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Impact of Human Factors
in Process Safety Management
Risk Based Process Safety Management
S. K. Hazra
Chairman SHE Expert Committee
Process Safety Centre
Indian Chemical Council5th Dec.2009
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Catastrophic Incidents-Human Errors
In safety critical industries, simple humanmistakes/oversight can cost hundreds of livesand billions of dollars
Top NASA and contractor personnels poortechnical decision making over a period ofseveral years was the Fundamental reason
Challenger Disaster (5 deaths, Loss $ ?Bil.)
A designer error in cabin air pressurisationvalve compounded by Mtc. Engr, allowed itremain partially open during flight
Helios Airline accident in Greece (121 death)
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AttentionfailuresSlips Plan of action satisfactory but
action deviated from intentionin some unintentional wayUnintended
actionserrors
MemoryfailuresLapses
Rule-based
Misapplication of good rule orapplication of a bad rule
Mistakes
Knowledge-based
No situation tackled bythinking out answer from
scratch ready-made solution,new
Unsafeacts
RoutineHabitual deviation from
regular practices
ExceptionalNon-routine infringementdictated by extreme local
circumstancesIntendedactions
Violations
Situational Non-routine infringement
dictated by local
circumstancesActs of
sabotage
Types of human error
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Human Factors
It is imperative that preventive measures focus onunderstanding
Whywell-intentioned and correctly trainedprofessionalssometimes make serious mistakes
Whichcircumvent the considerable defences of asafety system
This question transitions into a broad field labelledHuman Factors (or HF for short).
Considerable organisational effort need put into multi-layered, preventive measures aimed at reducing oreliminating all known risks arising out of HF
Prevention needs understanding reasons of Human failures
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uman Factors are about people in their living and workin
situations; about their relationship with machines, withprocedures and with the environment about them;and also their relationships with other people
.
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HF encompasses aspects of design (latent errors);
ergonomics (human-machine interfaces);
cognitive research (stimulus, memory, informationretrieval and processing);
bio-medical research (drugs, alcohol and the
circadian effects of shi working) and
systems engineering (processes and processcompliance in socio-technical systems in particular).
Human Factors
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HF approach
A method of accelerating the acquisitionand application of operational lessonslearned across an organisation to avoid
their reoccurrence
Seek out information about Hazards fromthe peoples errors who work inside the
systemTo design a process for them to share their
learning with others before any unwantedevents happen
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HF error reduction methods
Customer and product safety are declared asstrategic goals
Probabilistic risk assessments are used to
focus efforts on key hazards Risk management and risk mitigation risks
techniques are applied
Elimination of the opportunity for error, byfoolproof design.
Application of decision support systemsand/or clear safety policies.
Use of checklists, models and other visiblememory aids.
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HF error reduction methods
Leaders model a culture of trust, reporting,and openness
Multi-format, communication channels areused for error reporting and feedback.
Prompt action is taken by leaders to addressall reported hazards and errors.
O.D. and Learning interventions are used atdifferent organisational levels
Education for all on the underpinning HFtheory, principles and concepts. Training for competence in the actual tasks
being performed.
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HF error reduction methods
Training in hazard awareness and risksof specific errors.
Simulation of scenarios that could befaced in high-risk industries.
Behavioural training including surveysof group cultural norms
Leadership training to reinforcepersonal responsibility for safety.
Executive education on safety ethicsand decision making models
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Most of BPs five U.S. refineries have hadhighturnover of refinery plant managers, and process safety
leadershipappears to have sufferedas a result
BP has notadequately ensuredthat its U.S. refinery
personnel and contractors havesufficient
process safety knowledge and competence
ISOM operatorswere likely fatiguedfromworking
12-hour shifts for 29 or more consecutive days
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A poorly designed computerized control systemthat
hindered the ability of operations personneltodetermine if the tower was overfilling
BP managementallowed operators and supervisors
to alter, edit, add, and remove procedural steps
Supervisors and operatorspoorly communicated criticalinformationregarding the startup during the shift turnover.
