Examiners’ Report NEBOSH International Diploma in Occupational Health and Safety January 2008 examinations
CONTENTS
Introduction
2
Unit Unit IA – International management management of health and safety safety
3
Unit IB – International International control control of hazardous agents agents in the the workplace workplace
12
Unit Unit IC – International workplace and work equipment safety safety
19
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Introduction The The res resul ultts from from the seco second nd three Un Unit exam examinat inatio ion ns of the the In Intern ernatio ationa nall Dip Diplom loma res resu ulted lted in pas pass s rat rates of of 61%, 44% 44% and 50% 50% (Units A, B and C respectively). On a positive note, while while Exam E xaminers’ iners’ Reports Reports inevitably inevitably concentrate on some of the weaknesses found in candidates’ answers, every examination produces some excellent scripts from candidates who have obviously put much effort into their studies in order to achieve success. success. S uch effort does not go unrecognised.
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UNIT IA – International management of health and safety
Section A – all questions compulsory
Question 1
(a)
(b)
In relation to workplace behaviour outline what is meant by the term ‘attitude’.
(2)
Outline how the media can influence attitudes towards health and safety, making reference to suitable examples where appropriate.
(8)
For part (a) of the question, candidates could have referred to the term ‘attitude’ as a predisposition to act in a certain way which may be determined by ancestry, personal experience or training. There a number of ways in which the media can and have influenced attitudes towards health and safety. They have the facility to undertake a global coverage of events and can reach a wide audience using a variety of methods of delivery such as print, television, videos and the internet. The coverage is often sensationalist and can be influenced on occasions by pressure groups and other bodies such as Greenpeace. The influence exerted by the media may be advantageous or detrimental for the industry or organisation involved particularly those who have high media coverage which can affect the perceptions of customers, clients and other stakeholders. To support their answers, candidates were expected to refer to the media coverage of incidents such as the Perrier incident of 1990, Chernobyl, BP Texas and Piper Alpha.
Question 2
An employee has been seriously injured after being struck by material transported using an overhead crane. Using the categorisation of human failure published in the Health and Safety Executive (HSE) ‘Reducing error and influencing behaviour’ (HSG48) guidance, give examples of the human failure that may have contributed to the accident.
(10)
By following the categorisation of human failure contained in HSG48, candidates could have stated that skilled-based behaviour involves a low level, pre-programmed sequence of actions where employees carry out routine operations. Errors (human failure) may arise if a similar routine is incorrectly selected, if there is 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. In the scenario described in the question, errors that may have contributed to the accident include the operation by the crane driver of the wrong switch or control or commencing the lifting operation out of sequence when workers were not prepared. Rule-based behaviour involves actions based on recognising patterns or situations and then selecting and applying the appropriate rule set. An error would involve the application of the wrong rule for example the driver lifting instead of lowering or the worker crossing the path of the lifting operation. Knowledge-based behaviour on the other hand, is involved at the higher problem solving level, when there are no set rules and is based on having knowledge of the system. Errors will consequently occur if there is a lack of knowledge or inadequate understanding of the system. In the case described, the driver may have had little experience of the type of lifting operation being carried out and was carrying the load at the wrong height while the injured person may have been unaware that a lifting operation was taking place. 3
Finally, the accident may have been caused by a deliberate failure to follow rules – a violation - where for example, the driver had failed to operate the siren before commencing the lifting operation or the injured person had intentionally walked too close to the load being lifted.
Question 3
(a)
A mixing vessel that contains solvent and product ingredients must be thoroughly cleaned every two days for process reasons. Cleaning requires an operator to enter the vessel, for which a permit-to-work is required. During a recent audit of permit records it has been discovered that many permits have not been completed correctly or have not been signed back. Outline possible reasons why the permit system is not being followed correctly.
(b)
(5)
A sister company operating the same process has demonstrated that the vessel can be cleaned by installing fixed, high pressure spray equipment inside the vessel which would eliminate the need for vessel entry. You are keen to adopt this system for safety reasons but the Board has requested a cost-benefit analysis of the proposal. Outline the principles of cost-benefit analysis in such circumstances. (Detailed discussion of individual cost elements is not required).
(5)
There are many reasons to account for the failure to adhere to a permit to work system. They include the lack of competence of both the permit issuer and the receiver; the level of training and information that has been given to both; a poor health and safety culture within the organisation; routine violations; pressure to complete the task and the complexity and impracticability of the system which makes it difficult to understand. Additionally, there could have been an inadequate level of supervision, a lack of routine monitoring and the nonavailability of the permit issuer to activate the ‘sign back’ procedure and cancel the permit once the work had been completed. For part (b), candidates should have outlined that the preparation of a cost-benefit analysis with reference to the given scenario, would involve calculating the total costs, including capital and ongoing, of each option. Wherever possible, the benefits that would accrue from the use of the proposed system should be quantified and these would include process efficiency gains, lower operating costs and a reduction in accidents and cases of ill-health and their associated costs. Once the costs and benefits of the proposal have been identified, a comparison might then be made with those of the system currently in use.
Question 4
Outline a range of external individuals and bodies to whom, for legal or good practice reasons, an organisation may need to provide health and safety information. In EACH case, indicate the broad type of information to be provided.
(10)
This question required candidates to outline the external bodies and individuals to whom an organisation may need to provide health and safety information for legal or good practice reasons. Candidates who did best were those who structured their answers under the headings of ‘body or individual’ and ‘type of information’.
4
Individuals and bodies who would be provided with information for legal reasons included the enforcing authorities with respect to information required by law or in accordance with the ILO Code of Practice or as part of inspection or investigation activities; the emergency services on the inventories of potentially hazardous/flammable materials used or stored on the site and on the means of access and egress to the site; customers who have to be given health and safety information on articles and substances they might use for work activities; members of the public concerning information on emergency action plans for major hazards; visiting contractors who need to be advised on safe working arrangements and procedures; waste disposal contractors who should be given information on controlled or hazardous waste produced by the organisation; transport companies who should be given information on the precautions to be taken in transporting hazardous substances from the organisation’s site; and legal representatives or courts who would have to be given information regarding civil claims. It would, additionally, be good practice to supply information: to trade associations and trade unions on performance and social responsibilities; to insurance companies on the safety management systems in place and to shareholders on the organisation’s level of performance as far as health and safety was concerned.
