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Examiners Report

NEBOSH Internat ional Diploma inOccupational Health and Safety

January 2008 examinations

CONTENTS

Introduction 2

Unit IA International management of health and safety 3

Unit IB International control of hazardous agents in the workplace 12

Unit IC International workplace and work equipment safety 19

2008 NEBOSH, Dominus Way, Meridian Business Park, Leicester LE19 1QWtel: 0116 263 4700 fax: 0116 282 4000 email: [email protected] website: www.nebosh.org.uk

The National Examination Board in Occupational Safety and Health is a registered charity, number 1010444

T(s):exrpts/J /J -0801 DW/DA/REW


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Introduction

The results from the second three Unit examinations of the International Diploma resulted in pass rates of 61%, 44% and 50% (Units A, B and C respectively). On a positive note, while Examiners Reports inevitably

concentrate on some of the weaknesses found in candidates answers, every examination produces someexcellent scripts from candidates who have obviously put much effort into their studies in order to achievesuccess. Such 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) In relation to workplace behaviour outline what is meant by the termattitude. (2)

(b) 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 apredisposition to act in a certain way which may be determined by ancestry, personalexperience or training.

There a number of ways in which the media can and have influenced attitudes towardshealth and safety. They have the facility to undertake a global coverage of events and canreach a wide audience using a variety of methods of delivery such as print, television, videosand the internet. The coverage is often sensationalist and can be influenced on occasions bypressure groups and other bodies such as Greenpeace. The influence exerted by the mediamay be advantageous or detrimental for the industry or organisation involved particularlythose who have high media coverage which can affect the perceptions of customers, clientsand other stakeholders. To support their answers, candidates were expected to refer to themedia coverage of incidents such as the Perrier incident of 1990, Chernobyl, BP Texas andPiper Alpha.

Question 2 An employee has been seriously injured after being struck by materialtransported using an overhead crane.

Using the categorisation of human failure published in the Health and SafetyExecutive (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 havestated 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 asimilar routine is incorrectly selected, if there is interruption or inattention causing a stage inthe operation to be omitted or repeated or if checks are not carried out to verify that thecorrect routine has been selected. In the scenario described in the question, errors that mayhave contributed to the accident include the operation by the crane driver of the wrongswitch or control or commencing the lifting operation out of sequence when workers werenot prepared.

Rule-based behaviour involves actions based on recognising patterns or situations and thenselecting and applying the appropriate rule set. An error would involve the application of thewrong 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 higherproblem solving level, when there are no set rules and is based on having knowledge of thesystem. Errors will consequently occur if there is a lack of knowledge or inadequateunderstanding of the system. In the case described, the driver may have had littleexperience of the type of lifting operation being carried out and was carrying the load at thewrong height while the injured person may have been unaware that a lifting operation wastaking place.

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Finally, the accident may have been caused by a deliberate failure to follow rules aviolation - where for example, the driver had failed to operate the siren before commencingthe lifting operation or the injured person had intentionally walked too close to the load beinglifted.

Question 3 (a) A mixing vessel that contains solvent and product ingredients must bethoroughly cleaned every two days for process reasons. Cleaningrequires an operator to enter the vessel, for which a permit-to-work isrequired. During a recent audit of permit records it has been discoveredthat many permits have not been completed correctly or have not beensigned back.

Outline possible reasons why the permit system is not being followedcorrectly. (5)

(b) A sister company operating the same process has demonstrated that thevessel can be cleaned by installing fixed, high pressure spray equipmentinside the vessel which would eliminate the need for vessel entry. You

are keen to adopt this system for safety reasons but the Board hasrequested 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 withinthe organisation; routine violations; pressure to complete the task and the complexity andimpracticability of the system which makes it difficult to understand. Additionally, there couldhave been an inadequate level of supervision, a lack of routine monitoring and the non-

availability of the permit issuer to activate the sign back procedure and cancel the permitonce the work had been completed.

For part (b), candidates should have outlined that the preparation of a cost-benefit analysiswith reference to the given scenario, would involve calculating the total costs, includingcapital and ongoing, of each option. Wherever possible, the benefits that would accrue fromthe use of the proposed system should be quantified and these would include processefficiency gains, lower operating costs and a reduction in accidents and cases of ill-healthand 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 goodpractice reasons, an organisation may need to provide health and safetyinformation. In EACH case, indicate the broad type of information to beprovided. (10)

This question required candidates to outline the external bodies and individuals to whom anorganisation may need to provide health and safety information for legal or good practicereasons. Candidates who did best were those who structured their answers under theheadings of body or individual and type of information.