BP did not have a shift turnover communicationrequirement for its operations staff result
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BPs safety management systemdoes not ensure
adequate identificationandrigorous analysisofprocess hazardsat its five U.S. refineries
An extra operatorwas not assigned to assist,
despite a staffing assessment thatrecommended
an additional operatorfor all ISOM Start up
Thesesafety system deficienciescreated a
workplaceripe for human error to occur
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Thesesafety system deficienciescreated aworkplaceripe for human error to occur
BP managementhas not ensuredtheimplementation ofanintegrated, comprehensive, andeffectiveprocesssafety management systemfor BPs five U.S. refineries
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Culture & working environment
National, local & workplace cultures, social & community values
Job:
Task, workload,
environment,
display & controls,procedures
Individual:Competence,
skills, personality,attitudes, riskperception
Organisation:
Culture, leadership,resources, workpatterns,
communications
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uman factors refer toenvironmental,organisationalandjob factors, and
umanandindividualcharacteristicshich influence behaviourat work in aay which can affect health and safet
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Interrelated aspects of Human Factors
The Job
nature of the task
workload
the working environment the design of displays and controls
the role of procedures
The Task
match the physical limitation in accordance with ergonomic principles
match the mental capability As per peceptual,attentional and decision
making needs
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Interrelated aspects of Human Factors
The Individual
Competence
can be enhanced
Skills can be enhanced
Personality
fixed
Attitude can be changed
Risk perception
can be improved
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Interrelated aspects of Human Factors
The Organisation
Work pattern
Culture of workplace
Resources
Communication
Leadership
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Managing human failures
Common Pitfalls Stating that operators are highly motivated and thus not
prone to unintentional failures or deliberate violations
Ignoring the human component completely, failing to
discuss human performance at all in risk assessments,leading to the impression that the site is unmanned
Inappropriate application of techniques, such as detailingevery task on site and therefore losing sight of targetingresources where they will be most effective
Producing grand motherhood statements that human erroris completely managed (without stating exactly how).
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Managing human failures
Three Serious ConcernConcern 1: An imbalance between
hardware and human issues and focusingonly on engineering ones
Concern 2: Focusing on the humancontribution to personal safety rather thanto the initiation and control of major
accident hazards andConcern 3: Focussing on operator error
at the expense of system and
management failures.
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Concern 1:Hardware vs human issues
and the focus on engineering
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Despite the growing awareness ofthe significance of human factors insafety, particularly major accidentsafety, the focus of many sites isalmost exclusively on engineeringand hardware aspects, at the
expense of people issues.
Concern 1:Hardware vs human issues and the focus on
engineering
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MAH Site
Due to the ironies of automation, it is notpossible to engineer-out humanperformance issues
All automated systems are still designed,built and maintained by human beings.
An increased reliance on automation mayreduce day-to-day human involvement
Maintenance is Critical, as performanceproblems have been shown to be asignificant contributor to major accidents
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MAH Site
May have determined that an alarm system is safety-critical
May have examined the assurance of their electro-mechanical reliability
But they may fail to address the reliability of theoperator in the control room who must respond to thealarm
If the operator does not respond in a timely and
effective manner then this safety critical system willfail
Therefore it is essential that the site addressesand manages this operator performance.
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MAH Site
Operator moves from direct involvement to amonitoring and supervisory role in a complexprocess control system
Operator will be less prepared to take timelyand correct action in the event of a processabnormality
In these infrequent events the operator, often
under stress, may not have situationalawareness or an accurate mental model ofthe system state and the actions required
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Concern 2:
Focus on personal safety
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There needs to be a
distinct focus in themanagement system onmajor hazard issues
Concern 2:Focus on personal safety
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The majority of major hazard sites still tend to focuson occupational safety rather than on process safety
Those sites that do consider human factors issues
rarely focus on those aspects that are relevant tothe control of major hazards.
