unit 12 work equipment _cont

8/3/2019 Unit 12 Work Equipment _Cont.

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1.13.1 UNIT 12

Work Equipment(Cont.)


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Work Equipment (Cont.)

Welcome back. We have a few questions regarding machinery hazards before we start.

An example of _____ is moving tables, robot arms, slides and counterweights.

1. ? Ejection2. ? Impact3. ? Contact4. ? Entanglement

An example of _____ is where physical touch can cause injury by cutting, friction,abrasion, heat or cold burns, corrosive reaction, electric shock.

1. ? Impact2. ? Entanglement3. ? Contact4.

? Ejection

An example of _____ is where the operator's clothing may become caught up in movingcomponents.

1. ? Impact2. ? Ejection3. ? Contact4. ? Entanglement

An example of _____ is stabbing, cutting or puncture wounds caused by material orsparks thrown out from the workpiece, or by rapidly moving machine parts, or bycomponent failure.


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1.1. ? Ejection2. ? Contact3. ? Entanglement4. ? Impact

1.14 Methods of Protection

Within this section, we will examine the various methods of protection,

exploring their principles, merits and limitations:

Fixed guards.Fixed guards.Fixed guards.Fixed guards. Interlocked guards.Interlocked guards.Interlocked guards.Interlocked guards. Trip devices (Trip devices (Trip devices (Trip devices (lightlightlightlight curtains, foot mats and sensitive edges).curtains, foot mats and sensitive edges).curtains, foot mats and sensitive edges).curtains, foot mats and sensitive edges). Adjustable/selfAdjustable/selfAdjustable/selfAdjustable/self----adjusting guards.adjusting guards.adjusting guards.adjusting guards. TwoTwoTwoTwo----hand controls.hand controls.hand controls.hand controls. Protective appliances.Protective appliances.Protective appliances.Protective appliances. Personal protective equipmentPersonal protective equipmentPersonal protective equipmentPersonal protective equipment.... Information, instruction,Information, instruction,Information, instruction,Information, instruction,trainingtrainingtrainingtraining and supervision.and supervision.and supervision.and supervision.

Guards or protection devices must be used to protect risks such as moving

parts.

These must be of robust construction and not be easy to bypass. Fixed guards

must be held in place by fixings which can only be undone with tools.

Movable guards should be interlocked. Adjustable guards should be readily

adjustable without the use of tools.

Electrical and other energy supply hazards must be prevented. There must be

no risk ofinjury from temperature, explosion, noise, vibration, dust, gases or

radiation. There must be proper provision for maintenance and servicing.

Sufficient indication and warning devices must be provided. Machinery shall

be provided with instructions for safe installation, use, adjustment etc.

There are special requirements for agri-foodstuffs, hand-held, wood working

machines and also lifting and underground equipment.


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1.14.1 Methods of Protection

Fixed (enclosing) guards.

If the hazard is on a part of the machinery which does not require access, it should be

permanently guarded with fixed enclosing guards.

Interlocked guards.

These are movable guards with interlocking switches.

If access is required, there needs to be a movable (openable) guard which is interlocked

with the power source of the hazard in a manner which ensures that whenever the guarddoor is not closed, the hazardpower will be switched off.


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This approach involves the use of an interlocking switch fitted to the guard door.

The control of the power source of the hazard is routed through the switch section of the

unit. The power source is usually electrical but it could also be pneumatic or hydraulic.

When guard door movement (opening) is detected, the interlocking switch will isolate thehazardpower supply either directly or via a power contactor (or valve).

Some interlocking switches also incorporate a locking device which locks the guard door

closed and will not release it until the machine is in a safe condition.

For many applications, the combination of a movable guard and an interlock switch withor without guard locking is a reliable and cost-effective solution.


Trip devices.

These include:

light curtains; foot mats; sensitive edges.

When frequent access is required, physical guarding at the hazard is sometimes too

restrictive for part loading or adjustment.

In this situation, a device is required which prevents dangerous motion while

allowing unrestricted access by sensing the presence of the operator and sending astop signal.


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PhotoPhotoPhotoPhoto----electricelectricelectricelectric lightlightlightlight curtains.curtains.curtains.curtains.

These devices emit a curtain of harmless infrared light beams in front of the hazard

area. When any of the beams are blocked, the light curtain control circuit sends a stopsignal to the guarded machine. There are many factors which affect the type and

positioning of a light curtain.

Light curtains are extremely versatile and can guard areas many metres wide. Bythe use of mirrors, the light beams can be diverted round corners to enclose a machine.

They are available with different light beam spacings, making them suitable for many

applications, ranging from totally enclosing perimeter guards for industrial robots to pointof access guards for certain types of presses.


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Pressure sensitivePressure sensitivePressure sensitivePressure sensitivesafetysafetysafetysafetymats.mats.mats.mats.

These devices are used to guard a floor area around a machine. A matrix of

interconnected mats is laid around the hazard area and any pressure (e.g. an operator'sfootstep) will cause the mat controller unit to send a stop signal to the guarded machine.

Pressure-sensitive mats are often used within an enclosed area containing several

machines e.g. flexible manufacturing or robotics cells. When access may be required into

the cell (for setting or robot teaching, for example) they prevent dangerous motion if theoperator strays from the safe area.


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PressurePressurePressurePressure----sensitive edges.sensitive edges.sensitive edges.sensitive edges.

These devices are flexible edging strips which can be fixed to the edge of a

moving part such as a machine table or powered door where there is a risk of acrushing or shearing hazard.

If the moving part strikes the operator (or vice versa), the flexible sensitive edge isdepressed and will send a stop signal to the power source.

Sensitive edges can also be used to guard machinery where there is a risk of

operator entanglement. If an operator becomes caught up and dragged by themachine, he will be pulled onto the sensitive edge thereby tripping its switching

action.


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These trip devices do not actually restrict access but only sense it. They rely

entirely on their ability to both sense and switch for the provision of safety,therefore it is important that their control circuit be control reliable.

Also, they must only be used in correct applications. In general, they are only

suitable on machinery which stops immediately after removal ofpower. Becausean operator can walk or reach directly into the hazard area, it is necessary that thetime taken for the motion to stop is less than that required for the operator to reach

the hazard after tripping the device.

Adjustable/selfAdjustable/selfAdjustable/selfAdjustable/self----adjusting guards.adjusting guards.adjusting guards.adjusting guards.

Adjustable guards are guarding systems which require manual adjustment to giveprotection. They are used on woodworking machinery; milling machines; lathes; drills;

and grinding wheels.

Many of the guards are designed so the work-piece can be observed during machineoperation. Windows of polycarbonate or armoured plate glass allow the operator a clearview.


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Some systems are made with telescopic fencing or a slotted movable casting, both systems

allowing observation of the work-piece.

A further diagram of an adjustable guard, this time for a Circular Saw is below.

The cover is adjusted so that the height "H" is just large enough for the work-piece

to be cut by the saw. This kind of guarding can be difficult for the operator to use and is

easy to defeat. However, it is sometimes the only practicable method.