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Individuals and bodies who would be provided with information for legal reasons includedthe enforcing authorities with respect to information required by law or in accordance withthe ILO Code of Practice or as part of inspection or investigation activities; the emergencyservices on the inventories of potentially hazardous/flammable materials used or stored onthe site and on the means of access and egress to the site; customers who have to be givenhealth 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 hazardouswaste produced by the organisation; transport companies who should be given informationon the precautions to be taken in transporting hazardous substances from the organisationssite; and legal representatives or courts who would have to be given information regardingcivil claims.

It would, additionally, be good practice to supply information: to trade associations and tradeunions on performance and social responsibilities; to insurance companies on the safetymanagement systems in place and to shareholders on the organisations level of performance as far as health and safety was concerned.

Question 5 (a) Outline the reasons for establishing effective consultation arrangementswith employees concerning health and safety matters in the workplace. (4)

(b) Outline the range of formal and informal arrangements that maycontribute to effective consultation on health and safety matters in theworkplace. (6)

This question, based on Element A5 of the syllabus, was designed to test candidatesknowledge of the reasons for and the arrangements that might be made for ensuringeffective 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 onthis to include the development of ownership of safety measures amongst employees;improving perception about the value and importance of health and safety; gaining the inputof employee knowledge to ensure more workable improvements and solutions; andencouraging the submission of improvement ideas by employees.

Part (b) required candidates to outline arrangements that might contribute to effectiveconsultation. Marks were available for referring to arrangements such as: the establishmentof safety committees; consultation with safety representatives; planned direct consultation atdepartmental meetings, team briefings or similar; consultation as part of accident/incidentinvestigation or as part of the completion of risk assessments; day to day informalconsultation 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 andsuggestion schemes.

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Question 6 A publicity campaign was used to encourage improvement in compliance withsafety standards within a particular organisation. During the period of thecampaign the rate of reported accidents significantly increased and thecampaign was considered to be a failure.

(a) Outline reasons why the rate of reported accidents may have been a

poor measure of the campaigns effectiveness. (2)

(b) Outline FOUR proactive (active) monitoring techniques which might beused to assess the organisations health and safety performance. (8)

For part (a) of the question, candidates could have identified that a reason why the numberof reported accidents had increased was because they may have previously been underreported, perhaps because some employees were unaware of the requirement to report andthat raised awareness, prompted by the advertising campaign, could have led to previouslyunreported accidents now being reported. In the absence of any other data, it would bealmost 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 untilsome time after the campaign has ended.

In answering part (b), proactive monitoring techniques which might be used to assess theorganisations health and safety performance include physical inspections of the workplaceto identify hazards and unsafe conditions; safety audits where the systematic criticalexamination of all aspects of an organisations health and safety performance against statedobjectives is carried out; safety tours involving unscheduled inspections to observe theworkplace 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; safetysampling of a specific area or particular items of plant with repeat sampling to observetrends; safety surveys involving in depth examinations of specific issues or procedures suchas changes in working practices; environmental monitoring and/or health surveillance; safety

climate measures such as the use of employee questionnaires; behavioural observation andmeasuring health and safety performance against set targets.

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Section B three from five questions to be attempted

Question 7 (a) Outline the principles, application and limitations of Event Tree Analysisas a risk assessment technique. (6)

(b) 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 beenestimated that a fire will occur once every five years (f=0.2/year).Reliability data for the system components are as follows:

Component ReliabilityDetector 0.9

Power supply 0.99Extinguishing gas release mechanism 0.95

(i) Construct an event tree for the above scenario to calculate the

frequency of an uncontrolled fire in the computer suite. (10)(ii) Suggest ways in which the reliability of the system could be

improved. (4)

Event Tree Analysis is based upon binary logic and is often used to estimate the likelihoodof success or failure of safety systems. It starts with the initiating event and ends with theprobability 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 orfailure 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 describedin the question. An acceptable answer would have been:

0.1

0.9

0.99

0.01

0.05

0.95

f=0.2/yr

Fire

0.2 x 0.1 =0.02

0.2 x 0.9 x 0.01 =0.002

0.2 x 0.9 x 0.99 x 0.05 =0.009

p (failure) =0.009 +0.002 +0.02 =0.031 per year

f =once every 32 yrs

p (success) =0.2 - 0.031 =0.169SUCCESS

FAILURE

detector power gas

Marks were awarded for the general construction of the tree; for calculations of failure ratesfrom component reliability data; for calculation of system failure rate from individual failurerates; and for conversion of failure rate per year to failure every X years which in this casewas once in every 32 years.

