Ergonomics Guide
For Intergraph Systems
DHA011510
February 1997
Copyright and Trademark Information
Intergraph Corporation hereby grants the licensee a non-exclusive, non-transferable,
royalty-free license to copy and distribute this Ergonomics Guide to all employees of the
licensee who are Intergraph system users, or for distribution with the Intergraph system
itself. The licensee shall not alter, modify, amend, or translate this Ergonomics Guide
without the prior written consent of Intergraph Corporation. The licensee shall provide
proper attribution and notice of Intergraph Corporation copyrights in all reproductions of
this Ergonomics Guide.
Intergraph and the Intergraph logo are registered trademarks of Intergraph
Corporation. Other brands and product names are trademarks of their respective
owners.
1995, 1997 Intergraph Corporation.
Intergraph Corporation
Huntsville AL 35894-0001
Introduction
This Ergonomics Guide gives you information to help you do the
following:
u Establish a proper work environment.
u Develop proper work habits.
Keep this Ergonomics Guide with the Intergraph system at all times.
All users should read this document before using the system. Follow
the guidelines in this document to ensure proper use of the system.
Injury may result from improper use.
Free Ergonomics Guides and help with ergonomic issues are available
from Intergraph:
Telephone 1-800-263-3746
Electronic Mail
World Wide Web
U. S. Mail Intergraph Corporation
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ergo@ingr.com
http://www.intergraph.com
Design & Ergonomics Department
Mail Stop CR 2901
Huntsville AL USA
35894-0001
Getting Started
If you can adjust the work surface or the keyboard support, adjust the
chair to rest your feet flat on the floor and to firmly support your
thighs with the seat base. Leave the chair at this adjusted position as
you go through the following steps.
If you cannot adjust the work surface or the keyboard support, adjust
your seating position as described in the following steps.
Step 1: Arms
Rest your fingers on the keyboard. Relax your upper arms; they
should be nearly vertical at your sides. Your forearms should bend
nearly at right angles to your upper arms.
u If your upper arms are not vertical, adjust the distance between the
chair and the keyboard until they are.
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u If your forearms are not at right angles to your upper arm, adjust
the height of the keyboard or the chair until they are.
u If your elbows rest on the chair’s armrests, do not let this cause
you to raise your shoulders from their relaxed position.
Step 2: Wrists
Rest your fingers on the keyboard. Your wrists should be straight with
your forearms.
u If your wrists bend upward or downward, adjust the height of the
keyboard or chair to align your wrists properly with your
forearms.
u If your wrists bend inward or outward, adjust the position of your
hands to align your wrists properly with your forearms.
You may find it helpful to use a wrist support for short periods of rest.
Step 3: Head and Eyes
The monitor screen should be between 18 inches (45.1 centimeters)
and 31 inches (78.7 centimeters) from your eyes (Humanscale, MIT
Press). Your head should be angled downward slightly when you look
at the center of the screen. If you are continually referring to a
document, place the document at the same height and angle as the
screen.
u If the monitor is too high or too low, use a suitable support to
place it at a comfortable height.
u Do not assume that using the system base unit as a support places
the monitor at the correct height.
Step 4: Back
The chair should firmly support your back when you sit up straight,
and your thighs should be at right angles to your torso. The chair
should also support the lumbar curve of your back.
u If the chair’s backrest does not provide lumbar support, use a pad
or pillow to provide lumbar support.
u If you can adjust the chair’s backrest angle, make sure your thighs
and your torso are nearly at right angles when your feet rest on the
floor.
u If you can adjust the chair’s backrest tension, make sure it is firm
enough to support your back while working. It should only tilt
back under force.
Step 5: Legs
Your lower legs should be at right angles to your thighs. Your upper
legs should be positioned so the knees are slightly above the hip joint.
Your feet should rest flat on the floor.
u If your lower legs are not at right angles to your thighs, adjust the
chair to be higher.
u If your feet do not rest flat on the floor, adjust the chair to be
higher. You may need to use a footrest to support your feet and
maintain the correct position relative to the keyboard.
u If your thighs are compressed on the seat pan, the chair is too
high. Some chairs offer a seat pan tilt adjustment for a greater
range of lift.
Step 6: Environment
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Do not work in a cold room. The American Society of Heating,
Refrigeration, and Air Conditioning Engineers (ASHRAE)
recommends the following office climate for the average clothed
individual:
u Temperature between 73.0 and 79.0 degrees Fahrenheit (22.7 and
26.1 degrees Celsius) during the summer.
u Temperature between 68.0 and 74.5 degrees Fahrenheit (20.0 and
23.6 degrees Celsius) during the winter.
u Relative humidity between 30 and 60 percent all year.
Adjust the room lighting and the position of the monitor screen to
minimize screen glare and reflections. Do not work in an over- or
under-illuminated room; an average illumination of 50 foot-candles is
usually sufficient. Below this level, you should provide task lighting
for documents. Older individuals may require higher average
illumination, up to 100 foot-candles.
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Reducing the Risk of Injury
Do the following to reduce the risk of injury:
u Do not hold any posture for an extended period of time. If
possible, change your working posture several times a day. If you
can, work part of the day sitting and part of it standing.
u Take periodic rest breaks during the day. A study sponsored by
the National Instate for Occupational Safety and Health (NIOSH;
R. Henning, University of Connecticut, 1992) found that adding
distributed rest breaks to the traditional work schedule
“forestall(ed) the development of discomfort in repetitive VDT
work.”
Try using this recommended minimum rest break schedule:
− A 30-second break after each 10 minutes of work.
− A 3-minute break after each 50 minutes of work.
− A 15-minute break mid-morning.
− A lunch break.
− A 15-minute break mid-afternoon.
During each rest break, gently and slowly stretch your hands and
arms. During longer rest breaks, get up, walk around, and gently
stretch as much of your body as you can. Set a schedule of rest
breaks and make yourself take them. It is easy to focus on your
work and forget to take rest breaks; use a timer or a software
reminder program to help you remember.
During each rest break, focus on something far way to relax your
eye muscles. Avoid close focus activities like reading during a
rest break to allow your eyes to rest.
u Keep your hands and arms warm. Warm up and gently stretch
your hands before you start working. You may find it helpful to
wear warm, fingerless gloves.
u Keep a straight, or “neutral,” wrist position. Use wrist rests and
other supports during pauses to help you keep a comfortable wrist
position.
u Use the minimum force necessary to activate switches (of any
type, on any device). Many people use far more force than is
required; this is frequently true for point-and-drag operations
using a mouse. Excess force puts unnecessary strain on tendons,
joints, and soft tissues. You may have to teach yourself to use
minimum force.
u Be aware that home and hobby activities can contribute to any
discomfort or pain you may experience at work.
u Maintain good overall muscle tone with a sensible exercise
program. See a physician for recommendations, or before starting
any exercise program.
u If you experience any discomfort or pain, evaluate your work
habits, your work environment, and your personal activities.
Consult a physician if the discomfort or pain persists.
u Seek professional medical attention if you experience a problem.
Take an active part in alleviating the problem. Do not rely on
self-diagnosis.
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