5th Edition
Prepared by the Canadian Centre
for Occupational Health and Safety
Summary
Ergonomics deals with the compatibility between workers
and their work. 鈥淲ork鈥? is made up of the work environ-
ment, workstations, and tasks. Poor ergonomic conditions
exist when the 鈥渨ork鈥? is incompatible with the workers鈥?
bodies and their ability to continue working. Such
conditions may cause discomfort, fatigue and pain and,
subsequently, injury.
Injuries resulting from poor ergonomic conditions are
collectively known as musculoskeletal injuries (MSI),
repetitive strain injuries (RSI) or repetitive motion
injuries (RMI) or work-related musculoskeletal disorders
(WMSD). The causes of these injuries are prolonged
work involving repetitive movements, forceful move-
ments and awkward body postures. WMSD are painful
and often disabling injuries which affect mainly the
wrists, back, legs, shoulders, neck, muscles and joints.
Adequate environmental conditions are important for the
overall well-being of workers and productivity. When the
work area is too cold or too hot, poorly lit, noisy, poorly
ventilated, or contains unpleasant odours it results in
annoyance, stress, fatigue, eye strain, headache and
other conditions.
Injuries and illnesses related to poor ergonomic conditions
can be prevented by making the workplace and the work
organization fit the physical and mental ability of each
individual worker.
Table of Contents
Introduction
Section I. Ergonomic Hazards in the Office Workplace
1. What is Ergonomics? . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. What are WMSD? . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Why Is There So Much Commotion . . . . . . . . . . . . . .
about Ergonomics? . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. What are the Common Symptoms of WMSD? . . . . . 5
Musculoskeletal Injuries . . . . . . . . . . . . . . . . . . . . . . 6
Pain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. How do Work-related Musculoskeletal . . . . . . . . . . . .
Disorders (WMSD) Occur? . . . . . . . . . . . . . . . . . . 8
6. How do WMSD Affect our Body?. . . . . . . . . . . . . . 10
Joint Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Muscle Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Tendon Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Nerve Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Thoracic Outlet Syndrome . . . . . . . . . . . . . . . . . . 13
Carpal Tunnel Syndrome. . . . . . . . . . . . . . . . . . . . 14
Back Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Prevention of Back Injury . . . . . . . . . . . . . . . . . . . 17
7. What to Do if You Notice Symptoms of WMSD. . . 19
8. How are WMSD Treated? . . . . . . . . . . . . . . . . . . . . 19
Restriction of Movement . . . . . . . . . . . . . . . . . . . . 19
Application of Heat and Cold . . . . . . . . . . . . . . . . 20
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Medication and Surgery . . . . . . . . . . . . . . . . . . . . 20
Section II. Office Ergonomics Program
1. What is an Office Ergonomics Program? . . . . . . 22
2. How to Identify Ergonomic Hazards. . . . . . . . . . 23
3. How to Control Ergonomic Hazards . . . . . . . . . . 24
Workstation Design. . . . . . . . . . . . . . . . . . . . . . 25
Working in a Standing Position . . . . . . . . . . . . 32
Work Organization . . . . . . . . . . . . . . . . . . . . . . 34
Tool, Equipment and Furniture Design . . . . . . 36
Manual Material Handling. . . . . . . . . . . . . . . . 37
Work Environment. . . . . . . . . . . . . . . . . . . . . . . 41
Lighting and Vision. . . . . . . . . . . . . . . . . . . . . . 45
4. Ergonomic Aspects of Visual Display Terminals 48
VDT Workplace Checklist. . . . . . . . . . . . . . . . . 48
Common Health Hazards . . . . . . . . . . . . . . . . . . 50
WMSD Related to Using Computers. . . . . . . . . . 51
Common Symptoms and Causes . . . . . . . . . . . . . 52
VDT Workstation Adjustment . . . . . . . . . . . . . . 53
Using the Computer Mouse . . . . . . . . . . . . . . . 56
Selecting the Right Mouse . . . . . . . . . . . . . . . . 56
Placement of a Computer Mouse . . . . . . . . . . . 58
Using the Telephone while Operating a VDT . . 61
Radiation from VDTs . . . . . . . . . . . . . . . . . . . . 62
Working with VDTs in a Standing Position . . . 64
VDT Workplace鈥揓ob Design. . . . . . . . . . . . . . . 66
5. Office Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6. Exercises to do in the Office . . . . . . . . . . . . . . . . 69
7. Education and Training . . . . . . . . . . . . . . . . . . . . 74
Section III. Ergonomic Regulations, Standards . . . . . . . . . .