In answering part (b) (ii), candidates could have suggested ways such as choosing morereliable components or using components in parallel. Credit was given for recognising thatthe detector was the least reliable component and so would be a logical first choice for suchtechniques. 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) 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)

(b) Excluding ergonomic issues, outline ways in which human reliability inthe 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 thedesign of equipment, task and environment to take account of human limitations andcapabilities; that of anthropometry the collection of data on human physical dimensionsand 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 errorwith each action.

In part (b), candidates were asked to outline ways in which human reliability in the workplacemight be improved, structuring their answers round individual, job and organisational issues.Human reliability plays a significant role in health and safety at the workplace andcandidates were expected to have a good understanding of this issue.

As far as the individual is concerned, this would involve careful selection taking into accountskills, qualifications and aptitude; the provision of appropriate training both at the inductionstage and to meet subsequent job specific needs; the consideration of the special needs of those who may be more vulnerable; monitoring personal safety performance; usingworkplace incentive schemes and assessing job satisfaction and providing healthsurveillance 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; thedesign of work patterns and shift organisation to minimise stress and fatigue; the use of jobrotation to counter monotony; the introduction of good communication arrangementsbetween individuals, shifts and groups and using a sufficient number of personnel to avoidconstant time pressures.

Finally, for issues connected with the organisation, candidates could have referred to thedevelopment of a positive health and safety culture; the provision of good leadershipexample and commitment; the introduction of effective health and safety managementsystems and maximising employee involvement in health and safety issues; ensuringeffective arrangements for employee consultation; the introduction of procedures for changemanagement and the provision of an adequate level of supervision.

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Question 9 (a) 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)

(b) Outline the mechanism by which the International Labour Organisation(ILO) can influence health and safety standards in different countries. (10)

(c) Describe what is meant by the term self regulation in relation to healthand safety management within organisations. (4)

In answering part (a) of the question, candidates could have described corporate probationas a supervision order imposed by a court on a company that has committed a criminaloffence. When applied to a health and safety offence, the order might require the companyto review its safety policy or its health and safety procedures, initiate a training programmefor its directors and senior management or reduce the number of its accidents. Its aim is to

instigate a change in the organisations culture under the supervision of the court. The intention of an adverse publicity order would be to publicise the failings of anorganisation and seek to change its conduct through public perception.

Punitive damages are damages not awarded to compensate the plaintiff, but in order toreform or deter the defendant and similar persons from pursuing a course of action such asthat which damaged the plaintiff.

In answering part (b) on the mechanisms by which the International Labour Organisation caninfluence health and safety standards in different countries, candidates were expected torefer to matters such as the development of international labour standards throughconventions supplemented by recommendations containing additional or more detailed

provisions; the ratification of the conventions by member states which commits them toapply the terms of the convention in national law and practice; the requirement for memberstates to submit reports to the ILO detailing their compliance with the obligations of theconventions they have ratified; the initiation of representation and complaint proceduresagainst countries for violation of a convention they have ratified; the provision of technicalassistance to member states where this is seen to be necessary and indirectly through thepressure 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 safetylegislation to set standards and objectives and leave it to the duty holder to determine howbest to achieve them. More particularly it could refer to the means by which members of aprofession, trade or commercial activity are bound by a mutually agreed set of rules often setout 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 willnormally be a procedure for resolving complaints and for the application of sanctions againstthose 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 keyfunctions of the role of a health and safety practitioner in a medium size organisation suchas helping to develop, implement and revise health and safety policies; giving advice onrisks in the workplace and the appropriate control measures to be adopted; drawing upprocedures for vetting the design and commissioning of new plant and machinery; assistingmanagement in setting performance standards and carrying out proactive and reactivemonitoring; advising management on the requirements of health and safety legislation;organising and reviewing emergency procedures; promoting a positive health and safetyculture within the organisation; investigating accidents and cases of ill-health; carrying out orassisting in the audit of the health and safety management system; liaising with enforcementauthorities 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 thevisitors 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 befollowed in order to collect evidence for an investigation of the accident. (8)

(c) The investigation reveals that there have been previous incidents of forklift trucks skidding which had not been reported. The companytherefore decides to introduce a formal system for reporting near missincidents. Outline the factors that should be considered when

developing and implementing such a system. (8)

