Oxford Handbook of Occupational Health (2 edn)
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Ergonomics hazards: overview
Definitions
Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data, and methods to design in order to optimize human wellbeing and overall system performance.
International Ergonomics Association
Human factors refer to environmental, organizational and job factors, and human and individual characteristics, which influence behaviour at work in a way which can affect health and safety.
HSE
Industries
Ergonomics hazards to employees are ubiquitous, affecting almost every type of work. Ergonomics issues can also affect service users, the general public, and the environment. They are most important in safety-critical industries, e.g. transport and nuclear industries, and in the health services.
Specific ergonomics factors
The most important of these are covered separately in this chapter. However, ergonomics hazards often occur in combination with each other, and are commonly addressed together in designing risk controls. This list is not exhaustive.
Task-related (physical or cognitive)
Loading (lifting and handling)
Poor posture
Repetition, particularly at high speed
High forces
Poor equipment and workplace design
Task overload/under load
Mental workload
Poor system reliability
Poor design of information, displays, controls.
Individual factors
Anthropometry
Social support
Personality
Attitude and behaviour
Risk perception
Human error.
Organizational factors
Long working hours
Shift work
Short deadlines
Poor staffing levels
Lack of worker involvement in system design
Control over work.
Adverse effects of poor ergonomics design (including health effects)
Accidents
Injuries
Musculoskeletal disease (back, neck, and upper limb pain)
Psychological morbidity (including stress)
Critical incidents (including environmental disasters)
Decreased efficiency, poor productivity
Failure of complex systems
Job dissatisfaction
Low staff morale
High job turnover.
Ergonomics risk management
Relevant legislation
There is no specific legislation on ergonomics hazards, but some statutory instruments contain direction on ergonomics issues:
Control of Major Accident Hazards Regulations 1999 (COMAH)
Railways (Safety Critical Work) Regulations 1994
The Manual Handling Operations Regulations 1992 (as amended)
The Health and Safety (Display Screen Equipment) Regulations 1992
Provision and Use of Work Equipment Regulations 1998 (PUWER)
The Working Time Regulations.
Further information
International Ergonomics Association. Available at: 
http://www.iea.cc/
Ergonomics society. Available at: http://www.ergonomics.org.uk/
European Agency for Safety and Health at Work. Available at: http://osha.europa.eu/en/front-page
Health and Safety Executive: human factors guidance. Available at: http://hse.gov.uk/humanfactors/index.htm
Lifting and handling
Manual lifting or handling of loads constitutes one of the most common and important ergonomics hazards.
Definitions
The term manual handling comprises any non-mechanized (or incompletely mechanized) manipulation of a load, including lifting, pushing, pulling, sliding, or carrying. Loads may be inanimate or living (people and animals).
Specific industries
Manual handling is a ubiquitous exposure, which is common in a wide range of industries. However, of particular note are:
Construction
Warehousing and logistics
Heavy engineering
Airport baggage handling
Agriculture
Health care (patient-handling).
Risk assessment
See Table 4.1.
| Factor | ↑ Risk | ↓ Risk |
|---|---|---|
Load: weight shape stability others | 15 kg or more Awkward shape, large size, poor grip Liable to shift or move Sharp edges, heavier thananticipated by the handler Centre of gravity of load eccentric | <15 kg Small, easy to grip Stable, predictable |
Lever (distance from employee’s centre of gravity) | Load held away from body | Load close to body, with arms vertical and parallel to trunk |
Vertical distance (height) | Lifts above elbow height Lifts below knee height | Transfer at trunk height |
Posture | Bent or twisted trunk Constrained posture | Straight trunk |
Task | Long carrying distances (>4m = moderate risk) Frequent or repetitive lifting Prolonged lifting High effort (resistance) | Short distance Short duration |
Environment | Limited space Steep slopes Slip or trip hazards Poor visibility Extremes of temperature | Level non-slip surface Comfortable temperature |
Individual susceptibility | Previous history of back pain Pregnancy | |
Work organization | Short deadlines Poor communication Lack of control Excessive demands | Reasonable pace of work Good support Good control and flexibility Reasonable volume of work |
| Factor | ↑ Risk | ↓ Risk |
|---|---|---|
Load: weight shape stability others | 15 kg or more Awkward shape, large size, poor grip Liable to shift or move Sharp edges, heavier thananticipated by the handler Centre of gravity of load eccentric | <15 kg Small, easy to grip Stable, predictable |
Lever (distance from employee’s centre of gravity) | Load held away from body | Load close to body, with arms vertical and parallel to trunk |
Vertical distance (height) | Lifts above elbow height Lifts below knee height | Transfer at trunk height |
Posture | Bent or twisted trunk Constrained posture | Straight trunk |
Task | Long carrying distances (>4m = moderate risk) Frequent or repetitive lifting Prolonged lifting High effort (resistance) | Short distance Short duration |
Environment | Limited space Steep slopes Slip or trip hazards Poor visibility Extremes of temperature | Level non-slip surface Comfortable temperature |
Individual susceptibility | Previous history of back pain Pregnancy | |
Work organization | Short deadlines Poor communication Lack of control Excessive demands | Reasonable pace of work Good support Good control and flexibility Reasonable volume of work |
Risk controls
The following list is not exhaustive, but includes the most common examples of risk controls. Extensive guidance on risk controls (including industry-specific guidance) is readily available (references under Further information and guidance on p. 122).
