Nebosh-2

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NEBOSH InternationalCertificate

Day 9Day 9

Programme for Today

• Fire Safety.• Radiation.• Ergonomics• Display Screen Equipment.• Manual Handling.

Crown copyright material is reproduced under the terms of the Click-Use Licence.

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Fire Safety

The Fire Triangle

Terminology• Flash point: temperature at which sufficient gas and

vapour is evolved so that burning will occur with the application of an external ignition source, but cannotbe maintained if that source is removed.

• Fire point: temperature at which sufficient gas and vapour is evolved so that burning will occur with the application of an external ignition source and can be maintained even when that source is removed.

• Auto ignition point: temperature at which a fuel will ignite without the application of an external ignition source.• Flammability limits: maximum and minimum concentrations of a gas or vapour in air, which will

burn, e.g. methane = 5-15%.

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Classes of Fire

Class A: combustible solids (often organic), e.g. wood, cloth and paper.

Class B: l iquids, e.g. oil, petrol and alcohol.Class C: gases, e.g. propane and methane.Class D: metals, e.g. magnesium and

aluminium.Class F: high temperature fat or oil.

Fire Spread

DIRECT BURNING

• Smoking materials.• Faulty or misused

electrical equipment.• Malicious ignition.• Portable heaters.• Unsafe storage of

flammable materials.

• Unsafe use of flammable liquids and gases.

• Hot work - welding, cutting, etc.• Mechanical heat -

ov erheating bearings and sparks.

Principal Causes of Workplace Fires

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Fire Prevention• Design and

maintenance of electrical equipment.

• Control of portable heaters.

• Control of smoking.• S ite security .• Control of oxygen.

• Control of contractors.• Control of hot work.• Correct storage and

use of flammables, particularly liquids and gases.

• Housekeeping.

Fire ProtectionF ire resistant materials:• Building regulations often dictate.• Non-flammable building materials.• Structural steel often clad in concrete.• Materials w ill often be fire rated, e.g one hour.• Lining materials can have a dramatic effect on

fire characteristics.

Compartmentalisation:• C reating enclosed/sealed boxes

in a building.• F loors and walls.• Self-closing fire-resistant doors.• Automatic shutters for ventilation

shafts (may rely on fusible links for operation).

• Intumescent sealants for gaps.

Fire Protection

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Fire Precautions• Means of detection and warning.• Means of escape.• Training and information for employees and

v isitors.• Means of fighting fire.

Means of Detecting Fire• People looking (in the simplest

workplace).• Interlinked domestic smoke

alarms: – May be suitable for small, low -risk workplaces.

• Automatic fire detection:– Point-type smoke detectors

linked to warning devices.– Ionising smoke detectors

are commonly used.

Means of Warning• An audible means of sounding the alarm.• Shouting or a handbell:

– May be adequate for small, low -risk workplaces.

• Electronic fire alarm system:– With manual call points on exit routes and adjacent to the final exit.– Clearly audible at all locations.– Linked to detection sy stems.

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Means of Escape“A continuous route by way of a space, room, corridor, staircase, doorway or other means of passage, along or through which persons can trav el from wherev er they are in a building to the safety of the open air at ground level, by their own, unaided efforts.”

Must be:• Unobstructed.• Adequately lit.• Identified.

Maximum travel distance:• 18 m if only one exit.• 35 m if more than one exit.

Means of Escape

Dead-End Corridor

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Inner Rooms

Means of Escape• F ire exit and direction signs:

– Must carry a pictogram.– May carry words and an arrow.

• Emergency lighting:– At night or where there is no natural light.– To indicate escape routes.– To indicate call points and fire-fighting

equipment.– To allow safe mov ement.

