examiner reports july 2009 unit ic

8/12/2019 Examiner Reports July 2009 Unit IC

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July 2009

Examiners Report

NEBOSH InternationalDiploma inOccupational Health

and Safety (Unit IC)


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Examiners Report

NEBOSH INTERNATIONAL DIPLOMA

IN OCCUPATIONAL HEALTH AND SAFETY

Unit IC International workplaceand work equipment safety

JULY 2009

CONTENTS

Introduction 2

General comments 3

Comments on individual questions 4

2009 NEBOSH, Dominus Way, Meridian Business Park, Leicester LE19 1QW

tel: 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-C0907 EXTERNAL DW/DA/REW


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Introduction

NEBOSH (The National Examination Board in Occupational Safety and Health) was formed in 1979 asan independent examining board and awarding body with charitable status. We offer a comprehensiverange of globally-recognised, vocationally-related qualifications designed to meet the health, safety,environmental and risk management needs of all places of work in both the private and public sectors.Courses leading to NEBOSH qualifications attract over 25,000 candidates annually and are offered byover 400 course providers in 65 countries around the world. Our qualifications are recognised by therelevant professional membership bodies including the Institution of Occupational Safety and Health(IOSH) and the International Institute of Risk and Safety Management (IIRSM).

NEBOSH is an awarding body to be recognised and regulated by the UK regulatory authorities:

The Office of the Qualifications and Examinations Regulator (Ofqual) in England

The Department for Children, Education, Lifelong Learning and Skills (DCELLS) in Wales

The Council for the Curriculum, Examinations and Assessment (CCEA) in Northern Ireland

NEBOSH follows the GCSE, GCE, VCE, GNVQ and AEA Code of Practice 2007/8published by theregulatory authorities in relation to examination setting and marking (available at the Ofqual websitewww.ofqual.gov.uk). While not obliged to adhere to this code, NEBOSH regards it as best practice todo so.

Candidates scripts are marked by a team of Examiners appointed by NEBOSH on the basis of theirqualifications and experience. The standard of the qualification is determined by NEBOSH, which isoverseen by the NEBOSH Council comprising nominees from, amongst others, the Health and SafetyExecutive (HSE), the Department for Education and Skills (Df ES), the Confederation of BritishIndustry (CBI), the Trades Union Congress (TUC) and the Institution of Occupational Safety andHealth (IOSH). Representatives of course providers, from both the public and private sectors, are

elected to the NEBOSH Council.

This report on the Examination provides information on the performance of candidates which it ishoped will be useful to candidates and tutors in preparation for future examinations. It is intended tobe constructive and informative and to promote better understanding of the syllabus content and theapplication of assessment criteria.

NEBOSH 2009

Any enquiries about this report publication should be addressed to:

NEBOSH

Dominus WayMeridian Business ParkLeicesterLE10 1QW

Tel: 0116 263 4700Fax: 0116 282 4000Email: [email protected]

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http://www.ofqual.gov.uk/http://www.ofqual.gov.uk/


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UNIT IC International workplace and work equipment safety

Section A all questions compulsory

Question 1 Outlinethe precautions that should be taken when construction work isto take place under or near overhead power lines that will remain liveduring the work. (10)

In answering this question, candidates would have done well to have structured theirresponses round the key elements described in HSE Guidance Note GS6. The initialprecaution to be considered would have been the possibility of rerouting the cables

but if this was not possible then the local electricity supply company would need to beapproached for advice on the precautions to be taken. This would include advice onthe maximum working heights and horizontal distances permitted near the overheadlines. The next step would be to establish the maximum height and vertical reach ofplant to be used on site including those of sub contractors and those which couldpenetrate the safe distances would have to have physical limiting equipment fitted.Safe routes where plant could travel and operate would have to be marked, barriersand solid goal posts erected which would need to be monitored on a regular basis toensure they remained intact and in place, and appropriate warning signs displayed.Non-conductive equipment, for example wooden ladders, would have to be used onsite. Workers and sub contractors should be briefed on the hazards associated withthe work and the safe systems of work to be followed and drivers of visiting vehicleswould also have to be instructed on the routes to be followed. Procedures for dealing

with an emergency would be necessary and information on these procedures wouldagain have to be passed on to workers. Finally a high level of supervision would haveto be provided to ensure that there was strict adherence with the precautionarymeasures that had been put in place.

Answers were generally to a reasonable standard though some candidates treated itas an electricity, rather than a construction, question and wrote of the precautionarymeasures to be taken to deal with the possible presence of buried cables. If markswere lost it was because candidates produced a list rather than the outline that wasrequired.

