Ergonomics and Human Factors
EIND413
Activity 3
DUE: 24 September 2019
Problem
Select an office chair in which you spend a significant amount of time. It could be a chair at home, where
you work, where you study, or anywhere else where you spend time. In addition, find another office
chair different from the first chair. Use the attached Cornell Ergonomic Seating Evaluation form to
evaluate each chair. The provide a no more than 2‐page, 1” margin, single spaced, 12 point font report
that describes your findings. Include copies of your evaluation forms.
CORNELL ERGONOMIC SEATING EVALUATION v21 ADMINISTRATION INSTRUCTIONS
Background
The seating evaluation v21 is designed as a practical guide to help practitioners make comparative design
decisions about different ergonomic chairs. The form started life as a >50 item list that was
compiled based on published literature on seating evaluation research studies. Through iterative use
and analysis the form was revised to a 25 items version, and then a 15 item version. With advances in chair
design the original evaluation form has been expanded to a 21 item form and the scoring process has been
improved. This short evaluation form is still designed to be quick and easy to use by nonergonomists as well as ergonomists to help guide decisions about seating products.
The content of the evaluation form is based on those questions that most differentiate between chairs
(or sitting experiences) and those that relate to ergonomic design considerations. The form does not
valuate design issues, such as color, style etc., nor does it cover esthetic or economic considerations,
it only addresses those features of greatest ergonomic importance.
How to score the evaluation form
The form is to be used to compare different chairs rather than as an absolute evaluation tool. Say that
4 chairs are being compared, then each user would be allowed to sit in each chair for a specified
period of time (it may be as brief as a few minutes, but this will limit some reactions, e.g. to seat pan
comfort, and it is preferably that this is at least 90 minutes, unless the user really doesn’t like the
chair). At the end of this test period for each chair the user then rates their experiences of sitting in
that chair.
The use of the 11 point scale is based on a 10cm linear rating scale design, but the defined intervals
are given to speed the scoring process. The use of 11 points gives a true mid-point value of 5 that represents a us
experience is average for the chair, and the extremes are the scale bipolar anchors with a minimum of
0 defined as unacceptable and 10 as exceptional on the same acceptability scale so that responses to
all items can be directly compared. If a chair does not have a feature then it scores 0 on that item.
The rating responses are subjective and the focus is on factors such as the usability and comfort of the
chair. The scale is organized into 5 Separate sections (4 component sections: chair adjustments, seat
comfort, ease of use, and body support, and 1 overall comfort rating section). The scores for each
section are totaled and the section scores are summed and an overall % ergonomic design score is calculated.
In this way different chairs can be compared either on individual items, on each of the 4 feature sections
and on overall subjective performance, or the total chair performance is indicated by the % ergonomic design
score (%EDS).
CORNELL ERGONOMIC SEATING EVALUATION FORM v21
This form was revised and updated in 2007. The form can help you to evaluate the ergonomic design of a chair. You should
answer each question by giving a rating out of 10, with higher scores indicating better performance. This form can be used as
part of your chair evaluation process and to compare the designs of different chairs. You can copy this form without permission
for noncommercial and educational purposes. If you have any questions or comments please contact Professor Alan Hedge at
the Department of Design & Environmental Analysis at Cornell University (ah29@cornell.edu).
Evaluator Name: _________________________________
Date: ____________________________
Chair Manufacturer _______________________________
Model ___________________________
Evaluation Criteria
Marks out of 10
A: Chair Adjustments (are these available and how usable are they?)