FireAction

IF YOU D ISCOVER A FIRE1. Sound the alarm2. Close all windows and doors3. Leave the building by the nearest availableexit and report to the assembly point

ON HEARING THE ALARM1. Close all windows and doors2. Leave the building by the nearest available exit and report to the assembly point

ASSEMBLY PO INT:

• Do n ot att e mpt to fig ht a majo r fi re .• Do n ot tak e risks.• Do n ot sto p t o c ollec t p er so nal bel on gin gs.• Do n ot us e t he lif ts.• Do n ot re -e nte r t he b uildi ng until a uth oris ed to d o s o.

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Training and Information• Fire instructions:

– Displayed at suitable locations.– Brought to the attention of staff

and visitors.• Training:

– Fire drills.– Fire alarm tests.– Fire extinguisher use.– Fire warden or fire team

training.

Types of Extinguisher• Water:

– Suitable for Class A fires.– Not suitable for Class B fires or electrical fires.– Gas cartridge and stored

pressure ty pes.• CO2:

– Suitable for all classes, especially electrical fires.

– Not suitable for confined spaces.– Stored pressure (liquid CO2).

• Foam:– Different ty pes of foam (protein, fluoro-protein, fluoro-chemical and synthetic).– Suitable for Class B fires.– Aqueous film forming foam (AFFF) can be used

on electrical fires.– Gas cartridge and stored pressure types.

• Powder:– Suitable for all types of fire.– Gas cartridge and stored pressure types.

Types of Extinguisher

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��Electr icity present.

��Flam mable gases, e.g. pr opane and natura l gas.

C��Flam mable liqu ids,

e.g. oi ls and pa ints.B��Paper, wood and

textiles.A

�

Types and Siting of Extinguishers• Vaporising liquid (halons):

– Suitable for all classes.– Toxic by inhalation and produce even more

toxic by-product, on contact with fire.• Siting of extinguishers:

– Fire certificate may specify.– 30 m maximum travel distance.– Minimum of 1 per 200 m2 floor space and one per floor.– Conspicuous and accessible (handle not over 1.1 m above floor).– In corridors, inside doorways or at a point of specific use.

Fixed Installations• F ire reels.• Sprinkler sy stems:

– Used to protect large open plan areas, e.g warehouses, unfrequented areas, e.g. store rooms and means of escape.– Often water, but can incorporate foam,

e.g. flammable liquid store.• F lood sy stems:

– Used to protect critical installations, e.g. computer rooms.– Often require special precautions to prevent activation when areas occupied, e.g. halon system.

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Typical Sprinkler Head

Maintenance of Fire Arrangements• F requency of maintenance of facilities and

procedures.• Detection equipment and alarms.• Extinguishers.• Escape routes.• Emergency lighting.• Evacuation procedures.• Details of maintenance to be recorded in a

Fire Book.

Fire Risk Assessment• Identify the fire hazards.• Identify the location of people at significant risk.• Evaluate the risk:

– Existing fire safety measures.– Carry out improvements.

• Record findings and action taken.• Rev iew and rev ise.

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Exam Question

Identify the main hazards associated with excavation work on construction sites.

(8 marks)

(Sourc e: IGC, Septembe r 2005)


Radiation

Radiation

• Sources can be natural or man-made.

• It is found in two types:- ionising radiation.- non-ionising radiation.

• Background radiation –we are all exposed to all forms, all of the time!

What is Radiation?• Radiation is a form of energy. It travels as a

stream of particles or as waveform from a source.

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Radiation• Ionising radiation:

Is a form of energy, which has the strength to alter the electrical charge of an atom or molecule, i.e. to ionise it.

It can also penetrate the body and cause serious and permanent harm to a person, dependent on the dose.

Radiation• Ionisation:

An atom is made up of the nucleus which contains protons and neutrons, and electrons which orbit the nucleus.

Protons are positively charged and neutrons are neutrally charged. They both have a measurable mass.Electrons are negatively charged and have neglible mass.If unstable, atoms fall apart (decay), releasing radiation.

The Concept of Half-Life

What is the half-life of this substance?

The half-life is the time taken for half of radionuclide to decay.

