Feedback from Examiners NEBOSH Internat ional Diploma in Occupational Health and Safety July 2007 examinations
CONTENTS
Introduction
Unit IA – International management of health and safety
3
Unit IB – International control of hazardous agents in the workplace
8
Unit IC – International workplace and work equipment safety
13
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Introduction The results from the first three Unit examinations of the International Diploma resulted in pass rates of 43%, 45% and 43% (Units A, B and C respectively). Comments from Examiners suggest that some candidates were simply unprepared for the level of the Diploma and showed both a lack of knowledge of key material (theoretical, technical and/or legal issues) and a lack of understanding of how the concepts should be applied to often complex situations. This Report provides some pointers in this respect but the onus for acquiring the level of knowledge and understanding required must rest with the student, with the help and support of course providers. On a positive note, while Examiners’ Reports 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. Such effort does not go unrecognised.
2
UNIT IA – International management of health and safety
Section A – all questions compulsory
Question 1
The accident rate of two companies of similar size and producing identical products is found to differ. Explain possible reasons for this difference.
(10)
Most candidates considered ‘real’ differences (in terms of safety management issues) and apparent differences, caused by variations in levels of reporting and in calculating rates. Candidates should also have suggested additional reasons such as differences in workplace layout and the age and type of the equipment used, and human resource issues such as the selection, training and competence of the workforce together with the possible difference in the companies’ level of communication and consultation with the staff.
Question 2
The reliability of a safety critical system depends on a single component. (a)
Outline ways of reducing the likelihood of failure of the component.
(4)
(b)
Describe additional ways to increase the reliability of the safety critical system.
(6)
In answer to this question, candidates were expected to explore the range of techniques that could be used to improve the reliability of both the component and the system in the circumstances described. This should have included such issues as: burning-in; planned replacement before wear-out; planned maintenance; component design, material specification and quality assurance; use of parallel components and standby systems or redundancy; operational and protective systems to maintain the system within its design specification; use of hazard analysis techniques to predict failure routes; and the collection and use of failure data.
Question 3
(a)
Define the term ‘safety culture’.
(2)
(b)
Outline a range of organisational issues that may act as barriers to the improvement of the safety culture of an organisation.
(8)
For part (a), most candidates were able to define the term “safety culture” referring to the shared attitudes, perceptions, beliefs, behaviour patterns and values that members of an organisation have in the area of health and safety. In answering part (b), candidates were expected to outline organisational issues that could act as barriers to the improvement of the safety culture of an organisation such as the lack of senior management commitment; a failure to allocate adequate resources to support improvement; the absence of effective means of communication with employees to secure their involvement; high staff turnover making cultural improvement difficult to embed; a history of poor industrial relations; the existence of a blame culture and the lack of positive decision making by management on the level of priority accorded to health and safety leading to uncertainty among the workforce.
3
Question 4
‘Perception’ may be defined as the process by which people interpret information that they take in through their senses. Outline a range of factors that may affect how people perceive hazards in the workplace.
(10)
There are many factors that can affect the way that hazards are perceived in the workplace such as sensory impairment or health status; intelligence and/or mental capability; the effect of drugs or alcohol; the nature of the hazard which may not be readily detectable; environmental factors that may distract or confuse such as noise or poor lighting; interference by the use of personal protective equipment; the effect of inadequate information and training; the presence or absence of previous experience of, or exposure to the hazard; the effect of expectation following exposure to similar situations; and sensory overload, work pressures, stress and fatigue.
Question 5
An organisation has decided to adopt a self regulatory model for its health and safety management system. Explain the: (a)
benefits;
(6)
(b)
limitations,
(4)
of self regulation in connection to the management of health and safety. The benefits of an organisation adopting a self regulatory model would include that it can be developed by those who understand the organisation; it can be quicker to achieve than compliance with statutory regulation; it can generate a sense of ownership which in turn can result in higher levels of compliance and it can be easily adapted or updated. The limitations of an organisation adopting a self regulatory model would include that all those involved may not operate within the self-regulatory rules; there is a danger of self interest being put ahead of employee and public interest; there is no third party or independent auditing to provide an objective view and a self regulatory model can ultimately result in it not being valued highly by stakeholders.
Question 6
Outline, with examples, the benefits and limitations of: (a)
prescriptive legislation
(5)
(b)
goal-setting legislation.