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Question 2 In 1974 a plant in Flixborough, United Kingdom, producing highlyflammable pressurised gas developed a leak on the fifth of six reactors.In order to continue production the fifth reactor was removed from serviceand a bypass assembly then installed between the fourth and sixthreactor. The bypass assembly subsequently ruptured and an unconfined

vapour cloud explosion followed.

(a) Describe the mechanism for an unconfined vapour cloudexplosion. (3)

(b) Outline the technical failings that contributed to this majoraccident. (7)

The incident at Flixborough occurred following the uncontrolled release of a gas,cyclohexane, from a temporary pipeline which had been used to bypass a reactortaken out of service for repair. On release the gas formed a flammable mixture in airwithin explosive limits and the large vapour cloud either immediately came across a

source of ignition or travelled some distance to find one where it was quicklydetonated causing rapid flame propagation.

In answering part (b), candidates should have descrined the absence of aprofessionally qualified mechanical engineer on site to oversee the modificationbetween the fourth and fifth reactor. The plant modification took place without a fullassessment being made of the potential consequences of its installation. There wasan absence of drawings for the proposed modification, no reference was made to anyrecognised standard, the constructed assembly was of unknown strength and flowand pressure calculations were undertaken on a straight bypass line and not a dog legas subsequently fitted. Pneumatic tests that were carried out were for leak testing andnot in order to assess the strength of the assembly. There was apparently noappreciation that the pressurised assembly would be subject to a turning moment,

imposing lateral shear forces on the bellows nor an appreciation of a hydraulic thruston them and consequently no calculations were undertaken for the dog leg line or thebellows to withstand these strains. No reference was made to the Designers guide sothat bellows were used out of line without adequate support, and insufficient supportprovided for the newly installed pipe work under working conditions. Finally and inshort, those concerned with the design, construction and lay out of the modificationdid not consider the potential for a major disaster to occur instantaneously.

Answers provided for this part of the question were particularly disappointing. Somecandidates described what happened rather than why it happened and someappeared unfamiliar with Flixborough.

Question 3 (a) Outlinethe purpose of non-destructive testing (NDT) on items ofplant. (2)

(b) Outline the principles, benefits and limitations of the followingNDT techniques:

(i) dye penetrant; (4)

(ii) radiography. (4)

The purpose of non-destructive testing (NDT) is to check for faults such as cracks incomponents before they develop into total failure without affecting the integrity of the

component.

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In answering part (b) of the question, candidates were expected to outline that the useof the dye penetrant technique makes cracks visible as dye penetrates into them. It isa relatively cheap and simple operation but it does not detect sub-surface faults, is nottotally reliable, interpretation of the indications may be difficult, there is a possibleelement of toxicity involved and there is no permanent record available of the resultsof the test.

With radiography, x-rays or gamma rays are used to penetrate the item to leave animage on film. Any defects are shown up by the differences in the intensity of theradiation striking the film. The benefits of this technique are that it detects internaldefects and produces a permanent record of the test. However, the operation is timeconsuming, expensive and requires bulky equipment and skilled radiographers.Additionally, there is a danger of radiation exposure.

In general answers to this question were to a good standard.

Question 4 A scaffolder is lowering scaffold poles from the third floor of a scaffold

assembly to a colleague below using a pulley wheel and rope. Next to thescaffold tower there is a shop entrance. The scaffolder on the groundfloor places the scaffold poles horizontally onto the back of a lorry parkedon a busy road. The scaffolders have already received information,instruction, training and suitable supervision.

Outlinethe additional practical measures that could minimise the risk ofinjury to the scaffolders and others that may be affected by this activity. (10)

The first option would be to investigate the possibility of using an alternative means oflifting such as a crane. If this was not possible then there would be a need to ensurethat the pulley wheel and rope were in good condition and had been subjected to the

required statutory inspections and that the safe working load of the equipment was notexceeded. The workmen would need to adopt the correct slinging techniques andrigging on the scaffold poles and use guide ropes where necessary. Toe boards andhandrails would need to be fitted on the upper platform to protect both the scaffolderon that floor and the public below while belts or lanyards should also be worn by theworkman on the upper floor as fall protection. Attention should be given to nearbyhazards such as obstructions and power lines and signs and barriers erected atground floor level to prevent public access to the lowering area. There could be adanger from passing traffic and the placing of cones would help to prevent a collisionwith the lorry. Finally both workmen should be provided with and wear high visibleclothing, gloves and head protection.

Whilst there were a number of reasonable answers provided for this question, there

were a few who considered it to be predominantly a question dealing with scaffoldingand wrote about ensuring that it was correctly constructed and was in no danger offalling over.