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RadiationForms of ionising radiation:

1 . Alpha emission.2 . Beta emission.3 . Gamma rays.4 . Neutrons.5 . X-rays.

Alpha Particles• Made up of 2 protons and 2 neutrons.• Heavy and slow moving, charged (2++).• Short range and stopped by a few cms of

air, tin foil or outer layer of dead skin.• Only hazardous if inside the body. If

ingested, causes very localised ionisation, so then considered dangerous.

• O ccupational uses - smoke detectors (encapsulated), science and medical labs.

Beta Particles• Charged (-v e), but very light

(almost no mass) and very fast mov ing (<speed of light).

• Travel further (less likely to hit any thing).

• Penetrate further - through skin.• Can cause secondary radiation

emission.• Examples – sterilisation and

thickness gauges.

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Gamma Rays• A form of electromagnetic

radiation.• Much higher frequency and higher

energy than light.• Only emitted by radioactive decay.• Travel at speed of light, over vast

distances.• Very penetrating.• Used in industrial radiography –

source material is Caesium 137.

Ionising Radiation

X-Rays

• A nother form of electromagnetic radiation.• Lower frequency and energy than gamma rays.• C an be generated - bombard a metal target in a

vacuum tube w ith electrons.• C an be sw itched off.• Used in medical radiography.

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Occupational Sources

• Medical and Dental radiographic diagnosis – x-rays.

• Nuclear power: power stations and defence (nuclear submarines).

• Non-destructive testing – gamma rays.

• Laboratory analysis, diagnosis and research.

• Smoke detectors.

Ionising radiation - v ariable applications are found:

Health Effects• Ionising radiation changes DNA (cell nucleus).• High doses kill the cell (as in radiotherapy).• Survivable dose may prevent division (eventual

death) or cause mutation.• In somatic cells -may cause cancer.• In reproductive cells - may cause sterility,

mutation of offspring, etc.• Acute effects: skin burns, radiation sickness,

hair loss and death.• Chronic effects: cancers (including leukaemia),

sterility, mutations, damage to developing foetus, cataracts and skin damage.

DNA Molecule

Controlling ExposureBest achieved by dose limitation.

• Time limitation of exposure.

• Maintain distance from the source:– Inv erse square law applies.

• Shielding of the source.

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Controlling Exposure

• Appointment of specialists:Radiation Protection Advisors (RPAs) and Radiation Protection Supervisors (RPSs) may need to be appointed to offer specialist advice and offer supervision.

• Designated areas may need to be defined and managed. Access must be restricted. Warning signs used, named authorised workers and SSWs.

Key aspects of radiation control


International C ommission on Radiological Protection (ICRP) has set dose limits to exposure:

• General public must not be exposed to more than 1 mSvper y ear.

• Occupational exposure must not exceed 20 mSv per year.

Dosimetry and Medical Surveillance


• Medical ExaminationRoutine examination conducted before employment and every 12 months.

• Area monitoringLevels assessed and equipment maintained regularly.

Dosimetry and Medical SurveillanceEnsure compliance to the limits by means of: • Personal Monitoring

Workers in controlled and supervised areas use personal dosimeters, either whole body or part of body.

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Non-Ionising Radiation• Non-ionising radiation:

Is a form of radiation without the ability to ionise tissue, but it can cause harm. Most forms of non-ionising radiation have an effect on the skin and eyes and can cause damage to them.

Non-Ionising RadiationThis type of radiation is electromagnetic and does not cause ionisation of the material through which it passes. Forms occurring are:• U ltraviolet.• Infrared.• Microwaves.• Radio waves.• LASERs.

Non-Ionising Radiation• Ultraviolet:

– Sunburn, skin cancer and premature ageing.

– Retinal damage - snow blindness and arc eye.

– e.g. welding and sunlight.

– Cover skin.– Goggles.

• Infrared:– Emitted from hot

sources.– Heating of skin,

Cornea and lens (causing cataract).