1. Usability and range of seat pan depth adjustment
Unacceptable(0) ----- Average(5) ---- Excellent(10)
0-1-2-3-4-5-6-7-8-9-10
2. Usability and range of back height adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
3. Usability and range of backrest recline adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
4. Arm support range of adjustability
0-1-2-3-4-5-6-7-8-9-10
5. Chair seat, back and arms adjust independently to allow comfortable sitting
0-1-2-3-4-5-6-7-8-9-10
A: Chair Adjustments Score =
B: Seat Comfort
Unacceptable(0) ----- Average(5) ---- Excellent(10)
6. Seat pan/cushion comfort (evaluate after at least 90 min. of sitting)
0-1-2-3-4-5-6-7-8-9-10
7. Seat edge contour comfort (no pressure points under buttocks, thighs, knees)
0-1-2-3-4-5-6-7-8-9-10
8. Backrest cushion comfort (evaluate at various recline positions)
0-1-2-3-4-5-6-7-8-9-10
9. Armrest comfort (when sitting back and resting arms)
0-1-2-3-4-5-6-7-8-9-10
B: Seat Comfort Score =
C: Ease of Use
Unacceptable(0) ----- Average(5) ---- Excellent(10)
10. Ease of chair seat height adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
11. Ease of seat pan depth adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
12. Ease of armrest height adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
13. Ease of backrest recline adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
14. Ease of cleaning chair parts and materials
0-1-2-3-4-5-6-7-8-9-10
C: Ease-of-use Score =
D: Body Support
Unacceptable(0) ----- Average(5) ---- Excellent(10)
15. Mid/Upper back support at various recline positions (no forward push or fall back)
0-1-2-3-4-5-6-7-8-9-10
16. Lumbar (low back) support (evaluate at various recline positions)
0-1-2-3-4-5-6-7-8-9-10
17. Seat pan support at various backrest recline positions
0-1-2-3-4-5-6-7-8-9-10
18. Armrest height support range (below thigh level to above seated elbow height)
0-1-2-3-4-5-6-7-8-9-10
D: Body Support Score =
E: Overall Chair Experience
Unacceptable(0) ----- Average(5) ---- Excellent(10)
19. Overall ease of use of the chair and controls (include training & adjustment time, # movements)
0-1-2-3-4-5-6-7-8-9-10
20. Overall appearance of the chair
0-1-2-3-4-5-6-7-8-9-10
21. Overall comfort of the chair
0-1-2-3-4-5-6-7-8-9-10
E: Overall Chair Experience Score =
TOTAL % ERGONOMIC DESIGN SCORE (%EDS) = ((A+B+C+D+E)/210) x 100 =
© Professor Alan Hedge, Cornell University, Oct 07
CORNELL ERGONOMIC SEATING EVALUATION FORM v21
This form was revised and updated in 2007. The form can help you to evaluate the ergonomic design of a chair. You should
answer each question by giving a rating out of 10, with higher scores indicating better performance. This form can be used as
part of your chair evaluation process and to compare the designs of different chairs. You can copy this form without permission
for noncommercial and educational purposes. If you have any questions or comments please contact Professor Alan Hedge at
the Department of Design & Environmental Analysis at Cornell University (ah29@cornell.edu).
Evaluator Name: _________________________________
Date: ____________________________
Chair Manufacturer _______________________________
Model ___________________________
Evaluation Criteria
Marks out of 10
A: Chair Adjustments (are these available and how usable are they?)
1. Usability and range of seat pan depth adjustment
Unacceptable(0) ----- Average(5) ---- Excellent(10)
0-1-2-3-4-5-6-7-8-9-10
2. Usability and range of back height adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
3. Usability and range of backrest recline adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
4. Arm support range of adjustability
0-1-2-3-4-5-6-7-8-9-10
5. Chair seat, back and arms adjust independently to allow comfortable sitting
0-1-2-3-4-5-6-7-8-9-10
A: Chair Adjustments Score =
B: Seat Comfort
Unacceptable(0) ----- Average(5) ---- Excellent(10)
6. Seat pan/cushion comfort (evaluate after at least 90 min. of sitting)
0-1-2-3-4-5-6-7-8-9-10
7. Seat edge contour comfort (no pressure points under buttocks, thighs, knees)
0-1-2-3-4-5-6-7-8-9-10
8. Backrest cushion comfort (evaluate at various recline positions)
0-1-2-3-4-5-6-7-8-9-10
9. Armrest comfort (when sitting back and resting arms)
0-1-2-3-4-5-6-7-8-9-10
B: Seat Comfort Score =
C: Ease of Use
Unacceptable(0) ----- Average(5) ---- Excellent(10)
10. Ease of chair seat height adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
11. Ease of seat pan depth adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