and Guidelines
1. Canadian Standards . . . . . . . . . . . . . . . . . . . . . . . 76
2. International Standards . . . . . . . . . . . . . . . . . . . . 76
Section IV. Occupational Health and Safety Legislation
1. Canadian Legislation . . . . . . . . . . . . . . . . . . . . . . 78
2. US Legislation . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Section V. Information Sources
Canadian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
US . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Appendices
A1: Sample Ergonomics Survey Questionnaire . . 106
A2: Sample Health Survey . . . . . . . . . . . . . . . . . . 114
A3: Sample Ergonomic Checklist . . . . . . . . . . . . . 118
Introduction
Work-related musculoskeletal disorders (WMSD) are the
most commonly occurring hazards in modern offices.
These injuries result from poorly designed workstations,
and inadequate job design.
Two common types of WMSD are muscular strain in
the neck, shoulders and back, due to prolonged sitting;
and injury to joints and muscles due to excessive repe-
tition of movements. Injuries due to repetitive move-
ment are known as repetitive strain injury (RSI), repeti-
tive motion injury (RMI), musculoskeletal injuries
(MSI) and work related musculoskeletal disorders
(WMSD). In this guide we will use the term WMSD to
describe such injuries.
The following table summarizes common ergonomic and
safety hazards in office work.
6. How do WMSD Affect our Body?
We can group WMSD in four categories:
joint injury;
muscle injury;
tendon injury; or
nerve injury.
Joint Injury
A joint is the connecting point for two or more bones.
Joints are of three types: (i) freely movable, (ii) slightly
movable and (iii) immovable. The elbow, shoulder and
spine are examples of joints. At the joint, the opposing
surfaces of the bones are lined with flexible tissue called
cartilage, made up of fibrous tissues and soft tissues.
Cartilage provides a smooth surface for movements.
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The shoulder, elbow
The spinal column 鈥? a series
and wrist joints
of many joints
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Work Environment
The work environment includes:
ventilation;
noise;
temperature and Humidity; and
lighting and Vision.
Ventilation
The purpose of ventilation is to control the indoor
temperature, humidity, odour, and airborne contaminants
and to introduce outdoor air (fresh air).
There are two kinds of ventilation
1. Dilution ventilation.
2. Local exhaust ventilation.
Dilution ventilation 鈥? This type of ventilation reduces the
indoor air contaminants by the dilution process. The
used (contaminated) indoor air is exhausted at a preset
rate replaced by taking in outdoor air at an equal rate.
The ventilation system evenly distributes the air through-
out the occupied space.
Dilution ventilation is used when:
airborne contaminants are relatively non-toxic;
emission sources are widely distributed in an
area; and
dilution air is not contaminated.
Local exhaust ventilation 鈥? The purpose of local ventila-
tion is to exhaust the toxic gases, fumes, dusts and
vapours near the point of emission to prevent mixing of
these toxic emissions with the indoor air. Fume hoods
are the most commonly used local exhaust ventilation.
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The VDT Workstation
4. Shoulder Roll
Purpose: To relax shoulder muscles.
Slowly roll your shoulders backward five
times in a circular motion. Then roll
shoulders forward.
Back, Side and Leg Exercises
1. Back/Side Stretch
Purpose: To relax the back
and side muscles.
Interlace fingers and lift arms overhead,
keeping elbows straight. Press arms as far
back as you can. To stretch sides, slowly
lean to the left, then to the right.
2. Middle/Upper Back Stretch
Purpose: To stretch upper and
middle back muscles.
Hold your right arm with your left hand just
above the elbow. Gently push your elbow
toward your left shoulder. Hold stretch for
5 seconds. Repeat on left arm.
3. Back Curl
Purpose: To stretch lower back
and legs.
Grasp shin. Lift leg off the floor.
Bend forward (curling the back),
reaching nose toward the knee.
Repeat with the other leg.
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