Editable
PowerPoint
Slides for
Lecturers
Phil Hughes
and Ed Ferrett
By
MBE
Chapter
11
Work equipment
hazards and control
Work equipment
hazards and control
After reading this chapter, you should be able to:
1.
Outline general principles for selection, use and
maintenance of work equipment
2.
Outline the hazards and controls for hand tools
3.
Describe the main mechanical and non-mechanical hazards
of machinery
4.
Describe the main methods of protection from machinery
hazards.
Figure 11.2 CE mark and typical
declaration used in the European Union
Figure 3 Work equipment hazards and control
Figure 11.4 Bench mounted abrasive wheel
Figure 11.6 Typical electrically powered
compressor with air receiver
Figure 11.7 Design features of
equipment controls
Figure 11.8 Emergency stop buttons
Figure 11. 9 Typical hand tools
Figure 11.10 Typical hand held power tools
Figure 11.11(a) Electric percussion drill
Figure 11(b)
Heavy duty electric hammer drill
Figure 11.12 Disc sander
Figure 11.13(a) Rotary drum floor sander
Figure 11.13(b) Orbital finishing sander
Figure 11.14 Range of mechanical hazards
Figure 11.15 Range of fixed guards
Pedestal
drill
Figure 11 Adjustable guard for a
rotating shaft such as a pedestal drill
Guard adjusts
itself as the saw
cuts through the
wood
Figure 17 Self-adjusting guard on a
circular saw for cutting wood
Hinged guard
activates the switch
as it rotates
Sliding guard activates
the switch as it moves
Figure 11.18 Typical sliding and
hinged interlocking guards
Figure 11.19 Schematic diagram of a
telescopic trip device fitted to a radial drill
Buttons need to be pressed
at the same time to
activate machine. Buttons
are shrouded to prevent
accidental starting
Figure 20 Pedestal-mounted free-standing
two-hand control device
• The machines are provided
with an all-enclosing case
which prevents access to the
internal moving, hot or
electrical parts
• The access doors are
interlocked so that the
machine is automatically
switched off when gaining
access to clear jams or maintain
the machine. It is good practice
to switch off when opening the machine
• Internal electrics are insulated and protected to prevent contact
• Regular inspection and maintenance should be carried out
• The machine should be on the PAT schedule
• Good ventilation in the machine room should be maintained
Figure 11.21 Typical large office
photocopier safeguards
• Enclosed fixed guards surround the
cutters with restricted access for paper
only, which prevents fingers reaching the
dangerous parts
• Interlocks are fitted to the cutter head
so that the machine is switched off when
the waste bin is emptied
• A trip device is used to start the machine
automatically when paper is fed in
• Machine should be on PAT schedule
and regularly checked
• General ventilation will cover most dust problems except for very large
machines where dust extraction may be necessary
• Noise levels should be checked and the equipment perhaps placed on a
rubber mat if standing on a hard reflective floor
Figure 11.22 Typical office shredder safeguards
• Wheel should be enclosed as much
as possible in a strong casing
capable of containing a burst wheel
• Grinder should be bolted down to
prevent movement
• An adjustable tool rest should be
adjusted as close as possible to the
wheel
• Adjustable screen should be fitted
over the wheel to protect the eyes of
the operator. Goggles should also be worn
• Only properly trained competent and registered people should mount
an abrasive wheel
• The maximum speed should be marked on the machine so that the
abrasive wheel can be matched to the machine speed to ensure
that the wheel permitted speed exceeds or equals the machine
max speed
• Noise levels should be checked and attenuating screens used if
necessary
• The machine should be on the PAT schedule and regularly checked
• If necessary extract ventilation should be fitted to the wheel encasing
to remove dust at source
Figure 11.23 Typical bench mounted
grinder safeguards
• Motor and drive should be fitted with
fixed guard
• Machine should be bolted down to
prevent movement
• The spindle should be guarded by an
adjustable guard, which is fixed in
position during the work
• A clamp should be available on the
pedestal base to secure work-pieces
• The machine should be on the PAT
schedule and regularly checked
• Cutting fluid, if used, should be
contained and not allowed to get onto
clothing or skin A splash guard may be
required but is unlikely
• Goggles should be worn by the
operator
Figure 11.24 Typical Pedestal drill safeguards
• Machine should be designed
to operate with the grass
collection box in position to
restrict access to the bottom
blade trap. A warning sign
should be fitted on the
machine
• On pedestrian-controlled
machines the control handle
should automatically stop the
blade rotation when the
operator’s hands are removed. It should take two separate actions
to restart
• Ride-on machines should be fitted with a device to automatically
stop the blades when the operator leaves the operating position.