(5)
The merits of prescriptive legislation are that its requirements are clear and easy to apply, it provides the same standards for all and it is not difficult to enforce. Its limitations are that it is inflexible, may be inappropriate in some circumstances by requiring too high or too low a standard and may need frequent revision to take account of changes in technology and knowledge. The merits of goal-setting legislation, on the other hand, are that it has more flexibility in the way that compliance may be achieved, it is related to actual risk and can therefore apply to a wide variety of workplaces, and it is less likely to become out of date. These are countered by the fact that it may be open to wide interpretation and the duties it lays and the standards it requires may be unclear until tested in courts of law. As a result it may be more difficult to enforce and may require a higher level of expertise to achieve compliance.
4
Section B – three from five questions to be attempted
Question 7
As the Health and Safety Adviser to a large organisation, you have decided to develop and introduce an in-house auditing programme to assess the effectiveness of the organisation’s health and safety management arrangements. Describe the organisational and planning issues to be addressed in the development of the audit programme. You do not need to consider the specific factors to be audited.
(20)
This question was designed to examine candidates’ understanding of the organisational and planning issues to be addressed in the development and implementation of an audit programme, an important challenge for many health and safety professionals. A strategic approach was required and some of the issues that needed to be addressed included a consideration of the logistics and resources required and obtaining the support and commitment of senior managers and other key stakeholders. Other matters for consideration were the nature, scale and frequency of the auditing relative to the level of risk involved; the standards against which the management arrangements were to be audited; and the identification of the key elements of the process such as the planning, interviews and verification, feedback routes and the preparation and presentation of the final report. There would also have to be recognition of the need to develop audit protocols and consider issues such as scoring or the use of proprietary software. The types of auditing (such as comprehensive or horizontal or vertical slicing); its scope (such as management system elements or selected performance standards); the use of a single auditor or audit teams; and the training of auditors and briefing of those members of the organisation who were likely to be affected could also have been mentioned to gain marks.
Question 8
A small company producing a range of chemical products operates from a site on which it employs about 50 staff. The site poses a risk to employees, the neighbouring community and the environment. (a)
(b)
Identify the types of emergency procedure needed to deal with incidents affecting the safety of employees on site.
(5)
Identify the factors that should be considered during the development of a major incident procedure and outline the arrangements that should be in place to ensure that such a procedure is effective.
(15)
The intention of part (a) of the question was to require candidates to address the types of emergency the site might experience and the procedures that should be in place. These included chemical spillage and /or release procedures, fire evacuation, first aid treatment, and major incident procedures. Credit was also given for other credible procedures such as those required for sabotage or bomb threats. For part (b), better answers focussed first on the development of a plan and then on its implementation. Factors that would need to be considered during the development of a major incident procedure would be the level of the risk involved taking into account the nature of the chemicals, the potential rates of release, the people affected and the environmental issues involved; the existence of relevant guidance and standards and the availability of internal and external emergency resources.
5
Arrangements that could have been described include consultation with staff and contractors and external stakeholders such as the emergency services on the development of the plan; the development of clear responsibilities as part of the plan including arrangements for initiating the procedure and for the call-out of key staff and support services; the provision of a control centre containing key information and communication facilities; the provision of equipment for communication between control parties in the event of an incident; the provision of emergency equipment and personal protective equipment such as that needed for spill containment, vapour suppression and fire control; arrangements for liaison and communication with off-site residents and neighbours; press management arrangements; business continuity issues and arrangements for periodic practice and review of the procedures together with comprehensive training of site personnel particularly those with key responsibilities.
Question 9
Extensive repair work is needed to the roof of the main production area of a large factory. The factory is to remain fully operational during the work. (a)
(b)
Outline the criteria that might be used when selecting a contractor for the work in order to ensure they have the necessary competence in health and safety.
(8)
Describe the ways in which the factory management should control the work of the contractor to ensure that risks to factory employees are minimised.
(12)
In part (a) of the question, when selecting a contractor the types of criteria that might be used would include method statements / procedures, health and safety policies, health and safety performance statistics eg accident statistics, the qualifications and skills of a contractors workforce, insurance details and experience of a contractor in the type of work to be undertaken. In part (b) of the question Examiners were looking for answers that considered contract specific risk assessments; provision of separate storage areas for materials and equipment; periodic pre-planned meetings with the contractors undertaking the work; checking of statutory inspections to ensure compliance; site rules such as restricted areas for contractors and factory employees; stringent housekeeping expectations; periodic checks on contractor performance to observe if the work is being undertaken as agreed and regular reviews of the contractors’ health and safety performance.