There are many reasons for investigating accidents such as to identify their causes, bothimmediate and underlying; to prevent a recurrence; to assess compliance with legalrequirements; to demonstrate managements commitment to health and safety and torestore employee morale; to obtain information and evidence for use in the event of anysubsequent civil claim; to provide useful information for the costing of accidents and foridentifying 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 realisticchronological order including taking photographs and making sketches and taking

measurements of the scene of the accident before anything was disturbed; obtaining anyCCTV footage available; examining the condition of the fork lift truck and determining itsspeed at the time of the accident; determining the load that was being carried, the safeworking load of the truck and any forward visibility problems with the load in place; findingout the reasons for the oil spillage, the emergency spillage procedures in place and thereasons why they were not followed on this occasion; assessing the competence of the forklift truck driver and examining the workplace to determine any contributing environmentalfactors such as the condition of the floor and the standard of lighting and interviewingrelevant witnesses such as the visitor, where this is possible, and reception personnel toidentify current working practices as compared with the laid down written procedures fordealing with visitors.

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Those who did best in answering part (c) outlined a range of practical, communication andmanagement issues referring to factors such as: arriving at and setting out a clear definitionof a near miss; holding consultations with employees on the proposed system; arranging forinformation and training to be given to all employees; ensuring that the reporting methodsare simple and easy to operate and establishing clear reporting lines; introducing andpractising a no blame culture; arranging for investigation of incidents by line management toidentify and implement any remedial action necessary; ensuring the introduction of areporting 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 aregular basis.

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UNIT IB International control of hazardous agents in the workplace


Question 1 A process in a textile mill produces high levels of heat and steam.

(a) Identify FOUR parameters that could be measured when making anassessment of the thermal environment stating in EACH case the nameof an instrument that can be used to measure this parameter. (4)

(b) Outline the ways of reducing thermal stress amongst employees in thetextile 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 thermalenvironment and the instrumentation to be used, candidates should have referred toparameters such as ambient temperature ( mercury or alcohol thermometer), air velocity(anemometer or kata thermometer), relative humidity (hygrometer) and radiant heat (blackglobe thermometer).

For part (b), candidates should have outlined ways of reducing heat stress such as thereduction of heat output at source; the use of barriers or screens to shield workers fromsources of radiant heat; providing adequate ventilation and de-humidifying the working areato counteract the effects of steam; breaks away from the hot working environment; jobrotation and the use of adequate numbers of employees to reduce the work rate; and theprovision of training on the possible effects of working in such an environment and thecontrol measures to be adopted. General welfare considerations would include pre-employment screening of individuals (looking particularly at vulnerable groups); the gradualacclimatisation 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 isthought to be more effective. Outline the health and safety information thatshould be evaluated before a decision is taken to make the change. (10)

In answering this question, candidates were expected to outline the information that wouldenable a comparison to be made between the risks from the proposed substance with thoseof the existing one. Much of this information might be gained from the manufacturers safetydata sheets for both substances. Specific information on the proposed substance wouldrelate to: the physical form of the substance (eg whether aerosol or liquid); the possibleroutes of entry of the substance into the body; its flammability and volatility; its short andlong term health effects; applicable exposure limits such as WELs; the quantity of thesubstance that would be used; the number of persons likely to be exposed and the level andfrequency of their exposure; personal susceptibilities of those involved with particularreference to employees who might be especially vulnerable such as young persons oremployees with a liver or heart condition; additional control measures that might berequired; storage arrangements; and the procedures that might have to be introduced for thedisposal of the substance and for dealing with any emergency.

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Question 3 (a) 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)

(b) Outline the practical steps that the centres instructors can take tominimise the risks to themselves. (6)

In most cases the infection causes a flu-like illness with severe headaches and pain in thelower back, and legs. Other symptoms include fever, vomiting, abdominal pain, skin rashes,and conjunctival haemorrhage. The severe form of the disease (called Weils Disease afterthe doctor who first identified it) causes jaundice and liver damage.

The most common carriers are rats. It is generally assumed that across the developedworld, 1 in 5 wild rats are carriers of pathogenic leptospires. Rats live in close proximity towater and they are incontinent. Carrier-state rats emit bacteria in their urine, and this isdistributed everywhere they go. Normally this is inactivated once it dries out, but if it enterswater the bacteria can remain viable for longer periods. The bacteria can then enter thewindsurfers 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 preventingthe 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 handsthoroughly before eating; avoid swallowing water; wearing protective footwear andminimising skin contact by wearing a full-body wet suit; protecting all existing cuts andabrasions with waterproof dressings; seeking medical advice and treatment for any cuts orbites received whilst in the water (advising their doctor of their occupation to aid in earlydiagnosis); washing down equipment and wet suits and reporting any sighting of rats toensure effective rodent control in and around the water.

