Machine Safety

Syllabus
Selection of work equipment's: Principles of machine Safety,
Other hazards associated with machine operation, Machinery
guards, Machinery Safety Devices, Planned maintenance,
Lifting operations and lifting equipment's, Machine safety
assessment etc. Safety of scaffoldings and work platforms

Objectives
• The objective of Machine Safety is 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 for:
• (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;

Objectives
• ensuring that proper workplace safety and health
measures are implemented to identify, eliminate, prevent
and control risks arising from the use of machinery.

Principles of Machine Safety
• Unless a particular hazard is removed, the risk associated with such a
hazard can never be completely eliminated.
• The approach most commonly used is referred to as the hierarchy of
controls, from preferred to least desirable, as follows:
• (a) elimination;
• (b) substitution;
• (c) engineering controls;
• (d) administrative (procedural) controls; and
• (e) personal protective equipment (PPE).

Definitions
• Dangerous occurrence: Readily identifiable event, as
defined under national laws and regulations, with potential to
cause injury General provisions or disease to people at work
or the general public, for example a “near miss” or a “near
hit”.

Definitions
• Guard: A part of machinery specifically designed to provide
protection by means of a physical barrier.
• Hazard: The inherent potential to cause injury or damage to
people’s health.
• Incident: An unsafe occurrence arising out of or in the course
of work where no personal injury is caused.

Definitions
• Life cycle: All phases of the life of machinery, i.e.:
• (a) transport, assembly and installation;
• (b) commissioning;
• (c) use; and
• (d) decommissioning, dismantling and disposal.

Definitions
•Machinery: An assembly fitted with, or intended
to be fitted with, a drive system other than one
using only directly applied human or animal
effort, consisting of linked parts or components,
at least one of which moves, and which are
joined together for a specific application.

Definitions
• Maintenance: Workplace activities such as constructing,
installing, setting up, testing, adjusting, inspecting,
modifying, and maintaining machinery on a preventive,
periodic and predictive basis.
• These activities include lubrication, cleaning or
unjamming
• Safety and health in the use of machinery of machinery and
making adjustments or tool changes where a worker may be
exposed to the unexpected energization or start-up of the
machinery or release of hazardous stored energy.

Definitions
• Protective device: A safeguard other than a guard which
reduces risk, either alone or in conjunction with a guard.
• Risk: A combination of the likelihood of an occurrence of a
hazardous event and the severity of injury or damage to
health of workers used by this event.
• Risk assessment: The process of evaluating the risks to safety
and health arising from hazards at work.

Definitions
• Safety and health committee: A committee with
representation of workers’ safety and health representatives
and employers’ representatives established and functioning at
organization level according to national laws, regulations and
practice.

KEY PRINCIPLES OF MACHINERYAND EQUIPMENT
SAFETY
Mechanical hazards
• that cannot be eliminated must be controlled to prevent harm.
Non-mechanical hazards
• that cannot be eliminated must be controlled to prevent harmful
exposure.
Access hazards
• that cannot be eliminated must be controlled to provide safe access
(for operation, maintenance, repair, installation, service, cleaning or
decommissioning).

MECHANICAL HAZARDS
• Machines have moving parts. The action of moving parts may
have sufficient force in motion to cause injury to people.

MECHANICAL HAZARDS
• When reviewing machinery and equipment for possible mechanical hazards,
consider:
• machinery and equipment with moving parts that can be reached by
people
• machinery and equipment that can eject objects (parts, components,
products or waste items) that may strike a person with sufficient force to
cause harm
• • machinery and equipment with moving parts that can reach people
such as booms or mechanical appendages (arms)
• • mobile machinery and equipment, such as forklifts, pallet jacks, earth
moving equipment, operated in areas where people may gain access.

NON-MECHANICAL HAZARDS
NON-MECHANICAL HAZARDS
• Non-mechanical hazards associated with machinery and equipment can
include harmful emissions, contained fluids or gas under pressure,
chemicals and chemical by-products, electricity and noise, all of which
can 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. Where people are at risk of injury due to harmful emissions from
machinery and equipment, the emissions should be controlled at their
source.
• When reviewing machinery and equipment for possible non-mechanical
hazards, consider how machines and equipment can affect the area
(environment) around them.