– e.g. glass blowers.– Tinted glasses.

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Non-Ionising Radiation• Microwaves and

radio waves:– Cause internal heating

of the body organs.– It can’t be felt.– If can’t dissipate heat,

it cooks.– e.g. ovens and radio

antenna.

• Lasers:– Monochromatic and

coherent = >energy.– Eye damage.– Blink response adequate

for most bright light.– Classification.– e.g. communications and

metal cutting.

Classes of LaserClass 1 - Inherently safe (low power), protection by blinking.Class 2 - Low power and visible, adequate protection by blinking.Class 3A - Medium power, direct viewing with optical aids could be hazardous.Class 3B - Medium power, requiring interlocked enclosures and strict procedures, use eye protection at all times and restrict area.Class 4 – High-power lasers requiring extreme caution.


Ergonomics

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ErgonomicsBasic philosophy:

• To design equipment/environment which fit the capacity and needs of the individual, thereby promoting effective performance.

• To design work systems/environment which do not exceed physical capabilities and mental well-being, thereby promoting comfort.

ErgonomicsErgonomics is the study of the relationship between:

• Man.• The equipment he works with.• The environment.

It is the science of adapting the task (including equipment and the workplace), to the worker.

Principles of Ergonomics

• Positioning and design of DSE and other equipment, and also lighting to reduce visual stress.

• Organisation of tasks over time to reduce possibility of fatigue or injury to parts of the body.

• Organisation of task activities, including control, supervision and design of local environment to minimise mental stress.

Workstation design centres on:• Effective layout of physical objects in relation to worker,to minimise postural stress, and also reaching and manual

manipulation of equipment.

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Ergonomics – Ill-Health Effects• Physical stress.• Visual problems – due to excess brightness.• Mental stress.E.g. Work related upper limb disorder (WRULD).• A generic term for a range of musculoskeletal

disorders (MSDs), including RSI.Symptoms:• Pain.• Lack of jo int movem ent.• Soft t issue s we ll ing.• Sym ptom may have slow ons et. • Adapt ation to t ask affects other parts of t he body. • Acute stage r ap id ly proc eeds t o chronic stage.

Ill-Health Effects

• Keyboard operators and office staff.

• Assembly line workers.• S laughterhouse staff.• Supermarket checkout staff.

Why are checkout staff at risk?

Who is affected by WRULDs?

Specific Health ProblemsCarpal Tunnel SyndromeOther upper limb disorders:• Bursitis.• Epicondylitis.• Occupational cramp of the

hand.• Tendonitis.• Tenosynovitis.• Ulnar neuritis.• Thoracic outlet syndrome.

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Specific Health ProblemsAnatomy of the back:• 7 cerv ical v ertebrae.• 12 thoracic vertebrae.• 5 lumbar v ertebrae.• The sacrum.• C occy x.

Specific Health ProblemsSome back problems:• Sciatic pain.• Prolapsed interv ertebral

slipped disc.• A rthritic changes.• Fusion of v ertebrae.

Specific Health ProblemsSome other ill-health effects:• Hand-A rm Vibration Syndrome (HAVS).• Fatigue-related disorders.• Eye problems (usually caused by

excessiv ely bright light).- Eyestrain.- Inflammation.- Blurred v ision.- Headaches and vertigo fatigue.

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Cranfield Man

Ergonomic Risk FactorsWhat are the causes?There are three risk factors and activities:

• Physical requirements of the task.• The env ironment.• The equipment worked with.

We will look at these in turn, next.

Ergonomic Risk FactorsPhysical requirements of the task -key factors:• Posture and physical action.• Forces inv olved.• Repetition.• Duration and recovery time.

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Ergonomic Risk Factors

• Illumination and contrast of general lighting.

• Glare.• F lickering light.• Temperature.• Humidity.

The environment - key problem areas:

Ergonomic Risk FactorsThe equipment - key factors:• Physical characteristics of the

equipment itself: - Physical manipulation.- Encouraging poor posture.

