Mechanical Technology Grade 12 Chapter 3 Safety In The Workshop

SAFETY IN THE SAFETY IN THE WORKSHOPWORKSHOP

IT IS IN YOUR HANDSIT IS IN YOUR HANDS

DEFINING AN ACCIDENTDEFINING AN ACCIDENT

An accident is an unplanned, An accident is an unplanned, uncontrolled event caused by unsafe uncontrolled event caused by unsafe acts and unsafe conditions.acts and unsafe conditions.

All South African safety regulations All South African safety regulations are based on the Occupational are based on the Occupational Health and Safety (OHS) Act No. 85 Health and Safety (OHS) Act No. 85 of 1993.of 1993.

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What are the causes of What are the causes of accidents?accidents?

Poor housekeepingPoor housekeeping Loose clothingLoose clothing Improper use of toolsImproper use of tools Inaccurate setting-up of machinesInaccurate setting-up of machines

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House KeepingHouse Keeping Good housekeeping means working tidily and Good housekeeping means working tidily and

orderly. orderly. Always work neatly and return materials and tools Always work neatly and return materials and tools

to their proper places. to their proper places. Keep working areas unobstructed at all times; Keep working areas unobstructed at all times;

when using a machine, keep an unobstructed when using a machine, keep an unobstructed space (of 2,25 m2) around the machine. space (of 2,25 m2) around the machine.

Grease, oil, tools, loose objects and materials Grease, oil, tools, loose objects and materials lying around can easily cause a fall.lying around can easily cause a fall.

A clean, orderly workshop is a safe workshop.A clean, orderly workshop is a safe workshop. Also maintain floors, walkways, stairways and Also maintain floors, walkways, stairways and

gangways, ensuring they are skidfree (and leak-gangways, ensuring they are skidfree (and leak-free) and clear of obstructions.free) and clear of obstructions.

House KeepingHouse Keeping

Protective clothingProtective clothing

Protective clothingProtective clothing When welding, you need to protect your eyes and When welding, you need to protect your eyes and

respiratory system, as well as your body and your respiratory system, as well as your body and your clothing. clothing.

You should protect yourself against heat, flying You should protect yourself against heat, flying particles that are incandescent (glowing with particles that are incandescent (glowing with heat) and radiation.heat) and radiation.

You should always:You should always: wear safety goggles when using a grinding wear safety goggles when using a grinding

machine or lathe, or when chippingmachine or lathe, or when chipping not wear loose clothing, jewellery, ornaments, a not wear loose clothing, jewellery, ornaments, a

watch or key chain, or a strap when working close watch or key chain, or a strap when working close

to moving machinery.to moving machinery.  

Bench WorkBench Work

Bench WorkBench WorkTHE ACT REFERS TO THESE PRECAUTIONS:THE ACT REFERS TO THESE PRECAUTIONS: Make sure that sharp points of tools and material Make sure that sharp points of tools and material

do not stick out from your workbench.do not stick out from your workbench. When chipping metal with a chisel, chip in a When chipping metal with a chisel, chip in a

direction so that cut-off material cannot hit direction so that cut-off material cannot hit anyone.anyone.

For your own protection, use a guard where For your own protection, use a guard where necessary.necessary.

Do not use chisels with mushroomed heads.Do not use chisels with mushroomed heads. Ensure that rolling stock cannot roll off the Ensure that rolling stock cannot roll off the

workbench and injure your feet. Also place heavy workbench and injure your feet. Also place heavy objects away from the edge of the bench so that objects away from the edge of the bench so that they don’t fall.they don’t fall.

Bench WorkBench Work Right-handed people should cut with a hacksaw Right-handed people should cut with a hacksaw

on the right-hand side of the vice. If the blade on the right-hand side of the vice. If the blade breaks, your hand will move safely breaks, your hand will move safely away away from the from the vice and the work piece.vice and the work piece.

Ensure that files have handles.Ensure that files have handles. When using a hammer make sure the head is When using a hammer make sure the head is

securely fixed.securely fixed. Don’t put sharp or pointed tools in your pockets.Don’t put sharp or pointed tools in your pockets. Don’t strike hard metals directly with a hammer – Don’t strike hard metals directly with a hammer –

the metal may splinter and injure someone.the metal may splinter and injure someone. Place a piece of soft material (such as copper) Place a piece of soft material (such as copper)

over the metal to act as a shield.over the metal to act as a shield.

