Republic of the Philippines
POLYTECHNIC UNIVERSITY OF THE PHILIPPINES COLLEGE OF ENGINEERING
716-62-73
Republic of the Philippines
POLYTECHNIC UNIVERSITY OF THE PHILIPPINES COLLEGE OF ENGINEERING
716-62-73

In partial fulfillment for the requirements in Ergonomics

EXPERIMENT 1: ANTHROPOMETRIC PRINCIPLES IN WORKSPACE AND EQUIPMENT DESIGN

Submitted by:

Galang, Aaron Benedict C.
Gatdula, Geiana Kersha C.
Lavarias, Rochelle Anne C.
Lualhati, Lyndon A.
Manalo, Brenda C.
Mantes, Diovani Jr., J.
Martires, Lezeil B.
Mecate, Mark Paul C.
Mirano, Charmaine M.
Noveda, Engilbert C.
Yumol, Michael John A. B.S. Industrial Engineering 4-3 Submitted to:
Engr. Elaine Rodriguez
Adviser

Date:
July 10, 2014

EXPERIMENT 1: ANTHROPOMETRIC PRINCIPLES IN WORKSPACE AND EQUIPMENT DESIGN

I. THEORETICAL BACKGROUND

Anthropometry, sizes so you need to take these physical characteristics into account whenever you design anything that someone will use, from something. This is the branch of ergonomics that deals with the body shape and size. People come in all shapes and as simple as a pencilte something complex as a car. The word “anthropometry” means measurement of the human body. It is derived from Greek word anthropos (“man”) and metron (“measure”). Anthropometric data are used in ergonomics to specify physical dimension of workplaces, equipment, furniture, and clothing so as to “fit the task to the man” and to ensure that physical mismatches between the dimension of equipment and products and the corresponding user dimensions are avoided.

As a rule of thumb, if we take the smallest female and tallest male in a population, the male will be 30-40 percent taller, 100 percent heavier, and 500 percent stronger. Clearly the natural variation of human populations has implications for the way almost all products and devices are designed. Anthropometric data can be used to optimize dimensions of a diverse range of items – the length of toothbrush handles, and depth and diameter of screwtops on jars and bottles, the size of tools in toolkits supplied with automobiles, and almost all manual controls, such as those found in televisions, radios, etc. body size and proportion vary greatly between different population and racial groups-a fact which designers must never lost sight of when designing for an international market.

Ashby (1979) illustrated the importance of anthropometric considerations in design as follows:
If a piece of equipment was designed to fit 90% of the male U.S. population. It would fit roughly 90% of the Germans, 80% of Frenchmans,65% of Itallians,45% of Japanese, 25% of Thais and 10% of Vietnamese.
It is usually impracticable and expensive to design products individually to suit the requirements of every user (although this is a recent development in the history of design). Most are mass-produced and designed to fit the wide range of users-the custom tailor, dressmaker are perhaps the only remaining examples of truly user oriented designers in western industrial societies.

In the design of mass produced items the task of the ergonomist is to: 1. Characterize the way a product is to be used and then to identify the issues which may affect usability- including the constraints which are imposed on the design by the anthropometry of the user population. From this, anthropometric dimensions appropriate to the design of the product can be specified. 2. The necessary data from the corresponding consumer/user group are obtained for use in dimensioning either the product itself or its range(s) of adjustability.

From 1960 to 1962, the National Center for Health Statistics carried out a survey of 20 anthropometric variables both men and women. A survey of civilians weights and heights was carried out between 1971 and 1974, in Britain, several civilians have been published since 1950, but many of these suffer the same limitations as their U.S. counterparts- the data are often fragmentary, only relevant to the design problems of a particular industry and probably out of date. Marras and Kim (1993) present recent measurements of 12 anthropometric variables from 334 males and 124 females.

Abeysekera and Shahnavaz (1989) present data from industrially developing and developed countries and discuss some of the problems of designing for a global marketplace. Anthropometric surveys are expensive to carry out since large representative of the population under study. Apart from military populations, data are available for U.S., British, and other European Groups as well as Japanese citizens. Pheasant (1986) provides a useful and well-illustrated collection of anthropometric dimensions from data on stature. Problems with much of the anthropometric data from the United States and Europe are the age of data and the lack of standardization across surveys (not all researchers measure the same anthropometric variables). Marras and Kim (1993) note that the first large scale survey of civilian women in the U.S. was carried out in 1941 for garment sizing purposes.