12. Ease of armrest height adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
13. Ease of backrest recline adjustment while sitting
0-1-2-3-4-5-6-7-8-9-10
14. Ease of cleaning chair parts and materials
0-1-2-3-4-5-6-7-8-9-10
C: Ease-of-use Score =
D: Body Support
Unacceptable(0) ----- Average(5) ---- Excellent(10)
15. Mid/Upper back support at various recline positions (no forward push or fall back)
0-1-2-3-4-5-6-7-8-9-10
16. Lumbar (low back) support (evaluate at various recline positions)
0-1-2-3-4-5-6-7-8-9-10
17. Seat pan support at various backrest recline positions
0-1-2-3-4-5-6-7-8-9-10
18. Armrest height support range (below thigh level to above seated elbow height)
0-1-2-3-4-5-6-7-8-9-10
D: Body Support Score =
E: Overall Chair Experience
Unacceptable(0) ----- Average(5) ---- Excellent(10)
19. Overall ease of use of the chair and controls (include training & adjustment time, # movements)
0-1-2-3-4-5-6-7-8-9-10
20. Overall appearance of the chair
0-1-2-3-4-5-6-7-8-9-10
21. Overall comfort of the chair
0-1-2-3-4-5-6-7-8-9-10
E: Overall Chair Experience Score =
TOTAL % ERGONOMIC DESIGN SCORE (%EDS) = ((A+B+C+D+E)/210) x 100 =
© Professor Alan Hedge, Cornell University, Oct 07
EIND 413
Ergonomics & Human Factors
Workplace Design & Seating
Goals of Human Factors
• Design Systems that
– Reduce human error
– Increase productivity
– Enhance safety and comfort
• Improve fit between human and machine and
environment
1
Work Spaces
•
•
•
•
•
•
Clearance
Reach
Adjustability
Visibility
Work Surfaces
Component Arrangement
Clearance
• Provide access
• Prevent awkward postures
• Lower‐limit dimension
– Adequate for largest user (start at 95th percentile)
2
Reach
• Determined by capabilities of smallest user
– 5th percentile
• Reach envelope
– Three‐dimensional space around person that can
be reached without stretching or leaning forward
– Represents reach capability of individual
Adjustability
• Adjust the workplace
• Adjust the worker position relative to
workplace
• Adjust the work piece
• Adjust the tool
3
Visibility and Line of Sight
• Line of sight
– Preferred direction of gaze when eyes are in
resting condition
– ~10‐15 degrees below horizontal plane
Work Surfaces
• Height
– Standing
• 2‐4 inches below elbow level
– Seated
• At elbow level
• Depth
– Reach envelope
4
Workplace Design Guidelines
• Aim at dynamic work – avoid static work
• Work surface height depends on size of worker and
type of task
• Avoid overloading the muscular system
• Primary controls within the normal working area
– Secondary controls within maximum working area
• Strive for best mechanical advantage
• Work with both hands
• Hands should move in symmetrical and opposite
directions
• Use feet as well as hands
Workplace Design Guidelines (cont.)
• Design knowing the capacity of the fingers
•
•
•
•
•
•
•
– Do not overload
Avoid unnatural postures
Permit change of posture
Maintain proper sitting posture
Counterbalance tools > 3 pounds
Accommodate large individual
Use gravity, do not oppose it
Use bins with lips for storage and manual retrieval
of small parts
• Keep eye fixations to a minimum
• Train individuals in proper use of workspace facility
5
Office Ergonomics
Occupational Risk Factors
• There are four main risk factors people
may experience when dealing with
computer work
• Even though risk factors may be present,
this does not mean you are destined to
suffer an injury
• You will benefit from being aware of the
risk factors and how to minimize the risk
as much as possible
6
Risk Factors…
1. Repetition – task or series of motions performed
over & over.
2. Forceful Exertions ‐ amount of physical effort
required to complete task.
3. Awkward Postures ‐ reaching, twisting, bending,
holding fixed positions.
4. Contact Stress – localized pressure exerted
against the skin by external force.
Health Risk of Workstation
• Musculoskeletal
Disorder.
• Eye Strain.
• Work Related Stress
7
Musculoskeletal Disorder
Musculoskeletal Disorders (MSD’s) are injuries and
disorders of the musculoskeletal system. They may be
caused or aggravated by various hazards or risk factors
in the workplace.
A number of medical diagnoses are covered by the
term MSD, including:
•
•
•
•
•
Carpal tunnel syndrome
Epicondylitis (tennis elbow)
Muscle strain
Tension neck syndrome
Back pain
Source: http://www.safetyoffice.uwaterloo.ca/hse/ergonomics/musculoskeletaldisorders.htm
Eye Strain
More than 50 percent of computer users experience
eyestrain, headaches, blurred vision and other visual
symptoms related to sustained use of the computer.