Divide load into smaller units, or scale loads up, and switch to bulk handling systems
Ensure load is easy to grip and stable
Arrange lifting environment free from obstacles and on level surface
Address extremes of height, e.g. restrict transfers to levels below elbow and above knee height. Avoid lifting from the floor
Mechanical lifting aids appropriate to the task. There are many examples for different purposes. More common examples include:
hoists, cranes, and vehicles
powered and non-powered trucks and trolleys
scissor lifts or other height-adjustable surfaces
tracks, conveyors, chutes, and rollers
specialized equipment for ‘live’ loads (patients), e.g. slide sheets.
Health effects
Low back pain
Neck/shoulder pain
Osteoarthritis of the hip.
Specific legislative requirements
The Manual Handling Operations Regulations 1992 (amended) give a framework for the generic risk assessment, risk control, review cycle that is specifically relevant for hazards associated with manual handling.
Further information and guidance
Health and Safety Executive guidance and tools. Manual
handling. Available at: http://www.hse.gov.uk/msd/manualhandling.htm
HSE (2004). The Manual Handling Operations Regulations 1992. Available at: http://www.hse.gov.uk/pubns/priced/l23.pdf
Posture
The main component of risk is non-neutral posture.
Definitions
Non-neutral means that the head, trunk, or limbs deviate from the normal anatomical (neutral) position.
Specific industries
Adverse posture is widespread across many industries, affecting workers in office environments as well as heavy manual occupations. In particular:
Call centre operators
Display screen equipment users
Food industry, meat handlers
Assembly line workers.
Potential health effects
Low back pain
Upper limb pain (neck–shoulder, elbow, forearm, and wrist pain).
Risk assessment
Non-neutral posture is associated with ↑ risk of health effects if it is:
persistent—prolonged, constrained or awkward position of the trunk or limbs (e.g. sustained stooping)
repetitive—repeated adverse posture (e.g. bending up and down)
Extreme deviation from the anatomical position increases risk:
head or trunk flexed or extended, especially ≥20º
upper limbs—extreme flexion or abduction of the shoulders (work with arms above shoulder height), elbows, or wrists; as a general rule, risk increases most with upper arm flexion ≥90º, elbows flexed ≥90º, and wrists flexed or extended ?15º
Risk control
Appropriate seating that is adjustable to allow for anthropometric variations between operators
Controls that are within reach to avoid over-reaching or stretching
Attention to the height at which tasks are carried out in order to minimize bending or stooping
Task rotation, regular breaks, or variation in position in order to avoid prolonged constrained posture.
Risk controls for poor posture
Relevant legislation and guidance
The Display Screen Equipment (DSE) Regulations. Available at: http://www.opsi.gov.uk/si/si1992/UksI_19922792_En_1.htm
HSE (2004). The Manual
Handling Operations Regulations 1992. Guidance on
regulations Available at: http://www.hse.gov.uk/pubns/priced/l23.pdf
Health and Safety Executive. Reducing awkward postures. Available at: http://www.hse.gov.uk/msd/uld/art/posture.htm
Repetitive work
Definition
Repetitive work includes activities that are physically repetitive, or cognitively repetitive or monotonous. Physical and cognitive aspects of repetitiveness in work tasks often interact.
