NEBOSH INTERNATIONAL GENERAL CERTIFICATE

NEBOSH International General Certificate in Occupational Safety and Health

Unit IGC2

Element 8: Physical and Psychological Health Hazards and Risk Controls

1Learning Outcomes

On completion of this element, you should be able to demonstrate understanding of the content through the application of knowledge to familiar and unfamiliar situations. In particular you should be able to:

Outline the health effects associated with exposure to noise and appropriate control measuresOutline the health effects associated with exposure to vibration and appropriate control measuresOutline the health effects associated with heat, ionising and non-ionising radiation and basic protection techniquesOutline the causes and effects of stress at work and appropriate control measures2Unit IGC 2Element 8.1Noise

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Health effects:Temporary:reduction in hearing (temporary threshold shift)ringing in earsPermanent:tinnitusnoise-induced hearing loss (permanent threshold shift)Physical damage to hearing mechanismsStressSafety issues:Inability to hear vehicles, warnings, conversationsConcentration problems

Noise4The Human Ear

The hearing mechanism transmits noise from the outside environment through the outer and middle ear to the inner ear (the transmission route is ear canal; eardrum; hammer; anvil; stirrup; cochlea). Microscopically small sensory hairs in the inner ear then detect the noise and send nerve impulses to the brain. Exposure to excessively loud noise disturbs these microscopically small hairs.

One-off exposures to high noise levels (e.g. 4 hours of work in a high noise area) will probably cause a temporary loss of hearing sensitivity (called temporary threshold shift) and temporary ringing in the ears (tinnitus). The microscopically small hairs have been disturbed, but not damaged beyond repair. Repeated exposures result in permanent threshold shift - irreparable damage because the sensory hairs are parts of nerve cells that do not regenerate. This is noise induced hearing loss.This hearing loss does not normally occur quickly, but over years as noise exposure continues. The damage is progressive; once it starts any further exposure to excessive noise will result in further damage.

5The Human Ear

cilia6Identify occupations at risk from noise induced hearing loss and the potential causes.Group Activity7Construction workersPlant, machinery, e.g. concrete breakersUniformed servicesSmall arms and artilleryEntertainment sector workersLoud musicManufacturing sector workersIndustrial machineryCall centre workersAcoustic shock from headsetsOccupations at Risk8Sound pressure levelexpressed in decibels (dB)Decibel (dB)sound pressure level, loudnessFrequencypitch human ear detects 20Hz to 20,000HzA-weightingnoise measurement scale matching human hearingC-weightingnoise measurement scale accurate for impulse noiseDaily Personal Noise DoseTerminology

9Measurementin dB(A)Sound0Faintest audible sounds20-30Quiet library50-60Conversation65-75Loud radio90-100Power drill140Jet aircraft on take-off at 25mDecibel LevelsThe decibel scale is logarithmic An increase of just 3 dB = a doubling of sound

RRC Training10The Noise Table

Simple sound metermeasures instant noise levelssimple surveysIntegrating sound level metermeasures noise over a period of timeused for all surveysDosimeters worn by workerpersonal noise exposure

Noise Assessment

If a noise assessment is needed then some form of noise survey will probably have to be carried out. Before this is done information has to be obtained from the workplace (e.g. about the noise sources in the workplace and shift patterns). This background information can then be used to target the survey and can help in the interpretation of results.Different types of noise meter that can be used to undertake noise measurement include: Simple sound level meter measures instantaneous noise levels and can be used for spot checks or for very simple surveys. Integrating sound level meter measures noise over a period of time and gives a time-weightedaverage over that time period; useful for most noise surveys. Dosimeters integrating sound level meters worn by the worker to give a measure of personal noise exposure; useful for work areas where people move around a lot. The results of a noise survey need to be interpreted to give an accurate estimate of workers exposures. These exposures can then be compared to the legal standards and any necessary action identified.Noise measurement and assessment is a complex topic that should only be undertaken by a competent person.