This type of stress on the visual system can also cause
body fatigue and reduced efficiency at work.
Direct Computer Stress Symptoms
–
–
–
–
–
headaches
irritated and/or dry eyes
blurred vision
doubling of vision
frequently losing place when moving eyes between
copy and the screen
Source: Dr. Marc Grossman. Computer Eye Strain: How to Relieve It. (http://www.visionworksusa.com/computereyestrain.htm)
8
Eye Strain
Many computer users experience visual stress
due to:
1) an increase in the number and complexity of
necessary eye movements and focusing skills,
2) poor lighting conditions, glare and distracting
reflections,
3) screen flicker rate, and
4) above all, the extended amount of computer
use.
Source: Dr. Marc Grossman. Computer Eye Strain: How to Relieve It. (http://www.visionworksusa.com/computereyestrain.htm)
Work Related Stress
Workplace stress is the harmful physical and
emotional response that occurs when there is a poor
match between job demands and the capabilities,
resources, or needs of the worker.(Wikipedia)
Physical effect of work related stress include:
• Fatigue
• Muscular tension
• Headaches
• Heart palpitations
• Sleeping difficulties, such as insomnia
• Gastrointestinal upsets, such as diarrhoea or
constipation
Source: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/work‐related_stress
9
The Workspace for Comfort
Office Ergonomics
10
Neutral vs. Non‐Neutral Hand
Positions
Neutral Wrist Position
‐ Wrists and elbows are at the same height, parallel to the ground.
‐ No awkward postures.
‐ Everything within easy reach.
‐Wide or narrow shoulders? What does that do to your wrists? Do you need
a split or contoured keyboard?
Chair
1. Backrest height – adjust to support lumbar curve at
correct level
2. Lumbar tension – adjust for comfort and to fit low
back curve
3. Backrest tilt – adjust to sit upright; lock tilt control
4. Sit against backrest
5. Seat pan – supports thighs to just behind knees
6. Seatpan tilt – adjust so hips and knees are at same
level
7. Feet – flat on floor or use footrest if chair height is
raised
8. Arm rests – optional
– Height and width adjustable
– Positioned directly below elbows for support
Safe Sitting Guidelines
– Use a chair that fits you and is adjusted correctly
– Don’t stay in one position for prolonged periods of
time; get up and move or stretch every 20‐50 minutes
– Make sure your feet are flat on the floor
– Sit upright with back and shoulders against the
backrest
– Do not use armrests to slouch. Elbows and lower
arms should only rest lightly to avoid contact stress.
– Keep shoulders relaxed and slightly dropped while
keyboarding
11
Chair
Backrest
• General Design
95120°
– Easy to adjust
– 5‐leg base ‐‐ stability
Arm Rests
– Swivel and wheels ‐‐
ease of reaching &
Seat
getting in & out
Pan
Source: Harvard School of Public Health
Chair Design
• Seat Pan:
Backrest
95120°
– Slightly concave
– Softly padded
Arm Rests
– Rounded, waterfall
edge‐ reduce edge
Seat
compression
Pan
Source: Harvard School of Public Health
12
Chair Design
• Foot rest
Backrest
95120°
– only if necessary
– should be big & solid
• Backrest:
Arm Rests
– Supports entire back: head‐
lumbar ~ 85 cm
Seat
– Relieve spinal and musclePan
load
Source: Harvard School of Public Health
Adjust the chair
• Seat Height:
Backrest
95120°
– Feet flat on floor
– Knee should be at 90°
• Armrests:
Arm Rests
– Supports upper extremity
– Adjustable vertically and
Seat
horizontally
• Vertically for shoulders Pan
• Horizontally to keep elbows
in
Source: Harvard School of Public Health
13
Seating Design
Advantages of a Sitting Posture
• Provides stability required in tasks involving
high visual and motor control
• Less energy consuming than standing
• Places less stress on lower extremity joints
• Lowers hydrostatic pressure on lower
extremity circulation
14
The Vertebral Column
Sitting Postures
15
Anthropometric Measurements
Lumbar Support and Backrest Angle
16
Disc Pressure – Unsupported Sitting
Disc Pressure vs Backrest Inclination & Lumbar
Support
17
Armrest influence on Disc Pressure
Disc Pressure – Simulated Work Activities
18
General Principles of Seat Design
•
•
•
•
•
Promote lumbar lordosis
Minimize disc pressure
Minimize static loading of back muscles
Reduce postural fixity
Provide for easy adjustability
Case Study 1 – Aeron Chair
19
Aeron – Features and Benefits
• Broad range of seat height adjustment allows its users to choose
the forward-bias or semi-reclined position
• Kinemat tilt mechanism allows the body to pivot naturally and
simultaneously at the ankle, knees, and hips
• Pellicle material distributes weight evenly over the seat and
back, conforming to each person's shape.