Question 5
(a)
(b)
Outline the reasons for establishing effective consultation arrangements with employees concerning health and safety matters in the workplace.
(4)
Outline the range of formal and informal arrangements that may contribute to effective consultation on health and safety matters in the workplace.
(6)
This question, based on Element A5 of the syllabus, was designed to test candidates’ knowledge of the reasons for and the arrangements that might be made for ensuring effective consultation at the workplace on health and safety matters. In answer to part (a) candidates were initially expected to outline the requirement for consultation in accordance with the principles laid down in Article 20 of the ILO convention, C155 and then to expand on this to include the development of ownership of safety measures amongst employees; improving perception about the value and importance of health and safety; gaining the input of employee knowledge to ensure more workable improvements and solutions; and encouraging the submission of improvement ideas by employees. Part (b) required candidates to outline arrangements that might contribute to effective consultation. Marks were available for referring to arrangements such as: the establishment of safety committees; consultation with safety representatives; planned direct consultation at departmental meetings, team briefings or similar; consultation as part of accident/incident investigation or as part of the completion of risk assessments; day to day informal consultation by supervisors with employees at the workplace; tool box talks; use of departmental/team meetings for ad-hoc consultation on safety issues; discussion as part of safety circles or improvement groups; and the use of staff appraisals, questionnaires and suggestion schemes.
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Question 6
A publicity campaign was used to encourage improvement in compliance with safety standards within a particular organisation. During the period of the campaign the rate of reported accidents significantly increased and the campaign was considered to be a failure. (a)
(b)
Outline reasons why the rate of reported accidents may have been a poor measure of the campaign’s effectiveness.
(2)
Outline FOUR proactive (active) monitoring techniques which might be used to assess the organisation’s health and safety performance.
(8)
For part (a) of the question, candidates could have identified that a reason why the number of reported accidents had increased was because they may have previously been under reported, perhaps because some employees were unaware of the requirement to report and that raised awareness, prompted by the advertising campaign, could have led to previously unreported accidents now being reported. In the absence of any other data, it would be almost impossible to tell whether or not the increase was ‘real’. Using the number of reported accidents is an unsatisfactory way of measuring the effectiveness of the campaign since the anticipated improvement in health and safety standards may not be apparent until some time after the campaign has ended. In answering part (b), proactive monitoring techniques which might be used to assess the organisation’s health and safety performance include physical inspections of the workplace to identify hazards and unsafe conditions; safety audits where the systematic critical examination of all aspects of an organisation’s health and safety performance against stated objectives is carried out; safety tours involving unscheduled inspections to observe the workplace in operation without prior warning and to check on issues such as housekeeping, use of personal protective equipment, gangways and the maintenance of fire exits; safety sampling of a specific area or particular items of plant with repeat sampling to observe trends; safety surveys involving in depth examinations of specific issues or procedures such as changes in working practices; environmental monitoring and/or health surveillance; safety climate measures such as the use of employee questionnaires; behavioural observation and measuring health and safety performance against set targets.
6
Section B – three from five questions to be attempted
Question 7
(a)
Outline the principles, application and limitations of Event Tree Analysis as a risk assessment technique.
(b)
(6)
A mainframe computer suite has a protective system to limit the effects of fire. The system comprises a smoke detector connected by a power supply to a mechanism for releasing extinguishing gas. It has been estimated that a fire will occur once every five years (f=0.2/year). Reliability data for the system components are as follows: Component Detector Power supply Extinguishing gas release mechanism (i) (ii)
Reliability 0.9 0.99 0.95
Construct an event tree for the above scenario to calculate the frequency of an uncontrolled fire in the computer suite. Suggest ways in which the reliability of the system could be improved.
(10) (4)
Event Tree Analysis is based upon binary logic and is often used to estimate the likelihood of success or failure of safety systems. It starts with the initiating event and ends with the probability of a situation being controlled or not. It is limited by the lack of knowledge of component reliability and other data and since it considers only two possibilities – success or failure – it does not take into account partial downgrade (ie limited success). For part (b) (i), candidates were asked to construct an event tree for the scenario described in the question. An acceptable answer would have been: detector
power
gas
SUCCESS p (success) =0.2 - 0.031 =0.169
0.95 0.99
FAILURE
0.9 0.05
Fire
0.01
f=0.2/yr
0.2 x 0.9 x 0.99 x 0.05 =0.009 0.2 x 0.9 x 0.01 =0.002
0.1
0.2 x 0.1 =0.02
p (failure) =0.009 +0.002 +0.02 =0.031 per year f =once every 32 yrs
Marks were awarded for the general construction of the tree; for calculations of failure rates from component reliability data; for calculation of system failure rate from individual failure rates; and for conversion of failure rate per year to failure every “X” years which in this case was once in every 32 years. In answering part (b) (ii), candidates could have suggested ways such as choosing more reliable components or using components in parallel. Credit was given for recognising that the detector was the least reliable component and so would be a logical first choice for such techniques. Installing a second independent but parallel system was a additional way of improving the reliability of the system as was also the introduction of a regular programme of maintenance and testing.
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Question 8
(a)
(b)
Outline the meaning and relevance of the following terms in the context of controlling human error in the workplace: (i)
‘ergonomics’;
(ii)
‘anthropometry’;
(iii)
‘task analysis’.