12Subject to national lawGeneral agreement on daily personal noise dose of 85dB(A)Dose depends uponNoise level in dB(A)Duration of exposure

The daily personal noise exposure (LEP,d) is usually measured over 8 hours

Noise Exposure Standards

13European Standards (by way of example)Lower Exposure Action Value: 80 dB(A)Noise assessmentInformation, instruction and trainingProvide hearing protection

Noise Exposure Standards

These slides show the levels of noise which are acceptable/unacceptable by exampling the European standards. The delegates dont need to know the EU limits, it has just been included to illustrate the acceptable/unacceptable levels of noise.14Upper Exposure Action Value: 85 dB(A)Noise assessmentReduce noise exposure by engineering means, If noise is still above 85 dB(A)Mandatory hearing protection zoneInformation, instruction and training Provide hearing protection and enforce useHealth surveillance

Noise Exposure Standards

15A noise survey has been carried out and there are 2 work areas of concern:Machine shop - noise levels83 dB(A) throughout the shift Wood working area - noise levels 87 dB(A) throughout the shiftDiscuss the actions that would could be taken in each area

Group Exercise

Machine shopLower Exposure Action Value: 80 dB(A)Noise assessmentInformation, instruction and trainingProvide hearing protection but workers do not have to wear it

Wood working areaUpper Exposure Action Value: 85 dB(A)Noise assessmentReduce noise exposure by engineering means SFRPIf noise is still above 85 dB(A)Mandatory hearing protection zoneInformation, instruction and training Provide hearing protection and enforce useHealth surveillance

16Noise SourceStructure pathwayDirect Noise PathReflected Noise PathNoise Exposure ControlNoise: source, pathway, receiver17

SourceEliminateSubstituteModify processDampingSilencingMaintenancePathwayInsulationIsolationAbsorptionNoise Exposure ControlReceiverAcoustic havenHearing protection

18Discuss why hearing protection is an inefficient method of reducing noise exposure in a noisy workplace

Group Exercise

Dont enclose the sound only protects 1 person

Rely on:Use for all exposure time logarithmic scale means short exposure with out them has big effect on dose receivedUncomfortableRequire supervisionRequire maintenanceMay interfere with communications, alarms etc.Muffs:Muffs may be incompatible with other PPEGood fit no facial hair, jewellery etc. for muffsEar plugs:Must be fitted properly into ear canalMay introduce infectionNot easy to supervise cant see themMay be wrong frequency type or attenuation level19

Noise Reduction Techniques?Re-design or maintain- DampingAcoustic GuardAbsorb or ShieldEnclose the person or machineShadowNoise20Noise Transmission Pathways

Ear Defenders (muffs)Encase the ear and bones surrounding the earEar plugsFit into the ear canal

Hearing Protection

22Hearing ProtectionAdvantagesLimitationsEasy to supervise andenforce use as visibleUncomfortableLess chance of earinfectionsEfficiency affected by long hair, spectacles etcHigher level ofprotection possibleMust inspected, cleaned andmaintainedCan integrate with other PPEReusableEar defenders or muffs23Obviously a major issue with all hearing protection is that it makes communication difficult

Hearing ProtectionEar plugsAdvantagesLimitationsCheap and easy to useDifficult to see when fitted, supervision and enforcementdifficultDisposableRisk of infection if dirty or if cross-contaminated when insertedMore comfortable, range of designsNeed to be correctly sized for individualDo not interfere with other PPEEffectiveness decreases with usage24Obviously a major issue with all hearing protection is that it makes communication difficultInformation, instruction, trainingSafe storageCleaningMaintenanceReplacement

Hearing Protection

25Attenuation (reduction)Information is required on the:Noise in the workplacefrom surveyAttenuation characteristics (decrease of the effect or not) hearing protectionfrom manufacturerEar muffs give higher attenuation than ear plugs

Hearing Protection

26Note that ear defenders can give higher attenuation than ear plugs because some noise can be transmitted through the bone of the skull this transmission route is partly blocked by defenders but not by plugs. Also note that the attenuation characteristics of hearing protection are measured in laboratory conditions. Ear defenders in particular can give lower attenuation in practice because of hair or earrings which push the ear defender away from the side of the head.

Audiometry allows:Identification of workers withpre-existing hearing damagenew hearing damageRemoval/exclusion of such workers from high noise areasInvestigation of noise controls to rectify problems

Health Surveillance

27What are the health effects of exposure to high levels of noise?There are 3 main ways of reducing noise (fill in the blanks)Reduce noise at ________________Interrupt the __________from source to receiverProtect the ________ through engineering controls or PPEWhat types of PPE are available? What are the pros and cons of each?

