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Examiners’ Report

NEBOSH INTERNATIONAL DIPLOMA

IN OCCUPATIONAL HEALTH AND SAFETY

Unit IC – International workplaceand work equipment safety

JULY 2008

CONTENTS  

Introduction 2

General Comments 3

Comments on individual questions 4

©  2008 NEBOSH, Dominus Way, Meridian Business Park, Leicester LE19 1QW

tel: 0116 263 4700 fax: 0116 282 4000 email: info@nebosh.org.uk 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-C0807 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 2007/8” published 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 2008

 Any enquiries about this report publication should be addressed to:

NEBOSH

Dominus WayMeridian Business ParkLeicesterLE10 1QW

Tel: 0116 263 4700Fax: 0116 282 4000Email: info@nebosh.org.uk

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

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General comments

Many candidates are well prepared for this unit assessment and provide comprehensive and relevantanswers in response to the demands of the question paper. This includes the ability to demonstrateunderstanding of knowledge by applying it to workplace situations.

There are always some candidates, however, who appear to be unprepared for the unit assessmentand who show both a lack of knowledge of the syllabus content and a lack of understanding of howkey concepts should be applied to workplace situations.

In order to meet the pass standard for this assessment, acquisition of knowledge and understandingacross the syllabus are prerequisites. However, candidates need to demonstrate their knowledge andunderstanding in answering the questions set. Referral of candidates in this unit is invariably becausethey are unable to write a full, well-informed answer to the question asked.

Some candidates find it difficult to relate their learning to the questions and as a result offer responsesreliant on recalled knowledge and conjecture and fail to demonstrate any degree of understanding.Candidates should prepare themselves for this vocational examination by ensuring theirunderstanding, not rote-learning pre-prepared answers.

Recurrent Problems

It is recognised that many candidates are well prepared for their assessments. However, recurrentissues, as outlined below, continue to prevent some candidates reaching their full potential in theassessment.

−  Many candidates fail to apply the basic principles of examination technique and for somecandidates this means the difference between a pass and a referral.

−  In some instances, candidates are failing because they do not attempt all the requiredquestions or are failing to provide complete answers. Candidates are advised to alwaysattempt an answer to a compulsory question, even when the mind goes blank. Applying basichealth and safety management principles can generate credit worthy points.

−  Some candidates fail to answer the question set and instead provide information that may berelevant to the topic but is irrelevant to the question and cannot therefore be awarded marks.

−  Many candidates fail to apply the command words (also known as action verbs, eg describe,outline, etc). Command words are the instructions that guide the candidate on the depth ofanswer required. If, for instance, a question asks the candidate to ‘describe’ something, thenfew marks will be awarded to an answer that is an outline.

−  Some candidates fail to separate their answers into the different sub-sections of the questions.These candidates could gain marks for the different sections if they clearly indicated whichpart of the question they were answering (by using the numbering from the question in theiranswer, for example). Structuring their answers to address the different parts of the questioncan also help in logically drawing out the points to be made in response.

−  Candidates need to plan their time effectively. Some candidates fail to make good use of theirtime and give excessive detail in some answers leaving insufficient time to address all of thequestions.

−  Candidates should also be aware that Examiners cannot award marks if handwriting isillegible.

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UNIT IC – International workplace and work equipment safety

Section A – all questions compulsory 

Question 1  (a) Identify  the hazards associated with the use of mobile elevatingwork platforms (MEWPs). (5)

(b) Outline  the control measures that should be taken when usingMEWPs. (5)

For part (a), candidates needed to identify hazards such as falls from a height ofpersons or materials, instability of the vehicle, being struck by other vehicles, trappingand impact hazards, mechanical failure, contact with overhead lines or otherobstructions and exposure of employees to adverse weather conditions.

Having identified the hazards candidates were then required to outline the measureswhich would be required to reduce the risk when using the equipment. These includethe selection and training of operators; guarding scissor mechanisms to preventtrapping; correct positioning of the MEWP to prevent over-reaching and proximity todangers such as overhead lines; maintaining stability by the use of fully extended andlocked outriggers on firm ground; preventing the use of the equipment in adverseweather conditions; keeping within the safe working limit; prohibiting the transfer ofpersons or materials to or from the platform while it was in a raised position; regular

inspection and servicing of the equipment; preventing falls from the platform by theuse of hand rails or harnesses; controlling working areas by the use of barriers andsigns and providing head protection where appropriate.

Question 2  A vegetable packing plant employing 200 men and 60 women is about toopen. The plant will operate 24 hours a day on a three-shift system.

