Designing Healthy Work Environments
Vanessa del Aguila, M.Sc. AEP
Associate Ergonomist
Humanscale Corporation
LEARNING OBJECTIVES
designing healthy work environments
• Understanding of current workplace trends
• Definition of ergonomics and common misconceptions
• Identification of musculoskeletal risk factors
• Essential ergonomic concepts
• Key elements of an ergonomic workstation
WORKPLACE
trends
• The workplace is getting smaller; average square footage per
worker has decreased by 17% since 1994
• Our workforce is aging; by the year 2015, 50% of the US
population will be 40 or older
• Vision issues continue to be among the most common
musculoskeletal complaints
• Laptop computers have become increasingly popular
• Home computing is compounding exposure to
musculoskeletal risk factors
“I think there is a world market for maybe 5 computers.”
- Thomas Watson, Chairman, IBM, 1943
THE STAGGERING COST
of lost productivity
• Survey randomly sampled 28,902 working
adults
• A total of 52.7% of the workforce reported
having headache, backache, back pain, or
other musculoskeletal pain
• Average lost productive time was 5.2 hours
per week
• Costs associated with common pain
conditions and lost productivity in the U.S.
is estimated at $61.2 billion per year
Source: Stewart, W., et al. ‘Lost productive time and cost due to common pain conditions in the
US workforce’, Journal of the American Medical Association, 290(18), 2003.
IS THIS
an ergonomically designed workstation?
• This workstation
looks good but will
not accommodate all
• Individual differences
have not yet been
addressed
• What is likely to
happen next?
WHAT
is driving the need for these accessories?
• Employees respond to
discomfort through
workstation modification.
• Your design vision is
disrupted every time a work
environment is reconfigured
for productivity and comfort
HOW
does this happen?
• Employees redesign their
workstations to
compensate for poor
design
• What kind of work
experience is this
organization providing to
this employee?
DESIGN
to accommodate individual differences
• Health, comfort and performance
are moderated by design
• The job is not complete until
individual differences are
considered
• Workstations can be aesthetically
pleasing and functional at the
same time
HOW DOES ERGONOMICS
address these issues?
Office ergonomics applies science to
workplace design to maximize worker
productivity while reducing operator
fatigue, discomfort and injury.
MINIMIZE
awkward postures
Minimize postures that
require excessive muscle
activity to maintain and
tax the musculoskeletal
system.
MAXIMIZE
neutral postures
Maximize your time spent
in neutral postures that
require minimal muscle
activity to maintain
BREAK
old habits
Installing equipment does
not necessarily solve
postural problems
Elevate your awareness of
your posture throughout
the day
KEY ELEMENTS
of an ergonomic workstation
1)
The chair
2)
The keyboard and mouse
3)
Monitor and document
placement
4)
Proper Lighting
1970s CHAIRS
• No controls
• No adjustability
1980s and 1990s CHAIRS
• Too many manual controls
• Adjustability not used
ESSENTIAL CHAIR ADJUSTMENTS:
chair adjustments
Ergonomic chairs should offer adjustable:
• Seat height
• Seat depth
• Backrest / lumbar height
• Armrests
• Recline tension
ESSENTIAL CHAIR ADJUSTMENTS:
Recline Tension
• Adjust the recline tension to
support your body weight
• The backrest should move
freely and support you
throughout the recline range
KEY ELEMENTS
of an ergonomic workstation
1)
The chair
2)
The keyboard and mouse
3)
Monitor and document
placement
4)
Proper Lighting
ANATOMY
of the wrist
EFFECT OF WRIST EXTENSION ANGLE
on intracarpal tunnel pressure
•
Wrist extension angle,
intracarpal tunnel pressure,
and wrist extensor muscle
activity are directly correlated
•
30 degrees of wrist extension
correlates to a 27.5%
increase in forearm muscle
activity and greater than a
two-fold increase in
intracarpal tunnel pressure
Source: Weir, P, Wells, R. ‘The effect of typing posture on wrist extensor muscle loading’, Human
Factors, 44(3), 2002.
RECONSIDER
keyboard and mouse position
A decade of ergonomics research shows that using a negatively sloped,
adjustable keyboard tray maximizes the time spent working in neutral hand,
wrist and upper body postures. These postural benefits can’t be achieved by
just using a keyboard on a height adjustable work surface
- Dr. Alan Hedge, Cornell University
ARTICULATING KEYBOARD
tray research findings, Hedge, 1995
• Positioned hands in a neutral posture 62% of the time compared with 42% for
the traditional KB position
• Predicted carpal tunnel pressure remained below the critical threshold 82% of
the time compared with 48% for traditional KB position
• Significant improvements in upper body comfort found for shoulders, upper
arms, neck and back
• 91% of those using the tray said it helped their work performance and
preferred it to their previous system
MOUSING
challenges
“The use of a computer mouse is not necessarily benign. Evidence is
accumulating that computer mouse use is associated with a number of
upper extremity musculoskeletal disorders.”