End of Section Quiz1- Temporary reduction in hearing sensitivity as a result of short duration exposure to excessively loud noise. Temporary ringing in the ears as a result of short duration exposure to excessively loud noise. Noise induced hearing loss (NIHL) permanent loss of hearing as a result of repeated exposure to excessively loud noise. Tinnitus persistent ringing in the ears as a result of repeated exposure to excessively loud noise. Stress effects caused by irritating nuisance/ background noise.

2- Reduce the noise at source (through equipment selection or engineering controls) Interrupt the pathway from source to receiver. (through engineering controls) Protect the receiver (through engineering controls or PPE)

3- Ear defendersAdvantages of Ear DefendersEasy to supervise and enforce use as visibleLess chance of ear infectionsHigher level of protection possible through all sound frequencies; bone transmission is reducedCan be integrated with other PPE e.g. hard hatsReusable

LimitationsUncomfortable when worn for a long timeMust be routinely inspected, cleaned and maintainedEfficiency may be reduced by long hair, spectacles or earrings. Incompatible with some other items worn (e.g. spectacles)Needs dedicated storage facility

Ear PlugsAdvantages of Ear plusCheap and easy to useDisposableAvailable in a range of types and designsOften more comfortable to wearDo not interfere with any other items worn (e.g. PPE)

LimitationsDifficult to see when fitted, so supervision and enforcement difficultRisk of infection if dirty or if cross-contaminated when insertedNeed to be correctly sized to fit the individualEffectiveness decreases with usageInterfere with communication

28Unit IGC 2Element 8.2Vibration

29Hand-Arm Vibration Syndrome (HAVS)Vibration white finger (blanching)Nerve damageMuscle weakeningJoint damage

Effects of Exposure to Vibration

Typical vibration white finger(Source: HSE Guidance)(Reproduced under the terms of the Click-Use Licence)30HAVS normally results from long-term exposure (5 to 10 years or more) to hand vibration (e.g. from use of a chainsaw). It is an incurable condition. Once damage has been done it is unlikely to reverse and any further exposure to vibration will do further damage. The most appropriate treatment for most workers is for them to give up the use of vibrating hand-tools.

The Problem who is affectedSource: HSE statistics 20105 Million Workers Exposed to HAVS2 Million Works at potential danger level of exposure300,000 Workers with Advanced SymptomsHAV EffectsNeurological Disorders(numbness and tingling)

Circulatory Disorders(vibration induced white finger)

Muscular Disorders(grip difficulties and Reduced dexterity)

Articular Effects(bone and joint problems)

Brain, spinal cord, nerves, eyes & ears

Blood, heart & blood vessels

All muscle tissue & tendons movement and posture

Bones, joints, cartilage, ligaments, movement, shapeWhat occupations are most at risk of exposure to vibration?How can you reduce the risks?(Consider the use of a mechanical sander at home)

Group Exercise

33Effects of Exposure to Vibration

Whole-Body VibrationDamage to spinal discsVertigo(sort of dizziness / off balance)

Occupations:dumper truck drivingaircraft cabin crew

34Teacher notes: see INDG 296. Note that some of the ill-health conditions can also result from other routes too (e.g. Carpel Tunnel Syndrome can result from VDU use).Vibration Assessment

Vibration dose is determined as a personal exposure to vibration averaged over 8hrsVibration dose determined by:vibration magnitude (ms-2 )duration of exposure (hours/mins)

35Teacher notes: see INDG 296. Note that some of the ill-health conditions can also result from other routes too (e.g. Carpel Tunnel Syndrome can result from VDU use).Exposure StandardsExposure limit values and action values for hand-arm vibration

(a) the daily exposure limit value is 5 m/s2 A(8)

(b) the daily exposure action value is 2.5 m/s2 A(8)

Whole Body Vibration - WBVOccurs in a variety of situations in vehicles, on plant, in buildings.