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TwoTwoTwoTwo----hand controls.hand controls.hand controls.hand controls.

There are other ways of preventing access while the machine is in a dangerous

condition. The use of two-hand controls (also referred to as bi-manual controls) iscommon on certain types of machinery.

Two start buttons have to be operated at the same time to run the machine. This

ensures that both hands of the operator are occupied in a safe position (i.e. at the controls)

and, therefore, cannot be in the hazard area.

Note: This type of measure only protects the operatorThis type of measure only protects the operatorThis type of measure only protects the operatorThis type of measure only protects the operatorand does not give protection to other personnel.and does not give protection to other personnel.and does not give protection to other personnel.and does not give protection to other personnel.

A two-hand controlsystem depends heavily on the integrity of its control and monitoring

system to detect any faults, so it is important that this aspect is designed to the correct

specification.

The physical design should prevent improper operation (e.g. by hand and elbow).


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The machine should not go from one cycle to another without the releasing and pressing

of both buttons. This prevents the possibility of both buttons being blocked, leaving themachine running continuously.

Releasing of either button must cause the machine to stop. The use of two-hand control

should be considered with caution as it usually leaves some form of risk exposed.

It is very useful, however, on applications such as teach mode pendants and inching

controls because it can give enhanced levels of protection when used in conjunction with

other protective devices.

Protective appliances.

Protection appliances (jigs, holders, push sticks etc) can be used to feed a

work-piece while keeping the operator's body clear of the danger zone.These are often used in conjunction with guards.

There are other ways of preventing access while the machine is in a

dangerous condition. The use of two-hand controls (also referred to as bi-

manual controls) is common on certain types of machinery.

Two start buttons have to be operated at the same time to run the machine.

This ensures that both hands of the operator are occupied in a safe position

(i.e. at the controls) and, therefore, cannot be in the hazard area.

Note: This type of measure only protects the operator and does notThis type of measure only protects the operator and does notThis type of measure only protects the operator and does notThis type of measure only protects the operator and does notgive protection to other personnel.give protection to other personnel.give protection to other personnel.give protection to other personnel.

A two-hand controlsystem depends heavily on the integrity of its control

and monitoring system to detect any faults, so it is important that this

aspect is designed to the correct specification.


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The physical design should prevent improper operation

(e.g. by hand and elbow).

The machine should not go from one cycle to another without the releasing

and pressing of both buttons. This prevents the possibility of both buttonsbeing blocked, leaving the machine running continuously.

Releasing of either button must cause the machine to stop. The use of two-

hand control should be considered with caution as it usually leaves someform of risk exposed.

It is very useful, however, on applications such as teach mode pendants andinching controls because it can give enhanced levels of protection whenused in conjunction with other protective devices.

Protective appliances.

Protection appliances (jigs, holders, push sticks etc)can be used to feed a work-piece while keeping theoperator's body clear of the danger zone. These areoften used in conjunction with guards.


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Information, Training, Instruction and Supervision

(IT IS).

All users of work equipment must be provided withadequate health and safetyinformation.

The employer must make it available and may haveto provide written instructions on the use of workequipment. This means the workforce should haveeasy access to such information and be able tounderstand it.

Users must be trained to use equipment safely and

supervisors must also receive adequate training onpotential risks and precautions.

The training and supervision of each individualoperator will vary. It is essential that an assessmentis made of those needs by a person who iscompetent to make such an assessment.


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Assessment.

Assessment is in two stages, firstly to identify thetraining needs of the individual and secondly tomeasure the success of the training that has beengiven.

The assessors should be familiar not only with the

machining processes but also with the relevant legalrequirements and safe working practices

Trainers.

The correct selection of supervisors and managerswho undertake training is central to any successfultraining scheme. They should be competent in thesafe operation of the class and type ofmachine, thetype of work or operation on which training is to begiven and the risk and control measures to beadopted in each particular case.

Trainers should be able to communicate easily and

have the necessary technical understanding andknowledge of the legal requirements.


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Supervision.

What constitutes an adequate level will vary duringthe training process. Initially, supervision should be

continuous and on a one-to-one basis, with gradualrelaxation as the trainee becomes more competent.

As each new operation or trainingelement isintroduced, the level of supervision will need to riseagain, reducing gradually to a more general levelonly when the trainee has demonstratedcompetence by consistent adoption of safe workingpractices.

Competence.

No one should be allowed to work at a woodworking

machine unless they have demonstratedcompetence on the basis of a supervisor or trainer'sassessment.

Competence is demonstrated when the trainee hasbeen sufficiently trained, has the requisiteknowledge and safe working practice has been usedconsistently when working at the machine.

Authorisation.


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The authorisation, preferably in writing, shouldlist those machines and operations for whichauthorisation is given and it should be made clear tothe operator that other machines should not be used

until authorisation is given. A copy of theauthorisation should be given to the operator.

Personal Protective Equipment (PPE).

In addition to the above measures, it may also benecessary for the operator to use equipment such asspecial gloves, goggles, respirators etc.

The machinerydesigner should specify what sort ofequipment is required. The use ofpersonalprotective equipment will not usually form theprimary safeguarding method but will complementthe measures shown above.

Each measure from the hierarchy should beconsidered in turn, starting from the top and usedwhere practical. This may result in a combination ofmeasures being used.

If access is not required to dangerous parts, thesolution is to protect them by some type of fixedenclosing guarding.

If access is required, then life becomes a little moredifficult. It will be necessary to ensure that accesscan only be gained while the machine is safe.

Protective measures such as interlocked guarddoors and/or trip systems will be required. Thechoice of protective device or system should be


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heavily influenced by the operating characteristics ofthe machine. This is extremely important as asystem which impairs machine efficiency willrender itself liable to unauthorised removal or by-

passing.

The safety of the machine in this case will dependon the proper application and correct operation ofthe protective system even under fault conditions.

The proper application has now been dealt with bythe appropriate choice of general type of protectivesystem. The correct operation of the system mustnow be considered.

Within each type, there is likely to be a choice oftechnologies with varying degrees of performance offault monitoring, detection or prevention.

In an ideal world, every protective system would beperfect with absolutely no possibility of failing to adangerous condition. In the real world, however, weare constrained by the current limits of knowledgeand materials.

Another very real constraint is, of course, cost. Itbecomes obvious, because of these factors, that asense of proportion is required.

Common sense tells us that it would be ridiculous toinsist that the integrity of a safetysystem on amachine that may, at the worst case, cause mildbruising, to be the same as that required to keep a

jumbo jet in the air.

The consequences of failure are drastically differentand, therefore, we need to have some way of relatingthe extent of the protective measures to the level ofrisk obtained at the risk estimation stage.


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Whichever type of protective device is chosen, itmust be remembered that a safety related systemmay comprise many elements including theprotective device, wiring, power switching device and

sometimes parts of the machine's operationalcontrolsystem.