• Seat-height range - from a low of 14 3/8 inches (on the A-size
chair) to a high of 20 7/8 inches (on the B and C sizes).
• The forward-tilt adjustment positions the seat angle 5 degrees
forward.
• The lumbar pad can be adjusted vertically through a 4 1/2-inch
height range. Depth can be set at 3/4 inch or 1 1/4 inches.
• Armrests pivot inward 17.5 degrees to support forearms for
keying, outward 15 degrees for mousing.
• Arm heights adjust independently within a 4-inch range.
Aeron – Adjustments
20
Aeron – Kinematics of Sitting
Aeron – Anthropometric Approach
21
Aeron – Anthropometric Approach : 2
Aeron – Pressure Distribution
22
Case Study 2 – Leap Chair
Leap Chair – “Live Back”
• Spine does not move as a single unit
• Chair’s back changes shape to support the independent
movements of a person's upper and lower back when he or
she changes posture
• The upper and lower back regions require different amounts of
support
- Separate Upper and Lower Back Controls.
- Adjust the upper back control to provide an increasing amount of
force that increases as the user reclines.
23
Leap Chair – Features
• Designed to enable people to recline without changing
their orientation to their work
• Seat glides forward, so you can recline without departing
your Vision and Reach Zone
• Seat Edge Angle Control
Leap Chair – Features : 2
• Seat Height
• Standard six inch seat height adjustment (15" to 21").
• Adjustable Seat Depth
• People don't fit neatly into average sizes ("A," "B," "C").
• Adjustable seat depth (15-1/4" to 18-1/4").
• Adjustable Armrest
24
Case Study 3 – HumanScale Freedom
Freedom Chair – Features
• Single lever control – seat height
• Arms move in tandem when you
move forward
• TechnoGel – spreads weight
•“ It's like sitting in a puddle of your
own flesh”
•Counterbalance system
•As you recline, your weight
automatically balances the force
required to recline the chair
•Provides just the right amount of
recline tension to keep you fully
supported in all positions without
the need for locks or other manual
adjustments
25
CODE
DESCRIPTION
MEASUREMENT (in inches)
a
seat depth
16 - 19
b
seat height adjust. range
16 - 21
* LOW OPTION 14 - 19
* HIGH OPTION 17 - 22
1/3
1/2
1/2
1/3
c
base diameter
26 (diameter)
d
backrest width
21
e
height, standard chair
33 - 41
* LOW OPTION 31 - 39
* HIGH OPTION 18 - 42
1/2
1/4
1/2
1/2
1/4
f
seat width
21
g
back rest height
5
h
height, advanced chair
43 - 56
i
stool height
16 - 21
1/2
Keyboard and mouse
• Vertical Position
–
–
–
–
As low as possible
Arms parallel
g‐h key height = elbow height
mouse and keyboard at the
same height
– larger surfaces are better than
trays
Source: Harvard School of Public Health
26
Keyboard and mouse
• Horizontal Position
– Keyboard: Directly in
front of worker
– Mouse: Right or left of
keyboard
– Mouse: Directly in
front (mouse intensive
tasks)
– Trays can limit
horizontal adjustments
Source: Harvard School of Public Health
Keyboard and mouse
• Angle
– Keyboard: Flat or
negative sloped
• Keep wrists straight or
slightly flexed
Negative slope
– Wrist pad (obstacles)
can help (bio‐feedback)
Flat
Wrist pad
Source: Harvard School of Public Health
27
Monitor Positioning
• Vertically adjustable
18‐24”
– Top of screen not to exceed
the operator’s eye level
(preferably 1‐2 inches below
eye level)
– Viewing angle 15°‐ 30° W/R to
horizontal
• Horizontally adjustable
– Directly in front
– 18‐24” distance
• Same for document holder
Source: Harvard School of Public Health
Arranging Your Workspace
Arrange tools around your desk so you minimize the distance you
have to reach for them. Divide your work space into three zones:
Primary work zone ‐ the
distance from elbow to
hand. Things you touch on
a daily basis.
