Unit A10 Questions Ollie Flashcards
An inexperienced train driver has passed a stop signal. An investigation finds that the driver had seen the signal gantry but had not perceived the relevant signal correctly. He was unaware that there had been previous similar incidents at the signal gantry and had received no local route training or information.
The signal was hard to see being partly obscured by a bridge on approach and affected by strong sunlight. The light arrangement on the signal was non-standard. The driver had no expectation from previous signals that it would be on ‘stop’.
(a) Give reasons why the driver may not have perceived the signal correctly. (8)
(b) Outline actions that could be taken in order to help reduce the likelihood of a recurrence of this incident. (12)
(a) driver’s perception may have been distorted by fatigue / drugs / alcohol / medication; colour definition may have been impaired by sunlight / defective vision; signal fault may have indicated wrong colour; distraction may have led to incorrect interpretation of signal; signal obscured / visible for too short a time; expectation that signal would be “clear” led to false assumption; unusual configuration of signal may have led driver to misinterpret signal
b) Steps to reduce the likelihood of a recurrence include: careful recruitment / selection procedures - competence / aptitude / fitness / health / vision; re-design signal; re-position; standardise format; cab / task design to minimise distractions - ergonomic considerations; driver involvement / consultation on design / visibility / operational issues - cab glazing / reflections etc; signal maintenance; driver training - route familiarity; provide driver with information - signalling / SPADs etc; consultation; supervision; refresher training; breaks / shift rotation; drug / alcohol testing regime; re-design cab; set up / encourage near-miss / SPAD reporting and disseminate information; provide sunglasses / visors; install ATP / warning system
Routine, situational and exceptional are all categories of violations in the workplace.
(a) Distinguish between routine, situational and exceptional violations. (4)
(b) Outline how situational violations can be minimised. (6)
(a)Routine violation: where not following a laid-down procedure has become the norm (+ simple example: eg not using a PTW for confined space entry; paperwork has fallen into disuse -no-one ever checks; not wearing PPE - no-one else does; HOFE - setting sail with bow doors open was “standard practice”)
Situational violation: when a procedure cannot be followed if work is to continue (conflict between operational and H&S demands) eg where the equipment necessary to comply with the procedure has not been provided; must wear fall-arrest harness when working at height -no harness available; insufficient time available to complete safety checks
/ PTW procedures if deadline is to be met); no supervisor available to issue PTW but work goes ahead; Clapham Junction rail accident - formal supervisory checks on electrical wiring could not be made due to tight deadlines).
Exceptional violation: occurs when something has gone wrong and procedures are not followed in an attempt to correct the situation (eg Chernobyl - test of reactor systems leads to emergency -established plant operating procedures are not followed in an attempt to retrieve the situation; re-entering burning building to rescue someone).
(b)Situational violations may be minimised by the following:
• Allowing more time/ reducing time pressures
• Providing more staff to carry out the task
• Ensuring that spare equipment is available so that people don’t have to improvise
• Providing good, appropriate clothing for working in all conditions eg outside cold
(a) Outline the meaning and relevance of the following terms in the context of controlling human error in the workplace:
(i) ‘ergonomics’;(2) Two parts
(ii) ‘anthropometry’;(2)
(iii) ‘task analysis’.(6). SREDIM
(a) (i) Ergonomics is the study of how human beings interact with their environment; in H&S terms ergonomics is concerned with the design and layout of workstations / work environments so that they “fit” the user. In the context of human error in the workplace ergonomics is concerned with the design of equipment, tasks and work environments that take account of human physiological and psychological attributes and limitations so as to reduce the likelihood of human error.
Ergonomic issues that would impact on human error include: comfort - reducing fatigue and distractions - maintaining alertness; adjustability of seating, work equipment etc to suit individual - see comfort; environmental conditions - lighting, temperature, humidity, noise levels; layout of workstations - visibility, reach distances; design of control panels and instrumentation - clear, unambiguous, logical “intuitive”
(ii) Anthropometry is the study of human physical dimensions - height, arm length, reach distances, hand span etc (biometrics); this data provides the basis for ergonomic design, taking account of the range of human physical dimensions - male / female / racial differences etc. In the context of human error, applying anthropometric data in designing equipment / workstations etc. will help avoid fatigue, distractions, confusion when operating work-based equipment, control panels etc. For example, anthropometric data is used to design equipment / work stations etc that can typically accommodate the 5th percentile female to the 95th percentile male; also applied to machinery guarding.