The International Organization for Standardization has done some work on the standardization of anthropometric measurements (ISO DIS 7250, Technical Committee 159). The ISO list of variables will be of use in the planning of anthropometric surveys. A certain amount of data on the anthropometry of children exists but is often of limited value for the designers, having been obtained by clinicians and physical anthropologists to help define normal growth rates for particular populations (i.e. normal ranges of stature and body mass as a function of age). Even for these purposes, the data can be used only to assess individuals from the same population from which they were sampled.

TYPES OF ANTHROPOMETRIC DATA 1. STRUCTURAL NTHROPOMETRIC DATA
These are measurements of the bodily dimensions subject in fixed (static) positions. Measurements are made from one clearly identifiable anatomical landmark to another or to fixed point in space. (e.g., the height of the knuckles above the floor, the back of the knee above the floor, etc,). Some examples of the use of structural anthropometric data are to specify furniture dimensions and ranges of adjustments and to determine ranges of clothing sizes. It is advisable to study the tables, looking, in particular for differences in body proportion between different groups.

2. FUNCTIONAL ANTHROPOMETRIC DATA
These data are collected to describe the movement of a body part with respect to a fixed reference point. For example, data are available concerning the maximum forward reach of standing objects. The area swept out by the movement of the hand can be used to describe “workspace envelopes”- zones of easy or maximum reach around an operator. These zones can be used to optimize the layout of controls in panel design. The size and the shape of the workspace envelope depend on the degree of the bodily constraint imposed on the operator. The size of the workplace envelope increases with the number of unconstrained joints. For example, the area of reach of a seated operator is greater if the spine is unencumbered by a backrest and can flex, extend and rotate. Standing reach is also greater if the spine is unconstrained and greater still if there is adequate foot space to enable one or both feet to be moved. Somewhat counter intuitively, one way to increase a worker’s functional hand reach is to provide more space for the feet. However, existing functional anthropometric data are useful for designing workspaces and positioning objects within them-particularly in the design of crane cabs, vehicle interiors, and complex control panels in the process industries. 3. NEWTONIAN ANTHROPOMETRIC DATA
Such data are used in mechanical analysis of the loads in human body. The body is regarded as an assemblage of linked segments of known length and mass (sometimes expressed as percentage of stature and body weight). Ranges of appropriate angles to subtended by adjacent links are also given to enable suitable ranges of working postures to be defined. This defining enables designers to specify those regions of the workspace in which displays and controls may be most optimally positioned. The Newtonian data may be used to compare the loads on the spine from different lifting techniques.

Principles in the Application of Anthropometric Data

1. Design for extreme individuals – in designing certain features of our built physical world, one should try to accommodate all (or virtually all) the populations in question. In some circumstances a specific design dimensions or feature is a limiting factor that might restrict the use of facility for some people; that limiting factor can dictate either a maximum or minimum value of the population variable or characteristic in question. 2. Designing for Adjustable Range – certain features of equipment or facilities can designed so they can be adjusted to individuals who use them. Generally designing for an adjustable range is preferred method of design, but of course it is not always possible. 3. Designing for the Average – often designers design for the average as a cop-out so that they do not have to deal with the complexity of the anthropometric data. Such situation would probably involve non-critical work where it is not appropriate to design for an extreme and where adjustability is impractical.

Using Anthropometric data in design involves art as well as science.
As a general approach, however, the following suggestions are offered: 1. Determine the body dimensions important in the design. 2. Define the population to use the equipment or facilities. This establishes the dimensional range that needs to be considered (e.g., children, woman, different age groups, races, etc.) 3. Determine what principles should be applied. 4. When relevant, select the percentage of the population to be accommodate, whatever is relevant to the problem. 5. Locate anthropometric tables appropriate for the population and extract relevant values. 6. If special clothing is to be worn, add appropriate allowances. 7. Build a full-scale mock-up of the equipment or facility being designed and using the mock-up have people representative of large and small users walk through representative tasks. All the anthropometric data in the world cannot substitute for a full scale mock-up.

Basically there are three types of measurements: 1. Those that are useful in making decisions concerning REACH. It focuses on the smaller users of the system. To ensure that at least 95% of all users can reach a certain height, easily reach a set of controls, or are tall enough to reach or see over a cubicle wall, the 5th percentile measurements are typically used. 2. Those that are useful in making decisions concerning CLEARANCE. It helps to ensure that workplaces are large enough to easily accommodate the 95% of their users. In this case the focus is on the larger measurements, those that are in the 95th percentile. 3. Those form making decisions where RANGES of dimensions are important. Several measurements are most useful only when considering a full range of values. One of the most common example here is the adjustable chair.