This is normally a switch under the seat and it should be tested to
ensure that it is functioning correctly and is not defective
Figure 11.25 Typical cylinder mower
for fine grass cutting safeguards
• Drives and motor should be
completely encased with a
fixed guard
• The machine should only
be refuelled in the open
air with a cool engine,
using a suitable container
for highly flammable fuel
with a pourer to restrict
spillage. No smoking
should be allowed
• Hot surfaces like the
exhaust should be covered
• Engine must only be run in the open air to prevent a build up of fumes
• Noise levels should be checked and if necessary an improved silencer
fitted to the engine and where required hearing protection used
• Hay-fever-like problems from grass cutting are difficult to control.
A suitable dust mask may be required to protect the user
Figure 11.25 Typical cylinder mower
for fine grass cutting safeguards
• Moving engine parts should be enclosed
• Rotating shafts should be encased in a fixed
drive shaft cover
• Rotating cutting head should have a fixed
top guard, which extends out on the user
side of the machine
• Line changes must only be done either
automatically or with the engine switched off
• Engine should only be run in the open air
• Refuelling should only be done in the open air
using a proper highly flammable liquid
container with pouring spout
• Boots with steel toe cap and good grip, stout
trousers and non-snagging upper garments
should be worn in addition to hard hat fitted
with full face screen and safety glasses
Figure 11.26 Typical petrol
driven brush cutter safeguards
• If the noise levels are sufficiently high (normally
they are with petrol-driven units) suitable
hearing protection should be worn
• Low-vibration characteristics should be
balanced with engine power and speed of work
to achieve the minimum overall vibration
exposure. Handles should be of an antivibration type. Engines should be mounted on
flexible mountings. Work periods should be
limited to allow recovery
• Washing arrangements and warm impervious
gloves should be provided to guard against
health risks
• Properly constructed harness should be worn
which comfortably balances the weight of the
machine.
Figure 11.26 Typical petrol driven
brush cutter safeguards
1 – hand guard with integral chain brake; 2 – exhaust outlet directed to the
RHS away from the operator; 3 – chain breakage guard at bottom of rear
handle; 4 – chain designed to have low-kickback tendency; 5 – rubber antivibration mountings; 6 – lockout for the throttle trigger; 7 – guide bar
(should be protected when transporting chainsaw); 8 – bottom chain
catcher; 9 – PPE hand/eye/ear defender signs; 10 – on/off switch
Figure 11. 27 Typical rear
handle chainsaw components
• May only be operated by
fully trained, fit and
competent people. Using
chainsaws in tree work
should require a relevant
certificate of competence or
National competence award,
unless the users are undergoing such training and are adequately
supervised.
• Avoid working alone with a chainsaw. Where this is not possible,
establish procedures to raise the alarm if something goes wrong.
These may include:
• regular contact with others using either a radio or telephone
someone regularly visiting the work site
• carrying a whistle to raise the alarm
• an automatic signalling device which sends a signal at a preset time
unless prevented from doing so
• checks to ensure operators return to base or home at an agreed time
Figure 11. 27 Typical rear
handle chain saw safeguards
• Moving engine parts should
be enclosed
• Electrical units should be
double-insulated and cables
fitted with residual current
devices
• The saw must be fitted with
a top handle and effective brake mechanism
• Chainsaws expose operators to high levels of noise and hand-arm
Vibration which can lead to hearing loss and conditions such as
vibration white finger. These risks can be controlled by good
management practice including:
• purchasing policies for low-noise/low-vibration chainsaws (e.g.
with anti-vibration mounts and heated handles)
• providing suitable hearing protection
• proper maintenance schedules for chainsaws and protective
equipment
• giving information and training to operators on the health risks
associated with chainsaws and use of PPE, etc.