ACCESS HAZARDS
• People must be provided with safe access that is suitable for the
work they perform in, on and around machinery and equipment.
A stable work platform suited to the nature of the work that allows for
good posture relative to the work performed, sure footing, safe
environment and fall prevention (if a fall may occur) is a basic
requirement.
• As an example, cooling towers on building roofs may have poor
access, yet must be attended by a service person at predictable
times for water treatment, chemical dosing or monitoring of
automated dosing equipment. People performing these tasks must be
provided with the means to get themselves and any equipment they
require onto the roof with no risk or minimal risk of fall or injury.

ACCESS HAZARDS
Access
• Access needs can be predicted and access planning must occur in advance.
• People need access to machinery and equipment in the workplace (either continually or occasionally)
for tasks such as operation, maintenance, repair, installation, service or cleaning. These tasks are
examples of access that can be predicted.
• Access may vary during each stage of machinery and equipment life cycle.
• For example:
• • installation or removal
• – complete access from every area may be required, and involve
• disconnection or connection of services such water, air, pipes,
• installation of electrical cable to switch board, etc.
• • operation
• – access for set-up, operation and adjustment.
• • maintenance, repair, cleaning, alteration or adaptation
• – access to remote areas may be required.

EXAMPLES OF COMMON HAZARDS BY TYPE OF
WORKPLACE ACTIVITY
PEOPLE WHO INSTALL OR DISMANTLE MACHINES AND
EQUIPMENT COULD:
• • work in isolation
• • work on machines and equipment at height or over machinery or
equipment to connect services (such as electricity, air or water)
• • work in low light or with bright directional light
• • access machinery and equipment from the top, sides or underneath
• • work with/near cranes, forklift or rigging to lift machinery and equipment
• • work in confined spaces
• • use power tools, welders, extension leads, which present electrical hazards
if damaged or wet.

WORKPLACE ACTIVITY

WORKPLACE ACTIVITY
PEOPLE OPERATING MACHINES AND EQUIPMENT COULD:
• • be required to place their hands close to the mechanism of the machinery or
equipment that does the work, and may be injured if caught or trapped by moving
parts
• • be exposed to constant harmful noise, radiated energy or fumes being emitted
from the machinery and equipment they are operating or are close to
• • inadvertently bump or knock poorly placed control levers or buttons
• • be required to make adjustments to the mechanism of machinery and equipment
while the machine is in motion
• • be required to clear away scrap
• • make minor adjustments or reach into the moving mechanism of the machine
they are operating.

PEOPLE OPERATING MACHINES AND EQUIPMENT COULD

WORKPLACE ACTIVITY
PEOPLE PROVIDING MAINTENANCE OR REPAIR SERVICES COULD:
• • work alone
• • work on machines and equipment at height, or over machines and equipment to connect services
(such as electricity, air or water)
• • access machines and equipment from the rear or sides
• • need to enter confined spaces of larger machinery and equipment
• • be trapped by mechanism of the machinery and equipment through poor isolation of energy
sources or stored energy, such as
• spring-loaded or counter-balance mechanisms, compressed air or fluids, or parts held in position by
hydraulics or pneumatic (air) rams
• • move heavy parts when changing the set-up of machinery and equipment, or repairing failed parts
such as electric motors
• or gear box assemblies
• • disable or remove normal safety systems to access machines and equipment mechanism.

WORKPLACE ACTIVITY
PEOPLE PROVIDING CLEANING SERVICES COULD:
• • work alone
• • access machines and equipment from the rear or sides or in unexpected ways
• • climb on machines and equipment
• • enter confined spaces of larger machines and equipment
• • become trapped by mechanism of the machinery and equipment through poor
isolation of energy sources or stored energy, such as
• spring-loaded or counter-balance mechanisms, compressed air or fluids, or parts
held in position by hydraulics or pneumatic (air) rams
• • work with chemicals
• • operate electrical equipment in wet areas.