Question 10
A business operates separate management systems for health, safety, quality and the environment. Discuss the key potential benefits of: (a)
introducing an integrated management system;
(10)
(b)
retaining the existing system of separate management systems.
(10)
The arguments for and against the use of an integrated management system for safety, quality and environmental issues will need to be considered by many practitioners at some stage during their careers. This question invited candidates to discuss their understanding of the key benefits of both an integrated system and separate systems. The benefits of an integrated management system could have included: consistency of format and a lower overall cost through the avoidance of duplication in procedural, recordkeeping, compliance auditing and software areas; encouraging priorities and resource utilisation that reflect the overall needs of the organisation rather than an individual discipline; applying the benefits from good initiatives in one area to other areas; encouraging closer working and equal influence amongst specialists; encouraging the spread of a positive culture across all three disciplines; and providing scope for the integration of other risk areas such as security or product safety. 6
Benefits from retaining separate systems could have included: providing a more flexible approach tailored to business needs in terms of system complexity and operating philosophy (eg safety standards must meet minimum legal requirements whereas quality standards can be set internally – therefore, the need for a more complex system in one element may not be mirrored by a similar need in the other two elements); existing systems may work well and the process of integration may expend unnecessary resources and affect their effectiveness; separate systems might be clearer for external stakeholders or regulators to understand and work with; and they may encourage a more detailed and focused approach to auditing and standards.
Question 11
Describe what is meant by ‘skill-based’, ‘rule-based’ and ‘knowledge-based’ behaviour. Explain in each case how these operating levels can give rise to human error and how such errors may be prevented. Illustrate your answer with reference to practical examples and actual incidents.
(20)
Where candidates addressed this question in a structured way describing each type of behaviour and following this in each case by identifying the reasons for error, key preventive measures and examples they were able to achieve good marks. So for skill-based behaviour, they should have described that it involves a low level, pre-programmed sequence of actions where employees carry out routine operations. Errors 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. Preventive measures would be directed at designing routines and controls that are distinct from each other, ensuring adequate work breaks to maintain attention and using feedback signals together with training, competence assessment and a high level of supervision. Rule-based behaviour involves actions based on recognising patterns or situations and then selecting and applying the appropriate rule set. Errors may occur where, for example, the situation is not determined correctly through lack of information, experience or training or if there is a tendency to apply the usual rule or solution even if it is inappropriate. Preventive measures include clear presentation of information, logical and easy to follow rule sets, training, practice and competence assessment and systems designed to highlight infrequent or unusual events. Knowledge-based behaviour is involved at the higher problem solving level, when there are no set rules and is based on having knowledge and understanding of the situation that may present risk. Errors will consequently occur if there is a lack of knowledge or inadequate understanding, if there is insufficient time to carry out a proper diagnosis or if the problem is not properly thought through or evidence is ignored. Preventive measures would again involve training and competence assessment, the provision of adequate resources in terms of information and time and the use of checking systems such as group or peer review.
7
UNIT IB – International control of hazardous agents in the workplace
Section A – all questions compulsory
Question 1
In your role as a health and safety advisor you have been asked to prepare a company policy on drug and alcohol misuse. Explain the key points that such a policy should include.
(10)
A drug and alcohol policy would include: a general statement of aims, responsibilities for carrying out the policy (managers, employees, occupational health counsellors etc) and who is covered by the policy (employees, contractors, visitors etc); a definition of drug misuse that includes misuse of prescription drugs as well as prohibited drugs; statement of rules such as: no lunch time drinking, with any exceptions such as religious holidays or other celebrations included; any support, or help, that will be available to employees who have a drug or alcohol problem; recognition that treatment may result in absence which will be treated as normal sick leave; statement assuring confidentiality; clear statement when disciplinary action may result eg if help is refused, and in cases of gross misconduct; the company’s response to possession or dealing illegal drugs in the workplace; and the company’s approach to drug screening.
Question 2
Outline the mechanisms by which the body may defend itself against harmful exposures to chemical substances.
(10)
This question focused on the body’s defences against harmful exposure to chemical substances, which include those with corrosive or irritant as well as toxic properties. The first lines of defence may be provided by the sensory alarms, such as the sense of smell. The skin, too, can act as a barrier to entry. Defences against corrosive or irritant substances include the production of mucus and tears, coughing and sneezing, vomiting and the inflammatory response. Where the chemical substance is in a solid form and might be inhaled as a dust, respiratory filtration, phagocytosis and tissue repair such as the formation of scar tissue provide additional lines of defence as do chemical detoxification and excretion when a substance with toxic properties enters the body.