– Dr. Alan Hedge, Cornell University
Postural Risk Factors:
• Wrist Anchoring
• Wrist Extension
• Ulnar/Radial Deviation
• Over-pronation
Design Challenges:
• One size does not fit all
• Most designs do not
accommodate left handed users
DESIGN APPLICATION:
to minimize wrist extension and contact stress
KEY ELEMENTS
of an ergonomic workstation
1)
The chair
2)
The keyboard and mouse
3)
Monitor and document
placement
4)
Proper Lighting
MONITOR
and document placement
The monitor and any documents
for copy should be placed directly
inline with the keyboard to
minimize neck and trunk rotation
The top line of text on the monitor
should be at or slightly below eye
level and at an arms reach
MULTIPLE MONITOR
dilemma
•
As monitor width increases,
our viewing envelope is
compromised
•
As a result, monitors must be
positioned further away,
which can negatively effect
our ability to view the screen
•
Users prefer a viewing
distance of 75-83cm;
minimum distance is 40cm
MULTIPLE MONITOR
arrangement
Primary and Secondary Screens
•
If a single screen is used for
more than 70% of tasks, orient
the primary monitor with the
midline of the body
•
Place secondary monitor
adjacent, angled inward toward
user
MULTIPLE MONITOR
arrangement
Two Screens, ‘Equal’ Usage
•
If any single monitor is used
between 40% - 60% of the day
align the center of both
monitors with the midline of the
body. Angle screens inwards
FLAT PANEL MONITOR
facts and considerations
Flat panel monitors consume 60%
less energy and emit 80% less heat
than traditional CRT monitors
Workstations designed with flat panel
monitor technology can be 10-20%
smaller and maintain the same usable
work surface area
The reclaimed space afforded by
FPM’s is unusable unless the monitor
is mounted on an adjustable arm
Neutral Reach Zone
Courtesy of
Architecture
Magazine,
June 2003
Neutral Reach Zone
Courtesy of
Architecture
Magazine,
June 2003
KEY ELEMENTS
of an ergonomic workstation
1)
The chair
2)
The keyboard and mouse
3)
Monitor and document
placement
4)
Proper Lighting
RECONSIDER
existing lighting strategies
Single source lighting schemes are
inappropriate for accommodating today’s
range of computer users
THE MONITOR/DOCUMENT CONFLICT
• Monitors generate light, while paper reflects light
• Reading paper-based documents requires 4-5 times more
light than does viewing a monitor
LIGHTING REQUIREMENTS
as a function of age
Relative Contrast Required as a Function of Age
• Persons ages 61-70 require
more than 250% more contrast
than persons ages 20-30
• Task visibility is the primary
aspect of lighting that affects
performance
400
Relative Contrast Required
• The need for task lighting
increases with age
350
300
250
200
150
100
50
0
20-30
31-40
41-50
Age
51-60
61-70
CONTRAST REQUIREMENTS
as a function of age
Contrast requirements increase exponentially after age 40.
20 Years
60 Years
75 Years
BENEFITS
of a dual component lighting scheme
Single component:
• Too much light above eyes
• High energy waste
Dual component:
• Light level determined by user
• 30-40% less energy required
RECONSIDER THE USE OF
Under-Bin-Lighting
Under-Bin-Lighting:
• Provides lighting away from
where the tasks are actually
occurring!
• Does not offer individual
control of illumination level
• Is less energy efficient than
most controllable task lights
RECONSIDER THE USE OF
under-bin-lighting
Potential source of glare
Light is away from where work is occurring
ECONOMICS OF
improved lighting technologies
• Dual component lighting schemes
can reduce energy consumption by
one third compared to conventional
lighting systems
• A task and ambient lighting system
is effective in reducing energy
consumption because ambient
illumination levels can be
decreased while task illumination
levels can be increased
Comparison of energy consumption,
before and after refurbishment
Source: Akashi Y, Mukal K, Yanabe Y. A task and ambient lighting system providing
energy efficient savings without decreasing the overall brightness impression
ENCOURAGE
micro breaks
“Appropriate rest breaks, combined with stretching exercises, allow
computer workers to sustain work at an appropriate pace, while
minimizing postural injury risk.”
– Alan Hedge, Cornell University
• Proper rest breaks allow the
body to recover from repetitive
stress
• Changing tasks is also
beneficial
• 2-3 short rest breaks are
recommended per hour
ECONOMICS OF ERGONOMICS
success stories of ergonomic implementations
500
AT&T Global
• Decline in lost workdays from 298 before
implementation to 0 in the first two years
• Claims dropped 75% from $400,000 to
$94,000 in first year
• Savings of $1.48 million
450
Cost (in thousands)
American Express
• Within four years claims dropped 80% from
$484,000 in year 1 to $98,000 in year 5
484
400
350
300
250
208
200
150
98
100
65
60
50
0
1
2
3
4
5
Year
Source: GAO/HEHS-97-163 ‘Private Sector Ergonomics Programs Yield Positive Results’
FOUR KEY POINTS
to remember about ergonomics
1. Ergonomics is a preventative, design based discipline
2. Ergonomic interventions can benefit the masses, not
just those that are injured
3. Product interventions alone are not enough – training is
an integral part of an ergonomic program’s success
4. See ergonomics as a benefit to an organization, not as
a burden!
Thank you for your time!
Questions?
Vanessa del Aguila, M.Sc. AEP
E-mail: vdelaguila@humanscale.com
Phone: 347.277.0153