Machinery Guards
Guarding
• A guard can perform several functions: it can deny bodily access, contain ejected
parts, tools, off-cuts or swath, prevent emissions escaping or form part of a safe
working platform.
• Guarding is commonly used with machinery and equipment to prevent access to:
• • rotating end drums of belt conveyors
• • moving augers of auger conveyors
• • rotating shafts
• • moving parts that do not require regular adjustment
• • machine transmissions, such as pulley and belt drives,
• chain drives, exposed drive gears
• • any dangerous moving parts, machines or equipment.

Machinery guarding and protection
against mechanical hazards
Risk of loss of stability
• Machinery and its components and fittings should be stable enough to
avoid overturning, falling or uncontrolled movements during use,
transportation, assembly and dismantling.
• If the shape of the machinery itself or its intended installation does not
offer sufficient stability, appropriate means of anchorage should be
incorporated and indicated in the instructions.

Risk of break-up during operation
• The various parts of machinery and their linkages should be
able to withstand the stresses to which they are subject when
used.
• The durability of the materials used should be adequate for
the nature of the working environment foreseen by the
manufacturer, in particular as regards the phenomena of
fatigue, ageing, corrosion and abrasion, and the maintenance
schedule of the owner.

• Risks due to falling or ejected objects
• Measures should be taken to prevent risks arising from falling
• or ejected objects.
• Risks due to surfaces, edges or angles
• In so far as their purpose allows, parts that are accessible
• during use and maintenance of the machinery should have no sharp
• edges, sharp angles or rough surfaces likely to cause injury.

Risks related to combined machinery
• Where the machinery is intended to carry out several different
operations with manual removal of the piece between each
operation (combined machinery), it should be designed and
constructed in such a way as to enable each element to be
used separately, without the other elements constituting a risk
to exposed persons.

Risks related to variations in operating conditions
• Where the machinery performs operations under different
• conditions of use, it should be designed and constructed in
such a way Safety and health in the use of machinery that
selection and adjustment of these conditions can be carried
out safely and reliably.

Risks related to moving parts
• Prevention of hazards due to moving parts of machinery should take into
account:
• (a) the movement of machinery parts consisting basically of rotary, sliding
or reciprocating motion, or a combination of these, such as
• the movements of spindles, chucks, fan blades, counter-rotating gear wheels
or rollers, and stroking blades; and
• (b) the movement of machinery parts which may have the potential to cause
injury, for example by entanglement, friction or abrasion, cutting, shearing,
stabbing or puncture, impact, crushing, or drawing a person into a position
where injury can occur.

Choice of protection against risks arising from moving
parts
• Guards or protective devices designed to protect against risks
arising from moving parts should be selected on the basis of
the Machinery guarding and protection against mechanical
hazards type of risk

Moving transmission parts
• Guards designed to protect persons against the hazards generated by
moving transmission parts should be either:
• (a) fixed guards; or
• (b) interlocking movable guards.
• Interlocking movable guards should be used where frequent access is
envisaged.

Moving parts involved in the process
• When a process requires access to a danger zone and a fixed guard is
impracticable, an interlocking guard should be considered.
• Guards or protective devices designed to protect persons against the
hazards generated by moving parts involved in the process should be:
• (a) fixed guards;
• (b) interlocking movable guards;
• (c) protective devices; or
• (d) a combination of the above.

General requirements for guards
• Guards and protective devices should protect against danger,
• including risks from moving parts. They should:
• (a) be of robust construction;
• (b) be securely held in place;
• (c) not give rise to any additional hazard;
• (d) not be easy to bypass or render non-operational, or be easily defeated;
• (e) be located at an adequate distance from the danger zone;
• (f) cause minimum obstruction of the view of the production process; and
• (g) enable essential work to be carried out on the installation and replacement of tools and for
maintenance purposes by restricting
• access exclusively to the area where the work has to be done, if possible without the guard having
to be removed or the protective device having to be disabled.

Risk of break-up during operation
• Special requirements for guards
• Fixed guards
• Fixed guards should be used whenever practicable. They should be
designed so as to prevent access to the dangerous parts of the machinery.
• Fixed guards should be fixed by systems that can be opened or removed
only with tools.
• Their fixing (attachment) systems should remain attached to the guards or
to the machinery when the guards are removed.
• Where possible, guards should be incapable of remaining in place without
their fixings (attachments).