Percentile Ranks * Percentile values are needed for each critical dimension. In any distribution, the percentile rank of any specific value is the percent of cases out of the total that falls at or below the specific value. * Example: out of a group of 345 people, we wish to find the percentile rank that 115 fall at or below ----
(100) (115/345) = 0.33 (100) = 33. Thus the percentile rank is 33, or the 115th score is at the 33rd percentile.
The maximum score must have a percentile rank of 100, and the minimum score must have a percentile rank of 100(1/N), where N equals the total number of people in the group under study. The percentile rank of the median must be 50, since 50 percent of all observed values in a frequency distribution must lie at or below the median.

The Normal Distribution
For design purposes, two key parameters of the normal distribution are the mean and the standard deviation. Mean is the sum of all the individual measurements divided by the number of measurements. It is a measure of central tendency. The value of the mean determines the position of the normal distribution along the x-axis. The standard deviation is calculated using the differences between each individual measurement and the mean. It is measure of the degree of dispersion in the normal distribution. The value of the standard deviation determines the shape of the normal distribution.
In order to estimate the parameters of stature population (the mean and SD), one must measure a large sample of people who are representative of the population (e.g., African females, male Amazonian Indians, U.S. female bus drivers). x=i=1nxin s= i=1n(xi-x)2n-1
Estimating the Range * SD contains information about the spread of scores in a sample. It is known, for a normal distribution, that approximately two-thirds of the observations in the population fall within 1 SD above and below the mean. Thus, for a population with a mean stature of 1.75m and SD of 0.10m, approximately two-thirds of the population would be between 1.65 and 1.85m tall. The remaining third would lie beyond these two extremes. Using the SD and the mean, one can calculate estimates of stature below which a specified percentage of the population will fall. The area under the normal curve at any point in the along the x-axis can be expressed in terms of the number of standard deviations from the mean. For example if the standard deviation is multiplied by the constant 1.64 and subtracted from the mean, the height below which 5% of the population falls is obtained. If 1.64 is added from the mea, the height below which 95% of the population falls is obtained. These are known as the 5th and 95th percentile heights.
Minimum Dimensions – a high percentile value of an appropriate anthropometric dimension is chose. Examples are design of a doorway, sufficient headroom for very tall people has to be provided, and the 95th or 99th percentile stature could be used to specify the minimum height like the seat breadth and width of a chair. Maximum Dimensions – a low percentile value of an appropriate anthropometric dimension is chosen. Examples are the height of a door lock. Seats height and depths must not exceed the popliteal height and buttocks-knee lengths of small users. (Screw top lids)
Issues of Diversity 1. Ethnic differences. 2. Body shape – a soft tissue varies in shape and these variances may create differences in clearance and mobility requirements. * Mesomorph – body shape larger in the middle. * Ectomorph – very slender. * Endomorph – overweight or pregnant with a wider body overall. 3. Sex differences * Dimensions – Men exceed women in all linear body dimensions except hip breadth. The lengths of upper and lower limbs are absolutely and proportionally greater in men than women except for buttock-knee length.
Women exceed men for skin fold thickness. * Soft tissue distribution – generally, fat is a greater proportion of body weight, hips, thighs, and upper arms. Abdominal fat tends to accumulate below the navel in women and above the navel in men. 4. Growth and development – rates are very fast for children but decline with age.
Children – At birth, average weight is 7.26lb ‘ .88lb and average height is 19.7in ‘ .8in. trunk is 70% of body length at birth but only 52% of adult stature. Girls reach 50% of adult height before 2 years of age. Boys do the same at around 2 years of age. From birth to 20 years of age the body length increases 3-4 times and weight increases 20 times. Adolescents – Associated with puberty, boys begin a growth spurt from around 11.5 years of age which lasts until around 14 years of age. Girls spurt start earlier, at around 9 years of age. It reaches its maximum rate around 12 years old and is completed by around 16 years of age. At the same time height is changing, relative body proportions are as well. 5. Age group * Height – Average heights of adults in the UK and US steadily decline with age after 20 years of age. Around 40 years of age most people begin to shrink in stature. Women shrink more than men and shrinkage accelerates with age. This shrinkage occurs in the intervertebral discs of the spine, possibly causing rounding of the back. Some reduction in height may result from shrinkage of lower limbs around the joints. * Weight – The average weight of adults increases from ages 20-45. From age 50 onward men’s weight declines. From age 60 onwards women’s weight declines. Until 55 years of age weight increases for heights and there is an increase 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. There is a decrease in muscular strength but the mechanical tensile breaking strength of bone, muscle, and connective tissue decreases with age. 6. Pregnancy
Later stages of pregnancy decreases in the ability to lift, bend, reach, stand or walk for a long periods, turn head, etc. so 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).