Question 3
Hand-Arm Vibration Syndrome (HAVS) can be caused by frequent and prolonged use of hand-held power tools. (a)
Identify the symptoms of Hand-Arm Vibration Syndrome.
(2)
(b)
Describe a hierarchy of control measures that could be used to minimise the risks to employees of developing HAVS when using such power tools.
(8)
Symptoms of Hand-Arm Vibration Syndrome include: loss of feeling, numbness, tingling and dexterity in the finger tips; blanching (white finger); symptoms are generally worse during cold weather; and the condition can be progressive, affecting more fingers or parts of fingers, leading possibly to gangrene.
8
Candidates tended to focus on either organisational or technical control measures when answering this question. The best responses considered both types of control measure, relevant to the use of small hand tools and presented them in an appropriate hierarchy. Starting with: consideration of alternative work methods to eliminate the task; automating, or mechanising the work; avoiding tools that are too small and not powerful enough as these prolong the task; replacing the equipment with a lower vibration model along with regular maintenance to reduce vibration in tools and use of tools with heated handle grips to improve circulation. Organisation control measures would be to ensure the organisation’s purchasing policy takes account of vibration emissions (as well as other requirements); changing work station design to minimise loads on hands, wrists and arms for instance by use of jigs/ or suspension systems to grip heavy tools; planning work schedules to limit time of exposure to vibration; providing warm clothing and a warm environment to encourage good blood circulation; referring those experiencing early symptoms to Occupational Health as well as having a surveillance programme in place and a final control measure is to ensure that employees receive adequate information and training on risk, control and recognising symptoms.
Question 4
Outline the specific measures that a company should put in place in order to minimise the risks of ill-health associated with the use of Display Screen Equipment.
(10)
In answering this question, most candidates recognised the need to undertake an assessment of workstations and the key factors that would need to be considered in carrying out such an assessment, such as the position and size of the workstation and the suitability and adequacy of its lighting; the stability of the image on the screen and its adjustability and freedom from glare; the positioning of the keyboard with sufficient space in front of the keyboard to provide support for the hands and arms of the operator and the stability, adjustability and comfort of the seating provided. Other measures could include task rotation and for the operators to have regular short breaks taken away from the DSE workstation; supervisors carrying out monitoring of working practices to ensure that call handlers are adopting the correct posture at their workstation and are taking their scheduled breaks and the provision of user friendly software. A further important factor would be the provision of information and training for the operatives on the setting up and adjusting of their workstation; on the benefits to be gained from regular changes of posture and carrying out simple stretching exercises and on the recognition of the symptoms of inappropriate use of the display screen equipment.
Question 5
When respiratory protective equipment is in use it may not provide the level of protection stated by the manufacturer. Describe the possible reasons for this.
(10)
Examiners expected candidates to describe a range of reasons such as a reduction in battery power; the fitting of incorrect cartridges or a failure to replace them before saturation; equipment incorrectly fitted or incompatible with other personal protective equipment being worn; inadequate training in its use; poor maintenance and inadequate storage; damage occurring during use and inadequate monitoring and supervision to ensure the equipment was always used when required.
9
Question 6
A factory produces a range of painted and varnished furniture. Outline the factors to be considered when assessing the health risks to employees from exposure to solvents in this factory.
(10)
The health risks from exposure to solvents are determined initially by how the substances can enter the body (eg inhalation, skin absorption) and by the effects that they might cause (eg dermatitis, toxic effects). The physical properties of the materials (volatility in particular), the quantities used, the frequency and duration of exposure, and the work methods employed will determine the level of exposure or dose. In the scenario given, it is foreseeable, for example, that the range of painted and varnished finishes may be applied by brush or by spraying and each method will result in differing levels of exposure and therefore present different levels of risk. When making any assessment of risk it is necessary to consider who is being affected. This is in terms of the number of individuals exposed and also whether there are any individuals who are at particular risk. In this scenario, those with certain pre-existing health conditions and pregnant workers may require special consideration. An assessment of health risks needs to be based on good information. Much of this can be found in written form from manufacturers’ material safety data sheets but other sources (eg published guidance) may also need to be referred to, in particular to identify whether any of the solvents in question have been assigned exposure limits. If there are multiple exposures to different solvents, then additive effects will need to be taken into account. Synergistic effects may also be a possibility, although more difficult to determine. Analysis of health records and recorded incidents of ill-health will also form part of a proper assessment. Finally, the assessment should consider existing control measures in terms of their nature and adequacy. However, this is only one issue amongst a wide range of other risk factors.