Interlocking movable guards
• Interlocking movable guards should, as far as possible,
• remain attached to the machinery when open.
• Interlocking movable guards should be associated with an
interlocking device which:
• (a) prevents the start of hazardous machinery functions until the
guards are closed; and
• (b) gives a stop command whenever the guards are opened.

Interlocking Movable Guards
• Where it is possible for an operator to reach the danger zone
before the risk due to the hazardous machinery functions has
ceased, movable guards should be associated with a guard-
locking
device in addition to an interlocking device which:
• (a) prevents the start of hazardous machinery functions until
the guard is closed and locked; and

• (b) keeps the guard closed and locked until the risk of injury
from the
• hazardous machinery functions has ceased.
• Interlocking movable guards should be designed in such a
way that the absence or failure of one of their components
prevents starting, or stops the hazardous machinery functions.

• Adjustable guards restricting access
• Adjustable guards restricting access to those areas of the moving parts
strictly necessary for the work should be:
• (a) adjustable manually or automatically, depending on the type of
work involved; and
• (b) readily adjustable without the use of tools.

• Special requirements for protective devices
• Protective devices should be designed and incorporated into the control
system in such a way that:
• (a) moving parts cannot start up while they are within the operator’s reach;
• (b) persons cannot reach moving parts while those parts are moving; and
• (c) the absence or failure of one of their components prevents starting or
stops the moving parts.
• Protective devices should be adjustable only by means of an intentional
action.

against other hazards
• Electricity supply
• Where machinery has an electricity supply, it should be designed,
constructed and equipped in such a way that all hazards of an electrical
nature are or can be prevented, in accordance with national law and
practice.
• Static electricity
• Machinery should be designed and constructed to prevent or limit the
build-up of potentially dangerous electrostatic charges and be fitted
with a discharging system.

Energy supply other than electricity
• Where machinery is powered by sources of energy other
• than electricity, it should be so designed, constructed and equipped as
• to prevent all potential risks associated with such sources of energy

Errors in fitting
• Errors likely to be made when fitting or refitting certain parts which
could be a source of risk should be precluded by the design and
construction of the parts or, failing this, information explaining how to
fit them correctly should be provided on the parts themselves and their
housings. The same information should be provided on moving parts
and their housings where the direction of movement needs to be
known in order to prevent a risk.

Extreme temperatures
• Steps should be taken to eliminate any risk of injury arising
from contact with, or proximity to, machinery parts or
materials at very high or very low temperatures.
• The necessary steps should also be taken to avoid or protect
against the risk of very hot or very cold material being
ejected.

Effect of Climate
• When machinery is used in very high ambient temperatures and/or humidity (such
as in tropical or subtropical regions) or in very low ambient temperatures,
consideration in the design of machinery
• should be given to the following aspects:
• (a) the effect of extreme heat, cold and humidity on machinery;
• (b) the acceptability of PPE and the effect of climate on the protection
• provided by such equipment;
• (c) the effect of high and low ambient temperatures on workers in terms of fatigue;
• (d) the effect of high levels of sunlight;
• (e) heat stress problems in non-acclimatized personnel, particularly
• when the use of PPE is necessary;
• (f) the effect of climate on the stability of chemical substances used
• for operating machinery;

Effect of Explosion
Explosion
• Machinery should be designed and constructed in such a way as to
prevent any risk of explosion posed by the machinery itself or by
gases, liquids, dust, vapours or other substances produced or used by
the machinery.
• Where machinery is intended for use in a potentially explosive
atmosphere, it should be designed and manufactured to exclude or
minimize ignition sources and comply with any national laws and
standards applicable to explosive atmospheres.