Sites consider the personal safety of those carryingout maintenance
But what is important is how human errors in
maintenance operations could be an initiator ofmajor accidents
This imbalance runs throughout the safetymanagement system, as displayed in priorities, goals,the allocation of resources and safety indicators.
Major accident vs personnel safety
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Reliance on lost-time injury datain major hazard industries is
itself a major hazard.An airline would not make themistake of measuring air safety
by looking at the number of
routine injuries occurring to itsstaff.
\
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Major accident vs personnel safety
Safety is measured by lost-time injuries, or LTIs.
The causes of personal injuries and ill-health are notthe same as the precursors to major accidents
LITs are not an accurate predictor of majoraccident hazards, which may result in sites beingunduly complacent.
Notably, several sites that have suffered majoraccidents demonstrated good management of
personal safety, based on measures such as LTIs. Therefore, the management of human factors issues
in major accidents is different to traditional safetymanagement.
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Major accident vs personnel safety
A safety management system need tomanage the right aspects to be effective incontrolling major accidents
Performance indicators closely related tomajor accidents may include the movementof a critical operating parameter out of thenormal operating envelope.
The definition of a parameter could be quitewide and include process parameters,staffing levels or the availability ofcontrol/mitigation systems.:
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Performance Indicators
Effectiveness of the training program;
Number of accidental leakages of hazardoussubstances
Environmental releases;
Process disturbances;
Activations of protective devices;
Time taken to detect and respond toreleases;
Response times for process alarms;
Process component malfunctions;
if there is frequentoperation of a
pressure relief valvethen cause of the
pressure rise needs tobe established and action
taken
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Performance Indicators
Number of inspections/audits;
Number of outstanding maintenance activities;
Maintenance delays (hours);
Frequency of checks of critical components; Number of inspections/audits;
Emergency drills;
Procedures reviews;
Compliance with safety critical procedures; Staffing levels falling below minimum targets
Non-compliance with company policy on workinghours.
is the maintenance ofsafety critical equipment
being undertaken as
planned and if not what isdone about it.
are the right drills beingcarried out in the rightplaces, do they cover
suitable scenarios, are allshifts involved, etc.
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Concern 3:Focus on the front-line operator
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In general, most safety activities in complexsystems are focussed on the actions and behavioursof individual operators those at the sharp end.
However, operators are often set up to fail by
management and organisational failures, Rather than being the main instigators of an accident,
operators tend to be the inheritors of system defectscreated by poor design, incorrect installation, faultymaintenance and bad management decisions.
Their part is usually that of adding the final garnish toa lethal brew whose ingredients have already beenlong in the cooking
Concern 3:Focus on the front-line operator
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Management and Safety Culture
Feedback from audits carried out by the HumanFactors Team on major hazard sites often revealsareas that require attention in the managementsystem which have not been identified (or reported)in previous audits.
Audits of management systems frequently fail toreport bad news. Following the Piper Alpha offshore platform fire it is
reported that numerous defects in the safetymanagement system were not picked up bycompany auditing.
There had been plenty of auditing, but the inquiryreported that: It was not the right quality, as otherwise it would
have picked up beforehand many of the deficiencieswhich emerged in the inquiry . (B Appleton, PiperAlpha, 1994)
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Management and Safety Culture
If culture, understood here as mindset, is to be thekey to preventing major accidents, it ismanagement culturerather than the culture of theworkforce in general which is most relevant. What is
required is a management mindset that every majorhazard will be identified and controlled and amanagement commitment to make availablewhatever resources are necessary to ensure that theworkplace is safe. (Hopkins, Lessons from
Longford, reference 2)
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The incident involved threeinterconnected process
vessels.A loss of feed to vessel 1
caused the valve A to close
to prevent the vessel beingemptied.
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As vessel 2 emptied, valve Bclosed, trapping in the remainingliquid.
As heat was still being applied, thisliquid vaporised, and the vesselvented into the flare system,through the flare stack knock-outdrum, which catches liquid toprevent it going to flare
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Meanwhile, the feed to vessel 1 had been
restored, and valve A was opened. This should have caused valve B to open,
but this did not occur.