Question 4 Operatives on a food manufacturing production line have to pick up rectanglesof pasta from a delivery conveyor and place them into foil trays on a separateconveyor. This involves 8 hour shifts and is carried out standing in front of theconveyor.

Following complaints from a number of employees about pains in their armsand shoulders you have been asked to carry out an ergonomic risk assessmentfor this operation and make recommendations.

(a) Outline the ergonomic risk factors to be taken into account when makingsuch an assessment, indicating how these may be contributing to theproblems experienced by the employees in this situation. (5)

(b) Total automation of the process is not possible. Suggest other controlmeasures that could be taken to reduce the ill-health effects beingexperienced by employees. (5)

In carrying out an ergonomic risk assessment of the operation described in the scenario, thefactors that would need to be taken into account include the repetitive nature of the taskinvolving frequent movements of the upper body to pick up the pasta and place it in foiltrays; the continuous nature of the operation over an eight hour shift; the posture adopted bythe operators including standing and reaching from one conveyor to another; the expectedwork rate and the speed of the conveyors; the height of the conveyor in relation to that of theemployees and the total pattern of continuous work with the number and length of thebreaks allowed.

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In answering the second part of the question, candidates were expected to suggest controlmeasures 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 preventover reaching; providing seating for the operators to enable them to change their positionfrom time to time; reducing the speed of the feed conveyor; introducing job rotation withother 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 anyproblems 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 movingand handling of patients in a hospital. (10)

This question called for an application of the main elements of a risk assessment on manualhandling to the given scenario and good answers, therefore, provided a structured outlinebased 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 abath or in pushing wheelchairs and lifting stretchers; the need for frequent or prolongedphysical 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 potentialincreased risk when working alone, particularly in coping with an emergency situation. Lackof 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 ahuman being and this results in risks such as the heavy weights involved which may bedifficult to estimate; the risk of the patient fainting or collapsing presenting a shock load; thefact that the patient may be unwilling to be assisted and may struggle or be violent; medicalequipment may be attached to the patient making handling more difficult; and problems thatmay 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 causedby 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 maybe issues with unmatched team handling.

Question 6 (a) Outline , using a relevant example, why and how a retrospective case

control study is carried out. (5)

(b) 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 aretrospective 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 involvesthe use of two groups, one with the disease and one without. The study starts at a point inthe past and follows the first group forward in order to determine past exposure histories to acertain substance using records of employment, medical records and interviews to collectdata. These are compared with the control group who do not have the disease. Relevantexamples 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; theavailability 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-occupationalexposure 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 thatthe group may not be representative of the exposed population; and the possible effect of other occupational exposures.


Question 7 A distribution company employs 300 employees as drivers, warehouseoperatives and office staff, processing telephone and internet orders.

(a) Identify the possible functions of the companys occupational healthdepartment in this particular company:

(i) when recruiting new employees; (4) (ii) when an employee returns to work after ill-health. (5)

(b) Outline other ways in which the occupational health department canassist the management team to improve health and safety within thisorganisation.(You do not need to consider those functions you have alreadyaddressed in part a). (11)

During the recruitment of new employees, the occupational health department would havean important part to play in carrying out screening of the applicants and reviewing theirhealth history so that they might be in a position to advise management on their suitability foremployment. In particular they would need to check the fitness and ability of potentialwarehouse staff to undertake manual handling tasks, check the eyesight of applicants forpositions as drivers whether of road or internal vehicles and also screen them for evidenceof the possible misuse of alcohol or other substances. Additionally it would be important tocarry out eyesight tests on those who would be employed in the office to use display screenequipment.

As for those employees preparing to return to work after a period of ill-health, anassessment of their current health condition would enable recommendations to be made tomanagement on whether the return should be phased or whether the employee should beredeployed on other or lighter duties. This would necessitate liaison with the employeesmedical practitioner and where necessary arranging for or even providing rehabilitationtreatment in house.

In answering part (b), candidates were expected to outline other ways in which theoccupational health department could assist management in improving health and safety inthe organisation such as maintaining health records of employees and carrying outmonitoring of sickness absence; providing first aid treatment and training for employeesappointed as first aiders; providing information and advice to employees on weightmanagement, exercise and smoking cessation; undertaking health surveillance; providingtraining in manual handling and the management of stress; providing an input to thedevelopment of policies and procedures and participating in management team meetingsand meetings of the health and safety committee; making a specialist input to riskassessments 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 manufacturingprocess. The solution is applied by hand brushing. Other methods of application have been found to be impracticable.