(6)
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)
For part (a) of the question, an acceptable outline of the meaning and relevance of ergonomics in the context of controlling human error in the workplace would have been – the design of equipment, task and environment to take account of human limitations and capabilities; that of anthropometry – the collection of data on human physical dimensions and its application to equipment design; and that of task analysis – the breaking down of tasks into successively more detailed actions and the analysis of the scope for human error with each action. In part (b), candidates were asked to outline ways in which human reliability in the workplace might be improved, structuring their answers round individual, job and organisational issues. Human reliability plays a significant role in health and safety at the workplace and candidates were expected to have a good understanding of this issue. As far as the individual is concerned, this would involve careful selection taking into account skills, qualifications and aptitude; the provision of appropriate training both at the induction stage and to meet subsequent job specific needs; the consideration of the special needs of those who may be more vulnerable; monitoring personal safety performance; using workplace incentive schemes and assessing job satisfaction and providing health surveillance and a counselling service for those recognised as suffering from the effects of stress. Issues connected with the job include the introduction of task analysis for critical tasks; the design of work patterns and shift organisation to minimise stress and fatigue; the use of job rotation to counter monotony; the introduction of good communication arrangements between individuals, shifts and groups and using a sufficient number of personnel to avoid constant time pressures. Finally, for issues connected with the organisation, candidates could have referred to the development of a positive health and safety culture; the provision of good leadership example and commitment; the introduction of effective health and safety management systems and maximising employee involvement in health and safety issues; ensuring effective arrangements for employee consultation; the introduction of procedures for change management and the provision of an adequate level of supervision.
8
Question 9
(a)
(b)
(c)
In relation to the improvement of health and safety within companies, describe what is meant by: (i)
corporate probation;
(2)
(ii)
adverse publicity orders;
(2)
(iii)
punitive damages.
(2)
Outline the mechanism by which the International Labour Organisation (ILO) can influence health and safety standards in different countries.
(10)
Describe what is meant by the term ‘self regulation’ in relation to health and safety management within organisations.
(4)
In answering part (a) of the question, candidates could have described corporate probation as a supervision order imposed by a court on a company that has committed a criminal offence. When applied to a health and safety offence, the order might require the company to review its safety policy or its health and safety procedures, initiate a training programme for its directors and senior management or reduce the number of its accidents. Its aim is to instigate a change in the organisation’s culture under the supervision of the court. The intention of an adverse publicity order would be to publicise the failings of an organisation and seek to change its conduct through public perception. Punitive damages are damages not awarded to compensate the plaintiff, but in order to reform or deter the defendant and similar persons from pursuing a course of action such as that which damaged the plaintiff. In answering part (b) on the mechanisms by which the International Labour Organisation can influence health and safety standards in different countries, candidates were expected to refer to matters such as the development of international labour standards through conventions supplemented by recommendations containing additional or more detailed provisions; the ratification of the conventions by member states which commits them to apply the terms of the convention in national law and practice; the requirement for member states to submit reports to the ILO detailing their compliance with the obligations of the conventions they have ratified; the initiation of representation and complaint procedures against countries for violation of a convention they have ratified; the provision of technical assistance to member states where this is seen to be necessary and indirectly through the pressure applied internationally on non participating countries to adopt ILO standards. For part (c), self regulation in general terms might refer to the trend in health and safety legislation to set standards and objectives and leave it to the duty holder to determine how best to achieve them. More particularly it could refer to the means by which members of a profession, trade or commercial activity are bound by a mutually agreed set of rules often set out in a code of practice or conduct. It governs their inter relationship and the way they operate. The rules may be accepted voluntarily or they may be compulsory. There will normally be a procedure for resolving complaints and for the application of sanctions against those who infringe the rules.
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Question 10
Describe, using appropriate examples, the possible functions of a health and safety practitioner within a medium-sized organisation.
(20)
In answering this question, Examiners were looking to candidates to highlight the key functions of the role of a health and safety practitioner in a medium size organisation such as helping to develop, implement and revise health and safety policies; giving advice on risks in the workplace and the appropriate control measures to be adopted; drawing up procedures for vetting the design and commissioning of new plant and machinery; assisting management in setting performance standards and carrying out proactive and reactive monitoring; advising management on the requirements of health and safety legislation; organising and reviewing emergency procedures; promoting a positive health and safety culture within the organisation; investigating accidents and cases of ill-health; carrying out or assisting in the audit of the health and safety management system; liaising with enforcement authorities and maintaining health and safety information systems.
Question 11
A forklift truck is used to move loaded pallets in a large distribution warehouse. On one particular occasion the truck skidded on a patch of oil. As a consequence the truck collided with an unaccompanied visitor and crushed the visitor’s leg. (a)
State reasons why the accident should be investigated.
(4)
(b)
Assume that the initial responses of reporting and securing the scene of the accident have been carried out. Outline the steps which should be followed in order to collect evidence for an investigation of the accident.
(8)
The investigation reveals that there have been previous incidents of forklift trucks skidding which had not been reported. The company therefore decides to introduce a formal system for reporting ‘near miss’ incidents. Outline the factors that should be considered when developing and implementing such a system.
(8)
(c)
There are many reasons for investigating accidents such as to identify their causes, both immediate and underlying; to prevent a recurrence; to assess compliance with legal requirements; to demonstrate management’s commitment to health and safety and to restore employee morale; to obtain information and evidence for use in the event of any subsequent civil claim; to provide useful information for the costing of accidents and for identifying trends and to identify the need to review risk assessments and safe systems of work. Better answers to part (b) were those that outlined the steps to be followed in a realistic chronological order including taking photographs and making sketches and taking measurements of the scene of the accident before anything was disturbed; obtaining any CCTV footage available; examining the condition of the fork lift truck and determining its speed at the time of the accident; determining the load that was being carried, the safe working load of the truck and any forward visibility problems with the load in place; finding out the reasons for the oil spillage, the emergency spillage procedures in place and the reasons why they were not followed on this occasion; assessing the competence of the fork lift truck driver and examining the workplace to determine any contributing environmental factors such as the condition of the floor and the standard of lighting and interviewing relevant witnesses such as the visitor, where this is possible, and reception personnel to identify current working practices as compared with the laid down written procedures for dealing with visitors.
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Those who did best in answering part (c) outlined a range of practical, communication and management issues referring to factors such as: arriving at and setting out a clear definition of a ‘near miss’; holding consultations with employees on the proposed system; arranging for information and training to be given to all employees; ensuring that the reporting methods are simple and easy to operate and establishing clear reporting lines; introducing and practising a no blame culture; arranging for investigation of incidents by line management to identify and implement any remedial action necessary; ensuring the introduction of a reporting back procedure to persons and groups involved and ensuring that reports on the incidents are collated, the data analysed and any remedial action taken monitored on a regular basis.
