Machinery Safety | Health and Safety


Machinery Hazards

Machinery Safety | Health and Safety

“Safety of Machinery-Basic concepts, general principles for design” describes many hazards related to both the basic operation of machinery and unexpected eventualities arising from failures.

The intention is to provide designers with guidance for determining relevant, significant hazards that may be generated by a given machine in the environment that it is intended to be used.

The hazards outlined can be sub categorized as mechanical and non-mechanical.

Mechanical Hazards

Mechanical hazard associated with machinery, parts, tools, work pieces, loads, and materials include the following:
Entanglement.
Drawing in or trapping.
Crushing.
Shearing.
Impact.
Friction or abrasion.
Stabbing or severing and
Ejection of materials, including high-pressure fluid injection.

Entanglement-

Injuries can be caused by entanglement of limbs, hair, jewelry or clothing in rotating parts of machinery e.g. drill chucks, flywheels, spindles and shafts.

Traps (Drawing in /in running nips)-

Traps created between cogs or rollers, or where a moving belt or chain meets a roller or toothed wheel.

Crushing -

Where the body or a limb becomes trapped between moving, closing or passing motions of the machinery.

Shearing-

Where the body or a limb is caught in a shearing/cutting motion by two or more parts moving past each other (e.g. scissors movement), or between one moving part and a fixed surface.

Impact-

Where the body is struck by moving parts of machinery. Traditional machinery posing a risk of impact injury includes milling machines and fly wheel presses.

Friction or Abrasion-

Contact with sharp or abrasive surfaces normally operating at high speed resulting in burns, friction and abrasion injuries.

Stabbing or Puncture-

Injuries caused by sharp objects puncturing the skin e.g. sewing machines, nail guns, drills.

Cutting or Severing-

Injuries arising from contact with a cutting blade.

Ejection-

Injuries caused by flying objects e.g. sparks, chips, molten metal or broken components being ejected from the machinery. High pressure fluid injection is another potential cause of injury within this classification. A puncture of a hydraulic hose could cause a release of hydraulic fluid under high pressure.

Potential Severity of Injury

The potential severity of injury associated with these mechanical hazards is influenced by a range of factors including:
1.       The shape-cutting elements, sharp edges and angular parts, even if they are motionless.
2.       The location relative to walls or fixed objects can create crushing, shearing, and entanglement zones.
3.       Stability against overturning considering kinetic energy.
4.       The potential energy of components which can move under the effect of gravity.
5.       The kinetic energy of elements in controlled or uncontrolled motion.
6.       Acceleration and deceleration of moving parts.
7.       Inadequate mechanical strength, resulting in breakages or bursts.
8.       The potential energy of elastic elements (springs), or of liquids or gases under pressure or vacuum; and
9.       The working environment.

Non-Mechanical Hazards

Non-mechanical hazards related to machinery and equipment can include harmful emissions, contained fluids or gas with pressure, chemicals and chemical by-products, electricity and noise, all of which may cause serious injury if not adequately controlled. In some cases, people exposed to these hazards might 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.

Electrical hazard- 

The primary concern is electric shock arising from persons coming into contact with live parts. This may be a direct contact-where the conductors or conductive parts are intended to be energized in normal operation; or an indirect contact-where parts have become live under fault conditions.
Additional concerns include projection of molten particles or chemical effects from short-circuits or overloads and secondary consequences.

Thermal Hazards- 

Contact with machine parts or materials at extremes of temperature may cause burns or scalds. Heat sources may pose a fire or explosion hazard. Health effects (heat stress/frostbite) are associated with working with hot or cold machinery.

Noise-

Exposure to noise can cause permanent hearing loss and a range of other physiological and psychological effects. Noise may also impair verbal communication or of the perception of acoustic signals.

Vibration-

Vibration can be transmitted to the whole body and particularly to hands and arms. Vibration can cause vascular, neurological, and osteo-articular (skeletal joints) disorders.

Radiation-

Radiation hazards may arise from ionizing or non-ionizing sources. Effects may be acute or chronic.
Hazardous materials and Substances- Materials and substances used in the construction of machinery, or processed, used, produced or exhausted by machinery, may be hazardous to health and/or pose a fire/explosion hazard.

Poor Ergonomics-

A mismatch between machinery and human characteristics and abilities can result in: physiological effects from unhealthy postures, or repetitive movements, psycho-physiological effects arising from metal overload or under load; or an unacceptable level of human error/failure.
Slipping, Tripping and Falling Hazards-Inadequate floor surfaces or poor arrangements for access and egress may give rise to slips, trips and falls. Ejected materials or substances may also create tripping or slipping hazards.

Environmental Hazards- 

Where machinery is required to operate under potentially hazardous environmental conditions those hazards should be taken into account at the design stage.

Mechanical and Non-Mechanical Hazards Associated with Specified machines-

1.       Pedestal and Radial Arm Drills-

·         Mechanical Hazards- 
entanglement, crushing traps, drawing in to belt drive, ejection.
·         Non-Mechanical Hazards- Electrical, Thermal, noise, vibration, hazardous materials and substances, ergonomic, slip, trip and fall.

2.      Circular Saw -

·         Mechanical Hazards- entanglement, contact, trap, ejection.
·         Non-Mechanical Hazards- Electrical, Thermal, noise, vibration, hazardous materials and substances, ergonomic, slip, trip and fall.

3.       Abrasive Wheels-

·         Mechanical Hazards- entanglement, contact, trap, ejection.
·         Non-Mechanical Hazards- Electrical, Thermal, noise, vibration, hazardous materials and substances, ergonomic, slip, trip and fall.

4.       Mechanical and Hydraulic Presses-

·         Mechanical Hazards- entanglement, contact, trap.
·         Non-Mechanical Hazards- Electrical, noise, ergonomic, slip, trip and fall.

5.       Lathes-

·         Mechanical Hazards- entanglement, contact, trap.
·         Non-Mechanical Hazards- Electrical, noise, ergonomic, slip, trip and fall.

6.       Portable power tools (angle grinder, drill)-

·         Mechanical Hazards- entanglement, contact, trap, ejections.
·         Non-Mechanical Hazards- Electrical, thermal, noise, vibration, hazardous materials, slip, trip & fall and environmental.

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