Outline the specific welfare arrangements that will be necessary prior tothe factory opening. (10)

The specific welfare arrangements that the company would have to provide include asufficient number of sanitary conveniences which should be separate for men andwomen (or capable of being locked from the inside) and which should be adequatelylit, ventilated and kept clean; washing facilities situated close to the sanitaryconveniences and changing rooms, provided with a supply of hot and cold or warmwater, soap or other means of cleansing and means of drying; a clearly marked supplyof drinking water with cups; clothing accommodation and changing facilities whichshould be separate for men and women and contain means for drying wet clothingand for separate storage of contaminated clothing; decontamination facilities withshowers and a clear division between clean and dirty areas; rest and eating facilitiesincluding sufficient tables and seats, arrangements for preparing and heating food andfor boiling water, facilities for nursing mothers and means or procedures for preventingcontamination of the area where food and drink are taken; and adequate first aid

facilities including trained personnel taking into account the number of personsemployed and the proximity of emergency services.

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Question 3  In order to install a large item of machinery such as a turbine rotor it issometimes necessary to perform adjustments while the rotor is in motion.These adjustments are necessarily undertaken with the rotor in anunguarded condition.

Outline the elements of a safe system for such work. (10)

The elements of a safe system of work for carrying out the operation described in thequestion include: the use of experienced workers fully trained in the systems to beadopted since this is not a task to be carried out by the young or inexperienced; theprovision and use of a single one piece close fitting overall with no external pocketstogether with arrangements to ensure there are no other entanglement hazardspresent such as the wearing of jewellery, pendants for example, or long hair; the useof temporary guards on or the isolation of parts of the machine which areunnecessarily exposed; where practicable the use of jigs to ensure workers’ hands aredistanced from the unguarded rotor; the provision of a “stand by” man in direct contactwith the person carrying out the work with means of immediate communication such

as telephone or radio to ensure an emergency response should the need arise; theprovision, close at hand, of an emergency stop or braking arrangements; the use of aninching device to minimise the free rotation period or using the slowest speed possibleconsistent with the task; the provision of adequate lighting; the introduction of a permitto work to formalise the establishment of the safe system of work and the erection ofbarriers and signs to prevent the close approach of non-involved personnel.

Question 4  The transfer of an extremely flammable liquid from a bulk storage tank toa road tanker may generate static electricity. Outline  the controlmeasures which would reduce the risk of ignition of the extremelyflammable liquid vapour due to static electricity. (10)

In answering this question, candidates should have addressed the main methods ofavoiding the build-up of static electricity. These would have included: controlling thepump rate and transfer speed; earthing and bonding the pipeline, the tanker and thestorage tank to ensure all equipment was at zero potential after allowing sufficientrelaxation time; the provision of an interlock between the earthing arrangements andthe pump; the avoidance of splash filling and the selection of conductive/smoothmaterials for the transfer system; elimination of possible contamination arising forexample from the presence of water in the pipeline; the use of a vapour return system;nitrogen blanketing of the road tanker barrel to minimise the risk of explosion; theprovision of instrumentation, for example, to detect earth leakage and the use of antistatic clothing and footwear.

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Question 5  A company produces waste in the form of a hazardous sludge and isconcerned about the increasing cost of using an approved contractor todispose of the waste at a landfill site.

Outline FIVE options that the company could consider to reduce the cost

and environmental impact of dealing with the waste. (10)

In answering this question, candidates should have referred to options such as:identifying recycling opportunities at all stages of the process; substituting processmaterials for ones that give rise to non-hazardous waste; improving productionefficiency in order to produce less waste; treating waste on site to reduce quantity, forexample by de-watering; treating waste to reduce hazardous properties; mixing thewaste with other waste streams to neutralise hazardous properties; selecting wastecontractors who can process the sludge; seeking opportunities to exchange wastestreams with companies that can use waste as raw material; exploring other means ofdisposal such as incineration, or directing liquefied waste to a sewer and exploring thepossibility of becoming approved to save costs.

Question 6  (a) In relation to automatic fire detection and alarm systems, outline the basic principles of operation of:

(i) heat detectors; (4)

(ii) smoke detectors. (4) 

(b) Identify  the circumstances in which EACH  type of detectorwould be inappropriate. (2)

For heat detectors, candidates were expected to distinguish between the fixedtemperature type and the rate of rise type. A fixed rate heat detector has a sensingelement fixed at a particular temperature. By means of a thermocouple or similararrangement, it detects when the predetermined temperature is reached. A rate of riseheat detector detects abnormally fast temperature rises by means of electronicresistors or thermistors.

