Human engineering

1. Human Engineering/
Human Factors/
Ergonomics/
Engineering Psychology

2. History and Scope of Engineering Psychology
• Prior to 1940, engineers made machines without
considering the human factor
• The worker was adapted to the machine through
time-and-motion studies
• WW II weaponry was complex but did not perform
up to expectations, thus giving rise to engineering
psychology
Example: There was no consistency in design of aircraft
controls. “On” position for some controls was up, for
others, down – difficult to remember in a dog fight.
Many pilots died as a result

3. History and Scope of Engineering Psychology
• Poor design resulted in many accidents
Three Mile Island in 1979 - poor design of controls
• Human factors research resulted in safer
automobiles, including redesigns of headlights,
brake lights, and tinted windows
• Other areas of effort include license plate
visibility, signage, cell phone use while driving,
driver aggression, and mailbag design
• Ergonomics has net gains of 1 to 12% over the
costs of human factors interventions

4. Engineering Psychology is a Hybrid
• Members of the Human Factors and Ergonomics
Society includes:
Psychologists
Engineers
Medicine
Sociology
Anthropology
Computer sciences
Other behavioral and physical sciences

5. Time and Motion Study
• An early attempt to redesign work tools and to
reshape the way workers performed routine,
repetitive jobs
• F.W. Taylor (1898) performed first empirical
demonstration of the relationship between work
tools and worker efficiency

6. Guidelines for Increasing Efficiency of Manual
Jobs
• Minimize reaching distance from worker
• Symmetrical movements of both hands
• Hands should never be idle
• Hands never do tasks that can be performed
by other parts of body
• Workbench height adjusted to prevent fatigue

7. Principles for Workspace Design
• All materials should be placed in order in which
they will be used so paths of movements will be
continuous
• Tools should be pre-positioned for use
• All parts and tools should be within comfortable
reach

8. Ergonomics :WHAT DOES IT
MEAN…..?
 Ergonomics is the science and the art of fitting the job and the
workplace to workers’ needs.
• It is the study of work
• It is a way to make jobs/tasks
fit the employees better
• It is a way to make work easier

9. Other Design Considerations
• Heights of all working surfaces should be
adjustable
• Hand tools should be designed for use without
bending wrists
Hammers with angled handles work better
• Properly designed tools affect productivity,
satisfaction, and physical health

10. Human Anthropometry
• A branch of engineering psychology concerned with
measurements of the physical structure of the body,
including
Height – standing and sitting
Shoulder breadth
Back height
Chest depth
Foot and hand length
Knee angle
• These measurements are applied to design of work areas
to determine normal and maximum reaching distances, tool
and desk height and arrangement, etc.

11. Human Factors in Everyday Life
• Human factors no longer confined to tanks,
airplanes and work areas
Telematics deals with wireless information
technology such as GPS, Satellite radio, and built-in
wireless phone for cars
Ergonomics also includes examining cell phone use
while driving (to prevent accidents)
Use of auditory signals to alert drivers which are too
close to another car

12. Types of ergonomics
• Physical ergonomics is the human body’s responses to
physical and physiological work loads.
Repetitive strain injuries from repetition, vibration, force,
and posture fall into this category.
• Cognitive ergonomics deals with the mental processes
and capacities of humans when at work.
Mental strain from workload, decision making, human
error, and training fall into this category.
• Organizational ergonomics deals with the organizational
structures, policies and processes in the work
environment,
shift work, scheduling, job satisfaction, motivation,
supervision, teamwork, telecommuting, and ethics.

13. ERGONOMIC RISK FACTORS
Repetition
Force
Static
Loading
Risk of injury increases with:
 Prolonged exposure to any of these ergonomic risk factors
 Presence of multiple risk factors within a single job task

14. WHAT TO DO…..?
Prevent, prevent, prevent
a) Warm up & stretch before activities that are
repetitive, static or prolonged
b) Take frequent breaks from ANY sustained
posture every 20-30 minutes
c) Respect pain- positions or stop painful activity
d) Recognize early signs of inflammatory
process, & tx early
e) Be aware of workstation environment.

15. Maintain Neutral Posture
a) Maintain erect position of back
& neck w/ shoulders relaxed
b) Position equipment & work directly in front of and
close to your major tasks
c) Keep upper arms close to the body, elbows 90-100
degrees
d) Keep feet flat on floor, upper body weight resting on
“sits bones”
e) Wrists as neutral as possible; safe zone for wrist
movement is 15 degrees in all directions

16. MSDs (Musculoskeletal Disorders)
Hardhat Ergonomics-PowerPoint Presentation 1.2 (November 2000)
A study done by the University of Iowa has shown that construction
workers hurt!
• 70% report pain in their
lower back
• 46% report pain in their
knees
• 43% report pain in their
wrists and hands
• 42% report pain in their
shoulders and necks
(The University of Iowa Construction Survey, 1996)

17. f) Avoid bending neck forward for prolonged
periods of time (*remember quadruple the
force); use a copy holder
g) Avoid static positions for prolonged time;
muscles fatigue---MOVE to circulation!

18. a) Alternate activities frequently; rotate heavy &/or
repetitive tasks w/ lighter less repetitive ones.
b) If sx become worse REASSESS task setup &
look for alternative methods
c) Avoid repetitive or prolonged grip activities
d) Avoid pinching w/ wrist in flexion or wrist
deviation (bending to side)
e) Take frequent breaks to stretch & rest hands
MODIFY TASKS:

19. ERGO REMINDERS

20. Correct & Incorrect Techniques

21. Practice Wellness at Work and Home !
Exercise
Nutrition
Relaxation
Body
Mind
Spirit

22. MOVE
STRETCH

23. ADVANTAGES
• A successful ergonomics program utilizes the skills
of many disciplines, including engineering,
psychology, medical, safety, management and the
employees or associates
• Applications range from the design of work areas
(including office furniture, automobile interiors, and
aircraft cockpits) to the disposition of switches and
gauges on the control panels of machinery to
determining the size, shape, and layout of keys on
computer terminals and character height, color, and
clarity on video displays.
•

24. ADVANTAGES
• The benefits of applying ergonomic principles:
- Maximize productivity, efficiency and quality;
- Reduce MSD risk by eliminating or
minimizing ergonomic risk factors;
- Improve employee morale; and
- Cost savings associated with injury-
related absenteeism, treatment, new hire training
and WCB claims.
• It can help you do work safely
• It can make you more comfortable
• It can prevent injuries

25. Summary
• Minimize ergonomic risk factors in your area
• Stretch throughout the shift especially before and after activities
that require awkward positions or lifting
• Pay attention to your body and know your physical limitations
• Report ergonomics issues through appropriate channels.
• Ergonomic injuries are preventable, and you own your own
safety

26. An ounce of Prevention is worth a
pound of cure !
THANK YOU