b) Outline four control measures to reduce the risk of injury to operators of pedestal drills.
2) Outline four main categories of guards and safeguarding devices that may be used to minimize the risk of contact with dangerous parts of machinery.
Moving machine parts have the potential to cause severe workplace injuries, safeguards are essential for protecting workers from these preventable injuries. Some of the safeguarding that may be used on the machines may include:
Fixed Guards – which forms the permanent parts of the machines, these types of guards is usually preferable to all other types because of its relative simplicity and performance:
Adjustable Guards – These guards can be adjusted according to the work or workplace. It is important that such guards are properly adjusted and maintained for them to be effective:
Automatic Guards – These guards are self-adjusting and can be automatically moved into position as the machine or the cycle starts:
Self-adjusting guards – These types automatically opens and closes as the workpiece is put in and pulled out:
Interlock guards – When this type of guard is opened or removed, the tripping mechanism or power automatically shuts off or disengages, the moving parts of the machines are stopped and the machine cannot cycle or be started until the guards are back in place
The different types of safeguarding devices that may be used may include the following:
Presence sensing devices – The photoelectric presence sensing device uses a system of light sources and controls which can interrupt the machines operating cycle:
Pullback devices – Pull back device utilizes a series of cables attached to the operator's hands, wrists and arms. This type of device is primarily used on machines with stroking actions.
Safety trip controls: Safety trip controls provide a quick means for deactivating the machine in an emergency situation:
Two hand controls – Concurrent use of two hands on separate controls prevents hands from being in danger area when the machine cycles start. The two hand control requires constant, concurrent pressure by the operator to activate the machine.
3) A pedestal electric drill is being used on a building site.
a) Other than electricity, identify four hazards associated with the use of the drill.
b) Outline four precautions that could be taken to reduce the risk to workers.
a) The other hazards associated with the use of pedestal drills are:
1) Entanglement with the rotating drill bit or chuck
2) Stabbing or puncture by the drill bit during normal use or if the drill bit breaks
3) Drawing in at nip points between the motor and the drive mechanism
4) Puncture can result from the sward ejected during the metal cutting
5) Hot surfaces can result in burns
6) The cutting fluids used for the operation can cause dermatitis
7) Noise generated during the operation
b) The precautions that can be used may include:
By providing the fixed guards over the motor and drive mechanisms can avoid hazards like entanglement and draw in, Adjustable guards can be provided over the chuck and the drill bit, Eye and hearing protection may be necessary, routine maintenance including inspection and portable appliance testing, Using trained and competent operators.
4) Identify eight types of nonmechanical hazards associated with the use of machinery.
Machinery may also present other hazards and suitable measures need to be taken to prevent the injury.
Some of the non – mechanical hazards are:
_ Electrocution to the workers can happen if they come in contact with the naked wires or other electrical parts connections of the machine
_ Burns result on contact with the hot parts of the machine
_ Dust and fumes from the point of operation or from the exhaust systems
_ Fire / Explosion due to leakages of fuel
_ Noise and vibration
_ Radiation from the activities done on the machine
_ Flying chips and sparks from the point of operation
_ Hazardous chemicals
_ Manual handling
5) a) Identify the hazards associated with the use of a cement mixer
b) For the hazards identified above, outline the control measures that can be used to reduce the risk.
(a)_ Entanglement with the rotating parts of the machinery
_ Trapping of the body parts or clothes inside the moving parts
_ Drawing in at nip points between motor and drive mechanism
_ Crushing between drum and drum stop when tipping
_ Friction or abrasion on contact with moving drum
_ Ergonomics and Manual handling injuries
_ Health hazards due to dust inhalation and contact with the wet cement
_ Electrocution
_ Noise and Vibration
_ Ejection of materials while working
(b) To protect the workers from the above-mentioned hazards, the following control measures should be taken into consideration. Cement mixer should always be located on a firm and level surface. It should be placed away from the
ongoing traffic or should be cordoned so as to avoid collision with other vehicles. The rotating parts or other moving parts of the machinery should be protected by means of adequate guards or body coverings. Safe storage of petrol and control of ignition sources for petrol powered equipment. Routine inspection and portable appliance testing and use of the residual current device for electrically powered equipment. Provide workers with ear plugs / muffs to protect them from the noise generated by the mixer. When removing the drum for storage or transportation makes sure the
machine is properly switched off and unplugged. Avoid putting anything like hand, shovel or anything other than the mix into the drum while it is rotating.
6) Outline the hazards and risks to which a worker could be exposed when cutting down a tree using petrol driven chainsaw.
Worker performing such an activity by using petrol driven chain saw may be exposed to different types of hazards like: his hand or body may suffer cut injuries upon contact with the moving blade, Body parts or clothing may get entangled
with the moving blade, Drawing in may happen at the nip points between the blade and the casing, Penetration or puncture injuries my result due to the ejected parts, Burns may happen as a result of contact with the hot surfaces of the equipment, High noise and vibrations involved during the activity can result in risks to health. Since petrol is used as a source of power there can be chance of fire and explosion. The dusts and smoke generated during the activity can cause health hazards. Performing the task in awkward pose can result in ergonomic hazards to health.
7) Outline control measures to reduce the risk to workers when using non – powered hand tools.
The control measures that can be used to reduce the risk to workers when using a non powered hand tools may include:
Tools must be suitable for the task that they are going to perform and for the environment in which they are to be used.
Tools should be visually inspected routinely before use to ensure that they are in an acceptable condition.
Users should be given appropriate information, instruction, and training. Tools should be maintained in a safe condition. Good supervision should be ensured.
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