All these elements of the system (including guards, fixings,wiring etc) should have suitable performance characteristicsrelevant to their design principle and technology.

A typical methods of protection for a Circular Saw may be

1.

? interlocked guards2. ? adjustable guard3. ? fixed guards4. ? trip devices

1.15 Stopping dangerous motion


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Emergency stops.

Wherever there is a danger of an operator gettinginto trouble on a machine, there must be a facilityfor fast access to an emergency stop device.

The usual way of providing this is in the form of amushroom-headed push button which the operatorstrikes in the event of an emergency.

They must be strategically placed in sufficientquantity around the machine to ensure that there isalways one in reach at a hazard point.


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Grabwire switches.

For machinery such as conveyors etc., it isoften more convenient and effective to use agrabwire device along the hazard area.

These devices use a steel wire rope connectedto latching pull switches so that pulling on the ropewill operate the switch and cut off the machine'spower.

Telescopic trip switches.

Other variations include telescopic antennaswitches where deflection of the antenna causes theswitch to cut off the machinepower.

These devices are more commonly used as tripdevices on machinery such as pillar drills. Theswitch is mounted on the drill and the antenna isextended down next to the drill bit.

In the event of the operator becoming entangledwith the drill, he will be pulled onto the antennawhich operates the switch.


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1.16 Basic requirements for guards and safety devices

In short, these requirements are that guardsand safetydevices should be compatible with theprocess, have adequate strength, be maintained,allow maintenance without removal, not increaserisk or restrict view and not be easily by-passed.

We will now consider the above further, by reviewingthe advantages and limitations of the guards and

safetydevices we have already covered.


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GUARDS.

Method Safeguarding Action Advantages Limitations Means of Overriding

Fixed.

Provides a barrier.

Permanently in place

after installation (e.g.welded, riveted).

Normally require

special tool to remove.

--Can be

constructed to suit

many specificapplications.

--In-plantconstruction is

often possible.

--Can providemaximum

protection.

--Usually requires

minimummaintenance.

--Can be suitableto highproduction,

repetitive

operations.

--May interferewith visibility.

--Can be limited to

specific operations.--Machine

adjustment and

repairs often

require its removal,thereby

necessitating other

means of protectionfor maintenance

personnel.

--Special tool for

removal may be too

widely available.

Interlocked

Shuts off or

disengages power andprevents starting of

machine when guard is

open; should require

the machine to bestopped before the

worker can reach into

the danger area

--Can providemaximum

protection.

--Allows accessto machine for

removing jams

without timeconsuming

removal of fixed

guards.

--Requires careful

adjustment and

maintenance.

--May be easy todisengage jams.

Bending connectorsout of position.

Usually difficult on

well designed systems.

Adjustable

Provides a barrier that

may be adjusted to

facilitate a variety ofproduction operations

--Can be

constructed to suit

many specific

applications.--Can be adjusted

to admit varyingsizes of stock.

--Hands may enterdanger area -

protection may not

be complete at alltimes.

--May require

frequent

maintenance and/oradjustment.

--The guard may be

made ineffective bythe operator.

--May interfere

with visibility.

Can be adjusted out ofrange.


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Self-

adjusting

Provides a barrier that

moves according tothe size of the stock

entering the dangerarea

Off-the-shelf

guards are often

commercially

available

--Does not alwaysprovide maximum

protection.

--May interferewith visibility.

--May requirefrequent

maintenance andadjustment.

Can be adjusted out ofrange.

1.17 Basic requirements for guards and safety devices

continued.

DEVICES.

MethodSafeguarding

ActionAdvantages Limitations

Means of

Overriding

Photoelectric

Machine will notstart cycling when

the light field is

interrupted.

Can allow freer

movement foroperator.

Does not protectagainst

mechanical

failure.

.

When the light fieldis broken by any

part of the

operator's bodyduring the cycling

process, immediatemachine braking isactivated.

-Simplicity of

use.

--Used by

multipleoperators.

--Provide

passer-byprotection.

--No

adjustmentrequired.

Limited to

machines that can

be stopped.

Radio frequency(optical)

--Machine cycling

will not start when

the capacitance field

Can allow freer

movement for

operator.

--Does not protect

against

mechanical


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is interrupted.--When the

capacitance field is

disturbed by anypart of the

operator's bodyduring the cycling

process, immediatemachine braking is

activated.

failure.--Antennae

sensitivity must

be properlyadjusted; this

adjustment mustbe maintained

properly.--Limited to

machines that can

be stopped.

Electromechanical

--Contact bar or

probe travels a

predetermineddistance between

the operator and the

danger area.--Interruption of thismovement prevents

the starting of

machine cycling.

Can allowaccess at the

point ofoperation.

Contact bar or

probe must be

properly adjustedfor each

application; thisadjustment mustbe maintained

properly.

Pullback

As the machine

begins to cycle, the

operator's hands arepulled out of the

danger area.

Eliminates the

need for

auxiliary

barriers orother

interference at

the danger area.

--Limits

movement ofoperator.

May obstruct

work space

around operator.

Restraint(holdback)

Prevents the

operator fromreaching into the

danger area.

Little risk of

mechanical

failure.

--Adjustments

must be made for

specific

operations and foreach individual.

--Requires

frequentinspections and

regular

maintenance.

--Requires closesupervision of the

operator's use of

the equipment.--Limits

movement of

operator.


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--May obstructwork space.

Safety trip

controls:-Pressure-sensitive

body bar

-Safety triprod

-Safety tripwire

Stops machine

when tripped.

Simplicity of

use.

--All controls

must be manually

activated.

--May be difficultto activate

controls becauseof their location.

--Only protects

the operator.--May require

special fixtures to

hold work.--May require a

machine brake.

People can avoid.

Two-hand control

Concurrent use of

both hands isrequired, preventing

the operator from

entering the dangerarea.

--Operator's

hands are at apre-determined

location.

--Operator's

hands are freeto pick up a

new part after

first half of

cycle iscompleted.

--Requires apartial cyclemachine with a

brake.

--Some two-handed controls

can be rendered

unsafe by holding

with arm orblocking, thereby

permitting one-

hand operation.--Protects only the

operator.

Two people, eachholding one handle.

Two-hand trip

Concurrent use oftwo hands on

separate controls

prevents hands from

being in danger areawhen machine cycle

starts.

--Operator's

hands are awayfrom danger

area.

--Can beadapted to

multiple

operations.

--Noobstruction to

hand feeding.

--Does notrequire

adjustment for

each operation.

--Operator may

try to reach intodanger area after

tripping machine.

--Some trips canbe rendered

unsafe by holding

with arm or

blocking, therebypermitting one-

hand operation.

--Protects only theoperator.

--May require

special fixtures.

As above.


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Gate

Provides a barrier

between danger area

and operator or

other personnel.

Can prevent

reaching into or

walking into

the danger area.

--May requirefrequent

inspection and

regularmaintenance.

--May interferewith operator's

ability to see thework.