The operators were aware that vessel 2 was
still overfilling, so they opened valve C toprovide another route out of that vessel.
This resulted in a high liquid level in the flarestack knock out drum.
Due to a previous modification, there was nofacility to pump out the knock-out drumquickly
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By this time, the operators wereconcentrating on the screens
that showed the problems invessels 1 and 2, and were notbeing helped by the flood of
alarms being generated.
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The combination of a high liquid levelin the knock-out drum, and vessel 2venting into the flare system again,caused a slug of liquid to be carriedthrough the knock-out drum and intothe flare line,
Pipeline collapsed at a weak point.
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Texaco Refinery, UK
Twenty tonnes of hydrocarbon were releasedand exploded when a slug of liquid was sentthrough the flare system pipeline, which failed.
The site suffered severe damage, and UKrefinery capacity was significantly affected.Only luck prevented multiple deaths. It was aSunday, and some people had left the area
just before the explosion.
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Key Findings on Alarm System
The control displays and alarms did notaid operators to act in time.
The alarms appeared faster than theycould be responded to
87% of the 2040 alarms displayed as"high" priority, despite many being
informative onlyKey alarms were missed in the flood
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Safety critical alarms were notdistinguishable from the rest
A Human Factor review wouldhave helped diagnosis-.
H F t C t l R t
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Human Factor-Control Room operators
Action recommended by HSE
Removal of 'alarms' which in fact were statusindicators only or which were not intended for actionby the control room operators i.e. alarms do notrequire a defined operator response?
Elimination of alarm list flooding with repeatingalarms - introduction of single line annunciation.
The previous requirement to both accept all alarmsand accept their later clearance to be removed
(except in some carefully-defined special cases) sothat clearance no longer routinely required anoperator response
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Human Factor-Control Room operators
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The designers set out with the best intentionsseeking to alarm virtually any parameter that moved inthe Process,
But may not consider the operators' needs in controlroom that is best met by providing them An effective control system with alarms only for Critical
Parameter in simplest possible form
The Project and commissioning engineers may notrealise this problem because of their familiarity withthe system from first design onwards
If operators HF is not considered in the design,theirspecific needs will not be adequately taken intoaccount.
Then operators being human (hence inventive) willeffect shortcuts by routinely 'shelving', or 'fixing',alarms so that they could focus better on ones theythink are the key ones.
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Collect Data
Basic data collectioAn-ControlRm Determine Mitigation Strategies
Management of Safety
Critical Staff
Alarm Audit andReorganisation
Alarm and Interlock Schedule Recruitment & Selection Proof testing of Alartms
Training & competenceLogic diagrams Critical Alarm Report
Procedures
Planning for upsetconditionsHealth management
Data
driven,
continuousFatigue management Assess the existing
SchemeCommunications
improvement Interact and freeze theOptimum Scheme
Analyse Data Briefings & education
Prioritise Alarms SimulatorsDevelop and Implementrevised Alarm schemeTable top exercise/Mock DrillOperator Response to Alarms
Human Failures/Risk Factors
Operational Risk Factors
Piping Instrumentation Diagram
Managing Human Factor-Control Room operators
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Ignorance Iceberg
4% of senior managersare aware of errors(above the waterline)
6% of managers are
aware of errors (abovethe waterline)
75% of first linesupervisors are awareof errors below the
waterline) 100% of employees are
aware of errors (belowthe waterline)
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The further one moves from the
Plant floor, the less knowledge ofthe organisations errors are known to him
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Importance of HF in MAH Industries
Major accidents Causes: Insufficient staffing levels
Increased workload
Reduction in supervision
Team-working deficiencies
Loss of competence /experience
Unclear roles & responsibilities
Conflicting priorities Poor communications
Reduced morale /motivation
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1: Accept humans can and will
fail
2: Get better at
explaining failures predicting failures 3: Apply the hierarchy of
controls
1.
Accept
thefacts
of life
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