(iii) Task analysis is the process whereby a work activity is observed and the various tasks involved broken down into sub-routines so that hazardous activities or safety-critical “nodes” can be identified; a systematic approach which breaks the job down into tasks and sub-tasks - sometimes referred to as “Hierarchical Task Analysis”. Task analysis can help reduce human error by identifying key high risk safety-critical elements of the task which can then be modified or safeguards introduced to eliminate or lower the likelihood of error occuring.
(b)Excluding ergonomic issues, outline ways in which human reliability in the workplace may be improved. In your answer, consider ‘individual’, ‘job’ and `organisational’ issues. (14)
b) As set out in HSE’s publication “Reducing Error, Influencing Behaviour” HSG 48, human reliability may be improved by addressing the following:
Individual issues: selection -“ fitness”, special needs, skills, aptitude, training, qualifications, awareness, experience; attitudes, motivation, perception (= competence); health surveillance (?); counselling service(?); monitoring performance(?); assessing job satisfaction(?)
Job issues: design, suited to the individual - level of interest and “challenge” appropriate; avoidance of distractions;
variation in tasks; job design to take account of realistic demands in terms of workrate, hours, deadlines, breaks, repetition, variation; boredom, variation!
Organisational issues: development of a positive H&S culture - as represented by management commitment / leadership, management setting an example; effective communication, consultation arrangements, staff involvement, effective supervision; appropriate demands - hours, work rate, deadlines, breaks, incentives; suitable information and training; resources allocated
A control panel aimed at reducing the likelihood of human error is installed.
Outline the desirable design features of:
(a) controls; (12)
for this control panel.
Desirable design features of controls include
• Minimising the number of controls needed so as to avoid operator confusion.
• Place controls in positions where they are easily operated
• Ensure that controls are ordered logically – in such a way that the operation of controls follow the logical order of the process being controlled
• Design controls so that they require positive action in order to be operated and cannot operated
accidently or knocked, for example a hand brake of a car cannot be released simply by pushing down
on the lever
• Ensure that feedback is available to the operator to indicate successful operation of control.
• Obey any stereotyping / conventions that might already exist for that type of control. For example,
switch up for off, down for on; knobs turn clockwise for increase, etc. It may be possible and desirable to position controls next to corresponding displays. For example – if a knob alters temperature it might be desirable to site the knob next to the temperature readout.
• Emergency control should be prominent and distinctive so that they are easy to see and activate. They might be positioned near to the operator’s position so that they are within easy reach in the event of emergency.
• Controls that have to be operated frequently might be closely positioned to the operator for ease for access, whilst those that are used infrequently might be positioned further away.
• Controls might be laid out in an arc around the operator so that they can all be activated without need to over reach.
• Controls that require force to operate should be power or servo assisted.
• The type of control should be appropriate to the degree of control required, for example a lever may be
more appropriate than a knob.
• A system restart should again only occur after operating a control after a deliberate or non-intentional
stop. A stop function should be easy to activate and override start and adjust control.
• Labelling, shape or colour can be put to effective use to ensure controls are easily identified.
Control panel displays
b) displays (8
Design Features of displays includes:
• Display must be visible to the operator from their normal operating position.
They must also be large enough to be easily visible.
• Display should be placed so as to avoid glare
• They must be appropriately labelled, so that the parameter they are displaying is clear to the operator,
this might require the use of pictograms (which might also help overcome language barriers).
• The positioning of safety critical displays must be carefully selected so that they are in the operator’s
normal line of sight and in a commanding position
• Again, any conventions / stereotyping that exist should be recognised and used, for example, colours
on dials relating to danger and safe conditions would normally use green for safe, red for danger
• Read out dials should all increase the same way, normally clockwise.
• Careful selection of analogue vs digital displays should be made. There are times when a digital
readout is perfectly acceptable and desirable. There are other times when analogue is preferred since the position of the needle on an analogue dial can be determined by a quick glance that does not require the accurate reading of numbers.