1.17.1 Guard Construction

Today, many builders of single-purpose machinesprovide point-of-operation and power transmissionsafeguards as standard equipment. However, not allmachines in use have built-in safeguards provided

by the manufacturer.

Guards designed and installed by the builder offertwo main advantages:

They usually conform to the design andfunction of the machine.

They can be designed to strengthen themachine in some way or to serve someadditional functional purposes.

User-built guards are sometimes necessary for avariety of reasons. They have these advantages:

Often, with older machinery, they are theonly practical safeguarding solution.


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They may be the only choice for mechanicalpower transmission apparatus in olderplants, where machinery is not powered byindividual motor drives.

They permit options for point-of-operationsafeguards when skilled personnel designand make them.

They can be designed and built to fit uniqueand even changing situations.

They can be installed on individual devicesand feeding mechanisms.

Design and installation ofmachinesafeguards by plant personnel can help topromote safetyconsciousness in the

workplace.

However, they also have disadvantages:

User-built guards may not conform well tothe configuration and function of themachine.

There is a risk that user-built guards may bepoorly designed or built.

Point-of-Operation Guards

Point-of-operation safeguarding is complicated bythe number and complexity of machines and also bythe different uses for individual machines. For thesereasons, not all machine builders provide point-of-operation guards on their products.


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In many cases, a point-of-operation guard can onlybe made and installed by the user after a thoroughhazard analysis of the work requirements.

Poorly-designed, built or installed guards may createa hazard rather than eliminate one.

To be effective, they must safeguard the employeewhile allowing the work to continue with minimumdisruption to the production process.

Mechanical Power Transmission Apparatus Guarding.

A significant difference between power transmissionguards and point-of-operation guards is that theformer type needs no opening for feeding stock.

The only openings necessary for power transmissionguards are those for lubrication, adjustment, repair,and inspection.

These openings should be provided with interlockedcovers that cannot be removed except by using toolsfor service or adjustment.

To be effective, power transmission guards should

cover all moving parts in such a manner that no partof the operator's body can come in contact withthem.


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Guard Material.

Under many circumstances, metal is the bestmaterial for guards. Guard framework is usually

made from structural shapes, pipe, bar, or rodstock.

Filler material generally is expanded or perforated orsolid sheet metal or wire mesh. It may be feasible touse plastic or safetyglass where visibility isrequired.

Guards made of wood generally are notrecommended because of their flammability and lack

of durability and strength. However, in areas wherecorrosive materials are present, wooden guards maybe the better choice.

1.17.2 Maintenance & Repair

Good maintenance and repair procedures contributesignificantly to the safetyof the maintenance crew aswell as that ofmachine operators.

The variety and complexity of machines to beserviced, the hazards associated with their power

sources, the special dangers that may be presentduring machine breakdown and the severe timeconstraints often placed on maintenance personnelall make safe maintenance and repair work difficult.

Training and the aptitude of people assigned tothese jobs should make them alert for intermittent


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electrical failure, the worn part, the inappropriatenoise, the cracks or other signs that warn ofimpending breakage or that a safeguard has beendamaged, altered or removed.

By observing machine operators at their tasks andlistening to their comments, maintenance personnelmay learn where potential trouble spots are and givethem early attention before they develop into sourcesof accidents and injury.

Sometimes, all that is needed to keep things runningsmoothly and safely is machine lubrication oradjustment.

Anydamage observed or suspected should bereported to the supervisor; if the condition impairssafe operation, the machine should be out of servicefor repair.

Safeguards that are missing, altered, or damagedalso should be reported so appropriate action can betaken to insure against worker injury.

If possible, machine design should permit routinelubrication and adjustment without removal ofsafeguards. But when safeguards must be removed,and the machine serviced, a lockout procedure mustbe adhered to.

The maintenance and repair personnel must neverfail to replace the guards before the job is consideredfinished and the machine released from lockout.

Is it necessary to oil machine parts while a machineis running? If so, special safeguarding equipmentmay be needed solely to protect the operatorresponsible for oiling from exposure to hazardousmoving parts.


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Maintenance personnel must know which machinescan be serviced while running and which cannot. "Ifin doubt, lock it out." Obviously, the danger ofaccident or injuryis reduced by shutting off and

locking out all sources of energy.

In situations where the maintenance or repairworker would necessarily be exposed to electricalelements or hazardous moving machine parts in theperformance of the job, there is no question that allpower sources must be shut off and locked outbefore work begins.

Warning signs or tags are inadequate insurance

against the untimely energising of mechanicalequipment.

Thus, one of the first procedures for themaintenance person is to disconnect and lock outthe machine from all of its power sources, whetherthe source is electrical, mechanical, pneumatic,hydraulic or a combination of these.

Energy accumulation devices must be "bled down."

1.17.3


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Electrical Hazards in Machinery Maintenance & Repair

Electrical.

UUUUnexpected energising of anyelectricalequipment that can be started by automatic ormanual remote control may cause electric shock orother serious injuries to the machine operator, the

maintenance worker or others operating adjacentmachines controlled by the same circuit.

For this reason, when maintenance personnel mustrepair electrically powered equipment, they shouldopen the circuit at the switch box and padlock theswitch (lock it out) in the "off" position.

This switch should be tagged with a description of

the work being done, the name of the maintenanceperson and the department involved.

When more than one worker is to be engaged in theservicing/maintenance function, a typical lockouthasp to which each may affix a personal lock isshown below.


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1.17.4 Basic requirements for guards and safety devices

Mechanical

TTTThe diagram below shows safetyblocks beingused as an additional safeguard on amechanical power press, even though themachine has been locked out. The safetyblocksprevent the ram from coming down under itsown weight.


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Pneumatic and hydraulic

Before the valve can be opened, everyone workingBefore the valve can be opened, everyone workingBefore the valve can be opened, everyone workingBefore the valve can be opened, everyone workingon theon theon theon the machinemachinemachinemachine must use his or her own key tomust use his or her own key tomust use his or her own key tomust use his or her own key torelease the lockout.release the lockout.release the lockout.release the lockout.

A slidingA slidingA slidingA sliding----sleeve valve exhausts line pressure atsleeve valve exhausts line pressure atsleeve valve exhausts line pressure atsleeve valve exhausts line pressure atthe same time it cuts off the air supply.the same time it cuts off the air supply.the same time it cuts off the air supply.the same time it cuts off the air supply.

Valves used to lock out pneumatic or hydraulicValves used to lock out pneumatic or hydraulicValves used to lock out pneumatic or hydraulicValves used to lock out pneumatic or hydraulic----powered machines should be designed to acceptpowered machines should be designed to acceptpowered machines should be designed to acceptpowered machines should be designed to acceptlocks olocks olocks olocks or lockout adapters and should be capabler lockout adapters and should be capabler lockout adapters and should be capabler lockout adapters and should be capableof "bleeding off" pressure residues that couldof "bleeding off" pressure residues that couldof "bleeding off" pressure residues that couldof "bleeding off" pressure residues that couldcause any part of thecause any part of thecause any part of thecause any part of the machinemachinemachinemachine to move.to move.to move.to move.


