

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SECTION 12

OTHER TYPES OF HAZOP STUDY

95

Other types of Hazop study

Hazop methodology can be extended:

• Batch Process Hazop

• Procedural Hazop

• Control System or Computer Hazop (Chazop)

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Batch Process Hazop

• Characterised by a sequential series of actions
• Similar in principle to continuous process
• Additional guidewords:
– Action - more, none, less, wrong
– Time - more, none, less, wrong
– Sequence - sooner, later, not at all

• Likely to take more time per P&ID

97

Batch Hazop study duration data

Type of

Hazop P&ID no Nodes/P&ID Working days Nodes/day

Exist. 1 12 2.0 6 4.0

Exist.2 6 1.8 3.25 3.3

Exist. 3 9 0.7 6.75 0.9

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Procedural Hazop
• Studies a written procedure
• Deviations (guidewords and parameters) selected in
accordance with the nature of the procedure;
– e.g. starting a large compressor
• Use most of the 'classic' deviations as well as batch process deviations-
• flow, temperature, pressure, level(?) action, time, sequence.

– e.g. studying the 'Permit to Work' procedure

• action, time, sequence, noise, toxicity, flammability, isolation, ergonomics

99

Control Hazards and Operability (Chazop) Study

• Control systems and computer systems

• Studies deviations from the intended function
• Highly specialized
• Control system parameters: current, voltage, resistance,
capacitance
• Same guidewords generate:
– More current
– Less current No current
– Reverse current
– etc.

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SECTION 13

OTHER METHODS OF HAZARD

IDENTIFICATION

101

Metode-metode lain
• Preliminary Hazards Analysis (PHA)
• Structured What-if Technique (SWIFT)
• Failure mode and effects criticality analysis (FMECA)
• Quantitative Risk Assessment (QRA)

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Preliminary Hazard Analysis (PHA)

• Effect driven consequence identifier
• Conducted at conceptual stage
• Hazardous properties of materials
• Inventories of materials
• Safety critical plant and equipment
• Environmental factors (flood, earthquake, hurricane)
• Plant layout
• Mitigation

Useful, quick, early impression of range and extent of hazards.

103

Example PHA record sheet

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Structured What-if Technique (SWIFT)

• High level approach
• Systems oriented
• Avoids lengthy discussions on known hazards
• Avoids discussion on areas where no hazards exist
• Less rigorous than Hazop
• Feasibility / Scouting study stage
• List of categories
• Checklist for each category
• Multi-disciplinary team
• Recorder, log sheets

105

SWIFT Categories
• Material problems
• External Effects and influences
• Operating Errors and other Human factors
• Analytical or sampling errors
• Equipment/Instrumentation malfunction
• Process upsets
• Utility Failures
• lntegrity failure or loss of containment
• Emergency Operations
• Environmental release

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SWIFT Checklist for Material Problems

• Flammability
• Thermal stability
• Flash point
• Static electricity
• Reactivity
• Toxicity
• Exposure limits
• Corrosivity
• Radioactivity

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Example SWIFT log sheet

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Failure Mode Effect and Criticality Analysis

(FMECA)
• Primarily reliability oriented e.g. Space shuttle, F1 car,
Dynamic Positioning Systems
• Examines systems, modules within systems, components
within modules
• How can system/module/component fail?
• What is the consequence of system/module/component
failure?

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FMECA (2)
• Primary use to ensure single component failure cannot lead
to catastrophic system failure
• All component failures examined even if they have no
significant effect
• Resource intensive, extensive documentation

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Generic Failure Approach - QRA

• Seeks to quantify risk, and identify optimum risk reduction
measures using cost/benefit analysis.

• What can go wrong? Hazard lD

• How bad could it be? Consequence analysis
• How often might it happen? Frequency estimation
• What are the chances? Risk Assessment
• What can I do to? Risk management

Seeks to reduce risks to As Low As Reasonably Practical (ALARP)

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Engineering Codes and Standards

• Refer to individual items of equipment:
– Heat exchanger TEMA
– Pipeline ASTM piping classification
– Pressure relief API 521 design of press. relief systems
– Pressure vessels British Standards Institute BSI

Specify minimum standards for service, but don’t take into account the
context in which they are used

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Thanks

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