• Displays should also clearly indicate the change, match expectation and attract the appropriate sense such as flashing to draw visual attention
Train drivers may spend long periods of time in the cab of a train and may be susceptible to loss of alertness. This can increase the risk of human error.
Outline a range of practical measures that could reduce loss of alertness in train drivers. (10)
Two Parts
Factors affecting driver alertness include:
working hours, shift work (early morning starts / late night / overnight ), and shift patterns (4 days on / 4 days off; alternating days / nights etc); breaks and rest periods - meals / refreshments;
also non-work activities - lack of sleep; use of alcohol / drugs; stress and domestic issues - leading to fatigue and loss of concentration; fitness and physical health of the driver - medical conditions / use of medication can lead to loss of attention / tiredness / inability to concentrate; boredom / lack of interaction / lone working / routine activities;
environmental conditions - lighting, noise, temperature, seating, ergonomic design of workstation (or lack of it) can distract; presence of distractions in cab - listening to the radio, reading the newspaper, playing Sudoko, using a mobile phone; excessive demands - dealing with signals, data handling, communicating with control centre etc can distract the driver from other activities eg watching the track! Being alert in one area can reduce alertness to others.
Therefore, practical measures to reduce lack of alertness in drivers include:
• pre-employment and regular medical - health / fitness assessment / checkups
• ensure suitable shift patterns / breaks / recovery time etc
• alcohol / drug screening programme
• search and inspection - no cab distractions
• ergonomic design of cab: control panel - clear / unobstructed; seating - adjustable etc; suitable
environmental conditions (air conditioning); sun visors
• variation of routes
• regular interaction / communication with guard
• hold-to-run / “dead man’s handle” operation
• audible / visual warnings / prompts requiring cancellation
(a) Give the meaning of the term ‘motivation’. (2)
(b) Outline Maslow’s model of the hierarchy of human needs AND give a suitable example within EACH stage of the model. (8)
PSLES
Motivation is a driving force or incentive which encourages people to behave in a certain way and to do something willingly.
Maslow’s hierarchy is a list of needs, normally presented as a triangle, whereby a person addresses the needs from the bottom such that people in a poor society will be mostly concerned with physiological and safety needs. Starting from the bottom:
Physiological – air, food, water, shelter, sleep, clothes, reproduction
Safety – personal security, employment, resources, health, property
Love & belonging – friendship, intimacy, family, sense of connection
Esteem – respect, self esteem, status, recognition, strength, freedom
Self actualisation – desire to develop his or her full potential
Outline content of typical behavioural change programmes. (20)
This question is An example of the Deming cycle PDCA
Management leadership and commitment
• Appoint project team to lead and oversee the project
• Identify the specific observable behaviour that needs changing, e.g. wearing of hearing protectors in a high noise environment.
• Measure the level of the desired behaviour by observation.
• Identify the cues (or triggers) that cause the behaviour and the consequences (or pay offs) (good and bad)
that may result from the behaviour.
• Development of suitable checklist or recording system
• Train a group of workers to observe and record the safety critical behaviour.
• Role programme out to general workforce
• Praise/reward safe behaviour and challenge unsafe behaviour.
• Set goals for desired changes and review progress
• Feedback safe/unsafe behaviour levels regularly to workforce
A poor organisational safety culture is said to lead to higher levels of violation by employees.
(a) Give the meaning of the term violation' AND outline the classification of violation as routine’, `situational’ or ‘exceptional’. (6)
(a) Violation: a “deliberate” deviation from a rule, instruction, procedure, regulation;
Routine violation: where not following a laid-down procedure has become the norm (+ simple example: eg not using a PTW for confined space entry; paperwork has fallen into disuse -no-one ever checks; not wearing PPE - no-one else does; HOFE - setting sail with bow doors open was “standard practice”)
Situational violation: when a procedure cannot be followed if work is to continue (conflict between operational and H&S demands) eg where the equipment necessary to comply with the procedure has not been provided; must wear fall-arrest harness when working at height -no harness available; insufficient time available to complete safety checks
/ PTW procedures if deadline is to be met); no supervisor available to issue PTW but work goes ahead; Clapham Junction rail accident - formal supervisory checks on electrical wiring could not be made due to tight deadlines).