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UNIT IB – International control of hazardous agents in the workplace
Section A – all questions compulsory
Question 1
A process in a textile mill produces high levels of heat and steam. (a)
(b)
Identify FOUR parameters that could be measured when making an assessment of the thermal environment stating in EACH case the name of an instrument that can be used to measure this parameter.
(4)
Outline the ways of reducing thermal stress amongst employees in the textile mill, with reference to both the thermal environment AND other controls.
(6)
In identifying parameters that should be measured in making an assessment of the thermal environment and the instrumentation to be used, candidates should have referred to parameters such as ambient temperature ( mercury or alcohol thermometer), air velocity (anemometer or kata thermometer), relative humidity (hygrometer) and radiant heat (black globe thermometer). For part (b), candidates should have outlined ways of reducing heat stress such as the reduction of heat output at source; the use of barriers or screens to shield workers from sources of radiant heat; providing adequate ventilation and de-humidifying the working area to counteract the effects of steam; breaks away from the hot working environment; job rotation and the use of adequate numbers of employees to reduce the work rate; and the provision of training on the possible effects of working in such an environment and the control measures to be adopted. General welfare considerations would include preemployment screening of individuals (looking particularly at vulnerable groups); the gradual acclimatisation of new employees to the environment; the provision of suitable clothing (cool, loose, low clothing indices) and the provision of adequate fluids (water, isotonic).
Question 2
A company is considering substituting a solvent it currently uses for one that is thought to be more effective. Outline the health and safety information that should be evaluated before a decision is taken to make the change.
(10)
In answering this question, candidates were expected to outline the information that would enable a comparison to be made between the risks from the proposed substance with those of the existing one. Much of this information might be gained from the manufacturers’ safety data sheets for both substances. Specific information on the proposed substance would relate to: the physical form of the substance (eg whether aerosol or liquid); the possible routes of entry of the substance into the body; its flammability and volatility; its short and long term health effects; applicable exposure limits such as WELs; the quantity of the substance that would be used; the number of persons likely to be exposed and the level and frequency of their exposure; personal susceptibilities of those involved with particular reference to employees who might be especially vulnerable such as young persons or employees with a liver or heart condition; additional control measures that might be required; storage arrangements; and the procedures that might have to be introduced for the disposal of the substance and for dealing with any emergency.
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Question 3
(a)
(b)
The risk of contracting Leptospirosis is a concern to users of a local water sports centre. Provide advice to these users which outlines: (i)
the ill-health effects associated with this disease;
(2)
(ii)
why users might be at risk.
(2)
Outline the practical steps that the centre’s instructors can take to minimise the risks to themselves.
(6)
In most cases the infection causes a flu-like illness with severe headaches and pain in the lower back, and legs. Other symptoms include fever, vomiting, abdominal pain, skin rashes, and conjunctival haemorrhage. The severe form of the disease (called ‘Weil’s Disease’ after the doctor who first identified it) causes jaundice and liver damage. The most common carriers are rats. It is generally assumed that across the developed world, 1 in 5 wild rats are carriers of pathogenic leptospires. Rats live in close proximity to water and they are incontinent. Carrier-state rats emit bacteria in their urine, and this is distributed everywhere they go. Normally this is inactivated once it dries out, but if it enters water the bacteria can remain viable for longer periods. The bacteria can then enter the windsurfers’ bodies via cuts to the skin, nose, mouth or other mucous membranes. In the scenario set out in the question, practical steps that can be taken involve preventing the bacteria getting into the body. These include measures such as maximising dry training (to limit the potential contact time); showering after being in water and washing hands thoroughly before eating; avoid swallowing water; wearing protective footwear and minimising skin contact by wearing a full-body wet suit; protecting all existing cuts and abrasions with waterproof dressings; seeking medical advice and treatment for any cuts or bites received whilst in the water (advising their doctor of their occupation to aid in early diagnosis); washing down equipment and wet suits and reporting any sighting of rats to ensure effective rodent control in and around the water.
Question 4
Operatives on a food manufacturing production line have to pick up rectangles of pasta from a delivery conveyor and place them into foil trays on a separate conveyor. This involves 8 hour shifts and is carried out standing in front of the conveyor. Following complaints from a number of employees about pains in their arms and shoulders you have been asked to carry out an ergonomic risk assessment for this operation and make recommendations. (a)
(b)
Outline the ergonomic risk factors to be taken into account when making such an assessment, indicating how these may be contributing to the problems experienced by the employees in this situation.
(5)
Total automation of the process is not possible. Suggest other control measures that could be taken to reduce the ill-health effects being experienced by employees.
(5)
In carrying out an ergonomic risk assessment of the operation described in the scenario, the factors that would need to be taken into account include the repetitive nature of the task involving frequent movements of the upper body to pick up the pasta and place it in foil trays; the continuous nature of the operation over an eight hour shift; the posture adopted by the operators including standing and reaching from one conveyor to another; the expected work rate and the speed of the conveyors; the height of the conveyor in relation to that of the employees and the total pattern of continuous work with the number and length of the breaks allowed.
13
In answering the second part of the question, candidates were expected to suggest control measures such as adjusting the height of the conveyors and re-positioning them in parallel; arranging the work so that it might be carried out from both sides of the conveyor to prevent over reaching; providing seating for the operators to enable them to change their position from time to time; reducing the speed of the feed conveyor; introducing job rotation with other less demanding tasks; providing information to the employees on the benefits of changing their posture and stretching on a regular basis; encouraging them to report any problems that might arise and carrying out pre-employment health screening to determine existing problems which might make applicants unsuitable for the task.
Question 5
Outline the factors to consider when undertaking an assessment on the moving and handling of patients in a hospital.