• Position in relation to worker:- Requiring bending.- Reaching down.- Reaching up.


Display Screen Equipment(DSE)

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DSE - Terminology

What is Display Screen Equipment?Any alphanumeric display screen regardless of the display process involv ed.

Who is the user? An employee who habitually uses DSE as a significant part of their working day.

What is an operator?A self-employed user.

Ill-Health Effects of DSESuggested Ill-Health Effects:• Work Related Upper Limb

Disorder (WRULD). • Temporary ey estrain.• Fatigue and stress. • Facial dermatitis.• Radiation.• Photosensitiv e epilepsy.

Ill-Health Effects of DSE

What does DSE include?

• Equipment.

• Env ironment.

• Interface of computer and user.

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DSE – Workstation

(Source: L26, First edition)

Display Screen EquipmentInteraction of User and EquipmentChairs - adjust ab il ity

footr estsScreens - adjust ab il ity

constructiongla re

Keyboard - adjust ab il ityconstruction

Work surf ace - areadocument holde rs

Env ir onment - spacelight ingno iseheat

Soft wa re - includes ergonomics

An Example of Good Posture

Optimum Work sta tion Se t-Up

Spac e in fr on t of th e keyb oa rd to re st w rist s

(wris t s up po rt).

Scre en: gl ar e a nd refl ecti on mi nimis ed .

Scre en abl e t o tilt a nd swiv el.

Keyb oa rd de tac ha ble with f aciliti es to tilt.

Dept h of des k to p >6 0c m with w or kto p heig ht

app ro x. 60c m f ro m th e floo r.

A foo tr est m ay b e req uir ed to mi nimi se

pre ssu re o n th e und er sid e o f th e t hig h.

5 st ar ba se with adju sta ble se at

heig ht an d back re st. Low er ba ck s up po rt

at b elt hei gh t.

Shoul de rs rel axe d an d upp er a rm ve rtic al. Seat hei gh t s o th at

for ea rm s a re ap pr ox. hori zo ntal .

Dista nce 3 5 - 60 c m.

Scre en hei gh t a djus ta ble so t ha t t he mo nito r t op is le vel with th e e yes ,

givin g a 1 5- 20 de gr ee dr op i n vi sio n.

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DSE AssessmentWorkstation AssessmentMinimum standards for the equipment and environment relate to:• Screen, keyboard, desk, chair and

footrest.• Space, light, reflection and glare, noise, heat, radiation and humidity.

Preventative/Precautionary Measures• Engineering Controls:

Physical layout.

• Systems of Work:Planning work routine:- Regular breaks.- Task or job rotation.- Work sharing.- Extension of job responsibilities – i.e. the same task not performed repeatedly.

- Limitation of overtime work.

Preventative/Precautionary Measures

• Individual measures:- Information and training -

in correct use of equipment and software.

- Eye test and spectacles -should be at cost of employer.

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Manual Handling

Manual Handling

What is manual handling?

“Transporting or supporting of a load (including the lifting, putting down, pushing, pulling, carry ing or mov ing thereof) by hand or by bodily force.”

The Scale of the Problem

Handling

M/cFallsStruck

Trip

Other

Over a third of all lost-time incidents reported in the UK every year, are manual handling related.

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Manual Handling

• Disc injury.• Trapped nerv es. • Muscle strains.• Hernias.• Sprains and strains

(ligaments and tendons).• F ractures, burns, lacerations and bruising.• WRULDs.

Common injuries:

Anatomy of the Spine

The spine is made up of:• Vertebrae.• Intervertebral discs.• Tendons and ligaments.• Muscles.• The spinal cord.• Nerves.

The SpineVertebrae from the middle part of the back.

Vertebrae from the lower back.