Exceptional violation: occurs when something has gone wrong and procedures are not followed in an attempt to correct the situation (eg Chernobyl - test of reactor systems leads to emergency - established plant operating procedures are not followed in an attempt to retrieve the situation; re-entering burning building to rescue someone).
(b) Outline the reasons why a poor safety culture might lead to higher levels of violation by employees. (4)
LACK OF
b) Poor H&S culture characterised by absence of shared perception / understanding / attitudes regarding H&S matters - may result in increased violations arising from: a lack of training / competence - results in misperception of hazard therefore precautions not adopted ; lack of resources allocated / lack of commitment from management - results in careless attitudes to procedures and controls - belief that rules are bureaucratic and unimportant; inadequate communication - results in lack of awareness of hazards / precautions and controls required; lack of co- operation / conflict - results in mistrust and peer pressure to ignore procedures / rules; lack of monitoring / supervision - acts as an indication that the rules are not important and / or violation not likely to be detected
A fatality occurred when an unsupported excavation collapsed on an employee. An initial investigation into this accident revealed that there had been a number of minor collapses in the days before the accident and yet the danger of a full collapse had not been recognised. No effective measures were taken to deal with the danger.
(a) With reference to the Hale and Glendon model of individual behaviour in the face of danger determine possible reasons why this accident occurred. (12)
(a) The Hale Glendon model assumes that danger is always present and that when faced with danger people may, through their actions, create danger or take action to control that danger and therefore prevent harmful outcomes. It involves the steps of:
• Hazard identification
• Assessment of risks
• Selection and adoption of measures to reduce risk
It considers both active and latent failures and considers the different areas of knowledge, Rules and skills. In the case of the excavation above, the workers who had experienced the minor collapses represent an active failure did not take the necessary action to prevent the major collapse. They may not have realised the potential for a larger failure. They may not have known the rules regarding the reporting system or they may not have been motivated to report them. It is not clear whether any measures were introduced following the minor collapses, but if they were, it would appear that those involved did not have the required level of skills.
Latent failures may have been made by the designers, safety advisors or emergency planners who failed to foresee the potential for the collapse and failed to provide the necessary supports for the excavation. Managers may have also failed to provide sufficient levels of supervision and also failed to make clear what the near miss reporting system was if they had any concerns.
(b) Outline methods of improving human reliability so that similar accidents can be prevented in the future. (8)
(b) Methods of improving human reliability include:
Individual factors:
• Training (Safety induction, Job specific and refresher) – in the absence of proper, effective training,
worker will not know how to behave correctly and they will do what they see as the best.
• Incentive Scheme: if worker see some form of reward for good behaviour then they are more likely
to comply with the rules, etc. and they are also more likely to exercise care when performing their duties because they have a personal reason for caring about outcomes. Incentive can be financial in nature , but may have no financial value at all (e.g; Employee of the Month scheme )
• Individual characteristics such as personal attitudes, skills, qualifications and aptitude.
• The consideration of special needs of those who may be more vulnerable.
• Monitoring personal safety performance
• Assessing job satisfaction and a counselling service for those recognised as suffering from the
effect of stress.
Job factors:
• Allowing Appropriate rest breaks
• Introduction of task analysis for the critical task
• The design of work patterns
• Shift organisation to minimise stress and fatigue
• The use of job rotation to counter monotony and boredom and maintain a level of interest
• Usage of sufficient number of personnel to avoid constant time pressures
Organisation factors:
• Employee selection: recruiting the right worker for the job is an important measure. For example a worker with high IQ on a monotonous job is likely to bend and break the rules to relieve the monotony.
• Supervision: The provision of adequate level of supervision. It is vital that workers are supervised to an adequate level in the workplace so that non-compliance and errors are detected and corrected early. This prevents bad habits from forming and sends a clear message to the workers: rule breaking will not be tolerated.
• Demonstrable Management commitment - without strong leadership workers will not feel motivated to behave correctly.
• Development of a positive health and safety culture through:
- Introduction of effective health and safety management system - Maximising employees’ involvement in health and safety issues. - Ensuring effective arrangements for employees’ consultation.
• The introduction of good communication arrangements between individuals, shifts and groups, so that workers feel engaged in the decision making process in the workplace and therefore feel a greater level of commitment to work.
