Lecture 2: Ergonomics & Anthropometrics

in Environmental Design

ENVD 5380 Human Factors in Environmental Design

By Dr. Su-Jeong Hwang Shin

Environmental Design

• Environmental design– Fundamental to an understanding of the role of the

built environment in people's lives is an understanding of what is meant by “environment”, surround (Jon Lang, 1987).

– It is expected to provide certain levels of bodily comfort.

– It is created it to fulfill the basic need for shelter. • Examples: Buildings have been designed to respond to

climatic conditions to a greater or lesser extent in order to meet the basic metabolic needs of people.

– We are more aware when we feel uncomfortable.• Examples: feelings of psychological well-being,

dissatisfaction, discomfort.

Anthropometrics & Ergonomics

• Anthropometrics and ergonomics– They deal with the relationship between human

physiological capabilities and metabolic process and the build environment.

• Anthropometrics– The study of human physical dimensions, capabilities

and limitations (Jon Lang, 1987)• Ergonomics

– Focuses on human beings and their interaction with products, equipment, facilities, procedures, and environments used in work and every day living (Sanders,1993).

Anthropometrics & Ergonomicsin Environmental Design

• Bias thought:– Designer’s intuitive understanding of human

physiology was good enough for design.

Bias thought:• Chair design by Mies

van der Rohe– A symbol of elegance

and good taste but they are exceedingly difficult to get into and out of.

– Uncomfortable for a seated person.

Chair by Mies Van der Rohe,Source: Jon Lang (1987)

Bias thought:• Chandigarh, India

– The building are set in large open spaces for symbolic reason.

– Getting from one to another is arduous for even the heartiest soul especially on a summer day.

Source: Jon Lang (1987)

Bias thought:• Irish cottages

– Dictated, unselfconsciously, largely by life style and religious beliefs.

Source: Jon Lang (1987)

Anthropometrics & Ergonomics in Environmental Design

• Le Corbusier developed (what he believed to be) a universal tool, – based on

anthropometrical dimensions, for scaling the environment for both use and aesthetic purpose.

– He called the scale the “modulor”

– The basic height taken for a man in the scale 1.75 m was chosen for symbolic rather than statistically valid.

Notre Dame du Haut (Le Corbusier, 1954)

Anthropometrics & Ergonomics in Environmental Design

• Design for what to be, not who.– Some of the best known pieces of designs have been ridiculed for their

lack of comfort and sometimes impossibility of use.• The energy crisis has led to questions

– regarding the heavy reliance on mechanical systems to attain and maintain comfort levels in recent urban environmental design.

• There is an increasing awareness of the number of accidents– that occur in the workplace and at home due to the lack of congruence

between an activity and the milieu affording it.• Physiologically impaired people are demanding

– that they not be handicapped by the layout of the environment.• Designers are increasingly required to address these issues

– to meet the requirements of legislation.• Need to understand the relationship between the environment and

human behavior at a physiological level (Jon Lang, 1987)

Anthropometry

Anthropometry• Anthropometry

– Anthropometrics: the study of human physical dimensions, capabilities and limitations (Jon Lang, 1987)

– Anthropometry deals with the measurement of the dimensions (Sanders, 1993).

• There are two types of body measurements:– Static (Structural) dimensions:

• Measurements taken when the body is in a fixed (static) position.

– Dynamic (Functional)

Static Anthropometry• Static (Structural)

dimensions:– Measurements taken when

the body is in a fixed (static) position.

– They consist of:• Skeletal dimensions-

measures distance of bones between joint centers, or

• Contour dimensions –Skin surface dimensions such as head circumference.

Sitting height• Sitting height

– Stature differences are reduced when sitting down.– Relative sitting stature = sitting height~53% stature,

but varies by ethnicity.– Different ethnic groups have proportionally different

physical characteristics.• Many native African peoples have proportionally longer legs

than Europeans.• Asians have proportionally shorter lower limbs than western

Europeans.

Human dimension & Interior space

Sources from Panero & Zelink (1979). Human dimension & Interior space, NY: Whitney Library of Design.

Example: Dining space

Example: Cultural relativity

• The cultural relativity of anthropometric dimensions– They are not universally

applicable.– Picture 1 and 2 shows the

differences between Indian and North American in the use of tables for eating.

– Picture 3 shows the standard of eating while squatting are largely irrelevant to the American situation.

Picture 1 Picture 2

Picture 3

Dynamic Anthropometry• Dynamic (functional) anthropometry

– Distances are measured when the body is in motion or engaged in a physical activity.

– There is no systematic procedure for translating static anthropometric data into dynamic measurements.

– Kroemer (1983)’s rough estimates:• Heights (stature, eye, shoulder, hip): reduce by 3 percent• Elbow height: no change, or increase by up to 5 percent.• Knee or popliteal height, sitting: no change• Forward and lateral reaches: decrease by 30 percent for

convenience, increase by 20 percent for extensive shoulder and trunk motions.

Dynamic Anthropometry• Clearance Dimensions

– Body ellipse: in plan view the human body occupies an elliptical shape. So clearance values depend on postural orientation (e.g. in corridors, turnstiles, buses, aisles, etc.)