Effect of Noise
Noise
• Machinery should be designed and constructed in such a way that risks
resulting from the emission of airborne noise are eliminated or reduced
to the lowest possible level, taking account of technical progress and
the availability of means of reducing noise, in particular at source.
• Where applicable, information should be supplied with the machinery
on noise emissions, as required by national laws and standards, and on
any additional safety precautions required

Effect of Noise
• The level of noise to which workers are exposed should not exceed the limits established
by the competent authority or under internationally recognized standards.
• As regards noise reduction, employers should give consideration to the following,
normally referred to as a hearing conservation
• programme:
• (a) the appropriate choice of machinery which emits the least amount of noise, taking
account of the work to be done;
• (b) noise reduction by technical means:
• (i) reducing airborne noise, for example with shields, enclosures or sound absorbent
coverings;
• (ii) reducing structure-borne noise, for example with damping or isolation;
• (c) alternative working methods that require less exposure to noise;
• (d) the design and layout of workplaces and workstations;
• (e) organization of work to reduce noise:

Effect of Vibration
Vibration
• Machinery should be designed and constructed in such a way that risks
resulting from whole-body and hand-transmitted vibration produced
by the machinery are reduced to the lowest possible level, taking
account of technical progress and the availability of means of reducing
vibration, in particular at source.
• The level of vibration and duration of exposure should not exceed the
limits established by national laws and standards or internationally
recognized standards. Vibration measurements should be used to
quantify the level of exposures of workers and compared to nationally
or internationally agreed exposure limits.

Effect of Vibration
• to minimize exposure to mechanical vibration and
• its associated potential risks, taking into account in particular:
• (a) alternative working methods that require less exposure to mechanical
vibration;
• (b) the choice of machinery with an appropriate ergonomic design that takes
into account the kind of work to be done and produces the least possible
vibration;
• (c) the provision of auxiliary equipment that reduces the risk of injuries
caused by vibration, such as seats that effectively reduce whole body
vibration and handles which reduce the vibration transmitted to the hand–
arm system;

Effect of Vibration
• (d) appropriate maintenance programmes for the machinery, the
• workplace and workplace systems;
• (e) the design and layout of workplaces and workstations;
• (f) adequate information and training to instruct workers in the correct and
safe use of machinery in order to minimize their exposure to mechanical
vibration;
• (g) measures to limit the duration and intensity of exposure;
• (h) appropriate work schedules with adequate rest periods; and
• (i) the provision of clothing to protect exposed workers from cold and
damp, which can exacerbate the effect of vibration.

Ionizing and non-ionizing radiation arising
from the machinery
• Radiation emissions that are not essential to the functioning of the
machinery should be eliminated, or reduced to levels that Machinery
guarding and protection against other hazards
• do not have adverse effects on workers as determined by a competent
• person, in accordance with national law and standards.
• Any functional ionizing radiation emissions should be
• limited to the lowest level sufficient for the proper functioning of the
• machinery during maintenance and use. Where a risk exists, the necessary
• protective measures should be taken.

Ionizing and non-ionizing radiation arising
from the machinery
Any functional non-ionizing radiation emissions during maintenance and
use should be limited to levels that do not have adverse effects on workers.
• Machinery should be designed and constructed in such away as to prevent
any accidental emission of radiation.
• The level of exposure of workers to ionizing radiation should be assessed,
and the health of the workers should be monitored, in accordance with
national law and practice.
• When appropriate, the level of exposure of workers to nonionizing
• radiation and its impact on their health should be assessed in accordance
with national law and practice.

Risk of Being Trapped in Machinery
Risk of being trapped in machinery
• Machinery should be designed, constructed or fitted with a means of preventing a
worker from being enclosed within it or, if that is not possible, with a means of
summoning help

Risk of slipping, tripping or falling
• Parts of machinery on which workers are likely to move about or stand
should be designed and constructed in such a way as to prevent
workers from slipping, tripping or falling on or off these parts.
• Where appropriate, such parts should be fitted with handholds that are
fixed close to the operator to enable him or her to maintain stability.
• Where fall PPE is used for maintenance, it should be appropriate for
the purpose and anchor points should be provided in accordance with
national law and practice.

References
• Health & Safety at Work: An Essential Guide for Managers
• Introduction to Health & Safety in Construction: The Hand book: Phil
& Ferrett

Machine Safety

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