ANTHROPOMETRY Chap 10

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Islamic University of Gaza - Palestine

Department of Industrial Engineering

ANTHROPOMETRYChap 10


Learning outcomes

After completing this chapter students should be able to

• be aware of the application of Mannequins in Ergonomics in thepast,

• understand the concept and importance of Anthropometry,

• gain practical experience in collecting anthropometric data,

• learn the applications of Anthropometry,

3/7/2011

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Application of manikins in ergonomic analysis of furniture

Mannequins - a two-dimensional drawing or figure which articulates like ADAM (Anthropometric Data Applications Mannequin) with plastic parts snap together like clear moveable paper dolls or overlay transparencies.




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Common office environment posture measurements



The most common mannequins include the P5, P50, and P95 models for both males and females.

The 5th% female value for a particular dimension (e.g. sitting height) usually represents the smallest measurement for design in a population.

Conversely, a 95th% male value may represent the largest dimension for which one is designing.

The 5th% to 95th% range accommodates approximately 90% of the population.

To design for a larger portion of the population, one might use the range from the 1st% female to the 99th% male.


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When using anthropometric measurements in design, consider two points:

1. How recently data was collected?2. Type of population measured

First, some data may have been collected over 25 yearsago, and measurements such as height or weight may have changed in the current population.



The population one is designing for may not be represented by the anthropometric database being referenced.

For example, ANSUR data may not be applicable indesigning a table used by elderly individuals or children.Anthropometric measurements should be a guide for design.(Natick studies or ANSUR database.)


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Application of manikins in ergonomic analysis of furniture (1)

In 2000, the Civilian American and European Surface Anthropometry Resource (CAESAR) was compiled by the Society of Automotive Engineers (SAE) to measure civilian populations.

CAESAR contains anthropometric data and 3D body scans ofover 4,000 individuals from North America and Europe.


Introduction

• To assess the fit between a person and their work,ergonomists consider

q The job being done and the demands on the worker.

q The equipment used (its size, shape, and howappropriate it is for the task).

q The information used (how it is presented, accessed,and changed).


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Introduction (cont.)

• Ergonomics draws on many disciplines in its study ofhumans and their environments, includinganthropometry, biomechanics, mechanical engineering,industrial engineering, physiology, and psychology.


Anthropometry

• Anthropometry is the science of measurement and studyof the human body and its parts and capacities.

• Is the branch of ergonomics that deals with body shapeand size.

• The science of measuring the human body in order toascertain the average dimensions of the human form atdifferent ages, and in different divisions of race, classetc.


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Anthropometry (cont.)

• People come in all shapes and sizes so you need to takethese physical characteristics into account whenever youdesign anything that someone will use, from somethingas simple as a pencil to something as complex as a car.


Anthropometry Step by Step

1. Decide who you are designing for (user population).

2. Decide which body measurements are relevant

3. Decide whether you are designing for the 'average' or

'extremes‘

4. Think about other human factors


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Step # 1: User Population

• First of all you need to know exactly who you aredesigning for.

• If you were designing an office chair, you would need toconsider dimensions for adults of working age and notthose for children or the elderly. If you were designing aproduct for the home, such as a kettle, your user groupwould include everyone except young children(hopefully!).


Population Dimensions

• Define the user population.

• Consider the source of population dimensions

– Male/female

– Military/civilian

– Age

– Ethnicity

– Occupation


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Step # 2: Body Measurements

• You need to know which parts of the body are relevant to your design.

• For example, if you were designing a mobile phone, you would need to consider the width and length of the hand, the size of the fingers, as well as grip diameter.

• You wouldn't be too interested in the height or weight of the user (although the weight of the phone might be important!)


Step # 3: Average or Extreme?

• Nobody is 'average' in all body dimensions. Someone mightbe say, of average height but have a longer than averagehand length.

• The variation in the size and shape of people also tells usthat if you design to suit yourself, it will only be suitable forpeople who are the same size and shape as you, and youmight 'design out' everyone else!


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Percentiles

• You can design for the percentile.

• Percentiles are shown in anthropometry tables and theytell you whether the measurement given in the tablesrelates to the 'average' person, or someone who is aboveor below average in a certain dimension.


Percentiles (Cont.)


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Designing a door height

• For example, if we were designing a doorway using theheight, shoulder width, hip width etc., of an averageperson, then half the people using the doorway would betaller than the average, and half would be wider.

• Since the tallest people are not necessarily the widest,more than half the users would have to bend down or turnsideways to get through the doorway.

• Therefore, in this case we would need to design usingdimensions of the widest and tallest people to ensure thateveryone could walk through normally.


Designing a door height (cont.)

• Usually, you will find that if you pick the right percentile,95% of people will be able to use your design.