(10)
This question called for an application of the main elements of a risk assessment on manual handling to the given scenario and good answers, therefore, provided a structured outline based on the main headings of task, load, individual and environment. Elements of the task that should have been considered included the need for stooping, twisting or taking up extreme postural stances when physically assisting patients to take a bath or in pushing wheelchairs and lifting stretchers; the need for frequent or prolonged physical effort influenced by the length of the shift or the number of patients involved; working at different levels when transferring patients from beds to trolleys; and the potential increased risk when working alone, particularly in coping with an emergency situation. Lack of lifting aids could additionally exacerbate the level of risk. One of the main issues in manual handling for health workers is that the load is usually a human being and this results in risks such as the heavy weights involved which may be difficult to estimate; the risk of the patient fainting or collapsing presenting a shock load; the fact that the patient may be unwilling to be assisted and may struggle or be violent; medical equipment may be attached to the patient making handling more difficult; and problems that may arise in handling patients who may be physically frail or in pain. There is additionally the ever-present risk of infection. In terms of environment, risks that can arise include space constraints for example caused by equipment around beds or the restricted space in an ambulance and the hazard of tripping and falling caused by the condition or nature of floors. Particular individuals may be at risk where they have not been trained to lift human loads, where they may not be physically capable of carrying out such a task and where there may be issues with unmatched team handling.
Question 6
(a)
(b)
Outline, using a relevant example, why and how a retrospective case control study is carried out.
(5)
Outline factors that affect the reliability of this type of study.
(5)
In answering part (a) of this question, Examiners were looking to candidates to outline that a retrospective case control study is carried out to look for a link between cause (exposure) and effect (disease) and to determine if there is a dose/response link. The method involves the use of two groups, one with the disease and one without. The study starts at a point in the past and follows the first group forward in order to determine past exposure histories to a certain substance using records of employment, medical records and interviews to collect data. These are compared with the control group who do not have the disease. Relevant examples would involve exposure to asbestos or silica.
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For part (b), candidates could have referred to factors such as the size of the group; the availability and accuracy of historical data on exposure and health effects; the accuracy of diagnosis and of the recall of the individuals concerned; the fact that non-occupational exposure may have occurred; life-style factors such as diet, smoking and the consumption of alcohol may have contributed to the current ill-health; the possibility of selection bias in that the group may not be representative of the exposed population; and the possible effect of other occupational exposures.
Section B – three from five questions to be attempted
Question 7
A distribution company employs 300 employees as drivers, warehouse operatives and office staff, processing telephone and internet orders. (a)
(b)
Identify the possible functions of the company’s occupational health department in this particular company: (i)
when recruiting new employees;
(4)
(ii)
when an employee returns to work after ill-health.
(5)
Outline other ways in which the occupational health department can assist the management team to improve health and safety within this organisation. (You do not need to consider those functions you have already addressed in part a).
(11)
During the recruitment of new employees, the occupational health department would have an important part to play in carrying out screening of the applicants and reviewing their health history so that they might be in a position to advise management on their suitability for employment. In particular they would need to check the fitness and ability of potential warehouse staff to undertake manual handling tasks, check the eyesight of applicants for positions as drivers whether of road or internal vehicles and also screen them for evidence of the possible misuse of alcohol or other substances. Additionally it would be important to carry out eyesight tests on those who would be employed in the office to use display screen equipment. As for those employees preparing to return to work after a period of ill-health, an assessment of their current health condition would enable recommendations to be made to management on whether the return should be phased or whether the employee should be redeployed on other or lighter duties. This would necessitate liaison with the employee’s medical practitioner and where necessary arranging for or even providing rehabilitation treatment in house. In answering part (b), candidates were expected to outline other ways in which the occupational health department could assist management in improving health and safety in the organisation such as maintaining health records of employees and carrying out monitoring of sickness absence; providing first aid treatment and training for employees appointed as first aiders; providing information and advice to employees on weight management, exercise and smoking cessation; undertaking health surveillance; providing training in manual handling and the management of stress; providing an input to the development of policies and procedures and participating in management team meetings and meetings of the health and safety committee; making a specialist input to risk assessments and liaising with the enforcement authority on health issues.
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Question 8
A slightly corrosive solution is used as a treatment in part of a manufacturing process. The solution is applied by hand brushing. Other methods of application have been found to be impracticable. (a)
(b)
(c)
Outline the factors that should be considered in the selection of personal protective equipment (PPE). The equipment should ensure that the skin and the eyes of those involved in the process are adequately protected.
(10)
Identify the content of a training programme that will assist employees to use the PPE correctly.
(5)
List a range of practical measures (other than training) that can be taken to encourage the use of the protective equipment and maintain its effectiveness.
(5)
In answering part (a) of this question, for the selection of protective gloves, candidates should have considered factors such as: the appropriate chemical resistance for the solution and the chemical breakthrough time; the length of time the gloves can be worn before they require replacing; the level of dexterity required for the task; the length of glove for adequate protection; durability of gloves; ensuring a suitable range of sizes for the various users is available; and any allergies to the glove material or other skin problems. In the selection of eye protection, candidates should have considered: the risk of splashing the face as well as eyes; the use of goggles or a face shield (rather than spectacles) with the appropriate level of chemical resistance; and its compatibility with other PPE (if required). In the selection of body protection, it would be important to insist on chemical resistant aprons, overalls and appropriate footwear. Good answers would have concluded by considering factors such as consultation and user trials; comfort factors; the ease of maintenance; storage requirements and compliance with appropriate standards and ILO guidance. Good responses to the second part of the question would have identified that employees should receive training prior to the issue of the equipment in topics such as: the health risks of the chemical; the protective equipment to be used and the reasons for its use; the method of putting on and removing P PE without contamination, including decontaminating or discarding of gloves after use; the danger of contaminating other parts of the body whilst wearing gloves; how to examine PPE for damage or degradation (particularly gloves) and how to report any defects and obtain replacements; how to store the PPE correctly; and training in self examination of the skin and action to take if any problems occur. For the third part of the question, candidates were expected to list other practical measures to encourage the use of PPE such as: management leading by example; staff being involved in the selection; ensuring a range of sizes of gloves is available and that shields are fully adjustable; employees signing for PPE and maintaining records of issue; providing adequate storage facilities; the personal issue of PPE; the use of propaganda, signs and posters; supervision and monitoring of use; measures to be taken for non-use (eg disciplinary); and monitoring the effectiveness of PPE.