Smoke detectors are of two main types: ionising and optical or photoelectric. Thechamber of an ionising type has two plates set apart, one charged negatively and theother positively. A small radioactive source is used to ionise the chamber into whichsmoke may enter in the event of fire. The detector reacts to the change in electricalcurrent caused by the neutralisation of ions by the smoke particles. The optical type ofdetector has a number of variants but chiefly responds either to the obscuration of a

focused light ray or to the scattering of light from an optical ray. It therefore reactseither to a reduction in light at a receiver or, more commonly, to the sensing of light byan optical sensor placed in the chamber where light would not normally be detected.

In answers for part (b), candidates should have identified firstly that a smoke detectorwould be inappropriate in situations where smoke, steam or vapour might normally beexpected such as in kitchens while a heat detector might be considered inappropriatein situations where sudden temperature changes might be experienced in normalcircumstances or in situations where slow burning materials are involved which wouldhave an effect on the speed of response.

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Section B – three from five questions to be attempted 

Question 7  It is proposed to inspect, clean and repair the inside of a tank that is 6metres in diameter and 10 metres high and which has previously beenused for storing leaded petrol.

Outline  the steps that should be considered in order to enter thisconfined space and to carry out the work safely. (20)

Good answers to this question were those that approached the proposed work in alogical and sequential way, clearly outlining what would be required at each stage inorder to ensure the work was carried out in a safe manner. In order to develop a safesystem of work, a full risk assessment would have to be carried out whenconsideration would need to be given to the likelihood of flammable atmospheres from

the previous contents of the tank, the possibility of air contamination from the cleaningor repair methods used and the build-up of heat within the tank. The assessmentwould also need to look at other issues from the work to be carried out includingworking from height and the toxic effects of lead.

Completion of the risk assessment would point to appropriate precautions such as theneed to purge the tank with an inert gas, the use of forced ventilation, atmospherictesting before entry and while the work was being carried out and the provision ofpersonal protective equipment possibly including air-fed breathing apparatus. Attention would also need to be paid to the requirements for electrical equipment (forexample intrinsically safe or flameproof) and earthing arrangements. If heat were to bea foreseeable problem, then consideration should be given to issues such as jobrotation and fluid intake. Additionally, consideration should be given to the prevention

of falls from height and the means of access and egress in the event of escape andrescue. Procedural arrangements would centre on the implementation of an entrypermit system, limiting the number of people working in the tank, communication withstandby personnel and drawing up emergency arrangements.

The emergency arrangements to be considered would include issues such as theprovision and maintenance of cutting equipment, hoists, fire-fighting equipment,personal protective equipment such as breathing apparatus, first aid facilities includingresuscitation apparatus and liaison with the emergency services. Additionally,arrangements should be in place to ensure that all personnel involved in the operationhad received sufficient training in the work methods, the precautions needed and theemergency procedures.

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Question 8  Workers in a vehicle maintenance workshop undertake spray-painting ofvehicles using a solvent based paint that has a low flash point.

Outline the measures to be taken to ensure that the risks associated withthe spray-painting activity are adequately controlled. (20)

One of the first measures to be taken in this situation would be to carry out anassessment of the risks involved in carrying out the activity which would include thehazardous properties of the paints and solvents used (normally by reference to safetydata sheets), the circumstances in which the work was carried out, possible ignitionsources and the likelihood that a fire or explosion would occur. The control measuresto be taken would be firstly to ensure that the workshop was constructed of fireresistant material, and then to give consideration to the possibility of replacing thepaint in use with one that was less flammable. An external fire resistant storeroomwould have to be provided for the paints and solvents with the quantities present inthe workshop reduced to a minimum and kept in non-spill containers provided withlids. Procedures would have to be put in place for the containment and clean up of

spillages and for the cleaning of the spray guns. Local exhaust ventilation would haveto be provided in the workshop with care taken to ensure all electrical equipment wasto the standard appropriate for the conditions that might prevail, such as flameproof orintrinsically safe. Fire fighting equipment would have to be provided together withadequate fire escape routes and emergency procedures drawn up and communicatedto the workforce who would also need instruction and training on the risks involved inthe operation and the precautions to be observed.

Question 9  Corrosion is a major problem in many industrial processes.