Section B – three from five questions to be attempted
Question 7
(a)
Identify THREE different workplace situations where ionising radiation may be encountered AND state the source of the radiation.
(3)
(b)
Describe the possible health effects from exposure to ionising radiation.
(5)
(c)
Outline the control measures that should be in place when persons may be exposed to ionising radiation at work.
(12)
In part (a) most candidates were able to identify the likely workplace scenarios where ionising radiation may be encountered and the source of such radiation. In (b) the possible health effects from exposure to ionising radiation include burns, dermatitis, cataracts, cell damage, sterility, genetic defects and cancer. The control measures that should be in place when persons may be exposed to ionising radiation at work include control areas with written local rules, the exclusion of vulnerable groups eg young persons and pregnant women, the use of sealed sources of radiation, reduction of time of exposure, the use of glove boxes, shielding of an appropriate type, no eating and drinking in work areas and good personnel hygiene to prevent any further contamination. Further controls would be provision of PPE eg gloves, laboratory coats and overshoes, training in the health risks associated with ionising radiation and health surveillance.
10
Question 8
A noise assessment carried out at a manufacturing plant has revealed that personnel, working in the vicinity of machinery, are exposed to noise levels in excess of acceptable limits. It has been decided to investigate engineering methods of reducing noise exposures. Explain the purpose and design features of: (a)
an acoustic enclosure
(10)
(b)
an acoustic haven.
(10)
Most candidates were able to differentiate correctly between an enclosure and a haven – with one intended to keep noise in and the other to keep noise out. For part (a), candidates were expected to explain that the purpose of an acoustic enclosure is to surround the source of noise so as to contain it to a point which complies with any relevant statutory requirements. The design and construction requirements should include references to the walls and top of the enclosure being of heavy sound insulating material of double skin construction, the use of double glazed windows, flexible connectors in pipes and ducts to form vibration breaks and vibration mounts for services through the enclosure. Internal surfaces should be adequately lined to prevent reverberant build-up, gap stopping through effective sealing at floor level by the use of felt pads, any ducting into the enclosure to be lined with absorptive material and the use of acoustic louvers for ventilation. Access for maintenance should be considered in the form of removable panels or compression latches. The inner and outer skins must be able to withstand the working activities and not be affected by the environment and material entry and exit points should be sound-proofed. Further requirements could have included the correct materials being chosen to suit the frequency analysis of the noise emission, the acoustic balancing of different parts of the enclosure ie windows and walls and the use of exterior controls to eliminate personnel. In part (b) the purpose of an acoustic haven is to afford operatives a place of relative quiet in order to reduce their exposure time in a noisy environment to a point which is below any statutory requirements and to minimise the need for the use of hearing protection. The essential design features include construction from a soundproof material, sealed at the joins, base and around the doors; measures to avoid vibration transmission; the provision of adequate lighting and means of communication with those outside the haven; means of avoiding heat build-up; the provision of adequate visibility where needed with double glazed windows and a sound construction to withstand the environment in which it is sited (for example, fork lift trucks may be operating in the area).
Question 9
Draft a report to the Board of Directors of a large chemical processing company which outlines the role and functions that an occupational health service could have within the company.
(20)
The report to the Board of Directors should have included reference to medical examinations undertaken in relation to workplace hazards such as pre-employment health screening, health surveillance, examination of persons exposed to specific health hazards involving skin examination, audiometry, lung function tests and blood lead levels, and immunisations, for example, for hepatitis B. Additionally, it should have been noted that the occupational health service within an organisation has a role to play in monitoring absence because of sickness, the rehabilitation of employees, first-aid, health education and training, the provision of general health advice to employees and liaison with enforcement authorities.
11
Question 10
(a)
(b)
Describe the difference between workplace atmospheric monitoring and biological monitoring of an individual’s exposure to toxic substances. Compare and contrast the use of atmospheric and biological monitoring in the control of exposure to toxic substances. Make reference to the role of relevant benchmark standards and exposure limits in your answer.