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Question 9
You have been asked by the Board of a multi-national bank to provide advice on occupational stress. Prepare a briefing note for the Board of the bank that describes: (a)
(b)
the sources of information that may be used to assess the risk of high levels of stress;
(8)
the occupational factors that can contribute to the incidence of stressrelated problems amongst bank employees.
(12)
For part (a), sources of information could have included: face-to-face discussions between staff and line managers or supervisors, either informally or formally at, for example, performance appraisal reviews; discussions at safety committees or team briefings; sickness and/or absence data and return-to-work interviews; formal or informal complaints; staff turnover data and exit interviews; the use of a structured staff questionnaire with the appropriate analysis; and published external guidance and standards. For part (b), candidates were asked to describe the occupational factors that could increase the probability of stress occurring and apply them to a bank scenario. Good answers described and applied factors such as: the demands of the job (for example work overload or underload, monotony, poor physical environment, threat of violence); the amount of control that staff have over the way they carry out their work (citing lack of communication and consultation, autocratic management style); the degree of support offered by the organisation, management and colleagues; work relationships (eg bullying, harassment, mistrust); role (conflict, lack of clarity, etc); and the mismanagement of organisational change leading to insecurity. Better answers would have drawn particular attention to issues relevant to the banking scenario, such as the need to work with difficult members of the public and the threat of violence.
Question 10
A&B Printing Ltd operates a number of large printing machines producing magazines for the retail trade. They recognise that exposure to noise is a problem for all operatives within the open plan print workshop and so the company plan to undertake a noise survey. (a)
(b)
Identify the different types of equipment that could be used to measure exposure to noise, making reference to their respective features and roles in assessing noise exposure.
(10)
Following the noise survey the company decide to fit an acoustic enclosure to one of the large printing machines. Outline the design features of such an enclosure.
(10)
Part (a) of the question was designed to assess candidates’ understanding of the instrumentation that could be used in the assessment of noise in the workplace. An answer including the roles and capabilities of simple sound pressure level meters (SLMs), integrating meters and personal noise dosimeters was expected with reference being made to the working environment in which they might be used such as relatively constant or fluctuating noise levels or for peripatetic workers and their contribution to, and accuracy in, measuring or assessing Leq and LEP,d. Credit was also available for dealing with other related issues such as calibration, the use of an octave band filter set on SLM and integrating meters for assessing hearing protection adequacy and engineering noise control, the use of a type of SLM appropriate for the degree of precision required, the use of peak noise functions and response time issues and the training needs of users.
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For part (b), Examiners expected candidates to outline design features of an acoustic enclosure such as: the need for it to be of double skin construction with the walls and top being made of sound insulating material, robust enough to withstand the working environment; double glazing to be fitted where windows were considered to be essential and flexible connectors used in pipes and ducts leading into and out of the enclosure to form vibration breaks. Additionally, the enclosure should be effectively sealed at floor level, the internal surfaces lined to prevent reverberant build up, any ducts into the enclosure lined with absorptive material and if ventilation of the enclosure was required, it might be provided by means of acoustic louvers. The printing machinery would need to be mounted on dampers, with operating controls situated on the outside of the enclosure and the material entry and exit points sound-proofed. Finally, removable panels would need to be fitted to the enclosure to provide access for maintenance.
Question 11
Describe, with the aid of diagrams, the features and principles of operation of sampling equipment that could be used to collect the following airborne contaminants for subsequent quantitative analysis in a laboratory: (a)
total inhalable dust;
(5)
(b)
respirable particulate;
(5)
(c)
organic solvent vapour;
(5)
(d)
asbestos fibres.
(5)
This question required candidates to describe sampling equipment that could be used to collect four types of airborne contaminants. Total inhalable dust is dust taken into the respiratory system. The description and diagram should have shown how it could be collected by attaching the sampling device to a sampling pump that provides a controlled flow. The sampling device has a pre-weighed filter to collect contaminants with the filter being re-weighed at the end of the sampling period. Types of sampling head that may be used include the single hole, seven hole or IOM sampler. An alternative sampling device such as a parallel plate elutriator could have been provided as an answer. Respirable dust is made up of particles which may reach the alveoli of the lungs (eg <7/10µm). The description and diagram for part (b) should have shown collection of respirable dust by a cyclone that by its construction or design separates the respirable fraction from the rest of the total inhalable fraction. The sampler uses a controlled flow rate sampling pump and the filter is subsequently submitted for quantitative analysis. The description and diagram for part (c) should have shown the collection of organic solvent vapour by grab samplers (eg gas bags), a liquid impinger or adsorbent tube eg charcoal, tenax, silica gel, used with a controlled low flow rate sampling pump. A passive sampler could also have been illustrated and described. The description and diagram for part (d) should have shown the use of a cowled sampling head connected to a controlled flow sampling pump with the asbestos fibres being collected on a gridded membrane filter which can be cleared after analysis.
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UNIT IC – International workplace and work equipment safety
Section A – all questions compulsory
Question 1
Outline: (a)
the factors affecting the likelihood of an agricultural tractor overturning;
(6)
(b)
the measures that may be necessary to minimise the risk, or limit the effects, of a tractor overturning.
(4)
For part (a) candidates should have referred to factors affecting the possibility of overturning such as the angle of slope and direction of travel on gradients; uneven or soft ground; speed on cornering; wheel width; the condition and pressure of tyres; the effects of trailers and other attachments including power take-off seizure and the level of competence of the driver. In their answers to part (b) candidates were expected to outline measures such as seat restraints and roll-over protection to mitigate the effects of an overturn. Other appropriate measures to minimise the risk of tractor overturn include restricting the use of tractors on steep gradients; fitting counterbalance weights; fitting wider tyres and maintaining them on a regular basis; fitting a power take-off torque limiter such as shear pins and providing training for drivers.
Question 2
With the aid of labelled sketches, outline the characteristic features of, and factors that promote, the following types of materials failure: (a)
brittle failure;
(5)
(b)
ductile failure.