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In workshops where severalIn workshops where severalIn workshops where severalIn workshops where several maintenancemaintenancemaintenancemaintenance personspersonspersonspersonsmight be working on the samemight be working on the samemight be working on the samemight be working on the same machinemachinemachinemachine, multiple, multiple, multiple, multiple

lockout devices accommodating several padlocks arelockout devices accommodating several padlocks arelockout devices accommodating several padlocks arelockout devices accommodating several padlocks areused.used.used.used.

TheTheTheThe machinemachinemachinemachine cannot be reactivated until each personcannot be reactivated until each personcannot be reactivated until each personcannot be reactivated until each personremoves his or her lock. As a matter of generalremoves his or her lock. As a matter of generalremoves his or her lock. As a matter of generalremoves his or her lock. As a matter of generalpolicypolicypolicypolicy,,,,lockoutlockoutlockoutlockout controlcontrolcontrolcontrol is gained by the procedure of issuingis gained by the procedure of issuingis gained by the procedure of issuingis gained by the procedure of issuing

personal padlocks to eachpersonal padlocks to eachpersonal padlocks to eachpersonal padlocks to each maintenancemaintenancemaintenancemaintenance or repairor repairor repairor repairperson; no one but that person can remove the padlock,person; no one but that person can remove the padlock,person; no one but that person can remove the padlock,person; no one but that person can remove the padlock,

thereby each worker controls thethereby each worker controls thethereby each worker controls thethereby each worker controls thepowerpowerpowerpowersystems.systems.systems.systems.

Whenever machines or equipment are serviced, thereWhenever machines or equipment are serviced, thereWhenever machines or equipment are serviced, thereWhenever machines or equipment are serviced, thereare hazards encountered by the employees performingare hazards encountered by the employees performingare hazards encountered by the employees performingare hazards encountered by the employees performing

the servicing orthe servicing orthe servicing orthe servicing ormaintenancemaintenancemaintenancemaintenance which are unique to thewhich are unique to thewhich are unique to thewhich are unique to therepair orrepair orrepair orrepair ormaintenancemaintenancemaintenancemaintenance procedures being conducted.procedures being conducted.procedures being conducted.procedures being conducted.

These hazards may exist due to the failure of theThese hazards may exist due to the failure of theThese hazards may exist due to the failure of theThese hazards may exist due to the failure of the

employees doing the servicing oremployees doing the servicing oremployees doing the servicing oremployees doing the servicing ormaintenancemaintenancemaintenancemaintenance to stopto stopto stopto stopthethethethe machinemachinemachinemachine being worked on. Even if thebeing worked on. Even if thebeing worked on. Even if thebeing worked on. Even if the machinemachinemachinemachine hashashashasbeen stopped, thebeen stopped, thebeen stopped, thebeen stopped, the machinemachinemachinemachine can still be hazardous duecan still be hazardous duecan still be hazardous duecan still be hazardous due

to the possibility of theto the possibility of theto the possibility of theto the possibility of the machinemachinemachinemachine becoming rebecoming rebecoming rebecoming re----energised or restarting.energised or restarting.energised or restarting.energised or restarting.

In order to preveIn order to preveIn order to preveIn order to prevent these hazards, eachnt these hazards, eachnt these hazards, eachnt these hazards, each machinemachinemachinemachine or pieceor pieceor pieceor pieceof equipment should be safeguarded during theof equipment should be safeguarded during theof equipment should be safeguarded during theof equipment should be safeguarded during theconduct of servicing orconduct of servicing orconduct of servicing orconduct of servicing ormaintenancemaintenancemaintenancemaintenance by:by:by:by:

(1) notifying all affected employees (usually(1) notifying all affected employees (usually(1) notifying all affected employees (usually(1) notifying all affected employees (usuallymachinemachinemachinemachine or equipment operators or users) that theor equipment operators or users) that theor equipment operators or users) that theor equipment operators or users) that the


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machinemachinemachinemachine or equipmentor equipmentor equipmentor equipment must be shut down to performmust be shut down to performmust be shut down to performmust be shut down to performsomesomesomesome maintenancemaintenancemaintenancemaintenance or servicing;or servicing;or servicing;or servicing;(2) stopping the(2) stopping the(2) stopping the(2) stopping the machinemachinemachinemachine;;;;(3) isolating the(3) isolating the(3) isolating the(3) isolating the machinemachinemachinemachine orororor piece of equipment frompiece of equipment frompiece of equipment frompiece of equipment fromits energy source;its energy source;its energy source;its energy source;(4) locking out or tagging out the energy source;(4) locking out or tagging out the energy source;(4) locking out or tagging out the energy source;(4) locking out or tagging out the energy source;(5) relieving any stored or residual energy; and(5) relieving any stored or residual energy; and(5) relieving any stored or residual energy; and(5) relieving any stored or residual energy; and(6) verifying that the(6) verifying that the(6) verifying that the(6) verifying that the machinemachinemachinemachine or equipment isor equipment isor equipment isor equipment isisolated from the energy source.isolated from the energy source.isolated from the energy source.isolated from the energy source.

Although this is the general rule, there are exceptionsAlthough this is the general rule, there are exceptionsAlthough this is the general rule, there are exceptionsAlthough this is the general rule, there are exceptionswhen the servicing orwhen the servicing orwhen the servicing orwhen the servicing ormaintenancemaintenancemaintenancemaintenance is not hazardousis not hazardousis not hazardousis not hazardous

for an employee, when the servicing which isfor an employee, when the servicing which isfor an employee, when the servicing which isfor an employee, when the servicing which isconducted is minor in nature, done as an integralconducted is minor in nature, done as an integralconducted is minor in nature, done as an integralconducted is minor in nature, done as an integral

part of production, and the employer utilisespart of production, and the employer utilisespart of production, and the employer utilisespart of production, and the employer utilisesalternative safeguards whicalternative safeguards whicalternative safeguards whicalternative safeguards which provide effectiveh provide effectiveh provide effectiveh provide effective

protection.protection.protection.protection.