(a) Outline  the characteristics and causal factors of electrolytic

corrosion. (8)

(b) Outline  the strategies  AND  methods for identifying potentialcorrosion failures. (12)

Electrolytic corrosion is an electrochemical process in which one metal corrodespreferentially when in electrical contact with a different type of metal and both metalsare immersed in an electrolyte. The metals have different electrode potentials and theelectrolyte provides a means for ion migration whereby metallic ions can move fromthe anode to the cathode. This leads to the anodic metal corroding more quickly thanit otherwise would whereas the corrosion of the cathodic metal is retarded.Characteristics of corrosion include pitting and erosion and its products may affect

quality of product and may lead to a reduction in flow in pipe work.

 A strategy to prevent corrosion would aim to interrupt the formation of a corrosion cellby the removal of electrical contact or the removal of the electrolyte. Removal ofelectrical contact can be achieved by insulation using plastic or a similar insulatingmaterial, or by the use of protective coatings such as galvanising or painting. Additional methods of preventing corrosion include the use of a sacrificial anode madeof a metal which is more active than the protected metal; the connection of anelectrical power supply to oppose the corrosive current and the use of water treatmentand/or purification techniques. The use of visual inspections and NDT are a means ofidentifying the effects of corrosion as is also checking for the presence of contaminantin the product and the use of corrosion measure currents.

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Question 10  A worker has received an electric shock from a 240 volt portable drillwhilst installing a set of wooden shelves.

(a) Outline the physical effects the worker may have suffered fromthe accident. (5)

(b) State  the emergency action that should have been takenimmediately after the accident. (5) 

(c) Identify  the precautions that might have been taken to preventthe accident. (10)

For part (a), candidates should have outlined effects such as fibrillation of the heartmuscles with possible cardiac arrest, respiratory failure, muscular contraction orspasm, involuntary grip that can prolong current flow, burns to tissue and ultimatelydeath. There is also the possibility of secondary injuries such as those resulting froma fall.

Part (b) was concerned with the emergency action to be taken immediately after theaccident and it was expected that candidates would refer to matters such as isolatingthe source of power or using a non-conductive instrument to push the victim clear;wrapping the victim in insulating material and checking for breathing and pulse;administering mouth-to-mouth resuscitation if needed; placing the victim in therecovery position and contacting the emergency services.

Part (c) sought information on the precautions that might have been taken in order tohave prevented the accident. More successful candidates were those who provided astructured answer by looking at equipment selection, technical precautions andorganisational issues. In selecting equipment, consideration should be given to theuse of reduced voltage, battery-powered and/or double-insulated tools and conformity

with standards. Technical precautions include the use of residual current devices,ensuring earth integrity (where appropriate), using correctly rated cables and fuses,and ensuring that equipment or system components (plugs, sockets, cables etc) arefree from damage, while organisational issues relate to maintenance arrangements,inspection and testing of portable appliances and electrical systems, housekeepingstandards, and the provision of information, instruction and training – particularly inrelation to systems of work and pre-use checks.

Question 11  A company has been contracted to undertake maintenance work on theroof of a building, which is partly constructed of fragile material.

(a) Identify  the characteristics of the fragile material that maycontribute to the risk of falls through the roof. (5)

(b) Outline  the measures to be taken to reduce the risk to thoseinvolved in the roof work and those who may be affected by it. (15) 

In answering part (a) of the question, candidates should have referred tocharacteristics such as the age and condition of the material; the type of material suchas fibre board, asbestos or polycarbonate and its thickness; the sheet profile; the spanbetween roof supports; the design of the supporting structure such as the purlins; thecondition of the fixings; the slippery nature of the surface and the fact that the fragilematerial might well be camouflaged by deposits of dirt and other material.

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For the second part of the question, an initial reference should have been made to theimportance of completing a full risk assessment of the operation to be carried out andthe consequent production of a method statement detailing the safe system of work tobe followed. This would describe the proposed means of access to the area of worksuch as the provision of scaffolds and crawling boards and the erection of edgeprotection to prevent the falls both of persons and materials from the roof. It would

also be necessary to identify areas of the roof containing fragile materials, to markthem with barriers or signs and to prevent falls through them by the use of covers. Anadditional safeguard would be to provide safety nets and/or air bags under the areasof the roof which contained fragile materials. For certain tasks, the use of safetyharnesses with adequate fixing points might also be necessary. Arrangements, suchas a hoist, might be needed to transport tools, equipment and materials to the roof,while the use of chutes should be considered for the removal of rubbish. An importantfactor in carrying out this type of work is to ensure the use of competent personnelfully briefed and aware of the risks involved and the precautions to be observed.Finally, measures would have to be taken such as the erection of barriers and signs toprevent occupants of the building from passing beneath areas of the roof where workwas being carried out and also members of the public from passing in close proximityto the building.

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