• Reach– Reaching could be arm plus extended torso.

• Example: The limit of arm reach is also affected by shoulder movement, partial trunk rotation, possible bending

– Dynamic reach envelope (kinetosphere) influenced by:• Posture (sitting<standing).• Foot base (increased reach with increased foot base).• Weight in hands (heavy weight decreases reach).• Type of grip (pinch> power).• Proximity to obstacles (wall/obstacle behind person decreases

reach).

Zone of Convenient Reach (ZCR)

• Measuring zone of Convenient reach (ZCR)• Measure:

a= shoulder (acromion)-grip (center of hand) length.d= horizontal distance from shoulder to surface.r=√(a²-d²)r= radius of ZCRZCR defines the maximum working area.Zones of Convenient Reach + Optimal Visual Zones.

Working Area (NWA or MWA)• Normal working are (NWA)

– NWA allows hand motion to be made in a convenient zone with normal energy expenditure.

– Area described by the arms and hands with the elbows flexed at ~90 degree.

– Typically, the comfortable limit of outward rotation is about 25 degree.

• Maximum working area (MWA)– MWA is the intersection of

the ZCR with the horizontal surface such as table or bench.

Kinetosphere• Kinetosphere

– The dynamic reach envelope – Describes where the user is able to reach

• Examples: Grip strength and reach• Volumetric reach envelope

– Used to model optimal workspace layout (e.g. SAMMIE CAD).

• Read related article of Kinetosphere: – Toney, A. & Thomas (2006), “Considering Reach in

Tangible and Table Top Design”, Proceedings of the 1st IEEE international workshop on horizontal interactive human-computer systems. [Available online] http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1579192

Considering Reach (Kinetosphere)by Toney, A. & Thomas (2006)

An informal measure of reach •White tiles = Left hand•Black tiles = Right hand•Outer= Max ZCR•Inner= Comfortable ZCR

Considering Reach (Kinetosphere)by Toney, A. & Thomas (2006)

Considering Reach (Kinetosphere)by Toney, A. & Thomas (2006)

Ownership and Territoriality (Multi-user collaborative contexts)•Overlapping comfortable reach•Formal reach•Maximum reach

Myth or Principles?

in the application of anthropometric data……

Principles in the application of anthropometric data

• Design for extreme individuals (Sanders, 1993)– Designing for maximum population value, if a given high value of

some design feature should accommodate all people. (e.g. heights of doorway).

– Designing for minimum population value, if a given low value of some design feature has to accommodate all people ( e.g. the distance of a control button or light switches).

– Use the 95th male or 5th female of the population (not 100%)• Designing for adjustable range (Sanders, 1993)

– Applications: Chairs, desk heights, and footrests.– Provide for adjustments to cover the range from the 5th percentile

female to the 95th percentile male of the population characteristic (sitting height, arm reach, etc.).

• Designing for the average (Sanders, 1993)– No “ average” individual. Not easy to design for all.

Design Myths• Design for the “average” person ?

– Since there are no people whose body dimensions are all at the 50th percentile.

– Body dimensions aren’t linearly correlated so people with short arms don’t necessarily have short legs.

• Example: After about 4 dimensions, there’s no highly consistent correlation.

– While the use of the 5th and 95th percentiles on one body dimension for one homogenous population (e.g. all men) may exclude 10% of the population.

• Example: The use of these on 13 dimensions actually can exclude more than 50% of the population.

Variability and Reliability

Human dimension & Interior space

Sources from Panero & Zelink (1979). Human dimension & Interior space, NY: Whitney Library of Design.

Design Myths• Anthropometric data are universal ?

– NOT true: They are only specific to the populations which they describe. If the population is poorly specified the percentiles may be biased. Also, percentiles are only specific to the dimension which they describe.

• Design for an adjustable range ?– There can be significant cost/benefit tradeoffs as the

percentile range is extended. Each successive percent of the population to be accommodated increases the costs relative to the benefits.

– Many aspects of adjustability are only necessary is the users cannot be specified.

– Usability is most important.

Body Morphology• Sex differences

– Shape differences (hip breadth, breast size, abdomen depth) have important ergonomic consequences.

– Separate data are usually used for men and women.• Age differences

– Body grows then stoops with age• Body shape

– Soft tissue varies in shape and these variances may create differences in clearance and mobility requirements.

– Sheldon (1947) proposed 3 somatotpyes.• Mesomorphic- wide thorax, smaller abdomen, strong, muscular

body.• Ectomorph- Thin, slender, bony, flat chest.• Endomorph- Round, soft, large flat storage, pear shaped, full

abdomen, small thorax, short limbs, fine hair, smooth skin.

Body Morphology

Shape 2: Heavy shape (Athletic, Big & tall, or Big)

Shape 1: Slim (Tall) Shape 3: Slant inverted triangle shape (Regular)

Shape 4: Short round top (Stout, Portly)

Shin, S. (2009). Various men’s body shapes and the needs of standards, the 5th SizeUSA user’s meeting Webinar.

Stature Considerations• Height

– Average height of adults steadily declines with age after 20 years of age.