(5)
For this question, candidates were expected to outline with the aid of labelled sketches, the characteristic features of and factors that promote brittle and ductile fractures. A brittle fracture generally occurs without warning or prior evidence of distress. It is a crystalline structure failure with minimal plastic or elastic deformation. There are generally characteristic “chevron” marks from the point of initiation and the failure is sudden from rapid stress loading. The factors promoting a brittle fracture are high tensile stresses, residual or locked in stresses, sudden loading which does not give the material time to deform plastically, case hardening, low temperatures and the degree of brittleness of the material. A ductile fracture generally has a smooth fracture surface with plastic deformation of the material before final fracture. There is evidence of necking and the final fracture is often brittle because there is insufficient material left to sustain a load. This type of failure generally occurs as the result of a single stress overload though other promoting factors include high temperatures, cold work hardening and the plasticity of the material.
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Question 3
(a)
Outline the principles of an interlocked machine guard.
(4)
(b)
Outline the principles of operation of trapped key control systems.
(6)
For part (a), Examiners were looking for answers that included the fact that an interlocked guard is linked to the machine controls by mechanical, electrical, hydraulic or pneumatic means. The principles of operation are that the machine cannot become dangerous when the guard is open and, when the machine is in an otherwise dangerous condition, either the guard cannot be opened or opening the guard causes the machine to become safe. In answering part (b) candidates may have become confused between a captive key system and a trapped key system. In the first case, as the name suggests, the ‘key’ is at all times held captive in the guard locking mechanism that incorporates an electrical switch connected to the power supply to the machine. It is therefore necessary to turn the key to open the guard and this has the effect of switching off the machine (often in a two-stage process). With a simple trapped key system, the guard lock and the switch connected to the power supply to the machine are separate. The key is removable but is held in the guard locking mechanism until the guard is closed. On locking the guard, the same key can then be transferred to the switch to allow power to the machine. While power is on, the key is held in the switch.
Question 4
The residents of a village have recently been affected by a fallout of dust on their cars and property. They allege that the dust came from cement works situated a few miles away. Outline the steps that should be taken by those responsible for the cement works in order to investigate whether emissions from the works are the cause of the problem.
(10)
This question presented a scenario involving allegations of dust contamination from residents of a village situated a short distance away from a cement works. It involved a typical investigative process which would deal with the factors to be examined in order to confirm or dismiss them. In order to investigate whether the dust causing the problem emanated from the cement works, management would first need to carry out a desk study involving contact with the residents and a research into historical records, weather patterns, possible links with the prevailing wind direction and the existence of other potential sources of dust in the area. They would need additionally to check the plant for obvious faults and carry out continuous monitoring of the emissions on site together with off site background monitoring. Analysis of dust collected from the village would also help to establish whether it matched that produced at the alleged source.
Question 5
With examples of actual incidents, describe the principles and effects of a vapour cloud explosion.
(10)
A vapour cloud explosion may be confined for example in a tank or vessel or unconfined. Its key principles include the presence of flammable vapour at a concentration between the upper and lower explosive limits and an ignition source that exceeds the minimum ignition energy. Unconfined vapour clouds may travel a considerable distance before igniting or they may be dispersed to a concentration below the lower explosive limit depending on conditions. The effects of vapour cloud explosions include overpressure, thermal effects and the emission of debris. In confined explosion cases, vessel or containment rupture may occur resulting in a rapid release of liquefied gas. In unconfined explosion cases, damage to people and property may be caused by the pressure wave and thermal radiation. Suitable examples could have included Flixborough 1974, Abbeystead 1984, Grangemouth 1987 and Buncefield 2005. 20
Question 6
Outline the issues that should be included in a fire safety training session for employees.
(10)
This question was concerned with the issues to be covered in a fire safety training session for employees which would include: the principles of the fire triangle; the basic elements of fire prevention such as the storage of flammable materials, good housekeeping and the need to prevent the accumulation of rubbish; the action to be taken on discovering a fire such as raising the alarm, the procedure for calling the fire service and the action to be taken by personnel on hearing the alarm; the location and use of fire fighting equipment with practical training for selected employees; the escape routes and exits from the premises together with the assembly points and the roll calls that would have to be carried out; the arrangements for the evacuation of people with disabilities and for assisting visitors and members of the public; the identity and role of fire wardens and marshals; the importance of fire evacuation practices and drills and issues directly concerned with personal behaviour such as refraining from re-entering the building after evacuation until instructed to do so.
Section B – three from five questions to be attempted
Question 7
Outline the advantages and limitations of the following types of fall protection devices, giving a suitable application for each: (a)
safety harnesses;
(5)
(b)
safety belts;
(5)
(c)
safety nets;
(5)
(d)
air bags.
(5)
This question required candidates to outline the advantages and limitations of four types of fall protection devices and to indicate a suitable application for each type. Safety harnesses may be used in high fall potential areas where full arrest is required when carrying out short duration work when it would be impracticable to provide more sophisticated measures. Their limitations include the need for secure anchoring points, their restrictions on movement, their requirement for trained and competent users and the fact that they provide individual protection only. A suitable application for this device would be in general construction work. Safety belts, too, can be used in high fall potential areas for short duration work where the provision of more sophisticated measures would be impracticable. However, this device offers restraint rather than fall arrest, again requires anchoring points, provides individual protection only and may need to be supplemented with collective measures. A suitable application for this device would be to gain access to a pole or pylon. The advantage of safety nets is that they can provide collective protection (for the fall of persons and materials) for long term work where full arrest is required. Their installation, however, takes time and needs to be undertaken by competent persons. They can be used only in low to medium fall potential areas. They are most suitable for use over water or under fragile roofs. Finally, air bags can provide collective protection for falls and have the advantage of being available in different sizes. They do, however, provide only small areas of protection, need installation by competent personnel, require a continuous power supply and may be used only in low fall potential areas such as short run construction projects or around workplace transport. 21
Question 8
Outline the design features and procedural arrangements that may need to be considered in order to minimise risks associated with movement of vehicles in the workplace.