Figure 11. 27 Typical rear handle
chain saw safeguards continued
• Operators need to be trained
in the correct chain
sharpening techniques and
chain and guide bar
maintenance to keep the
saw in safe working condition
• Make sure petrol containers:
• are in good condition and clearly labelled, with securely fitting caps.
• do not allow operators to use discarded engine oil as a chain lubricant
when starting the saw
• Operators should maintain a safe working distance from other people and
ensure the saw chain is clear of obstructions
• Kickback is the sudden uncontrolled upward and backward movement of the
chain and guide bar towards the operator
• To avoid pull-in, always hold the spiked bumper securely against the tree or
limbs
• To avoid push-back, be alert to conditions that may cause the top of the guide
bar to be pinched and do not twist the guide bar in the cut
• Training in good manual handling techniques and using handling aids/tools
should reduce the risk of back injuries
• Avoid overhead and other service hazards
Figure 11. 27 Typical rear handle
chain saw safeguards continued
Kevlar gloves, over-trousers
and overshoes providing
protection against chainsaw
cuts. Helmet, ear and face
shields protect the head
Figure 11.28 Personal protective
clothing for chain saw use
• Access doors to the loading
area, which gives access to the
ram, should be positively
interlocked with electrical
and/or hydraulic mechanisms
• The ram pressure should be
dumped if it is hydraulic
• Drives of motors should be
properly guarded
• If the waste unit is removed
by truck, the ram mechanism
should be interlocked with the unit so that it cannot operate when
the unit is changed for an empty one
• The machine should be regularly inspected and tested by a
competent person
• If the hydraulic ram can fall under gravity, mechanical restraints
should automatically move into position when the doors are opened
• Emergency stop buttons should be fitted on each side
Figure 29 Typical retail compactor safeguards
• Operating position for the hopper hoist should
be designed so that anyone in the trapping
area is visible to the operator. The use of the
machine should be restricted to designated
operators only. As far as possible the trapping
point should be designed out. The hoist
operating location should be fenced off just
allowing access for barrows, etc., to the
unloading area
• Drives and rotating parts of engine should be
enclosed
• The drum gearing should be enclosed and persons kept away from the rotating
drum, which is normally fairly high on large machines
• No one should be allowed to stand on the machine while it is in motion
• Goggles should be worn to prevent cement splashes
• If petrol-driven, care is required with flammable liquids and refuelling;
• Engines must only be run in the open air
• Electric machines should be regularly checked and be on the PAT schedule
• Noise levels should be checked and noise attenuation, for example silencers
and damping, fitted if necessary
Figure 30 Typical cement mixer safeguards
• A fixed guard should be fitted to
the blade below the bench
• Fixed guards should be fitted to
the motor and drives
• An adjustable top guard should
be fitted to the blade above the
bench which encloses as much
of the blade as possible. An
adjustable front section should
also be fitted
• A riving knife should be fitted behind the blade to keep the cut timber apart
and prevent ejection
• A push stick should be used on short workpieces (under 300 mm) or for the
last 300 mm of longer cuts
• Blades should be kept properly sharpened and set with the diameter of the
smallest blade marked on the machine
Figure 31 Work Bench mounted
circular saw - safeguards
• Noise attenuation should be
applied to the machine, for example
damping, special quiet saw blades,
and, if necessary, fitting in an
enclosure. Hearing protection may
have to be used
• Protection against wet weather
should be provided
• The electrical parts should be
regularly checked in addition to all
the mechanical guards
• Extraction ventilation will be required for the wood dust and shavings and
suitable dust masks should be worn
• Suitable warm or cool clothing will be needed when used in hot or cold locations
• Space around machine should be kept clear
Figure 31 Work Bench mounted
circular saw safeguards continued