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Question 5 As Health, Safety and Environment Manager at a hazardous installationyou are responsible for emergency planning. The site is regulated underthe International Labour Organisation (ILO) Code of Practice Preventionof Major Industrial Accidents 1991. In the event of an uncontrolledrelease:

(a) outline the need for emergency planning; (3)

(b) outline the general emergency planning measures that shouldbe taken by the competent authorities in association with theworks management of the installation. (7)

For part (a), candidates should have outlined, that in the event of an uncontrolledrelease, there would be a need for emergency planning to localise the release and ifpossible, contain it; and to minimise the harmful effects of the release on people,property and the environment both inside and outside the installation by the use ofsafety systems, alarm systems and the emergency services. Clear and well defined

plans should be made available for quick and effective use and where emergencyequipment and manpower are limited, provision should be made for mutual assistancefrom neighbouring industrial activities.

For part (b), general emergency planning measures that should be taken by thecompetent authorities include the need: to establish arrangements for an on-siteemergency plan which should be drawn up by the management of the installation; toestablish arrangements for an off-site emergency plan to be drawn up by the localauthority in conjunction with the installations management, which should be preparedfollowing consultation with various bodies such as the fire and police authorities andthe hospital and ambulance services and which should be consistent with the on-siteemergency plan; to ensure that regular rehearsals were carried out in order to keepthe off-site plan in a state of readiness and also to ensure that information on safety

was provided to members of the general public.

Many candidates found this question challenging, in particular the second part with anumber concentrating on legal requirements including those contained in the COMAHRegulations. Examiners gained the impression that candidates provided answers forthe question they had anticipated and had practised rather than the one that actuallyappeared on the question paper.

Question 6 (a) Givethe meaning of the term confined space. (2)

(b) Outline the factors that should be considered to ensure that

emergency rescue arrangements for confined space work aresuitable and sufficient. (8)

An acceptable answer to part (a) of the question would have been that a confinedspace is any enclosed or partially enclosed place such as a chamber, tank, vat, silo,pit, trench, pipe, sewer or flue or other similar space in which, by virtue of its enclosednature, there arises a reasonably foreseeable specified risk such as a lack of oxygenor the possibility of drowning in free flowing solids.

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Part (b) required an outline of the specific factors that would have to be considered inensuring that arrangements for emergency rescue from a confined space weresuitable and sufficient. The factors would relate to the nature of the confined space,the risks identified and how an emergency rescue might take place and could includemethods of raising the alarm to advise those outside to initiate rescue procedures; thetype of equipment such as life lines, lifting equipment and breathing apparatus that

would be required; the means provided for emergency access/egress; the precautionstaken to protect rescuers from the risks to health and safety identified in theassessment; the identification of plant in the vicinity that may need to be shut downduring an emergency rescue; the number and competence of those who would beinvolved in the rescue; precautions taken to counter the possibility of fire such as theprovision of fire extinguishers; means provided for contacting public emergencyservices and supplying them with relevant information; the availability of first aidassistance until the arrival of professional medical help and the provision of training orrefresher training for persons likely to be involved in emergency rescue procedures.

There were some vague definitions of a confined space given in answer to part (a),while a number of candidates did not read the second part of the question withsufficient care and outlined the normal control measures that should be put in place

when carrying out work in a confined space.

Section B three from five questions to be attempted

Question 7 As a Health and Safety Officer you are asked to give advice to a liftsupervisor regarding a proposed lifting operation. The lift requires the useof two cranes working together (a tandem lift).

Outlinethe elements of a safe system of work you would expect to see

in order that the lift may be conducted safely. (20)

A prime requirement would be that the proposed lifting operation should be plannedby a competent person and be closely supervised in accordance with the level of riskinvolved. A risk assessment would need to be carried out which should addressmatters such as the weight, shape and centre of gravity of the loads and theavailability of lifting points; the positioning of the cranes and any available restingplaces for the loads; the number of times the lifting operation will be carried out; theavailability of the correct lifting equipment together with the availability of testcertificates and reports of statutory examination for the cranes; the precautions takento cordon off the area for the lift and the environment in which the lifting equipment willbe used and the likely weather conditions. The cranes will have to be positioned using

outriggers and jacks to ensure stability, and sited on firm ground away from trenchwork or other excavations and overhead and underground services. The lift should beunder the control of a competent person with knowledge of and training andexperience in carrying out a tandem lift. Crane drivers and banksmen would have tobe competent and there would need to be an effective means of communicationbetween them using standard methods of signalling, Calculations should be carriedout by a competent person to decide whether the cranes would need to be de-ratedand the lift should be carried out in such a way that the agreed individual safe workingload of either crane is not exceeded.