Bench WorkBench Work

You should always:You should always: Wear safety goggles when using a Wear safety goggles when using a

grinding machine or lathe, or when grinding machine or lathe, or when chippingchipping

Do not wear loose clothing, jewellery, Do not wear loose clothing, jewellery, ornaments, a watch or key chain, or ornaments, a watch or key chain, or a strap when working close to a strap when working close to moving machinery.moving machinery.

AssessmentAssessment

Name five safety precautions to Name five safety precautions to observe when working at a observe when working at a workbench.workbench.

Pg 22Pg 22

Bench GrinderBench Grinder

Bench GrinderBench Grinder Only use a machine once the guards are correctly Only use a machine once the guards are correctly

fitted.fitted. Check that there is no oil or grease on the floor Check that there is no oil or grease on the floor

around the machine.around the machine. Check that the tool rest is not more than 3 mm Check that the tool rest is not more than 3 mm

from the grinding wheel surface.from the grinding wheel surface. When starting the machine, don’t stand in front of When starting the machine, don’t stand in front of

the wheel. Before you start grinding, let the the wheel. Before you start grinding, let the machine idle for a few seconds.machine idle for a few seconds.

If the wheel is running unevenly, dress it with an If the wheel is running unevenly, dress it with an emery-wheel dresser.emery-wheel dresser.

Grind only on the face of a straight grinding Grind only on the face of a straight grinding wheel and never on the side. Use the various wheel and never on the side. Use the various wheels only for their intended purpose.wheels only for their intended purpose.

Bench GrinderBench Grinder Approach the wheel carefully and gradually, and Approach the wheel carefully and gradually, and

don’t ‘jab’ materials onto it.don’t ‘jab’ materials onto it. Never ‘force grind’ so that you slow or stop the Never ‘force grind’ so that you slow or stop the

motor.motor. Adjust the tool rest only when the wheel is Adjust the tool rest only when the wheel is

stationary.stationary. Clamp work pieces and holding devices safety Clamp work pieces and holding devices safety

and firmly.and firmly. Never allow the wheel to stand in cutting fluid as Never allow the wheel to stand in cutting fluid as

this may cause it to run ‘off balance’ when you this may cause it to run ‘off balance’ when you switch it on againswitch it on again

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Grinding WheelsGrinding Wheels All power-operated grinding machines should be All power-operated grinding machines should be

clearly marked with the recommended speed (in clearly marked with the recommended speed (in revolutions per minute) of the spindle. revolutions per minute) of the spindle.

This speed should not allow the peripheral speed of This speed should not allow the peripheral speed of the wheel to exceed the manufacturer’s the wheel to exceed the manufacturer’s recommendation.recommendation.

Every grinding wheel should have a guard that can Every grinding wheel should have a guard that can withstand the force of a rupturing wheel.withstand the force of a rupturing wheel.

Bench grinders should have a transparent shield to Bench grinders should have a transparent shield to protect an operator’s eyes.protect an operator’s eyes.

Each machine must carry a notice prohibiting persons Each machine must carry a notice prohibiting persons from performing, inspecting or observing grinding from performing, inspecting or observing grinding work without suitable protection for the eyes.work without suitable protection for the eyes.

Mounting of a Grinding Wheel Select the correct type of wheel for the job. Inspect the wheel for cracks and tap it to apply

the ‘ringing test’. Never use a grinding wheel which is damaged or

which is not properly dressed. Make sure that the wheel’s speed does not

exceed the manufacturer’s recommendation. On the left is an example of a manufacturer’s

recommendation. Never force the wheel onto the spindle. Use only one smooth paper spacer on each side

of the wheel.

Mounting of a Grinding Wheel Use true and correctly recessed flanges of the

same size and at least one third the diameter of the wheel.

Gently tighten the grinding wheel with a spanner only enough to hold it firmly.

Replace the guards correctly. Stand aside and set the machine in motion.

Let the machine idle before you dress the wheel, using an emery-wheel dresser.

Finally stop the machine and reset the tool rest to within 2 mm of the wheel surface. Ensure that the tool rest is parallel to the wheel surface.