When the servicing orWhen the servicing orWhen the servicing orWhen the servicing ormaintenancemaintenancemaintenancemaintenance is completed, thereis completed, thereis completed, thereis completed, thereare specific steps which must bare specific steps which must bare specific steps which must bare specific steps which must be taken to return thee taken to return thee taken to return thee taken to return themachinemachinemachinemachine or piece of equipment to service. These stepsor piece of equipment to service. These stepsor piece of equipment to service. These stepsor piece of equipment to service. These stepsinclude:include:include:include:

(1)(1)(1)(1) inspectioninspectioninspectioninspection of theof theof theof the machinemachinemachinemachine orororor equipment toequipment toequipment toequipment to

ensure that all guards and otherensure that all guards and otherensure that all guards and otherensure that all guards and othersafetysafetysafetysafetydevices are in place and functional,devices are in place and functional,devices are in place and functional,devices are in place and functional,

(2)(2)(2)(2) checking the area to ensure thatchecking the area to ensure thatchecking the area to ensure thatchecking the area to ensure thatenergisation and startenergisation and startenergisation and startenergisation and start up of theup of theup of theup of the machinemachinemachinemachine


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or equipment will not endanger employees,or equipment will not endanger employees,or equipment will not endanger employees,or equipment will not endanger employees,

(3)(3)(3)(3) removal of the lockout devices,removal of the lockout devices,removal of the lockout devices,removal of the lockout devices,

((((4)4)4)4) rererere----energisation of theenergisation of theenergisation of theenergisation of the machinemachinemachinemachine ororororequipment, andequipment, andequipment, andequipment, and

(5)(5)(5)(5) notification of affected employees that thenotification of affected employees that thenotification of affected employees that thenotification of affected employees that themachinemachinemachinemachine or equipment may be returned toor equipment may be returned toor equipment may be returned toor equipment may be returned to

service.service.service.service.

The steps to lockout described above are only a part ofThe steps to lockout described above are only a part ofThe steps to lockout described above are only a part ofThe steps to lockout described above are only a part ofthe total energythe total energythe total energythe total energy controlcontrolcontrolcontrol programme which must existprogramme which must existprogramme which must existprogramme which must existin the workplace.in the workplace.in the workplace.in the workplace.

In addition, the employee should have writtenIn addition, the employee should have writtenIn addition, the employee should have writtenIn addition, the employee should have writtenprocedures for all machines and equipment, employeesprocedures for all machines and equipment, employeesprocedures for all machines and equipment, employeesprocedures for all machines and equipment, employeesmust be trained in their duties and responsibilitiesmust be trained in their duties and responsibilitiesmust be trained in their duties and responsibilitiesmust be trained in their duties and responsibilitiesunder the energyunder the energyunder the energyunder the energy controlcontrolcontrolcontrol programme and periodicprogramme and periodicprogramme and periodicprogramme and periodicinspections must be conducinspections must be conducinspections must be conducinspections must be conducted to maintain theted to maintain theted to maintain theted to maintain theeffectiveness of the programme.effectiveness of the programme.effectiveness of the programme.effectiveness of the programme.

TheTheTheThe maintenancemaintenancemaintenancemaintenance and repair facility in the plantand repair facility in the plantand repair facility in the plantand repair facility in the plantdeserves considedeserves considedeserves considedeserves consideration here.ration here.ration here.ration here.

Are all the right tools on hand and in goodAre all the right tools on hand and in goodAre all the right tools on hand and in goodAre all the right tools on hand and in goodrepair?repair?repair?repair?


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Are lubricating oils and other commonAre lubricating oils and other commonAre lubricating oils and other commonAre lubricating oils and other commonsupplies readily available and safely stored?supplies readily available and safely stored?supplies readily available and safely stored?supplies readily available and safely stored?

Are commonly usedAre commonly usedAre commonly usedAre commonly used machinemachinemachinemachine parts andparts andparts andparts andhardware kept in stock so that the crews arehardware kept in stock so that the crews arehardware kept in stock so that the crews arehardware kept in stock so that the crews arenot encouraged (even obliged) to improvise, atnot encouraged (even obliged) to improvise, atnot encouraged (even obliged) to improvise, atnot encouraged (even obliged) to improvise, at

the risk of doing an unsafe repair, or tothe risk of doing an unsafe repair, or tothe risk of doing an unsafe repair, or tothe risk of doing an unsafe repair, or topostpone a repair job?postpone a repair job?postpone a repair job?postpone a repair job?

And don't overlook the possibility thaAnd don't overlook the possibility thaAnd don't overlook the possibility thaAnd don't overlook the possibility thatttt maintenancemaintenancemaintenancemaintenanceequipment itself may need guarding of some sort.equipment itself may need guarding of some sort.equipment itself may need guarding of some sort.equipment itself may need guarding of some sort.The same precaution applies to tools and machinesThe same precaution applies to tools and machinesThe same precaution applies to tools and machinesThe same precaution applies to tools and machinesused iused iused iused in the repair shop. Certainly, then the repair shop. Certainly, then the repair shop. Certainly, then the repair shop. Certainly, the maintenancemaintenancemaintenancemaintenanceand repair crew are entitled to the same protection thatand repair crew are entitled to the same protection thatand repair crew are entitled to the same protection thatand repair crew are entitled to the same protection that

their service prtheir service prtheir service prtheir service provides to theovides to theovides to theovides to the machinemachinemachinemachine operators in theoperators in theoperators in theoperators in theplant.plant.plant.plant.

Ergonomic Considerations ofMachine Safeguarding.

The ergonomic considerations ofmachinesafeguarding are as significant to the safety andhealth of the worker as are the multitude of techniques

to accomplish safety and health in the workplace.

Worker stress and fatigue can be averted by creditablework setups and well-integrated safeguarding. Thevarious industry consensus standards are only nowbeginning to address this issue.


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Future evaluations of safeguarding are likely todevote more attention to this aspect.

The diagram below shows a lockout valve. The lever-

operated air valve used during repair or shutdown tokeep a pneumatic-powered machine or itscomponents from operating can be locked open orshut.

1.18 Main Types of Hazards from Moving Machinery -

the Regulations

PROVISION AND USE OF WORK EQUIPMENT REGULATIONS 1998

We now move on to consider the main types of hazards from movingmachinery. There is a legal requirement for guarding to be provided on

dangerous parts of machines.

Under HSWA 1974, manufacturers or suppliers are obliged by law to

ensure that their products are designed and constructed so as to be safe inuse. They must provide clear instructions on the safe use of any machine,

warn of any inherent dangers and notify operators on how to avoid them.

Before 1992, the main specific requirements on guarding were contained in

the Factories Act 1961, but following an EUDirective, the Provision and

Use of Work Equipment Regulations 1992 (PUWER) were incorporatedinto British law. The Regulations were amended in 1994 and 1996.


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Machinery Hazards.

Following an EU Amending Directive, PUWER was updated by

the Provision and Use of Work Equipment Regulations 1998

(PUWER 98) and the Lifting Operations and LiftingEquipment Regulations 1998 (LOLER 98).

They are supported by HSE Guidance Note L22: Safe Use of

Work Equipment: Provision and Use of Work Equipment

Regulations 1998:Approved Code of Practice, a copy of whichshould be in your organisation's database.

PUWER 98 applies to all work equipment (new, second-hand,

hired or leased), including lifting equipment, whereas LOLER

applies over and above PUWER 98 in regard to lifting

equipment and operations.

Mobile work equipment (MWE) and lift trucks are now coveredby the work equipment regulations, as are power presses,

woodworking machines and abrasive wheels.

The main aim of these regulations is to ensure that equipment

provided for use at work is safe and is used safely. The intention

is that work equipment should not give rise to risks to health and

safety, regardless of its age, function or place of origin.