(a) Outline the meaning of ‘skill-based’, ‘rule-based’ and ‘knowledge-based’ behaviour. (6)
(b) With reference to practical examples or actual incidents explain how EACH of these types of operating behaviour can give rise to human error AND, in EACH case, how such error may be prevented. (14)
(a)
Skill-based - involves a “low level”, pre-programmed sequence of actions where employees carry out routine operations with minimal cognitive / conscious involvement (“on auto-pilot”).
Rule-based - involves actions based on recognising patterns or situations and then selecting and applying the appropriate rule set; involves a higher level of cognitive involvement.
Knowledge-based errors - occur at a “higher” cognitive level - involving problem-solving and decision-making; arise where there are no set rules so response/ decision is based on knowledge / understanding of the system.
(b)Skill-based errors may arise if a similar routine is incorrectly selected, if there is distraction, interruption or inattention causing a stage in the operation to be omitted or repeated, or if checks are not carried out to verify that the correct routine has been selected.
Prevention; design of routines and controls to be distinct from each other; use of feedback signals to warn of taking wrong course of action; training and competence assessment; supervision and monitoring to minimise the erosion of the required steps; breaks/job rotation/ reduced work rate etc.
Examples; SPADs (Paddington), mis-keying (Selby)
Rule-based errors may occur if; diagnosis is based only on previous experience; there is a tendency to apply usual rule/solution/action even if inappropriate; there is insufficient training to diagnose accurately; failure to remember rule.
Prevention; clear presentation of information, logical and easy to follow (unambiguous) rule sets; training, practice and competence assessment and systems designed to highlight infrequent or unusual events. Examples; Kegworth, Milford Haven, Piper Alpha, Three Mile Island.
Knowledge-based errors will occur if there is a lack of knowledge or inadequate understanding of the system, if there is insufficient time to carry out a proper diagnosis and if the problem is not properly thought through or evidence is ignored.
Prevention; measures would again involve training, particularly in risk and hazard assessment, the provision of adequate resources in terms of information and time and the use of checking systems such as group or peer review; supervision.
Examples; Flixborough, Port Ramsgate, Associated Octel.
An employee was seriously injured when struck by material being transported by the crane. Human failure has been identified as a significant factor in this accident.
Outline types of human failure which may have contributed to the accident and in each case give examples relevant the scenario to illustrate your answer. (10)
Types of human error that could have caused the accident described include: skill-based errors, mistakes and violations (see HSG 48 “Reducing error - influencing behaviour” )
Skill-based errors = slips eg slip of action - where a familiar, routine action is carried out incorrectly - crane operator presses wrong lever / switch - lowers load instead of raising - load strikes person.
Skill-based errors = lapses eg lapse of attention - daydreaming / distracted / focussing on movement of load- doesn’t notice person in lifting area or doesn’t notice banksman giving signal to stop lift. Alternatively, injured person doesn’t notice lift taking place or warning signs and wanders into lifting zone.
Mistakes = rule-based mistakes eg crane operator is following standard rules / procedures for lifting which are not applicable when persons present in lifting area - eg rule is “no banksman required for this type of lift”. Alternatively, injured person is following a “rule” that people are allowed in lifting area if wearing high vis clothing and hard hat!
Mistakes = knowledge-based mistakes eg didn’t know or not informed that persons were on site working in the lifting area; didn’t know that load was only to be lifted after signal that people are clear of area so proceeds with lift. Injured person not aware of site rules on lifting so remains in lift zone.
Violations = routine violation - where a deliberate / intentional breach of procedures has become standard practice - eg it has become standard practice to carry out lifting operations without a banksman / instructions even though company procedures require it; it has become the norm for people to have uncontrolled access to the lifting zone despite site rules.
Violations = situational violation - where a deliberate / intentional breach of procedures is “necessary” in order to satisfy other competing priorities - eg the lifting operation has to be completed within a strict timescale due to extra crane hire costs / weather conditions or whatever - therefore the lift goes ahead without required checks /or without banksman present. Alternatively, injured person knows restrictions but ignore because of time pressures / penalty clause.
Violations = exceptional violation - where a deliberate / intentional breach of procedures is made in an effort to retrieve a (dangerous / emergency) situation - eg load becomes unstable so crane operator lowers load hurriedly ignoring instructions from banksman. violations = optimising violation?