(a) Outline the factors that should be considered in the selection of personalprotective equipment (PPE). The equipment should ensure that the skin

and the eyes of those involved in the process are adequately protected. (10)

(b) Identify the content of a training programme that will assist employees touse the PPE correctly. (5)

(c) List a range of practical measures (other than training) that can be takento encourage the use of the protective equipment and maintain itseffectiveness. (5)

In answering part (a) of this question, for the selection of protective gloves, candidatesshould have considered factors such as: the appropriate chemical resistance for the solutionand 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 adequateprotection; durability of gloves; ensuring a suitable range of sizes for the various users isavailable; 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 aseyes; the use of goggles or a face shield (rather than spectacles) with the appropriate levelof 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 andappropriate footwear. Good answers would have concluded by considering factors such asconsultation and user trials; comfort factors; the ease of maintenance; storage requirementsand compliance with appropriate standards and ILO guidance.

Good responses to the second part of the question would have identified that employeesshould 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 methodof putting on and removing PPE without contamination, including decontaminating ordiscarding of gloves after use; the danger of contaminating other parts of the body whilstwearing gloves; how to examine PPE for damage or degradation (particularly gloves) andhow to report any defects and obtain replacements; how to store the PPE correctly; andtraining 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 measuresto encourage the use of PPE such as: management leading by example; staff being involvedin the selection; ensuring a range of sizes of gloves is available and that shields are fullyadjustable; employees signing for PPE and maintaining records of issue; providing adequatestorage 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 adviceon occupational stress. Prepare a briefing note for the Board of the bank thatdescribes:

(a) the sources of information that may be used to assess the risk of highlevels of stress; (8)

(b) the occupational factors that can contribute to the incidence of stress-related problems amongst bank employees. (12)

For part (a), sources of information could have included: face-to-face discussions betweenstaff and line managers or supervisors, either informally or formally at, for example,performance appraisal reviews; discussions at safety committees or team briefings; sicknessand/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 theappropriate 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 answersdescribed and applied factors such as: the demands of the job (for example work overloador 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 communicationand consultation, autocratic management style); the degree of support offered by theorganisation, management and colleagues; work relationships (eg bullying, harassment,mistrust); role (conflict, lack of clarity, etc); and the mismanagement of organisationalchange leading to insecurity. Better answers would have drawn particular attention to issuesrelevant to the banking scenario, such as the need to work with difficult members of thepublic and the threat of violence.

Question 10 A&B Printing Ltd operates a number of large printing machines producingmagazines for the retail trade. They recognise that exposure to noise is aproblem for all operatives within the open plan print workshop and so thecompany plan to undertake a noise survey.

(a) Identify the different types of equipment that could be used to measureexposure to noise, making reference to their respective features androles in assessing noise exposure. (10)

(b) Following the noise survey the company decide to fit an acousticenclosure to one of the large printing machines. Outline the designfeatures of such an enclosure. (10)

Part (a) of the question was designed to assess candidates understanding of theinstrumentation that could be used in the assessment of noise in the workplace. An answerincluding the roles and capabilities of simple sound pressure level meters (SLMs),integrating meters and personal noise dosimeters was expected with reference being madeto the working environment in which they might be used such as relatively constant orfluctuating noise levels or for peripatetic workers and their contribution to, and accuracy in,measuring or assessing L eq and L EP,d . Credit was also available for dealing with otherrelated issues such as calibration, the use of an octave band filter set on SLM andintegrating 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 peaknoise 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 acousticenclosure such as: the need for it to be of double skin construction with the walls and topbeing made of sound insulating material, robust enough to withstand the workingenvironment; double glazing to be fitted where windows were considered to be essential andflexible connectors used in pipes and ducts leading into and out of the enclosure to formvibration breaks. Additionally, the enclosure should be effectively sealed at floor level, theinternal surfaces lined to prevent reverberant build up, any ducts into the enclosure linedwith 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 ondampers, with operating controls situated on the outside of the enclosure and the materialentry and exit points sound-proofed. Finally, removable panels would need to be fitted to theenclosure 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 airbornecontaminants 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 tocollect four types of airborne contaminants.

Total inhalable dust is dust taken into the respiratory system. The description and diagramshould have shown how it could be collected by attaching the sampling device to a samplingpump 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. Analternative sampling device such as a parallel plate elutriator could have been provided asan answer.