GrindersGrinders

Every grinding wheel should have a guard Every grinding wheel should have a guard that can withstand the force of a rupturing that can withstand the force of a rupturing wheel.wheel.

Bench grinders should have a transparent Bench grinders should have a transparent shield to protect an operator’s eyes.shield to protect an operator’s eyes.

Each machine must carry a notice Each machine must carry a notice prohibiting persons from performing, prohibiting persons from performing, inspecting or observing grinding work inspecting or observing grinding work without suitable protection for the eyes.without suitable protection for the eyes.

AssessmentAssessment

1.1. Name five safety precautions to Name five safety precautions to observe when working with a observe when working with a grinding wheel.grinding wheel.

2.2. Name five steps to follow when Name five steps to follow when installing a grinding wheel.installing a grinding wheel.

Pg 25Pg 25

Drill PressDrill Press

Drill PressDrill PressAlways observe the following:Always observe the following: Choose the correctly sharpened drill for the Choose the correctly sharpened drill for the

type of work you need to do and the material type of work you need to do and the material you are about to drill.you are about to drill.

Do not leave the key in the chuck when you Do not leave the key in the chuck when you are not at the machine.are not at the machine.

Never leave the machine running if Never leave the machine running if unattended.unattended.

Clamp the work piece securely to the table Clamp the work piece securely to the table and do not hold it by hand.and do not hold it by hand.

Never attempt to stop the work piece by hand Never attempt to stop the work piece by hand if it slips from the clamp.if it slips from the clamp.

Drill PressDrill Press A drill should run at the correct speed for A drill should run at the correct speed for

the job.the job. Don’t force a drill into the work piece – this Don’t force a drill into the work piece – this

may cause broken or splintered drills and may cause broken or splintered drills and possiblepossible injury.injury.

Use a brush or wooden rod to remove Use a brush or wooden rod to remove chips from the drill – and not your fingers, chips from the drill – and not your fingers, waste or rags.waste or rags.

When reaching around a revolving drill, be When reaching around a revolving drill, be careful that your clothes do not get caught careful that your clothes do not get caught in the drill or drill chuck.in the drill or drill chuck.

Portable Electric ToolsPortable Electric Tools Portable electric tools must be earthed if Portable electric tools must be earthed if

they are not double insulated. they are not double insulated. They should be correctly maintained. They should be correctly maintained. Their flexible cords should be undamaged Their flexible cords should be undamaged

and their plugs in good order.and their plugs in good order.

Milling Machine and LatheMilling Machine and Lathe

Milling Machine and LatheMilling Machine and LatheObserve the following precautions:Observe the following precautions: Make sure that all guards are in place.Make sure that all guards are in place. Don’t use a machine or come close to its moving Don’t use a machine or come close to its moving

parts while wearing loose clothing. Keep any parts while wearing loose clothing. Keep any cleaning material such as waste and rags away cleaning material such as waste and rags away from rotating parts.from rotating parts.

Check that there is no oil or grease on the floor Check that there is no oil or grease on the floor around the machine.around the machine.

Don’t leave spanners or keys on rotary parts. Don’t leave spanners or keys on rotary parts. Always disconnect, remove or stand clear of hand Always disconnect, remove or stand clear of hand wheels, leverswheels, levers or chuck keys before setting your or chuck keys before setting your machine or feeds in motion.machine or feeds in motion.

Milling Machine and LatheMilling Machine and Lathe Never apply a wrench to revolving work.Never apply a wrench to revolving work. Always clamp work pieces and holding Always clamp work pieces and holding

devices safely and firmly. A loose fit, devices safely and firmly. A loose fit, especially of spanners and keys, may especially of spanners and keys, may cause slipping and result in injury.cause slipping and result in injury.

Do not use your hands to remove cuttings Do not use your hands to remove cuttings while a machine is in motion. Use a wire while a machine is in motion. Use a wire hook or a brush once the machine has hook or a brush once the machine has stopped.stopped.

Never adjust the cutting tool while a Never adjust the cutting tool while a machine is running.machine is running.

Milling Machine and LatheMilling Machine and Lathe

Resist the habit of leaning on machinery. Resist the habit of leaning on machinery. This dangerous ‘automatic’ practice often This dangerous ‘automatic’ practice often results in serious injury.results in serious injury.