Therefore, the regulations set out a number of general

requirements which apply to all equipment for use at work.

The definition of work equipment is extremely wide; it means

any machinery, appliance, apparatus, tool or installation for useat work (whether exclusively or not).

Use of work equipment covers any activity, including


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starting, stopping, programming, setting, transporting, repairing, modifying, maintaining, servicing and cleaning.

The main provisions are outlined below.

1.18.1 Machinery Regulations

General Requirements

Suitability (Regulation 4)

Work equipment must be suitable for the purpose for whichit is used and also appropriate for the workenvironment in

which it will be used.

So in practice, when equipment is provided it must be

appropriate for the work to be undertaken and must be usedin accordance with the manufacturer's specifications andinstructions.

If equipment is adapted, it must still be suitable for itsintended purpose. The location in which the work

equipment is used must be assessed to take into account any

risks from particular circumstances; for example,


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electrically-powered equipment used in wet or flammable

atmospheres.

Maintenance (Regulation 5)

Every employer shall ensure that work equipment is

maintained in an efficient state, in efficient working orderand in good repair.

Every employer shall ensure that where any machinery has amaintenance log, the log is kept up to date.

Inspection (Regulation 6)

There is a requirement for inspection of work equipment incases where its safety depends upon the installation

conditions, or where it is exposed to conditions liable to

cause deterioration to a dangerous state. Inspections should

cover:

initial inspection where incorrect installation maygive rise to a risk;

routine inspection where deterioration or exceptionalcircumstances may give rise to risk;

keeping records of such inspections;

relocated equipment must be accompanied by someform ofinspection log;

hired or borrowed equipment must not be usedwithout evidence of the last inspection, e.g. a report.

Specific Risks (Regulation 7)

If the use of work equipment is likely to involve a specificrisk to health and safety, every employer shall restrict the

use of that equipment to those persons given the task ofusing it, and any repairs, modifications, maintenance orservicing carried out on that equipment must only be

undertaken by people who have been specifically designatedto perform the work.


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Designated persons must receive adequate training in

respect of any operations to which they have beendesignated.

Information, Instruction and Training

(Regulations 8 and 9)

All users of work equipment must be provided with

adequate health and safety information. The employer mustmake it available and may have to provide written

instructions on the use of work equipment.

This means the workforce should have easy access to such

information and be able to understand it.

Users must be trained to use equipment safely and

supervisors must also receive adequate training on potentialrisks and precautions.

Conformity with EU Requirements

(Regulation 10)

Work equipment must comply with EU directives which laydown relevant standards. However, the minimum essential

safety requirements ofEU product directives (for example,

as implemented by the Supply of Machinery (Safety)

Regulations 2008) are not retrospective. (This does not

mean that such equipment is unregulated).

1.18.2 Specific Requirements for Machinery


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Specific Requirements.

In addition to the general requirements outlined above, the Regulationsalso contain specific requirements in Regulations 11 to 24. It is the

procedures and practices necessary to ensure compliance with these

regulations that we will be looking at in more detail in this and subsequentstudy units.

The requirements cover:

Prevention of access to the dangerous parts of machinery(Regulation 11).

Protection against specified hazards, such as materials falling or

being ejected from work equipment, fragmentation of equipmentparts, fire or overheating, discharge of a material or substance kept

in the equipment, explosion, etc. (Regulation 12).

Protection against high or very low temperature (Regulation 13).

Provision of adequate controls and control systems (Regulations

14 to 18). This group covers the employer's duty to ensure theprovision of readily-accessible stop controls, which function as kill

switches where necessary and which cannot be over-ridden by startswitches; where necessary, the provision of emergency stop

controls which cannot be over-ridden by start switches; and control

systems which fail to safety.

Provision to isolate from and reconnect to power sources withoutrisk (Regulation 19).

The stabilisation of equipment where necessary, by fixing, tying,

fastening or clamping, as appropriate (Regulation 20).

Provision ofsuitable and sufficient lighting (Regulation 21).

Construction of equipment so that maintenance work can becarried out safely and without risks to health (Regulation 22).


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Provision of any markings or warnings/warning devices

necessary for reasons of health and safety (Regulations 23 and 24).

Procedures and Practices to Ensure Compliance.

If work equipment is provided, the employer must comply with the general

requirements outlined above.

The employer should assess the safety of the work equipment from three aspects:

Its initial integrity (design, construction, quality, etc.).

The place where it will be used.

The purpose for which it will be used.

In deciding whether the requirements ofPUWER 98 apply to any given item of

work equipment, the following factors must be considered:

New equipment provided for use after 5th December 1998 mustmeet all of the requirements ofPUWER 98.

Equipment first provided for use before 5th December 1998must meet Regulations 1 to 24 and Regulations 31 to 35 of

PUWER 98 (the latter group covers power presses). Second-hand or used equipment is regarded as new at the date

when the purchasing employer puts it into use and is subject toall the requirements ofPUWER 98.


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Employers must select work equipment with care and ensure its suitability for

particular tasks.

Regular maintenance of equipment must be carried out and employees must begiven the necessary information, instruction and training, relevant to any risks

associated with the equipment.

Work tasks and standards often change, so there should be monitoring and review

of assessments. Risk assessments are not an explicit duty under PUWER 98, but

they are under the Management of Health and Safety at Work Regulations 1999.

Dangerous Parts of Machinery.

The term 'dangerous parts of machinery' is well-established in health and safety

law. Definitions and safeguarding measures which were used to comply with

earlier law are still appropriate.

The basic source of information regarding safety of machinery was the British

Standards Institution publication BS 5304: 1988, Code of practice for safety ofmachinery. As the result of harmonisation ofEU standards, it was adapted as an

EUstandard and republished as

BS EN 292: Part 1: 1991, Safety of machinery - Basic concepts,general principles for design Part 1, Basic terminology, methodology.

BS EN 292: Part 2: 1991, Safety of machinery - Basic concepts,general principles for design Part 2. Technical principles andspecifications.

Should you wish to consult these documents directly, it would be best to do so in alibrary, as they are an expensive purchase. There are other EU standards on

machinesafety, including BS EN 294: 1994, BS EN 349: 1993, BS EN 418: 1992,

and BS EN 811: 1997.


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BS 5304 listed the following hazards associated with the use of machinery. They

related only to mechanical hazards:

Entanglement. Friction and abrasion.

Cutting. Impact. Shear. Crushing. Drawing in.

Stabbing and punctures.

BS EN 292 extended the basis upon which hazards are described by incorporating

hazards associated with use. The following categories were introduced:

Mechanical (derived from the above list). Electrical. Thermal. Noise. Vibration. Materials and substances. Ergonomic principles. Combinations of above.

The mechanical hazards are described in more detail below.

All guards must be suitable for their purpose and a protection device orinterlocking system must be designed so that it will operate only as intended.

If the overall risk is high, then there should be adequate provision to counteract the

effects of failure.

Guards and protection devices must be of good construction and be capable ofdoing the job they are intended to do.

