[ppt]applied anthropometry and the workplace - wright...
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Applied Anthropometric and Workplace
Applied Anthropometry and the Workplace
Anthropometry A. Description of the physical
variation in humans by measurement; a basic technique of physical anthropology.
B. The measurement of the dimensions and certain other physical characteristics of the body.
Applied Anthropometric and Workplace
Measuring Types
A. Static (structural) - taken while the body is in a static position
1. Skeletal dimensions - joint-to-joint
measurement
2. Maximum body width
3. Data available on most characteristics of the body
NASA Anthropometric Source Book. (vol 2, 1978)
Applied Anthropometric and Workplace
Measuring Types
B. Dynamic (functional)
1. Measurements taken while the body is engaged in some kind of activity
a. Driving a car
b. Working at a desk /
VDT terminal
Applied Anthropometric and Workplace
Applications
Principles 1. Design for extremes of
individuals (or the population)
a. Maximum: automobile interiors, escape hatches, doorway
b. Minimum: applied
force, reach distances
c. Most designs cover 5th through 95th percentile
Applied Anthropometric and Workplace
Principles
2. Design with an adjustable range a. Design should "fit" 5th through 95th
percentile of relevant population b. Involves a trade-off with
cost/complexity
3. Design for the average - vs. design for the extreme(seat height, counter tops,
letter height)
Applied Anthropometric and Workplace
4. Variability of population -
Anthropomorphic measurements are a functionof age, gender, nationality, user type and several other factors
Principles
Applied Anthropometric and Workplace
Applications of Design Principles
A. Bittner
Taking 13 dimensions between 5th and 95th percentile excluded 52% of the population
B. Body dimensions are not
perfectly correlated
Short legs with a long torso in automobile design
Applied Anthropometric and Workplace
Applications of Design Principles
C. Physical modeling
1. Computer programs to model human movement
2. Dummies are used to represent
specific percentiles - crash tests for autos
Applied Anthropometric and Workplace
General Approach for Design Evaluation
A. Determine the body dimensions which will be important in the use of the system
B. Define the relevant (user) population
C. Which design principle will be used
Applied Anthropometric and Workplace
D. What percentage of the population it is to be designed for
E. Determine the relevant value from the anthropomorphic tables
F. Add appropriate allowances for special situations
General Approach for Design Evaluation
1. Bulky clothing worn in cold weather
2. Protective clothing worn by hazardous duty personnel
Applied Anthropometric and Workplace
Work Spaces (Envelopes)
A. Work Space Envelope Defined as the 3-dimensional space
around an individual in which it is reasonably optimal for persons to perform some type of manual activity
B. Seated personnel 1. Most important factor in this
position is arm reach a. direction ofreach b. task to be performed (grasp,
fingertip operation) c. type of reaching motion
(restricted/unrestricted)
Applied Anthropometric and Workplace
2. Design for the minimum (5th percentile) - Makes it useful for 95% of the population
3. Consider apparel worn
C. Standing Personnel
Work Spaces (Envelopes)
1. vs. seated
a. Larger workspace is defined (due to ability to bend/reach)
b. Workspace is dynamic
(moves as the person moves)
Applied Anthropometric and Workplace
Work Spaces (Envelopes)
D. Clearance Requirementsworkers need to fit into awkward or
restrictive spaces sometimes.i.e. maintenance or emergency
hatches.
Applied Anthropometric and Workplace
Work Surfaces
A. Horizontal Surfaces (tables, desks, counters)
1. Normal area - area covered by
sweep of the forearm while the upper arm remains in a natural position
2. Maximum area - area which can be reached by extending the arm from the shoulder
Applied Anthropometric and Workplace
B. Slanted Surfaces
vs. horizontal
a. Eastman and Kodat (use of slanted surfaces, 12-24 degrees, gives better posture, less fatigue/discomfort
b. Drafting tables, computer
keyboards
C. Height of Work Surfaces
Work Surfaces
Applied Anthropometric and Workplace
Work Surfaces
Guidelines
a. Make it adjustable where possible (legs/feet, slant)
b. Forearm should be level of
slightly down with shoulders relaxed (not hunched)
c. Allow for a "straight" spine
(posture) to reduce strain and fatigue in the back muscles/spine
d. Adjustable for type of activity
to be performed
Applied Anthropometric and Workplace
Work Surfaces
2. For Standing Personnel
a. Precision work (work level even with or slightly above elbow height)
b. Light / Heavy work (work level
should be below elbow height)
Applied Anthropometric and Workplace
Seating
Principles of Seat Design
1. Back support should be used
a. Lower support most critical to reduce fatigue and eliminate back pain
b. Lordotic (concave)
preferred over Kyphotic (convex)
Applied Anthropometric and Workplace
2. Seat height and slope
Seating
a. Generally, seat height should be low enough so as to reduce pressure on the underside of the thigh (reduces blood flow to the legs)
b. Common to design seats for
minimum (5th percent)
Applied Anthropometric and Workplace
3. Seat depth and width
a. For public seating, depth should be designed for a minimum while the width should be designed for the maximum
Seating
b. Spacing between seats should be at least 20 inches
Applied Anthropometric and Workplace
Guidelines for Seat Design
A. Seat back should provide support for lumbar (lower) area
B. Seat back should have moderate inclination (10-30 degrees)
C. Seat pan should slope back slightly
D. Angle between seat pan and back is 95-120 degrees
Applied Anthropometric and Workplace
E. Seat height and backrest should be adjustable
F. Seat height designed for
small people, width for large people
G. Use moderately contoured
seat pan for weight distribution
Guidelines for Seat Design
Applied Anthropometric and Workplace
Seat Height and Slope:- fixed height: 18 - 19”- adjustable height: 16 - 20.5”- slope: 0 - 10o backward tilt
Seat Depth and Width:- depth: 15 - 17”- width: 18.2”
Guidelines for Seat Design: ANSI Standard
Applied Anthropometric and Workplace
Guidelines for Seat Design: ANSI Standard
Contour and Cushioning:- contour: tradeoffs between even
weight distribution vs. restricting movement and postural fixity.
- cushion: 1.5 - 2” thick.
Seat Back:- angle: minimum 90 - 105o with respect
to the seat pan. Up to 120o prefered.- width: minimum 12” in the lumbar
region.- height: minimum 19.5”.- lumbar support: 6 - 9” high, 12” wide,
positioned 6 - 10” above seat reference point, and protrude ~ 2” from back rest.