Don’t attempt to stop a machine by Don’t attempt to stop a machine by placing your hand on the chuck while the placing your hand on the chuck while the machine is slowing down.machine is slowing down.

Give attention to cutting-fluid control Give attention to cutting-fluid control before switching on a machine.before switching on a machine.

AssessmentAssessment1.1. Name four safety precautions to follow Name four safety precautions to follow

when working with a lathe or a milling when working with a lathe or a milling machine.machine.

2.2. Name five safety precautions to follow Name five safety precautions to follow when working with a drill press.when working with a drill press.

3.3. State two safety precautions for each of State two safety precautions for each of the following:the following:

1.1. transmission beltstransmission belts

2.2. projecting shaft endsprojecting shaft ends

3.3. revolving shaftsrevolving shafts

4.4. general machine protection.general machine protection.

Pg 27Pg 27

Shears, Guillotines and PressesShears, Guillotines and Presses Where the opening at the point of operation Where the opening at the point of operation

(cutting) of a pair of shears, or a guillotine or a (cutting) of a pair of shears, or a guillotine or a press is greater than 10 mm, the machine should press is greater than 10 mm, the machine should have either a fixed guard which prevents hands have either a fixed guard which prevents hands or fingers reaching through, over, under or or fingers reaching through, over, under or around the guardaround the guard

A self-adjusting guard which automatically A self-adjusting guard which automatically adjusts to the thickness of the material being adjusts to the thickness of the material being worked, can also used.worked, can also used.

Some machines have manual or automatic Some machines have manual or automatic moving guards which completely enclose the moving guards which completely enclose the point of operation so that the working stroke point of operation so that the working stroke cannot be opened unless the ram or blade is cannot be opened unless the ram or blade is stationary.stationary.

Shears, Guillotines and Shears, Guillotines and PressesPresses

Another safety device is the automatic Another safety device is the automatic sweep-away or push-away which pushes sweep-away or push-away which pushes any part of the operator’s body out of the any part of the operator’s body out of the danger zone when the working stroke danger zone when the working stroke starts.starts.

Today there are electronic presence-Today there are electronic presence-sensing devices which stop the working sensing devices which stop the working stroke if the device senses any foreign stroke if the device senses any foreign object in the danger zone.object in the danger zone.

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Stacking ArticlesStacking Articles

Stacks which consist of successiveStacks which consist of successive

tiers on top of one another should nottiers on top of one another should not

be built unless:be built unless: they are under the personal supervision of they are under the personal supervision of

a qualified persona qualified person the base is level and strong enoughthe base is level and strong enough the articles in the lower tiers are capable the articles in the lower tiers are capable

of carrying the weight of the articles of carrying the weight of the articles stacked above themstacked above them

Stacking ArticlesStacking Articles

Stacking ArticlesStacking Articles

Stacks should also not be built unless: Stacks should also not be built unless: all the articles in a single tier are of the all the articles in a single tier are of the

same size, shape and masssame size, shape and mass pallets and containers are in good pallets and containers are in good

conditioncondition the support structure used for the stacking the support structure used for the stacking

is structurally satisfactory to support the is structurally satisfactory to support the articles to be stacked on itarticles to be stacked on it

Stacking ArticlesStacking Articles

Stacking ArticlesStacking Articles

An employer must ensure that:An employer must ensure that: persons engaged in stacking operations persons engaged in stacking operations

are safeare safe stacks that are in danger of collapsing are stacks that are in danger of collapsing are

dismantled immediatelydismantled immediately the stability of stacks is not endangered by the stability of stacks is not endangered by

vehicles or other machinery or persons vehicles or other machinery or persons moving past them.moving past them.

AssessmentAssessment

Name four safety precautions that Name four safety precautions that must be observed when considering must be observed when considering each of the following:each of the following:– stacking of articlesstacking of articles– ventilation lightingventilation lighting– machine toolsmachine tools– arc welding and gas welding.arc welding and gas welding.

Pg 29Pg 29

ResponsibilityResponsibility

The Act places the person in charge of The Act places the person in charge of machinery responsible for safety. This machinery responsible for safety. This person must:person must:

Install and properly maintain the machineInstall and properly maintain the machine Repair machineryRepair machinery Ensure that safety appliances, devices and Ensure that safety appliances, devices and

guards are in good condition and properly guards are in good condition and properly usedused

Stop anyone from using a dangerous Stop anyone from using a dangerous machine.machine.