Abdominal pain

Digestive disorders

Urinary problems

Balance, headaches and visual problems37Action Limits The regulations set out exposure limit values (ELVs) and exposure action values (EAVs). The daily ELV is the maximum amount of vibration an employee may be exposed to on any single day and is:5 m/s2 for hand-arm vibration and 1.15 m/s2 for whole body vibration.The daily EAV is the level of daily exposure to vibration above which it is required to take actions to reduce exposure. The EAV for hand-arm vibration is 2.5m/s2 and for whole body vibration is 0.5m/s2. Vibration Exposure Standards

Standards vary according to national lawAt or above the Daily Exposure Action ValueVibration risk assessmentReduce exposure levelTrainingHealth surveillanceAt or above the Daily Exposure Limit Value (ELV)Vibration risk assessmentReduce exposure below the ELV39Though the technical details vary it is easiest to demonstrate the general principle by considering one regulatory regime, that used in the EU. Here two different types of vibration exposure are recognised (hand-arm vibration and whole-body vibration) and two daily personal vibration exposure levels are set which put different legal requirements on the employer.Daily Exposure 2.5 m.s-2 hand-arm vibrationAction Value = 0.5 m.s-2 whole-body vibrationThe employer must: Carry out a vibration assessment. Reduce vibration exposure to the lowest level reasonably practicable. Provide information, instruction and training to employees. Carry out health surveillance.Daily Exposure 5.0 m.s-2 hand-arm vibrationLimit Value = 1.15 m.s-2 whole-body vibrationThe employer must: Carry out a vibration assessment. Immediately reduce exposure below the exposure limit value (ELV).Control of VibrationSource:EliminateSubstitute Change work methodMaintenancePathway:Isolate

Duration:Limit time exposedJob rotation

Person:PPE40Teacher notes: see INDG 296. Note that some of the ill-health conditions can also result from other routes too (e.g. Carpel Tunnel Syndrome can result from VDU use).At or above the Exposure Action ValueHealth surveillance allows:Identification of workers withpre-existing vibration damagenew vibration damageRemoval/exclusion of such workers from vibration sourcesInvestigation of vibration sources to rectify problems

Health Surveillance

Reproduced under the terms of the click-use licence41Teacher notes: see INDG 296. Note that some of the ill-health conditions can also result from other routes too (e.g. Carpel Tunnel Syndrome can result from VDU use).What are the symptoms of HAVs?What two factors are considered when calculating the dose of vibration?End of Section Quiz1- Vibration white finger (VWF) the blood supply to the fingers shuts down (often in response to cold) and the fingers turn white (known as blanching) and become numb. The blood supply returns after a time and the fingers become red and painful. Nerve damage the nerves carrying sensory information from the fingers stop working properly resulting in a loss of pressure, heat and pain sensitivity and feeling. Muscle weakening grip strength and manual dexterity reduce. Joint damage abnormal bone growth at the finger joints can occur.

2- The vibration magnitude (measured in m.s-2). The duration of exposure (in hours and minutes).

3- 42Unit IGC 2Element 8.3Radiation

43Two types:Ionisinghigher energycan change the structure of atomsNon-ionisinglower energyheating effectsdoes not change the structure of atoms

Radiation

44Ionising Radiation45Can penetrate the body and cause serious and permanent harm:Alpha particlesBeta particlesX-RaysGamma raysNeutrons

Types of Ionising Radiation46Weak penetrating powerStopped by thin material, e.g. paper, skinHealth effects:- outside body - not particularly hazardous- inside body (ingestion/inhalation) - very hazardousOccupational uses: - smoke detectors, medical labs

Alpha Particles

47Can penetrate skin and living tissueHealth effects:inside and outside body hazardousOccupational uses:- sterilisation, thickness gauges

Beta Particles

48Can be generated and switched offHigh penetrating powerHealth effects:inside and outside body - very hazardousOccupational uses:- medical radiography- baggage security scanners

X-Rays

49Very penetratingHealth effects:Inside and outside body - very hazardousOccupational uses- industrial radiography, e.g. pipelines

Gamma Rays

50Emitted by some radioactive sourcesVery high penetrationHealth effects:outside body - very hazardousOccupational uses- nuclear power stations

Neutrons

51Radiation sickness Nausea, vomiting and diarrhoeaBlistering and ulceration of skinHair lossDermatitisCataracts(type of eye disease)AnaemiaReduced immune systemInfertilityThe larger the dose, the greater the risk

Acute Health Effects

52CancerGenetic mutationBirth defects

The larger the dose, the greater the risk

Chronic Health Effects53Chronic effects can arise following exposure to high or low doses of radiation. There is no known safe level of exposure below which no chronic effects might occur instead there is a clear relationship between dose and the risk of these chronic effects (i.e. the larger the dose the greater the risk).