Respirable dust is made up of particles which may reach the alveoli of the lungs (eg


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UNIT IC International workplace and work equipment safety


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 theeffects, of a tractor overturning. (4)

For part (a) candidates should have referred to factors affecting the possibility of overturningsuch as the angle of slope and direction of travel on gradients; uneven or soft ground; speedon cornering; wheel width; the condition and pressure of tyres; the effects of trailers andother 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 seatrestraints and roll-over protection to mitigate the effects of an overturn. Other appropriatemeasures to minimise the risk of tractor overturn include restricting the use of tractors onsteep gradients; fitting counterbalance weights; fitting wider tyres and maintaining them on aregular basis; fitting a power take-off torque limiter such as shear pins and providing trainingfor 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, thecharacteristic features of and factors that promote brittle and ductile fractures.

A brittle fracture generally occurs without warning or prior evidence of distress. It is acrystalline structure failure with minimal plastic or elastic deformation. There are generallycharacteristic chevron marks from the point of initiation and the failure is sudden from rapidstress loading. The factors promoting a brittle fracture are high tensile stresses, residual orlocked in stresses, sudden loading which does not give the material time to deformplastically, 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 thematerial before final fracture. There is evidence of necking and the final fracture is oftenbrittle because there is insufficient material left to sustain a load. This type of failuregenerally occurs as the result of a single stress overload though other promoting factorsinclude 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 interlockedguard is linked to the machine controls by mechanical, electrical, hydraulic or pneumaticmeans. The principles of operation are that the machine cannot become dangerous whenthe guard is open and, when the machine is in an otherwise dangerous condition, either theguard 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 systemand a trapped key system. In the first case, as the name suggests, the key is at all timesheld captive in the guard locking mechanism that incorporates an electrical switch connectedto the power supply to the machine. It is therefore necessary to turn the key to open theguard 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 powersupply to the machine are separate. The key is removable but is held in the guard lockingmechanism until the guard is closed. On locking the guard, the same key can then betransferred 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 ontheir cars and property. They allege that the dust came from cement workssituated a few miles away.

Outline the steps that should be taken by those responsible for the cementworks 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 fromresidents of a village situated a short distance away from a cement works. It involved atypical investigative process which would deal with the factors to be examined in order toconfirm or dismiss them.

In order to investigate whether the dust causing the problem emanated from the cementworks, management would first need to carry out a desk study involving contact with theresidents and a research into historical records, weather patterns, possible links with theprevailing 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 continuousmonitoring 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 producedat the alleged source.

Question 5 With examples of actual incidents, describe the principles and effects of avapour cloud explosion. (10)

A vapour cloud explosion may be confined for example in a tank or vessel or unconfined. Itskey principles include the presence of flammable vapour at a concentration between theupper and lower explosive limits and an ignition source that exceeds the minimum ignitionenergy. Unconfined vapour clouds may travel a considerable distance before igniting or theymay be dispersed to a concentration below the lower explosive limit depending onconditions. The effects of vapour cloud explosions include overpressure, thermal effects andthe emission of debris. In confined explosion cases, vessel or containment rupture mayoccur resulting in a rapid release of liquefied gas. In unconfined explosion cases, damage topeople and property may be caused by the pressure wave and thermal radiation. Suitableexamples could have included Flixborough 1974, Abbeystead 1984, Grangemouth 1987 andBuncefield 2005.

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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 sessionfor 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 theneed to prevent the accumulation of rubbish; the action to be taken on discovering a firesuch as raising the alarm, the procedure for calling the fire service and the action to be takenby personnel on hearing the alarm; the location and use of fire fighting equipment withpractical training for selected employees; the escape routes and exits from the premisestogether with the assembly points and the roll calls that would have to be carried out; thearrangements for the evacuation of people with disabilities and for assisting visitors andmembers 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 behavioursuch as refraining from re-entering the building after evacuation until instructed to do so.


Question 7 Outline the advantages and limitations of the following types of fall protectiondevices, 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 whencarrying out short duration work when it would be impracticable to provide moresophisticated measures. Their limitations include the need for secure anchoring points, theirrestrictions on movement, their requirement for trained and competent users and the factthat they provide individual protection only. A suitable application for this device would be ingeneral construction work.

Safety belts, too, can be used in high fall potential areas for short duration work where theprovision of more sophisticated measures would be impracticable. However, this deviceoffers restraint rather than fall arrest, again requires anchoring points, provides individualprotection only and may need to be supplemented with collective measures. A suitableapplication 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 usedonly in low to medium fall potential areas. They are most suitable for use over water or underfragile 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, needinstallation by competent personnel, require a continuous power supply and may be usedonly in low fall potential areas such as short run construction projects or around workplacetransport.