(20)
In outlining the design features that should be considered in order to minimise risks associated with the movement of vehicles in the workplace, candidates should have referred to matters such as the provision of traffic routes with a smooth and stable surface and of sufficient width and headroom for the types of vehicle that will use them; the elimination of sharp bends, blind corners and steep gradients with the siting of convex mirrors on those corners that cannot be avoided; the installation of a one way system to minimise the need for reversing; the inclusion of passing places for vehicles; the introduction of speed limits and the provision of speed retarders; the provision of a good standard of lighting for the routes and particularly for the transition areas between the inside and outside of buildings; the segregation of vehicles and pedestrians including separate access and egress and the provision of clearly marked crossing places. As for procedural arrangements, they would include the selection and training of competent drivers who would be subjected to regular health screening; the provision of information on site rules for visitors including drivers visiting the site; the introduction of procedures for the regular maintenance both of the traffic routes and of in-house vehicles and for the reporting of defects; the rigorous enforcement of speed limits and the provision and use of high visibility clothing by employees working in close proximity to traffic routes.
Question 9
With respect to an electricity supply operating at 240v: (a)
(b)
(c)
outline the factors that determine the severity of the effects of an electric shock.
(6)
For each of the following protective devices describe their principles of operation: (i)
residual current devices;
(3)
(ii)
fuses;
(3)
(iii)
110v centre tapped to earth reduced voltage systems.
(3)
Outline other design features of electrical systems intended to improve safety.
(5)
In answering part (a) of this question, credit was given for reference to factors including the voltage, the nature of the current (whether alternating or direct), the body resistance of the individual with reference to age, gender, the amount of moisture (perspiration) on the body and the type of footwear worn, the route taken by the current through the body, the speed of action of any protective measures and the environmental conditions, such as the floor material and the presence of water. Knowledge of Ohm’s Law was useful in relating the size of current to voltage and resistance. In answering part (b), candidates were expected to describe that a residual current device is designed as a shock limiting device and not for system protection. It operates on an earth leakage fault. Any differential in the current passing through the line (neutral) and phase (live) conductors is detected, operating a switch to cut off the electrical supply to the apparatus and preventing severe electric shock. The device should operate within 30 to 50 milliseconds of the fault being detected.
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A fuse is a device placed in the live side of a circuit, designed to cut off automatically the power supply to the circuit within a given time when the current flow in the circuit exceeds a given value and produces sufficient heat to melt the fuse which is designed to do so at a predetermined temperature. It prevents the overload of an electrical system and overheating of electrical wiring. However, its speed of operation is generally too slow to protect people from electric shock. One of the better ways of reducing the risk from electricity is to reduce the voltage, achieved by the use of a step down transformer. A common reduction is to 110 volts and a transformer used to attain the reduction is described as centre tapped to earth in that the secondary winding of the transformer is earthed to its centre thus ensuring that the maximum voltage from live to earth involved in an electric shock will be 55 volts. For part (c), candidates could have outlined other design features intended to improve safety such as the selection of suitable cables and placing them out of reach wherever possible; the provision of effective means of isolation to ensure the secure disconnection and separation of electrical equipment from every source of energy; the use of earthed systems and Class 1 equipment or double insulated Class 2 equipment; the use of circuit breakers and the introduction of earth free zones.
Question 10
As part of its water treatment system, a manufacturer is to install a plant suitable for the reception and storage of a strong acid and a strong alkali, both of which will be delivered in bulk tankers. Outline the safety provisions required for the design, operation and maintenance of the proposed plant.
(20)
Candidates who divided the question into its component parts, ie design, operation and maintenance and dealt with the detail of these issues in turn achieved more success. Under the design issues, it was expected that candidates would deal with the need for the storage tanks and pipe work to be constructed of suitable chemical resistant material; the design and positioning of the delivery inlets to prevent connection being made to the wrong tank; the positioning of the storage tanks in separate bunds with the bunds being capable of holding the entire contents of the tanks plus 10%; the erection of hazard warning signs clearly identifying the contents of the tanks and the colour coding of pipework; the fitting of level indicators and high level alarms to prevent overfilling; the provision of good vehicle access including a hard standing for tankers with facilities for spill containment and the provision of a good standard of lighting. Operational issues should have included the introduction of a safe system of work including emergency procedures to deal with spillages and the provision and maintenance of a contingency supply of neutralising and absorbent materials and water; providing training for the personnel involved including tanker drivers in the risks associated with the operation and the control measures to be followed and the provision of personal protective equipment such as chemical suits, chemical resistant gloves and full face protection. In outlining the issues connected with maintenance, candidates were expected to refer to the arrangements for the examination and testing of safety critical plant; the use of permit to work systems; the completion of the flushing out of tanks and pipe work and their isolation before the start of maintenance work; regular cleaning of the bunds and the provision of training to maintenance staff in emergency procedures.
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Question 11
(a)
(b)
Organisations may use a range of reactive and proactive strategies for plant maintenance. Identify FOUR possible plant maintenance strategies AND outline the principles of EACH strategy.
(10)
Outline the factors that you would advise the Engineering Department of an organisation to take into account in deciding on a maintenance strategy following the installation of an item of process plant.
(10)
In answering part (a), candidates could have identified strategies such as planned preventive maintenance (P PM), breakdown maintenance, condition monitoring and emergency maintenance. The principles of PPM include the need for planned maintenance and parts replacement set against a schedule of time or running hours and driven by a record keeping system. Breakdown maintenance, being reactive, means that maintenance is undertaken in response to reports of malfunction of equipment and the maintenance activity is not required whilst the plant continues to operate effectively. Condition monitoring requires monitoring of specified parameters, (for example, vibration levels or metal content of cutting fluids, etc); specifying the level of each parameter when maintenance work needs to be undertaken and measuring continuously or to a schedule. Emergency maintenance includes maintenance undertaken to prevent more serious consequences such as reinforcement to prevent failure or the use of temporary supports to prevent collapse. For part (b), candidates could have outlined factors such as statutory requirements including examples of the types of work equipment involved such as cranes and air receivers, and the cost benefit analysis of P PM versus breakdown including the availability of spares, competent staff, and the expected life-time of equipment. Additional factors that could have been included in the advice to the Engineering Department are the outcome of risk assessments in terms of failure probability and consequences; the history of failure with example sources such as incident reports and maintenance data; any relevant manufacturer’s data or recommendations for the plant; the extent of and / or conditions of use; the opportunity for downtime and the integration with existing systems such as condition monitoring.
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