This was a popular question which produced a good standard of response althoughcandidates failed to gain marks by producing lists rather than outlines.

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Question 8 A factory manufactures upholstery using fabrics and plastic pellets.These raw materials are delivered to a warehouse. The fabrics andplastic pellets are machined to form furniture coverings and cushions.The plastic pellets have been sprayed with flame retardant. The finishedproduct is then stored in a despatch warehouse prior to distribution. The

movement of goods around the premises is carried out by LiquidPetroleum Gas (LPG) fuelled forklift trucks. The company is located onthe outskirts of a small town and employs 230 people.

Outlinethe range of factors that must be addressed to ensure a suitableand sufficient fire risk assessment is made for the premises. (20)

There are a number of factors to be considered in carrying out a suitable and sufficientfire risk assessment of the premises described in the scenario and they may begrouped under the general headings of fuels, ignition sources, people issues,preventive actions, mitigating actions, means of escape and management systems.

Factors connected with fuels which would have to be addressed include the LPG forthe fork lift trucks, the flammable covers and untreated fillings and structural issuessuch as the materials of construction of the premises themselves.

Ignition sources would include those connected with the use of electricity including thelikely presence of static, friction from machinery which may not be adequatelymaintained, illegal smoking by personnel, the controls (or lack of them) introducedfor maintenance which might include hot work, and the possibility of arson.

As for people issues, attention would have to be given to the number of persons to beevacuated in the event of a fire including visitors and contractors with the needs ofdisabled workers being particularly addressed.

Preventive actions would include compartmentalisation for higher risk areas such asthe plastics and LPG stores with the latter being segregated, bunded and providedwith a fixed sprinkler system; fixed protection systems in warehouses and anadequate supply of water and/of foam; the use of fire resistant cover materials;minimising the amount of stock kept on the premises and ensuring a good standard ofhousekeeping with facilities provided for the segregation of waste.

Mitigating actions would be concerned with the sufficiency and appropriate nature ofthe fire fighting equipment together with its location, smoke venting of warehousesand the provision of access for emergency services.

The assessment would need to give particular attention to the means of escape andthere would have to be assurance that these were continually maintained and that fire

doors were correctly specified. Attention would have to be given to travel distancesincluding multi-storey considerations, the provision of normal and emergency signageand emergency lighting together with refuges for subsequent evacuation and theprovision of assembly points in a place of safety.

Finally the assessment would have to consider the management systems introducedfor the maintenance and testing of fire precautions and mitigation equipment, thecarrying out of fire drills and the training given to workers both in evacuationprocedures and the use of fire fighting equipment.

Several candidates wrote about generic fire control measures and did not deal withthe potential hazards involved in the operations carried out in the premises describedin the question. A few limited their answers to the problems associated with the use of

LPG fuelled trucks.

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Question 9 A plastics injection moulding machine is supplied to your workplace.

Outline the moulding machines features that you would have expectedto have been addressed in order to demonstrate that the machine is safe. (20)

Features that should have been addressed to demonstrate the safety of the plasticsinjection moulding machine could have been outlined under the headings of generalfeatures, and those dealing with controls, protection against mechanical hazards,protection against other hazards, maintenance and indicators. Successful candidatesstructured their answers under these headings.

The general features of the machine include the safety integration principles such asthe control hierarchy applied, foreseeable abnormal use and ergonomicsanthropometry; the prevention of danger to the user from the materials used in theconstruction of the machine or products created during its use such as coolants; thelighting provided which gives adequate visibility without causing dazzle or producingstroboscopic effects; and the handling and installation of the machine so that sharp

edges are avoided and the machine is fitted with eyebolts.

With regard to controls and control systems, their safety and reliability should beaddressed to ensure they can withstand the rigours of normal use and take account oferrors in logic; that control devices are visible, identifiable, well positioned, logical andsufficiently robust; that there are adequate means for starting the machine byvoluntary actuation except where an automated cycle is in operation and a stoppingdevice is fitted which disengages power to the actuators and also an emergency stopwhich brings the machine to a halt quickly without creating additional risk; that a failureof the power supply and/or control circuit does not allow the machine to startunexpectedly and the protection devices remain effective, and that any interactivesoftware fitted is user friendly.

The features concerned with the protection against mechanical hazards which shouldhave been addressed include the stability of the machine; the risk of break up duringoperation; the risks caused by falling or ejected objects; the variations in speeds andrisks from moving parts which should be designed to avoid hazards or provided withprotective devices; the choice and characteristics of guards and protective deviceswhether fixed, movable or adjustable; and issues arising from working at heights.