(4)
(16)
The aim of the question was to test understanding of the roles of atmospheric and biological monitoring and the relevant standards against which the results of such monitoring could be compared. Good answers began with a description of what constitutes atmospheric monitoring (AM) and biological monitoring (BM). AM involves the monitoring of airborne workplace contaminants by personal monitoring or on occasions, by static monitoring. BM involves the measurement of indicators of the uptake of toxic substances in the body, such as in blood, urine or exhaled breath, in order to prevent health impairment. In comparing and contrasting the two techniques, important areas to explore included the limitations of AM in excluding skin and ingestion as routes of absorption, the advantages of BM for including non-occupational exposure and taking account of individual dose and metabolism and the advantages of AM for the number of available techniques, generally of a non-invasive nature and comparative standards such as WELs. The value of BM where there is a high dependency on PPE was also a relevant point.
Question 11
An employee working for a large engineering company has recently been diagnosed with Legionnaire’s disease. Describe the content of a presentation that might be given to the workforce to inform them about the disease and the controls adopted by the company to address any concerns they may have.
(20)
In answering this question candidates were expected to include an introduction to how Legionella is contracted, and the conditions the bacteria can be found in and proliferates. Typical symptoms of Legionella eg fever, chills, shivering headache, diarrhoea and vomiting should also have been discussed as should the major at risk groups – prevalence amongst 40 – 70 year age group, smokers, alcoholics and persons with cancer. Further marks were available for informing the workforce that only 1% of those exposed develop symptoms. Measures that the company could take to prevent and control legionella would be to undertake risk assessments to identify potential sources and those at risk, routine testing of the water systems, treating water systems with bacteriocides, maintaining water temperatures below 200C or above 650C, ensuring water systems are cleared of organic materials and keeping water tanks covered.
12
UNIT IC – International workplace and work equipment safety
Section A – all questions compulsory
Question 1
(a)
What is meant by the term ‘confined space’?
(2)
(b)
Outline the issues that should be considered to ensure that emergency rescue arrangements for confined space work are adequate.
(8)
Few candidates were able to provide a recognised definition of a confined space although a number attempted to gain the available marks by giving examples of confined spaces. In part (b) Examiners were looking for issues such as methods for raising the alarm with others outside the confined space eg radio, personal alarms etc, the equipment required eg life lines, breathing apparatus, ensuring that there are persons present who are competent to undertake resuscitation procedures, emergency means of access / egress, identification of plant which may need to be shut down during an emergency rescue and training for emergency personnel.
Question 2
Explain the term ‘fixed guard’ in relation to machinery safety and outline the factors to be considered in the design and use of fixed guards to ensure that persons are adequately protected.
(10)
In explaining the term “fixed guard” candidates should have stated that a fixed guard is a guard affixed in such a manner (eg by screws, nuts ,welding) that it can only be opened or removed by the use of tools or destruction of the affixing means. It provides appropriate protection against mechanical hazards when infrequent or no access is required to dangerous parts of a machine during its normal operation. In outlining the design features of a fixed guard, candidates should have referred to factors such as: the material of construction, which should be sufficiently robust to withstand the rigours of the workplace and be able to contain any ejected material, but still allow sight of the process when required; the method of fixing, usually requiring the use of a special tool for the guard’s removal; the need to ensure that any necessary openings in guards are such that they do not allow access to the dangerous parts (a function of the size of any opening in relation to the distance to the hazard); and the need to address the possibility of the guard reverberating and exacerbating a noise problem. Factors to be considered in the use of fixed guards include monitoring and supervision to ensure that the guard is not compromised; safe systems of work for carrying out maintenance operations with the guard removed and the provision of information and training for both operators and maintenance staff.
13
Question 3
Direct contact with a live, mains voltage electricity supply system within a workplace can result in serious injury or death. Outline a range of control measures that may prevent or limit the effect of such contact.
(10)
This question required candidates firstly to consider ways to "prevent contact" with a live mains voltage supply and measures such as working “dead” and using locking off devices were obviously relevant in this context. Further measures to prevent or deter contact would have included the insulation of live parts and the provision of barriers to prevent contact from any usual means of access and enclosures to prevent contact from any direction. Measures to prevent unintentional contact would include making the live parts safe by position and ensuring that only skilled persons or others under continuous and direct supervision are employed in those areas where contact might be made. Additionally reference could have been made to the use of a permit to work system and physical measures such as the provision of mats and appropriate tools. Ultimately, residual current devices would reduce the risk from electric shock should contact be made and fuses or circuit breakers in the phase conductor might also have a part to play.
Question 4
A compressed air system is to be installed in a motor vehicle repair workshop. Outline the safety requirements that should be met before the system is commissioned.