A pregnant lady is in need of an X-Ray for a suspected broken boneDiscuss the control measures in the X-Ray department of a hospital using:TimeDistanceShieldingto structure your answer

Group Syndicate Exercise

54Time:Minimise exposure time (Dose proportionate to time)

Distance:Not applicable

Shielding:Booths for radiographerRelatives stay outsideLead shield for pregnant women

Film badgeTraining supervision

Time:Minimise exposureDose proportionate to time (prolong exposure, less dose)Half life (the time it takes for a radioactive substance to lose half its radioactivity or the time required for half of the atoms of a radioactive substance to become disintegrated)Distance:Alpha, beta cant travel long distances through airShielding:Depends upon type of radiation

Protection from Ionising Radiation55Shielding

Protection from Ionising Radiation56International Commission on Radiological Protection (ICRP)Recommendations on exposure:General public < 1mSv per yearWorkers < 20mSv(milli Sieverts) per yearMeasured with a GeigercounterTranslated into legal limits inmost countries

Dose Limits

57Naturally occurring in Devon, Derbyshire, etc.Radioactive gasAlpha particlesHealth effects:- outside body - not particularly hazardous- inside body (ingestion/inhalation) - hazardous

Radon Gas

58Radon is a radioactive gas. It emits alpha particles. If an atom of radon gas spontaneously decays and emits analpha particle in air it will not cause significant harm. But if the gas is inhaled into the lungs and then decays and emits an alpha particle, then that alpha particle is inside the body and is more likely to be absorbed and cause harm. This effect is made worse by the fact that the breakdown product of radon decay is itself a radioactive element which will undergo further spontaneous decay in the lungs.

Radon- is a colorless, odorless, radioactive gas. It forms naturally from the decay of radioactive elements, such as uranium, which are found at different levels in soil and rock throughout the world. Radon gas in the soil and rock can move into the air and into ground water and surface water.Where naturally occurring levels are high:outside - low concerninside - poorly ventilated workplaces, e.g. basements can be a significant riskControl of risk above the action level:Radiation Protection Supervisorpositive pressure air fansradon sumps and extraction systems

Radon Gas

59Non-Ionising Radiation60You are going on holiday to a hot country with long hours of sunshineDiscuss how you will protect yourself from sunburn from the UV light using:TimeDistanceShieldingto structure your answer

Group Syndicate Exercise

61Time:Reduce time in the sunAvoid mid day

Distance:Not useful in this context

Shielding:Stay insideParasol ClothingHatsSunglasses Sun cream

TypesSourcesHealth Effects Ultra-violet (UV)SunlightArc weldingSkin burnsArc eye (photokeratitis)Skin cancerVisible lightlasersTemporary blindnessInfra-red (IR)Red hot steelGlass manufactureRedness and skin burns, retinal burns, cataractsMicrowavesFood preparationTelecommunicationsInternal heatingOrgan damageRadiowaves Radio, TVradarInternal heatingOrgan damageNon-Ionising Radiation

Arc Eye62TypesProtectionUltra-violet (UV)Cover exposed skinProtect eyesVisible light, lasersLow class: avoid shining in eyesHigh class: eye protection, shielding, non reflective surfacesInfra-red (IR)Cover exposed skinProtect eyesMicrowavesSafe distanceIsolate and lock offRadiowaves Safe distanceIsolate and lock offProtection from Non-Ionising Radiation

63May be legally required by an approved physician:Before working as a classified workerDuring periodic health reviews (medicals)Special surveillance if dose limit is exceededAfter ceasing work as a classified worker

Special consideration for pregnant or breastfeeding workersHealth Surveillance64Types of examination include:Skin checksRespiratory checksExposure recordsSickness recordsHealth SurveillanceIn the health surveillance the following types of examination may be carried out:Skin checks-to identify lesions which could allow radioactive materials to enter the bodyRespiratory checks-to ensure that workers who may be required to wear respiratory protection e.g. RPE are fit and able to do soExposure records-checks of the employees exposure records to determine if dose limits have been exceededSickness records-examination of the employees general health and absence history.