Secondary work zone ‐
within arm's reach. Use
this zone to position those
items that you use
frequently, but don't need
all the time.
Reference zone ‐ outside
arm's reach. Use this zone
for your least‐often used
items.
28
Take Breaks!
• Micro‐Breaks
– Every 20‐40 minutes
• From Stretching, by
Bob and Jean
Anderson, Shelter
Publications
13.
Wrists/Fingers
14 . Eyes ‐ Practice the 20/20/20 rule
After 20 minutes of computer use: look away
from the screen and focus on something 20
feet away that is out a window or down a
corridor. Focus on this sight for at least 20
seconds.
Workstation Environment
Appropriately placing lighting and selecting the
right level of illumination can enhance your
ability to see monitor images and avoid awkward
posture to see monitor. Ventilation and humidity
levels in office work environments may affect
user comfort and productivity.
• Lighting
• Glare
• Ventilation
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
29
Lighting
Potential Hazards:
• Bright lights shining on the display screen
"wash out" images. Straining to view objects
on the screen can lead to eye fatigue.
• Bright light sources behind the display screen
can create contrast problems, making it
difficult to clearly see your work
• High contrast in computer screen, horizontal
work surface, and surrounding areas cause eye
fatigue and headaches.
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
Lighting
Possible Solutions:
• Place rows of lights parallel to your line
of sight (Figure ).
• Provide light diffusers.
• Provide supplemental task/desk
• Use blinds on windows to eliminate bright
light.
• Reorient the workstation so bright lights from
open windows are at right angles with the
computer screen (Figure 1)
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
30
Glare
Potential Hazards:
• Direct light sources (for example,
windows, overhead lights) that
cause reflected light to show up
on the monitor (Figure) make
images more difficult to see,
resulting in eye strain and
fatigue.
• Reflected light from polished
surfaces, such as a keyboards,
may cause annoyance,
discomfort, or loss in visual
performance and visibility.
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
Glare
Possible Solutions:
• Place the face of the display screen at right
angles to windows and light sources.
• Clean the monitor frequently. A layer of dust
can contribute to glare.
• Use blinds or drapes on windows to help
reduce glare
• Tilt down the monitor slightly to prevent it
from reflecting overhead light.
• Use barriers or light diffusers on fixtures to
reduce glare from overhead lighting.
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
31
Ventilation
Potential Hazards:
• Users may experience discomfort from poorly designed or
malfunctioning ventilation systems.
• Dry air can dry the eyes.
• Temperatures above or below standard comfort levels can
affect comfort and productivity.
• Exposure to chemicals, volatile organic compounds,
ozone, and particles from computers and their
peripherals (for example, laser printers) may cause
discomfort or health problems.
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
Ventilation
Possible Solutions:
• Do not place desks, chairs, and other office furniture
directly under air conditioning vents.
• Keep relative humidity of the air between 30% and 60%.
• The recommended ambient indoor temperatures range
between 68° and 74° F during heating season and
between 73° and 78° F during the cooling season.
• Enquire about the potential for a computer or its
components to emit pollutants. Those that do should be
placed in well‐ventilated areas.
• Maintain proper ventilation to ensure that there is an
adequate supply of fresh air.
Source: http://www.osha.gov/SLTC/etools/computerworkstations/wkstation_enviro.html
32
Summary
• Avoid postures where you have to maintain
non‐neutral positions.
• Avoid extreme positions of body parts/joints.
• If it doesn’t feel right, it’s probably not right.
• Maintain proper sitting postures.
• Keep an open mind!
Web Resources
• What is RSI and what can you to do to
prevent it?
(http://www.youtube.com/watch?v=agZe‐
tyj_1s)
• Ergonomics: The Pen, The Mouse &
Repetitive Strain Injuries
(http://www.youtube.com/watch?v=aFCCultb
yMM)
• 7 Tips to Avoid Computer Vision Syndrome
(http://corporatefitnessproducts.com/blog/20
09/09/7‐tips‐to‐avoid‐computer‐vision‐
syndrome/)
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