• For example, if you were choosing a door height, youwould choose the dimension of people's height (oftencalled 'stature' in anthropometry tables) and pick the 95thpercentile value – in other words, you would design for thetaller people.

• You wouldn't need to worry about the average heightpeople, or the 5th percentile ones – they would be able tofit through the door anyway


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Designing an Airplane Cockpit

• If you were designing an airplane cockpit, and need tomake sure everyone could reach a particular control,

• You would choose 5th percentile arm length

• If they could reach the control, everyone else (with longerarms) would be able to.


Designing an Airplane Cockpit (cont.)

• Deciding whether to use the 5th, 50th or 95th percentile value depends on what you are designing and who you are designing it for.


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Step # 4: Other Human Factors

Like comfort, temperature,

• You may need to add corrections for clothing!

• Have you allowed for shoe heights!

• You generally add 20mm for fairly flat shoes, and more if youthink users will be wearing high heels.


Anthropometry Measurements

• Lengths (e.g. the length of the thigh bone)

• Breadths (e.g. the width across the shoulders)

• Girths (e.g. waist limits)

• Stature (height)

• Mass (how much you weigh)

• skinfold thickness at various sites on the body (e.g. atthe back of the upper arm)


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Anthropometry Measurements (cont.)

• Variety of people

Ø Monitoring athletes, tracking growth, development, andmotor performance in children,

Ø Linking physical activity and nutrition interventions tochanges in body size, shape and composition.

Ø Assessing changes in body dimensions in response todisease.

Ø Identifying markers for potential sporting performance.


Body Position Descriptions

• Planes– Saggital – divides the body into left and right half

(medial/lateral)

– Coronal – divides the body into front and back half (anterior/posterior)

– Transverse – divides the body into top and bottom half (superior/inferior)

• Limbs– Proximal: close to torso (body)

– Distal/lateral: further from torso


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Body Measurements

• Static Dimensions:

Ø Taken when the body is fixed (static) position,

Ø Skeletal dimensions (between the center of joints, such asbetween elbow and the wrist)

• Dynamic Dimensions:

Ø Taken under conditions in which the body is engaged somephysical activity,

Ø In most physical activities (where one is operating steeringwheel, assembling a mousetrap)


Body Mass Index (BMI)

• It is a statistical measurement which compares a person's weight and height,

• It does not actually measure the percentage of body fat, it is a useful tool to estimate a healthy body weight based on how tall a person is,


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Body Mass Index (cont.)

• It is easy in measurement and calculation,

• it is the most widely used diagnostic tool to identify weight problem within a population including:

q Underweight

q Overweight

q Obesity


BMI Formula

• Body mass index is defined as the individual's body weight divided by the square of his or her height


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BMI Interpretation

Category BMI range - kg/m2

Severely underweight less than 16.5

Underweight from 16.5 to 18.5

Normal from 18.5 to 25

Overweight from 25 to 30

Obese Class I from 30 to 35

Obese Class II from 35 to 40

Obese Class III over 40


Body Dimensions

Symbol Expression

A Stature

B Elbow Height

C Hip Height

D Knuckle Height

E Chest/Bust Depth


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Body Dimensions (cont.)

Symbol Expression

F Sitting Height

G Sitting Elbow Height:

H Shoulder-Elbow Length

I Shoulder-Grip Length

J Elbow-Fingertip Length

K Hand Length

L Buttock-Knee Length

M Buttock-Popliteal Length

N Popliteal Height

O Knee Height

P Foot Length


Body Dimensions (cont.)

Symbol Expression

Q Shoulder Breadth

R Hip Breadth


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Body Dimensions

• Sample 95th percentile dimensions (cm) of nude U.S. adult civilians.

Female Male

Stature (height) 173.73 186.65

Eye height 162.13 174.29

Thigh height (sitting) 18.02 18.99

Forward reach 79.67 86.70

Hip breadth (sitting) 43.22 41.16

Weight (kg) 84.8 99.3


Body Dimensions

% of total body weight

% of total body surface area

Head 7.28 8.5

Arm 4.9 9

Leg 16.10 18

Trunk 50.70 38


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Variations in Strength

• Females average 63% isometric strength of males.

• Strength of specific muscle groups varies depending on

– Limb: Leg approx. 3 times strength of arm

– Direction exerted: Strength may decrease by 50%

– Preferred hand/arm/leg: Strength may vary by 40–50%

• Left and right leg strengths do not differ appreciably.


Design for Population or Person?

• If for population, what population?

– Current employees?

– Potential employees?

– Everyone in the world?

• If for person, how?

– Adjustability?

– Discrete sizes?


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How Many Sizes?

• How much does the population vary?

• How well can a specific size fit part of the population?

• How many dimensions are relevant?

• Sizes and adjustability interact.


ANTHROPOMETRY Chap 10

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