65Identify the different types of ionising radiationIdentify different sources of non-ionising radiationWhat are the health effects of exposure to UV radiation?

End of Section Quiz1- alpha particles, beta particles, x-rays, gamma rays, neutrons,

2- Ultra violet, visible light, Infra red, microwaves, radiowaves

3- UV redness and burns to the skin (e.g. sunburn); pain and inflammation to the surface of the eye leading to temporary blindness known as photokeratitis (often called arc-eye or snow-blindness); increased risk of skin cancer; premature aging of the skin.

66Unit IGC 2Element 8.4Stress67Stress is:An adverse reaction to excessive pressureHealth effects:psychologicalphysical behavioural serious ill-health if prolonged

Stress

68Discuss what causes stress in your own life or others you have known to be stressed

Group Exercise

69Answers on next slide

Here discuss not only work issues but personal/out of work factors such as moving house, children etc. Though we are talking about work-stress in the following slide it is useful to acknowledge that not all stress is work related.

Change- uncertainty Demands - excessive Control - weak Support- poor Relationship- difficult Role- undefinedCauses of Stress

70These are workplace causes of stress from the UK HSE stress management standardsWhilst having your lunch outside, a tiger jumps out at you with a huge ROAR!!

What physical, psychological and behavioural symptoms might you experience at the time and also in the days/weeks after?Group Discussion PointThis is a fun discussion point which I have used many times. People may suggest comedy responses for they bodily response to a tiger giving them a fright that is fine, link it back to the fight or flight response that the body experiences under pressure. The situation was chosen as it is so extreme it is comical. Also remember that the victim might have difficulty sleeping, might have flash backs, be worried about going into the area again etc.

Wrap up by linking this silly scenario to a real one, such as witnessing a workplace accident, being involved in conflict etc.71

Effects of StressPsychologicalPhysicalBehaviouralAnxietyLow self-esteemDepression

SweatingHeart rateBlood pressureSkin rashesMuscle tensionHeadacheDizziness

SleeplessnessPoor concentrationPoor decision-makingMood swingsIrritabilityAlcohol consumptionDrug misuseAbsence from work72Prevention Strategies for Stress Demand- reasonable demands, sufficient resources Control- given as much control as possible Support- information, instruction, training, additional support Relationships- clear anti-harassment and bullying policies Role- clear job descriptions, responsibilities and authority Change- planning and preparation for change, communication, timescales 73What is stress?What are the three types of health effect that can result due to stress?What are the causes of workplace stress?End of Section Quiz1- The adverse reaction that people have to excessive pressure or other demands placed on them.

2- Psychological: anxiety, low self-esteem, depression. Physical: sweating, fast heart beat, high blood pressure, skin rashes, muscle tension, headache, dizziness. Behavioural: sleeplessness, inability to concentrate, poor decision-making ability, mood swings, irritability, increased alcohol consumption, drug misuse, increased absence from the workplace.

3- Answers can be shaped to fit around the following: Demands excessive demands of the job in terms of workload (too much or too little), speed of work and deadlines, as well as working hours (excessively long) and work patterns (e.g. changing shift patterns). Also consider the nature of the job: some jobs are inherently difficult (e.g. air traffic control) and some expose workers to highly emotional situations (e.g. social work). Control lack of control over work, especially where the work is demanding. Control means control over what work is to be done, how it is to be done, the priorities involved and even simple things like control over the working environment (light levels, temperature, background noise, etc.). Support lack of support in terms of information, instruction and training to do the work and having no-one to turn to when pressure increases. Relationships poor workplace relationships and in particular bullying and harassment (whether by managers, peers or even subordinates). Role lack of clarity about an individuals role, what responsibilities and authority they have, and how they fit in to the larger organisational structure. Change the threat of change and the change process itself, whether it is a change that affects just one worker (e.g. demotion, re-assignment) or the whole organisation (e.g. redundancies, management take-over). This can create huge anxiety and insecurity.

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