Protection against other hazards would need consideration of electrical risks, thosearising from fire and explosion, extremes of temperature, noise and vibration and theemission of dust and/or gases. As for maintenance, matters such as remoteadjustment and lubrication, automatic cleaning, isolation, and means of access shouldhave been addressed, while finally for indicators, issues which should have beenconsidered include the provision of unambiguous and easily understood information

and warning devices, the provision of instructions on the installation, use andmaintenance of the machine and its marking, in particular the CE mark, its serialnumber and details of the manufacturer.

This was not a popular question and was not well answered with some candidatesonly offering advice on how to use the machine safely.

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Question 10 (a) Describe the effects of a fire in a workplace on the followingstructural materials:

(i) steel; (4)

(ii) concrete; (4)

(iii) wood. (4)

(b) Outline the precautions that could be taken to prevent failure ofthese materials in the event of fire. (8)

In answering part (a) of the question, candidates should have recognised that steelexpands on heating, loses strength as the temperature rises and tends to deform andbuckle. It regains strength on cooling but its properties may have changed. Concreteon the other hand exhibits limited expansion and has a tendency to spall and crackwhich can be exacerbated by the expansion of steel reinforcement within theconcrete. The structural strength of concrete is lost on cooling and it loses structural

integrity. As for wood, while thin sections will burn and promote fire, the charredsurface of thicker structural members may act as an insulator to protect the innertimber. However, burning timber generates smoke and fumes and allows the surfacepropagation of fire. Some varieties of timber are more resistant to fire than otherswhile large timbers generally tend to retain their structural integrity.

Part (b) was concerned with the precautions that could be taken to prevent failure ofthe materials in the event of fire. Steel might be protected by the use of sprayedconcrete or intumescent coatings, while for concrete, the selection of the type of mixto improve fire resistance and increasing the thickness of concrete between theexternal face and reinforcement bars would provide some protection. Failure of woodmay be prevented by selecting fire resistant timber, increasing the thickness used toallow for a charring outer layer or impregnating it with fire retardant. Other general

precautions include the provision of means such as compartmentalisation to preventheat transfer through long steel members in the event of fire; automatic means ofapplying water to structural members should fire occur and the use of fire resistantsurface claddings or flammable sacrificial cladding.

Question 11 As part of a water treatment system, a manufacturer is to install a plantsuitable for the reception and storage of sulphuric acid and caustic soda,both of which will be delivered in road tankers. These substances arehighly corrosive and can react violently together.

Outline the safety provisions required for:

(a) the design; (10)

(b) the operation; (6)

(c) the maintenance of the proposed storage facility. (4)

Candidates who divided the question into its component parts, ie design, operationand maintenance and dealt with the detail of these issues in turn achieved moresuccess.

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Under the design issues, it was expected that candidates would deal with the need forthe storage tanks and pipe work to be constructed of suitable chemical resistantmaterial; the design, positioning and marking of the delivery inlets to preventconnection being made to the wrong tank; the positioning of the storage tanks inseparate bunds with the bunds being capable of holding the entire contents of thetanks plus 10%; the erection of hazard warning signs clearly identifying the contents of

the tanks and the colour coding of pipe work; the fitting of level indicators and highlevel alarms to prevent overfilling; the provision of good vehicle access including ahard standing for tankers with facilities for spill containment; provision of earthing andbonding for the tanker, connection and hoses; measures to avoid the tanker beingdriven away whilst still connected and the provision of drench showers and eyewashstations and a good standard of lighting.

Operational issues should have included the introduction of a safe system of workincluding emergency procedures to deal with spillages and the provision andmaintenance of a contingency supply of neutralising and absorbent materials andwater; providing training for the personnel involved including tanker drivers in the risksassociated with the operation and the control measures to be followed and theprovision of personal protective equipment such as chemical suits, chemical resistant

gloves and full face protection.

In outlining the issues connected with maintenance, candidates were expected to referto the arrangements for the examination and testing of safety critical plant; the use ofpermit to work systems; the completion of the flushing out of tanks and pipe work andtheir isolation before the start of maintenance work; regular cleaning of the bunds andthe provision of training to maintenance staff in emergency procedures.

Answers provided for part (a) were generally better than those for the other two partsof the question. Some candidates provided very general responses without paying toomuch attention to the scenario described, whilst others dealt with it as a question onhighly flammable liquids with the potential for a BLEVE or unconfined vapour cloudexplosion.

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The National ExaminationBoard in OccupationalSafety and Health

Dominus WayMeridian Business ParkLeicester LE19 1QW

telephone +44 (0)116 2634700fax +44 (0)116 2824000email [email protected]

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