Once constructed and installed, the law requires them to be maintained in efficient

working order and in good repair.


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A _____ Guard - Shuts off or disengages power and prevents starting ofmachine when

guard is open; should require the machine to be stopped before the worker can reach intothe danger area.

1.1. ? Interlocked2. ? Adjustable3. ? Self-adjusting4. ? Fixed

A _____ Guard - Provides a barrier that may be adjusted to facilitate a variety ofproduction operations.

1. ? Interlocked2. ? Self-adjusting3. ? Fixed4. ? Adjustable

A _____ Guard - Provides a barrier. Permanently in place after installation (e.g. welded,

riveted). Normally require special tool to remove.

1.1. ? Fixed2. ? Interlocked3. ? Self-adjusting4. ? Adjustable

A _____ Guard - Provides a barrier that moves according to the size of the stock entering

the danger area.

1. ? Self-adjusting2. ? Adjustable3. ? Fixed4. ? Interlocked


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2.0 Summary

This summary section will refer you back to the learning outcomes and summarise the

notes.

Outline general requirements for work equipment;

The Supply of Machinery (Safety) Regulations 2008

CE Marking

1. Guards and protection devices must:

be robust;be robust;be robust;be robust; not give rise to any additionalnot give rise to any additionalnot give rise to any additionalnot give rise to any additional risk;risk;risk;risk; be difficult to circumvent or put out of service;be difficult to circumvent or put out of service;be difficult to circumvent or put out of service;be difficult to circumvent or put out of service; be located an "adequate distance from thebe located an "adequate distance from thebe located an "adequate distance from thebe located an "adequate distance from the dangerdangerdangerdanger

zonezonezonezone""""

2. Fixed guards must be securely held in place by a system that can only beopened using the appropriate tools.

3. Type A movable guards should remain fixed to the machinery when open andshould have a locking device to prevent any accessible moving parts from starting.

4. Type B movable guards must be incorporated into the controlsystem so thatmoving parts cannot start while they are still accessible and that they cannot be reached

once they have started to move. Failure of a component must prevent the starting of

moving parts, or stop the moving parts if they are in motion. They should only be

adjustable by an intentional action, such as the use of a key or tool.

5. Adjustable guards restrict access to moving parts where operator intervention isnecessary. They must be easily adjustable, either manually or automatically, without theuse of tools.

6. Protection devices must be incorporated into the controlsystem so that the moving


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parts cannot start whilst they can still be reached by the operator and that the operator

cannot reach the moving parts once they have started. It should only be possible for anauthorised person to adjust the protection devices intentionally, i.e. by following a

prescribed action like using some sort of tool. If a protective device should fail, that

failure should either prevent the machine from starting or immediately stop its moving

parts.

Precautions to control risks from other hazards should be taken. These hazards wouldinclude electricity, extreme temperatures, fire, explosion, noise, vibration, radiation, dust

and gases.

Any points at which adjustments are made or machinery is lubricated and maintained must

be positioned some way from the danger zone.

Maintenance, repair and cleaning operations must be possible when themachinery is at a complete halt and all moving parts are still. Diagnostic fault-finding equipment should be used where necessary.

Machines must be provided with safe and sufficient means of access, such asstairs, to all areas used for production, adjustment and lubrication. Places of work

must be designed so as to prevent falls.

It must be possible to isolate machinery from all energy sources by some means.These "isolators" must be easy to recognise and it should be possible to lock them

where it is likely that reconnection to a power supply would expose people to

danger.

Machines must be designed and constructed so that any operator intervention is

kept to a minimum and that it is safe. Cleaning internal parts of machinery shouldbe possible without having to go inside it.


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Outline the hazards and controls for hand tools;

Hand ToolsHand tools are non-powered. They include anything from axes to wrenches. Thegreatest hazards posed by hand tools result from misuse and improper

maintenance. Some examples:

Using a screwdriver as a chisel may cause the tip of the screwdriver tobreak and fly, hitting the user or other employees.

If a wooden handle on a tool such as a hammer or an axe is loose,splintered, or cracked, the head of the tool may fly off and strike the user or

another worker.

A wrench must not be used if its jaws are sprung, because it might slip.

o Impact tools such as chisels, wedges, or drift pins are unsafe if they havemushroomed heads. The heads might shatter on impact, sending sharpfragments flying.

The employer is responsible for the safe condition of tools and equipment used byemployees but the employees have the responsibility for properly using and

maintaining tools.

Employers should caution employees that saw blades, knives, or other tools bedirected away from aisle areas and other employees working in proximity. Knives and

scissors must be sharp. Dull tools can be more hazardous than sharp ones.

Appropriate personal protective equipment, e.g. safety goggles, gloves, etc, should be

worn due to hazards that may be encountered while using portable power tools and

hand tools.

Safety requires that floors be kept as clean and dry as possible to prevent accidental

slips with or around dangerous hand tools.

Around flammable substances, sparks produced by iron and steel hand tools can be a

dangerous ignition source. Where this hazard exists, spark-resistant tools made from

brass, plastic, aluminium, or wood will provide for safety.


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Describe the main mechanical and non-mechanical

hazards of machinery;

Mechanical hazards can give rise to injury as a result of:

Contact or entanglement with the machinery. Trapping between the machine and any material or fixed structures. Contact or entanglement with any material in motion. Being struck by ejected parts of the machinery. Being struck by material ejected from the machinery.

Non-mechanical hazards: The use of machinery will also expose the operator tohazards other than those due to the mechanical actions of the machine. These can be

activities associated with the task or incidental environmental conditions and include the

following:

From falling or moving objects caused by insecure storage and poorhandling of materials.

From obstructions caused by poor storage and overcrowding. Due to poor handling and lifting facilities. From electricity (including static electricity), causing shock or burns.

From chemicals or substances that may be toxic, irritant flammable,corrosive or explosive.

Due to fire. Due to noise leading to loss of hearing, tiredness interference with speech

communication.

From extremes of temperature causing burns or scalds or health damagingeffects caused by a hot or cold workenvironment.

Due to mists, dusts and fumes that can cause ill-health or disease. From working conditions produced by poor lighting. Due to poor ergonomic design, leading to long-term musculo-skeletal

problems.

It is important to remember that minor hazards which pose little risk in isolation can

become a major risk when combined with other hazards.


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Describe the main methods of protection from

machinery hazards.

Methods of Protection

Fixed guards. Interlocked guards. Trip devices (light curtains, foot mats and sensitive edges). Adjustable/self-adjusting guards. Two-hand controls. Protective appliances. Personal protective equipment. Information, instruction, training and supervision.

Guards or protGuards or protGuards or protGuards or protection devices must be used to protect risks such asection devices must be used to protect risks such asection devices must be used to protect risks such asection devices must be used to protect risks such asmoving parts.moving parts.moving parts.moving parts.

Work Equipment (Cont.)

Congratulations - end of lesson reached

unit 12 work equipment _cont

Documents