(10)
This question required a description of the safety requirements that should precede the commissioning of a compressed air system in a motor vehicle repair workshop. Examples of the requirements that could have been outlined include: those relating to the siting of the equipment (protection from vehicles, protection of the public, separation from flammable atmospheres, noise, etc); system design issues such as capacity, materials of construction and layout of features; and installation issues such as the fitting of pressure gauges, relief valves and drain lines, the marking of safety-related information (eg safe working pressure) and suitable guarding. There would also be a need for the establishment of maintenance procedures and a written scheme of examination, for a competent person to undertake a pre-commissioning check, and for providing information to operators on safety features, limits and the correct operation of the system.
Question 5
Chemical reactions in a batch manufacturing process can lead to conditions which can cause a ‘runaway reaction’ unless appropriate precautions are taken. (a) (b)
Describe what is meant by ‘runaway reaction’ and identify the conditions that may give rise to such an event.
(6)
Outline methods of control of industrial chemical processes necessary to prevent runaway reactions.
(4)
Candidates could have described ‘runaway reaction’ as: a reaction rate increasing exponentially to the point where auto-ignition explosion or catastrophic over-pressure occurs; or as: increases in pressure and temperature from reaction serve to accelerate the reaction in accord with Le Chatelier’s principal. Candidates could then have gone on to identify conditions such as: strong exothermic reactions; inadequate provision, or failure in cooling of the reaction, and presence of contaminant catalysis. Carrying out a hazard and operability study (HAZOP) on the reaction process would be appropriate in this scenario; this may then have led to the inclusion of design features such as: high integrity temperature detection being linked to the cooling / reactant addition system; pressure rise detection linked to cooling / venting / auto shut-down; vessel protected by correctly sized bursting disc. Candidates could have included operational features such as ensuring that: only high calibre of operator required for such processes were employed; ensure that maintenance activities / raw material handling do not introduce potential catalysts into the reaction.
14
Question 6
Identify a range of industrial activities that may lead to the release of greenhouse gas emissions into the atmosphere.
(10)
This question was designed to test candidates’ awareness of the ways in which an organisation may contribute to global warming. The first part to the question required candidates to demonstrate that they understood that there is a wide range of ways in which activities can contribute to global warming, either directly or indirectly. A comprehensive answer would have included reference to: combustion of fossil fuels (oil, LPG, gas and coal) leading to release of carbon dioxide and other relevant gases through heating systems; transportation emissions; consumption of electricity generated from fossil sources and process use of fossil fuels; use of cement and bricks in construction leading to release of carbon dioxide from calcium carbonate in cement manufacture or greenhouse gases from energy used in manufacture; use of chemicals deriving from fossil fuel sources; disposal of waste to landfill leading to methane emissions; emission of VOCs used as process solvents or from fuels; emission of HFCs and chlorinated/fluorinated hydrocarbons; removal of greenhouse sinks leading to reduced capacity to absorb carbon dioxide through peat consumption and deforestation.
Section B – three from five questions to be attempted
Question 7
Outline the principles, advantages and disadvantages of: (a)
Dye penetrant;
(b)
Magnetic particle inspection;
(c)
Radiography;
(d)
Ultrasonics
as methods of non-destructive testing on the welded joints of a safety critical vessel.
(20)
This question was generally approached logically by taking each technique in turn and outlining its particular advantages and limitations. In answering part (a) Examiners were looking for answers that gave an outline of the principles of use of dye penetrant ie a liquid penetrant is sprayed onto the test piece, the excess is wiped off and an absorbent powder is then sprayed on which draws to the surface any penetrant that has seeped in to any cracks which will then highlight any defects. The advantages are that the use of a dye penetrant method is relatively cheap and is a simple operation. The disadvantages are that it does not detect sub-surface faults, is not totally reliable and interpretation of the indications may be difficult (although enhancement can sometimes be achieved by using a fluorescent penetrant with a UV source). Additionally, the penetrant used may have toxic properties. In part (b) magnetic particle inspection involves coating the joint to be tested with magnetic particles that may be in powder form or within a liquid. It is a simple and quick operation that is very sensitive to surface cracks and, in certain circumstances, can detect sub-surface defects. Its drawback is that the interpretation of results may be difficult, particularly on the inside surface of a pressure vessel.