Obedience to InstructionsObedience to Instructions

Use machines according to the Use machines according to the manufacturers’ instructions.manufacturers’ instructions.

Don’t use a machine without your Don’t use a machine without your teacher’s supervisionteacher’s supervision

Restricted AdmittanceRestricted Admittance

Only people authorised by the user Only people authorised by the user or entitled by law should enter a or entitled by law should enter a workshop. Each workshop should workshop. Each workshop should have a notice announcing this rulinghave a notice announcing this ruling..

FloorsFloors All workshop floors should be level, All workshop floors should be level,

clean, non-slippery and, as far as clean, non-slippery and, as far as possible, free from chips or loose possible, free from chips or loose material.material.

LightingLighting There must be adequate illumination There must be adequate illumination

(lighting) in the workplace.(lighting) in the workplace. The glare in any workplace must be The glare in any workplace must be

reduced to a level that does not impair reduced to a level that does not impair vision.vision.

The lighting on rotating machinery must The lighting on rotating machinery must not cause a stroboscopic (flashing) effect.not cause a stroboscopic (flashing) effect.

Lights and lamps must be kept clean and Lights and lamps must be kept clean and maintained.maintained.

Artificial light must not shine in a machine Artificial light must not shine in a machine operator’s eyes.operator’s eyes.

Dangerous PlacesDangerous Places

All elevated platforms, openings in All elevated platforms, openings in floors, pits, trap holes and other floors, pits, trap holes and other dangerous places should be securely dangerous places should be securely fenced or protected to prevent fenced or protected to prevent accidents.accidents.

First aid, emergency First aid, emergency equipment and proceduresequipment and procedures

Injuries and emergencies should be dealt Injuries and emergencies should be dealt with swiftly and carefully.with swiftly and carefully.

Where more than five employees are Where more than five employees are employed at a workplace, the employer employed at a workplace, the employer must provide an accessible first aid box.must provide an accessible first aid box.

The Act states what the box should The Act states what the box should contain and that the whereabouts of the contain and that the whereabouts of the first aid box be clearly sign-posted.first aid box be clearly sign-posted.

AssessmentAssessment

State two safety precautions to be State two safety precautions to be observed when practising first aid in observed when practising first aid in a workplace.a workplace.

Pg 30Pg 30

Colour coding and signsColour coding and signs

All colours are based on the SANS All colours are based on the SANS Code 1091 colour coding.Code 1091 colour coding.

Colour codingColour codingBlueBlue The colour blue is used as a colour-code indicator The colour blue is used as a colour-code indicator

on pipelines carrying drinkable water and should on pipelines carrying drinkable water and should not be used on machinery.not be used on machinery.

GreenGreenEmerald green is used to identify:Emerald green is used to identify: the location of first aid equipmentthe location of first aid equipment emergency exits and safety areasemergency exits and safety areas informatory signs (such as signs for toilets and informatory signs (such as signs for toilets and

parking areas)parking areas) starting devices on electrical equipmentstarting devices on electrical equipment miscellaneous safety conditions.miscellaneous safety conditions.

Colour codingColour codingRedRedSignal red is used to identify:Signal red is used to identify: DangerDanger fire protectionfire protection stopping devices.stopping devices.

YellowYellow Yellow is used for housekeeping markings such as Yellow is used for housekeeping markings such as

identifying identifying crane lifting crane lifting hooks,hooks, changes in floor level and similar tripping hazards, and changes in floor level and similar tripping hazards, and

low head room,low head room, indicate ‘No parking’ areas on the floor below fire indicate ‘No parking’ areas on the floor below fire

equipment and electrical switchgear panelsequipment and electrical switchgear panels..

Colour codingColour coding

OrangeOrangeThe colour orange is used to identify:The colour orange is used to identify: electrical switchgearelectrical switchgear electrical serviceselectrical services exposed and rotating machine parts (for exposed and rotating machine parts (for

example if a casing or guard is not example if a casing or guard is not completely closed).completely closed).

AssessmentAssessment

Name the five basic colours that are Name the five basic colours that are used to give information in theused to give information in the

workplace, and give three examples workplace, and give three examples of this colour coding.of this colour coding.

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