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Cross Section of Vertebra and DiscVertebraDisc

Tough outer coatCentre of disc

The Spine

Effect of Loads on the Discs

vertebra

disc

vertebra

The Spinal Cord and Nerves

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Discs

Nerves Ligaments

Three Stacked Vertebra

A Slipped Disc Trapping a Nerve

Spinal cordNerve bundle

Distorted disc

Employer’s Responsibility

• Avoid hazardous manual handling operations so far as possible, i.e. by elimination.

• Assess any hazardous manual handling activities that cannot be avoided.

• Reduce the risk of injury so far as is reasonably practicable, e.g. automation, mechanical aids, etc.

Employers should adhere to a strict hierarchy of measures in managing the hazard:

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Manual Handling

The Employer should -…so far as possible, avoidmanual handling where there is a risk of injury.

How Can I Avoid Manual Handling?

• Eliminate the need to move the load.

• Automate the movement.

• Mechanise the movement.

How Do I Know if There is a Risk of Injury?

• Do people puff, sweat and get very fatigued?

• A re work areas cramped?• A re loads excessiv e or awkward?• Is there a history of back pain and

absence?• Use the general guidelines filter .

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Lifting and Lowering FilterAssessment guideline filter - maximum weight guidance.

These are guideline values only.

Manual Handling Operations

Carrying• Guideline filter similar.• Hold load against body.• Rest every 10 metres.Pushing and Pulling

Lifting and Lowering Filter

Handling Whilst Seated• Guideline values much

reduced.• Applies to area of shoulder

to hip.

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Lifting and Lowering FilterBending and Twisting

45 degree twist = 10% reduction from filter guidelines.90 degree twist = 20% reduction.

Duties of EmployersThe employer should… make a suitable and sufficient assessment of the manual handling operation and reduce the risk of injury to the lowest level possible.

Employees must follow any safe sy stem of work introduced.

Duties of Employers

1. Load2. Indiv idual C apability3. Task4. EnvironmentRemember LITE.

How should the employer assess the Risk?What does a “suitable and sufficient” risk assessment mean?The follow ing four factors should be considered as part of the risk assessment.

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Duties of Employers

• Use mechanical assistance.

• Redesign of the task, load or env ironment.

• Team handling for heavy or unw ieldy loads.

• Good handling technique.

How Can I Reduce the Risk of Injury?

Mechanisation

Mechanical Assistance

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Factors to Assess

• Is it heavy ?• Is it bulky or unwieldy ?• Is it difficult to grasp?• Is it unstable?• Is it sharp, hot or

otherw ise hazardous?

The Load

Modifying the LoadHoneycombing the load may reduce the weight, depending on the type of material used.

Modifying the Load

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Modifying the LoadThis is a rudimentary form of mechanisation.

Factors to Assess

• Require unusual strength, height, etc.?

• Pose a risk to pregnant workers?• Pose a risk to young people?• Pose a risk to people with health

problems?• Other factors:

– Is protective clothing or equipment worn?

– Does this affect the operation?

The IndividualDoes the task…

Factors to Assess

• Being held at a distance from the trunk?• Twisting?• Stooping?• Reaching upwards?• Excessive lifting or lowering?• Excessive carrying distances?• Pushing or pulling?• Sudden movement of the load?• Frequent/prolonged physical effort?• Sufficient rest periods?• A rate of work imposed by a process?

The TaskDoes the task involve:

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Effect of Distance from Trunk

Capability %

Distance from thespine, cms

Modifying the Task

Modifying the Task

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Factors to Assess• Does lack of space prevent good posture?• Are floors uneven, slippery or unstable?• Are there variations in floor level?• Is it extremely hot or cold?• Is it extremely humid?• What is ventilation like?• Are there gusts of wind or strong air

movements?• What is the lighting like?

The Work Environment

Modifying the Environment

Training

1. Stop and think.2. Position the feet.3. Adopt a good posture.4. Get a firm grip.5. Keep the load close.6. Don’t jerk.7. Move the feet.8. Put down, then adjust.

Safe Lifting Technique

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