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In part (c) with radiography, x-rays or gamma rays are used to penetrate the welded joint to leave an image on film. Any defects are shown up by the differences in the intensity of the radiation striking the film. The benefits of this technique are that it detects internal defects and produces a permanent record of the test. However, the operation is time-consuming, expensive and requires bulky equipment and skilled radiographers. Additionally, there is the danger of radiation exposure. Finally, using an ultrasonic technique, short pulses of high frequency ultrasound are used on welded joints, with the reflected waves being detected and shown on an oscilloscope or digital display. This technique detects both surface and sub-surface defects, requires access to one side of the joint only and takes little time with portable equipment that can be used in most environments. The limitations of the technique are that it requires a high level of expertise and coupling the equipment probe onto rough surfaces can be difficult.
Question 8
(a)
(b)
Outline the features of computer controlled equipment (eg robots, Computer Numerical Controlled (CNC) machines, wireless operated lifting equipment) that may have particular implications on safety.
(6)
Describe how the risk of injury to personnel working with such equipment may be reduced.
(14)
____________________________________________________________________________________________
The features of computer controlled equipment that may have particular implications on safety include sudden, rapid and forceful movements, aberrant behaviour, software faults, dangers during teaching and maintenance, stored energy and leaking hydraulic and pneumatic fluid. Risk of injury to personnel working with such equipment may be reduced by carrying out a risk assessment which identifies the hazards and those at risk, restricting access ie 2m high fencing, interlocks and pressure mats, lock off procedures during maintenance, mechanical restraints, pre-startup warning signals, software checks and remote diagnostics. Further controls would include emergency stops, training of relevant people on the hazards and controls associated with CNC machines and planned maintenance.
Question 9
An independent scaffold is to be used as a working platform to enable minor repairs to be undertaken to a two-storey building. (a)
(b)
Describe the safety criteria that should be met in order to ensure that the scaffold is safe for use. Identify the inspection requirements for the scaffold.
(15) (5)
In answering part (a), candidates were expected to refer to criteria such as the need for the scaffold to be designed to a recognised standard, constructed of sound material, able to withstand the loads to be placed upon it and erected by competent persons. Other necessary criteria would include the use of base plates placed on sole plates on consolidated ground; the use of longitudinal and diagonal bracing; provided with fully boarded platforms sufficiently wide for the work which was to be carried out and fitted with guard rails, toe boards and sheeting or netting where required. It should also be provided with an exclusion zone at its base to prevent it from being struck by passing traffic. In part (b) candidates were expected to identify the specific inspection requirements for the scaffold such as by a competent person after erection, then at specified intervals, and additionally, after any alteration, damage or inclement weather.
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Question 10
A mobile crane is to be used to erect a telecommunications aerial on the roof of a three-storey office building. Describe the precautions that should be taken in order to minimise risks both to employees involved in the work and to other persons who may be affected by the operation.
(20)
In answering this question candidates were expected to describe precautions such as the selection of the crane with respect to its safe working load and reach and checking the existence of current test certificates; ensuring ground conditions were appropriate for positioning the crane and that outriggers were used; avoiding contact with overhead services and other buildings or structures; using adequate lifting gear and ensuring that there were competent people in control of and involved in the lifting operation. Additionally, with the scenario very much in mind, account would have to be taken of weather conditions and the need to follow safe roof work practices such as the provision of edge protection or the use of harnesses. The question specifically asks for the precautions needed in relation to the employees carrying out the work and others who might be affected by the operation. Such precautions would entail providing sufficient personnel on site to control access of the public to the area; the provision of adequate signing and traffic control; liaison with the local police and planning the lift for a time of day when few people would be in the vicinity.
Question 11
A conference centre is planning to extend its existing building to incorporate childcare facilities on the ground floor and additional conference rooms to hire out to local businesses on the upper floors. Outline the range of factors that would need to be reviewed following completion of the planned work to enable the company’s fire risk assessment to be updated.
(20)
Following completion of the planned work the additional risk factors would include small children; worried and possibly panicking parents if a fire was to occur; persons under the influence of alcohol following events held in the conference facilities ; the possible hazards of allowing smoking in the conference rooms and the potential number of extra people to be evacuated. This would call for additional precautions in terms of escape routes, holding fire drills for the children and delegates; an extension to the existing alarm system with additional call points; and additional equipment such as emergency lighting, fire fighting appliances and the notices and signage that would be required. It would also be necessary to consider the appointment of additional fire marshals particularly with the likely presence of a number of vulnerable people (children) and to train employees in the revised procedures.
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