Specific industries/tasks
Packaging
Assembly lines
Textile/garment production (sewing machine operators, cutting room)
Poultry processing (plucking, evisceration)
Fruit pickers
Computer data entry operators.
Health effects
Musculoskeletal disorders
Neck–shoulder pain
Elbow, wrist pain
Low back pain.
Risk assessment
See Table 4.2.
| Risk factor | ↑ Risk | ↓ Risk |
|---|---|---|
Cycle time | Rapid | Slow |
Grip strength | Tight grip | Loose grip |
Recovery time | Short | Long |
Synergism with posture | Awkward posture | Supported neutral posture |
Psychosocial factors | Lack of control over work (e.g. forced pacing) Excessive workload | Able to determine speed of work Able to intersperse repetitive tasks with other activities (both physical and cognitive) |
| Risk factor | ↑ Risk | ↓ Risk |
|---|---|---|
Cycle time | Rapid | Slow |
Grip strength | Tight grip | Loose grip |
Recovery time | Short | Long |
Synergism with posture | Awkward posture | Supported neutral posture |
Psychosocial factors | Lack of control over work (e.g. forced pacing) Excessive workload | Able to determine speed of work Able to intersperse repetitive tasks with other activities (both physical and cognitive) |
Risk controls
The following list is not exhaustive, but includes the most common examples of risk controls. Extensive guidance on risk controls is readily available (
p.
129).
Frequent rest breaks
Task rotation
Avoid forced pacing
Job enrichment and variety
Automation
Mechanization
Worker participation in job design and organization.
Further information
HSE (2002). Upper limb disorders in the workplace. HSG (60). ISBN 0717619788.
HSE (2003). Work with Display Screen Equipment: Health and Safety (Display Screen Equipment) Regulations 1992 as amended by the Health and Safety (Miscellaneous Amendments) Regulations 2002, L(26). ISBN 0717625826.
HSE (2003). The law on VDUs: an easy guide, HSG (90). ISBN 0717626024.
Health and Safety Executive. Assessment of repetitive tasks (ART) tool. http://www.hse.gov.uk/msd/uld/art/index.htm
Mechanical hazards
In the operation of machines a person may be injured as a result of:
Machine movement
Being trapped between the machinery and materials
Being struck by materials ejected from the machinery.
Identification of machinery hazards
It is useful to consider three factors:
The different phases of the machine’s life:
design and construction
installation
commissioning
operation
cleaning
maintenance
disposal
The circumstances giving rise to the injury
The hazards that can cause the injury.
Types of machinery hazards
For the different types and range of machines used, their hazards can be summarized as follows:
Traps:
reciprocating traps due to vertical or horizontal motion of machines
shearing traps produced by a moving part traversing a fixed part, and in-running nips where limbs are drawn in to a trap (e.g. where a moving belt or chain meets a roller or a tooth wheel).
Impact: machinery parts, which can cause injuries by their speed or movement if the person gets in the way
Contact: this may cause burns, lacerations, or injuries due to sharp, abrasive, hot, cold, or electrically live machine components
Entanglement: limbs, hair, or clothing may become entangled with unguarded moving parts
Ejection: machines may eject particles, metals, or actual parts of machines (e.g. grinding machines)
Injection: machinery leaks may inject hydraulic fluid into the skin at high pressure.
Risk assessment
Is the equipment fit for purpose?
Is it suitable for use in the intended work conditions?
Is it maintained in a safe condition?
Some equipment should be regularly inspected to ensure it remains fit for use, e.g. power presses:
any inspection should be by a competent person
a record should be kept of the inspection.
Risk controls
Mechanical hazards should be considered when purchasing equipment
Machinery should be fitted with suitable safety devices, e.g.
machine guards
emergency stop buttons
interlocks to prevent operation if guards are removed
Machinery should have appropriate warning signs
Worker information, instruction, and training
Safe systems of work including machine isolation before maintenance
Personal protective equipment, e.g. safety goggles.
Relevant legislation and guidance
HSE (2008). Approved Code of Practice Safe use of work equipment. Provision and Use of Work Equipment Regulations 1998, L22. HSE Books, Sudbury.
HSE (1999). Simple guide to the Provision and Use of Work Equipment Regulations 1998, INDG 291. Available at: http://www.hse.gov.uk/pubns/indg291.pdf