– Around 40 years of age most people start to shrink in stature. Women Shrink more than men and shrinkage accelerates with age.

– Some reduction in height may also result from shrinkage of lower limbs around the joints (Alan Hedge, 2007).

• Time of day– Because the cartilaginous discs of the spinal column get

compressed by body weight throughout the day we tend to be slightly shorter in the evening up to 0.9”. Additionally, extremities (like feet) swell throughout the day (Alan Hedge, 2007).

Body weight and Strength• Weight

– The average weight of adults increases from ages 20-45. From age 50 men’s weight declines. From age 60 women’s weight declines.

– Until 55 years of age weight increases and there is an increases in hip breadth.

– Fat is redistributed from subcutaneous areas to deeper positions especially around abdominal organs.

– Lean body weight decreases with age as muscles waste away.• Strength

– There is a decrease in muscular strength and the mechanical tensile breaking strength of bone, muscle, and connective tissue decreases with age.

Pregnancy• Pregnancy

– Later stages of pregnancy decreases in the ability to lift, bend, reach, stand, or walk for long periods, turn head. It is a form of temporary disability.

– Assuming a 0.02% pregnancy rate and 50,000,000 women of childbearing age, means an estimated 1,000,000 pregnant women at any time. Only recently have anthropometric surveys of pregnant women begun to be conducted in Japan (Alan Hedge, 2007).

Wheelchair User• Wheelchair Users

– Chair bound people actually suffer three limitations:• Condition which necessitates wheelchair use.• Lower eye-level: Eye level is 15~16” below that of most

standing people and the seated posture also influences reach, controls, and access.

• Possession of a cumbersome, awkward, space-consuming, distinctive and inelegant vehicle:

– While a standing person occupies 25” by 15” of floor space, requires 16” to 26” aisle width and can turn on the spot, a wheelchair user occupies up to 57” by 25” of floor space, requires minimum aisle clearance of 31.5” and needs a turning circle of between 59” and 67”.

Wheelchair Users• Design standards for wheelchair users

– (ANSI A1171.1-1980)– Available to assist with designs for wheelchair users.

• Wheelchair Users Dynamic Anthropometrics– Clearance

• The minimum space required for the body or body segment to pass through (or not). Maximum breadth and depth dimensions are used (person or technology- e.g. wheelchair)

• Inclusion- clearance to allow access (e.g. doorway, bathtub, crawlspace, hatch)

• Exclusion- clearance to prevent access (e.g. safety guard, cage, fan, cover, air vents).

Anthropometrics & Ergonomics Related to ENVD

Anthropometrics & Ergonomics Related to ENVD

• Human metabolic processes and the built environment– The body exchanges heat affected by:

• The nature of the ambient and radiant surroundings

• The pattern of behavior• Air movement• The relative humidity of the air.

– The quality of comfort afforded by the ambient environment (e.g. interiors).

Anthropometrics & Ergonomics Related to ENVD

• Illumination levels and design– Symbolic factors depend on the association meanings

of the illumination level.– Comfort, aesthetic pleasure, differentiate between

display areas and movements etc.• The physiology of color perception and design

– Large brightly colored areas fatigue the eye, eye catchers are confusing.

• Sound and noise• Barrier-free environments

– Affordances for mobility in environment. – Wheelchair-users, blind people, and hard of hearing.

Anthropometrics & Ergonomics Related to ENVD

• Behavioral system correlates of anthropometric dimensions– The perception of the quality of anthropometrical fit

between people and their built environments depends on more than just people’s anthropometrical characteristics.

– It depends on their personalities and social, cultural environment.

– Correlating body types and personality (Sheldon, 1954).

• Privacy, territoriality, and personal space.• Cultural relativity of anthropometrics.

Design limitations in ENVD

• Design limitations:– The physiological capabilities of people differ.– Ethnic differences in human physiology.– Many variables of concern in designing the

environment to afford specific behaviors.

Design concerns in ENVD• Design concerns:

– With the specific actions, body postures, and movement patterns of the individual or people involved.

• Work stations (K.K. H. Murrell,1965).– Provided an approximate basis for setting rest allowance based on the average

energy expenditure of the person’s job.– People could work steadily without rest when their energy expenditure on the job

results in a heart rate of 30 to 35 beats/minute above their basal rates. – If a person’s job requires an energy expenditure rate of b kc/ minute (where

b>5),rest should be provided for recovery in proportion to how much b exceeds the standard rate s.

• Requirements for domestic architecture (Etienne Grandjean,1984) .– Work efficiency, expressed as energy consumption (kJ) per unit of walking effort

(kg-m), of walking with shoes and bare foot as a function of walking speed.– Workspace design, standing heights for precision work, light work and heavy work

as related to elbow height. He suggest below elbow height.– Recommend for multipurpose chairs of various designs, the maximum luminance

ratio within an office, the reflectance of walls and ceilings.

Design concerns in ENVD• Design concerns:

– With psychological needs such as privacy, personal space, and territorial control.

• Alexander Kira’s The bathroom (1966) is a classical analysis of both anthropometric and psychological factors in equipment and room design.

Next Class

• Assignment #1 Due• Presentations & Discussions