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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 inthe workplace. (20)

In outlining the design features that should be considered in order to minimise risksassociated with the movement of vehicles in the workplace, candidates should have referredto 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 thosecorners that cannot be avoided; the installation of a one way system to minimise the needfor reversing; the inclusion of passing places for vehicles; the introduction of speed limitsand the provision of speed retarders; the provision of a good standard of lighting for theroutes 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 theprovision of clearly marked crossing places.

As for procedural arrangements, they would include the selection and training of competentdrivers who would be subjected to regular health screening; the provision of information onsite 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 reportingof defects; the rigorous enforcement of speed limits and the provision and use of highvisibility clothing by employees working in close proximity to traffic routes.

Question 9 With respect to an electricity supply operating at 240v:

(a) outline the factors that determine the severity of the effects of an electricshock. (6)

(b) 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)

(c) Outline other design features of electrical systems intended to improvesafety. (5)

In answering part (a) of this question, credit was given for reference to factors including thevoltage, the nature of the current (whether alternating or direct), the body resistance of theindividual 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 floormaterial and the presence of water. Knowledge of Ohms Law was useful in relating the sizeof current to voltage and resistance.

In answering part (b), candidates were expected to describe that a residual current device isdesigned as a shock limiting device and not for system protection. It operates on an earthleakage 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 theapparatus and preventing severe electric shock. The device should operate within 30 to 50milliseconds 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 thepower supply to the circuit within a given time when the current flow in the circuit exceeds agiven value and produces sufficient heat to melt the fuse which is designed to do so at apredetermined temperature. It prevents the overload of an electrical system and overheatingof electrical wiring. However, its speed of operation is generally too slow to protect peoplefrom 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 atransformer used to attain the reduction is described as centre tapped to earth in that thesecondary winding of the transformer is earthed to its centre thus ensuring that themaximum 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 safetysuch 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 andseparation of electrical equipment from every source of energy; the use of earthed systemsand Class 1 equipment or double insulated Class 2 equipment; the use of circuit breakersand the introduction of earth free zones.

Question 10 As part of its water treatment system, a manufacturer is to install a plantsuitable for the reception and storage of a strong acid and a strong alkali, bothof which will be delivered in bulk tankers.

Outline the safety provisions required for the design, operation andmaintenance of the proposed plant. (20)

Candidates who divided the question into its component parts, ie design, operation andmaintenance 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; thedesign and positioning of the delivery inlets to prevent connection being made to the wrongtank; 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 signsclearly 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 vehicleaccess including a hard standing for tankers with facilities for spill containment and theprovision of a good standard of lighting.

Operational issues should have included the introduction of a safe system of work includingemergency procedures to deal with spillages and the provision and maintenance of acontingency supply of neutralising and absorbent materials and water; providing training forthe 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 suchas chemical suits, chemical resistant gloves and full face protection.

In outlining the issues connected with maintenance, candidates were expected to refer to thearrangements for the examination and testing of safety critical plant; the use of permit towork systems; the completion of the flushing out of tanks and pipe work and their isolationbefore 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) Organisations may use a range of reactive and proactive strategies for

plant maintenance. Identify FOUR possible plant maintenance strategiesAND outline the principles of EACH strategy. (10)

(b) Outline the factors that you would advise the Engineering Department of an organisation to take into account in deciding on a maintenancestrategy following the installation of an item of process plant. (10)

In answering part (a), candidates could have identified strategies such as plannedpreventive maintenance (PPM), breakdown maintenance, condition monitoring andemergency maintenance. The principles of PPM include the need for planned maintenanceand parts replacement set against a schedule of time or running hours and driven by arecord keeping system. Breakdown maintenance, being reactive, means that maintenance isundertaken in response to reports of malfunction of equipment and the maintenance activityis not required whilst the plant continues to operate effectively. Condition monitoringrequires monitoring of specified parameters, (for example, vibration levels or metal contentof cutting fluids, etc); specifying the level of each parameter when maintenance work needsto be undertaken and measuring continuously or to a schedule. Emergency maintenanceincludes 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 includingexamples of the types of work equipment involved such as cranes and air receivers, and thecost benefit analysis of PPM versus breakdown including the availability of spares,competent staff, and the expected life-time of equipment. Additional factors that could havebeen included in the advice to the Engineering Department are the outcome of riskassessments in terms of failure probability and consequences; the history of failure withexample sources such as incident reports and maintenance data; any relevantmanufacturers 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 ascondition monitoring.

Documents

2008 Jan All_NoRestriction