M achines S afety
Dr. Hammad Khan
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Objectives
• To protect workers from the hazards of machinery and to prevent
accidents, incidents and ill health resulting from the use of
machinery at work by providing guidelines
a) Ensuring that all machinery for use at work is designed
and manufactured to eliminate or minimize the hazards
associated with its use
b) Ensuring that employers are provided with a mechanism
for obtaining from their suppliers necessary and sufficient
safety information about machinery to enable them to
implement effective protective measures for workers
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1. Introduction
Safe machine operations require
• Identify machinery and equipment hazards in the workplace
• Eliminate or reduce the risk of those hazards causing harm.
• Managing the risks associated with use of machinery and
equipment in the workplace.
• How to prevent?
• Safe use, safe design
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These incidents can cause
Damage to the body, e.g. cuts, crushing of limb, etc
Injuries by energies released from the machine, e.g. electrical shock, burn, etc
Fatalities
2. Incident History 5
Incidents occurred due to
3. Lack of maintenance
1- Lack of protection (e.g. equipment safeguards)
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3. Machine Hazards
When identifying the hazards related with machines, we shall consider:
Type of machines (lever, pully, screw, axel..) Operator position and controls
Layout of machines (static or moveable) Access for setting adjustments and
maintenance
Driven method (Electricity, air, etc.)
Operating parameters, e.g. Speed, pressure, Environmental factors, e.g. Dust, fumes,
noise, temperature, humidity etc
temperature, size of cut, mobility, etc.
Materials to be processed or handled and method Operating requirements including what
the operator needs to do
of feed (hard or soft)
3. Machine Hazards 7
Typical hazards related with operation of machines include:
• Machines have moving parts. e.g.
The action of moving parts may • High pressure fluid ejection
have sufficient force in motion to • Electrical shock
cause injury to people. • Noise and vibration
• e.g. crushing, shearing, cutting or • Contact with extremes of
temperature
severing, stabbing or puncture
• Ergonomics
3. Machine Hazards MECHANICAL HAZARDS
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HAZARD RISK
Rotating shafts, pulleys, sprockets
Entanglement
and gear
Hard surfaces moving together Crushing
Scissor or shear action Severing
Sharp Edge- moving or stationary Cutting or puncturing
Slips, trips and falls (e.G.,
Cable or hose connection
Oil leaks)
3. Machine Hazards MECHANICAL HAZARDS
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Unguarded Rotating Parts of Machine
Belt &
pully
Chain &
sprocket
Rack &
pinion
Rotating
cylinders
3. Machine Hazards NON-MECHANICAL HAZARDS
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• Associated with machinery and equipment can include harmful emissions, chemicals and
chemical by-products, electricity and noise.
• Cause serious injury if not adequately controlled.
• In some cases, people exposed to these hazards may not show signs of injury or illness for years.
Non- Mechanical HAZARD
When reviewing machinery and
Dust Mist (vapours/fumes)
equipment for possible non-mechanical Explosive or flammable
Noise
hazards, consider how machines and atmosphere
Heat (radiated or
equipment can affect the area Ignition source
conducted)
(environment) around them. High intensity light Chemicals
Heavy metals Pressurized fluids/gases
4. Machine Safety 11
Identify the existing controls Identify the need for additional control
• Any safeguards in place? • What is the risk level with the
• Any written procedures to consideration of existing controls?
control or mitigate the risk? • High risk must be reduced to at least
• What are the PPE used? medium risk before startup of work
• Whether the risk level can be further
reduced to As Low As Reasonably
Practical ?
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4. Machine Safety
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4. Machine Safety
Control Measures
4. Machine Safety 14
Types of machine guarding
1 . Fi xe d g u a rd
2 . I n t e rl o cke d g u a rd
3 . A d j u s t abl e g u a rd
4 . S e l f - a d j u s t i n g g u a rd
4. Machine Safety
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Ma ch ine G u a rd
1- Fixed Guard of Machine
Inspection panel
• Advantages
• Maximum protection
Fixed Guard
• Variety of applications
• In-house fabrication
• Low cost & maintenance
• Disadvantages
• Poor visibility
• Must remove for repairs
requiring LOTO
4. Machine Safety
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Ma ch ine G u a rd
2- Interlocked Guard of Machine
• Switch that when opened stops power
• Advantage
• Maximum protection
Interlocked guard on • Portion of guard easily removed for
revolving drum
access
• Disadvantage
• Can be overridden by employee
• High cost
• Maintenance required
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4. Machine Safety Ma ch ine G u a rd
3- Adjustable Guard of Machine
• Advantage
Bandsaw blade
adjustable guard • Flexibility
• In-house fabrication
• Disadvantage
• Not maximum protection
• Rely on worker to properly
position
• May prohibit easy access
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4. Machine Safety Ma ch ine G u a rd
4- Self-adjusting Guard
• Advantage
• Employee not involved in
positioning
• Readily available
Circular table saw self-adjusting
guard • Disadvantage
• Not maximum protection
• May need frequent fine
tuning
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4. Machine Safety
Devices 1-Pullback Device
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4. Machine Safety
Devices 2- Restraint Device
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4. Machine Safety
Devices 3- Safety Tripwire Cable
Tripwire
Cable
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4. Machine Safety
Devices 4- Two-hand Control
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4. Machine Safety
Devices 5- Gates
Gate Open Gate Closed
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4. Machine Safety
Devices 6- Sensor
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4. Machine Safety
7- Safeguard by Distance
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4. Machine Safety
8- Automatic Feed and Robot
Robot
Automatic Feed
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4. Machine Safety
8-Protective Shield
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4. Machine Safety Holding/Hand Tools
A hand tool is any tool that is powered by hand rather than a motor. Categories of hand tools
include
Spanner Screwdrivers
Hacksaws Pliers
Cutting and Slicing Tools
(Knives, Box Cutters,
Scissors, Razor Blades..
Hammers
Chisels
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4. Machine Safety Holding/Hand Tools
Spark Resistant 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, aluminum, or wood will provide for safety.
Power Tools Different types, determined by
their power source:
Purchase quality tools • Electric
• Pneumatic
Keep tools organized • Liquid fuel
Keep tools clean • Hydraulic
• Powder-actuated
Use the right tool for the job.
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4. Machine Safety Emergency Switch:
Emergency switch is provided when
emergency stopping of machine is necessary,
the switch shall:
Be easily accessible to the
operator
Be designed for unexpected
activation
When necessary, buddy system shall be considered.
Emergency
Switch
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4. Machine Safety
Lockout/Tagout (LOTO) - LOTO is used to control the unexpected release of energy from
electricity, steam or gas
Lockout/Tagout gets its name from the equipment used
Lockout/Tagout must be used whenever you are performing service or maintenance on any
machine where you or someone else could be injured by the unexpected startup or release of
stored energy
LOTO DOES NOT APPLY to single source plug and cord equipment when the equipment is
unplugged and under the exclusive control of the person performing the work
• Risk to individuals working on powered equipment or machinery can be
minimized by adhering to the six step process of LOTO.
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4. Machine Safety Types of LOTOs
LOTO Device
Caution Tag
Energy Isolating Device
Individual LOTO Lock
Supervisor Lock
Supervisor Tag
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4. Machine Safety Types of Lockout/Tagout Devices
Circuit
breaker
cover Physical Lockout for Circuit Breaker
Wall switch
cover
Gate valve locks
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4. Machine Safety Types of Lockout/Tagout Devices
Fuse cover
Plug lock Ball valve locks Hasp Group lockbox
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4. Machine Safety Types of Hazardous Energy
Mechanical
Pneumatic
• Relating to springs, rotating parts, etc.
• May be in cylinders, lines and pipes
Magnetic
• Can be found in capacitors and superconducting Thermal
magnetic energy storage • Can be hot or cold
Gravity
Chemical
• Can be found in machinery or equipment parts that
might descend, slide or fall if left unblocked • Produced as a result of a chemical reaction
Electrical Steam
• Relating to or operated by electricity – AC or DC • Water vapor kept under pressure so as to
supply energy for heating or mechanical
Hydraulic work
• Involving, moved or operated by a fluid under
pressure, either internal or external
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4. Machine Safety
What must workers do before maintenance
activities?
1. Prepare for shutdown
2. Shut down the machine
3. Disconnect or isolate the machine from
the energy source(s)
4. Apply the lockout or tagout device(s) to
the energy-isolating device(s);
5. Release, restrain, or render safe all
potential hazardous stored or residual
energy. Regularly inspect to avoid re-
accumulation of energy if necessary.
6. Verify the isolation and de-energization
of the machine.
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4. Machine Safety Lockout/Tagout (LOTO) Procedure
What must be included in the What must workers do before removing
LOTO Procedure? LOTO device and reenergize the machine?
A statement on how to use the procedures;
Step 1: Inspect machines or their
Steps to shut down, isolate, block, and secure components to assure that they are
machines; operationally intact and that nonessential
Steps designating the safe placement, removal, items are removed from the area
and transfer of LOTO devices and identifying Step 2: Check to assure that everyone is
who has responsibility for the LOTO devices; positioned safely and away from machines.
and
Requirements to determine and verify the
effectiveness of lockout devices, tagout
devices, and other energy-control measures.
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4. Machine Safety Lockout/Tagout (LOTO) Procedure
What are the limitations for tagout
devices?
A tagout device is a prominent warning
of the hazards
Tags do not provide the physical restraint
of a lock
Tags may evoke a false sense of security
Therefore, lockout devices is considered
more secure and more effective than
tagout devices in protecting employees
from hazardous energy.
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4. Machine Safety
Training PPE
Before using any machine, you should: Before using any machine, you should
ensure that:
Be trained by qualified person/agent
Proper PPE is used to conduct the work
Clarify any doubt on machine usage
The PPE is in good condition
Have the correct certificate, if required by
law Proper training has been given on how to
use PPE
Inspect the machine for good condition
(or inspected by qualified persons)
Do not operate machine unless
authorized
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Ergonomic Risk Factors
Risk of injury increases with: Ergonomic
Prolonged exposure to any of these 1. Awkward Posture
ergonomic risk factors 2. Force:
Presence of multiple risk factors 3. Repetition
within a single job task 4. Static Loading
5. Contact Stress
─ Exposure disorder 6. Vibration
─ Event disorder
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4. Machine Safety Ergonomics
Some basic tips to improve ergonomics:
Use correct
Use
material
equipment to
handling
aid material position
handling
Maintain
Do the work
comfortable with proper
position when tools
working
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4. Machine Safety
Use Tools with Better Grip Select the Correct Tool for the Job
• Work near elbow • Avoid overhead
height to avoid reaching and
bending excessive kneeling when
bending possible
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4. Machine Safety
Ergonomics
Adopt the Correct Posture
Select the Correct Tool
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4. Machine Safety
Safe Practices
The following practices shall be observed at all times:
Always use the safety devices correctively;
Do not wear loose clothing/ties when operating machines with rotating parts;
Tie up or cover up long hair;
Use devices to remove trapped materials from machine;
Switch off the machine before retrieving dropped material(s) from inside the
machine.
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Exercise
Identify the hazards associated with the machines used by you, considering:
• What control measures are in place to reduce the hazard?
• Whether the control measures are adequate, e.g. any incident occurred?
• What improvements can be made to reduce the risk?
Thank You