7. 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. Additionally, extremities (like feet) swell throughout the day, making them puffier in the evening.

III. OBJECTIVES
After the experiment, the students are expected to: 1. Understand Anthropometry and Its Uses. 2. Be able to use and interpret different charts / tables used in Anthropometric designs. 3. Appreciate the application of Anthropometry

IV. DESCRIPTION OF SET-UP
Get the anthropometric measures of the 40 PUP students using ruler and meter stick.

ANTHROPOMETRIC MEASURES
11. Thigh Clearance Height (Sitting): The subject sits erect on the flat surface, feet on an adjustable flat forms, knees flexed 90° and thighs parallel. With a tape, the vertical distance from the floor to the highest point on the right thigh is measured. The measure is useful on the design of seated work surfaces or in the selection of the adjustability levels of the chair.
12. Elbow Rest Height (Sitting): The subject sits erect with the feet resting on a surface so that the knees are bent at about right angle, the upper arm hanging at the side, and the forearm extended horizontally. With the anthropometer, the vertical distance from the sitting surface of the bottom of the elbow is measured. This measure defines the height at which there is little load on shoulder muscles and it is useful for the design of the seated workplace height.
13. Mid-shoulder Height (Sitting): The subject sits erect, upper arms hanging relaxed and forearms and hands extended horizontally. With the anthropometer the vertical distance from the sitting surface to the mid-shoulder landmark is measured. This measure defines the height at which the forward arm reach is as its maximum value. It is also defines the top of the torso for chair design.
14. Eye Height (Sitting): The subjects sits erect with the head level and with the feet resting on a surface adjusted so that the knees are bent at right angles. Eye height measured as the vertical distance from the vertical distance from the sitting surface to the inner corner of the eye (internal cantus). This measure is measured to define locations for visual displays in seated workplaces.
15. Sitting Height, Normal: The subject seats normally relaxed, hands in lap, looking straight ahead. The anthropometer is held vertically along the middle of the back, and the measuring bar is brought down into firm contact with the top of the head, in the midline. Height is measure from the sitting surface. These measure defines the vertical clearance needed for seated work.
16. Functional Overhead Reach (Sitting): This reach is measured with an anthropometer as the vertical distance from the seating surface to a pointer held horizontally in a cylindrical grasp when the arm is extended directly upward. The subject sits erect, looking straight ahead, with the knees bent at right angles. This measure defines the maximum height at which controls should be located in overhead panels.
17. Knee Height (Sitting): The subject sits erect, with the legs bent to form right angles at the knees. The vertical distance from the surface of the footrest or floor to the top of the knee at the kneecap is measured with an anthropometer. This measure is useful in the design of seated workplace heights.
18. Popliteal Height (Sitting): The subject sits on a table or bench, with the legs bent to form right angles at the knees. The vertical distance from the surface of the footrest to the underside of the right knee, the tendon of biceps femoris is measured with an anthropometer. The value is used to define seat height and adjustability and footrest needs for seated workplaces.
19. Leg Length (Sitting): The horizontal distance from the wall to the bottom of the foot measured, with the subject sitting against the wall, leg extended. This value is useful in defining maximum leg clearances for seated workplaces or for tasks where the person has to sit on the floor to do the task.
20. Upper-Leg Length (Sitting): The subject sits erect, with the feet on the adjustable flatform, knees flexed 90°, and thighs parallel to the floor. With a beam caliper held parallel to the long axis of the thigh, the horizontal distance from the most posterior aspect of the right buttocks to the most anterior aspect of the right knee is measured. This measure is useful in defining seat depth for chairs, for example, and minimum forward clearance for seated workplaces.
21. Buttocks to Popliteal Length: The subject sits erect, with the feet resting on a surface adjusted so that the knees are bent at right angles. Buttock to popliteal length is measured as the horizontal distance from the back of the buttock to the back of the knee. This value defines the minimum seat depth for a chair to ensure that pressure on the underside of the thigh is not excessive.
22. Elbow-to-Fist Length (Forearm Length): The subject holds a pointer vertically in a cylindrical grasp with the upper arm at the side and the lower arm parallel to the floor, forming a right angle at the elbow. The horizontal distance from the back of the elbow, or epicondyle to the pointer is measured with an anthropometer. This distance can be measured with the subject in either standing or sitting posture. This measure is useful in defining maximum forward reach in situations where elbow flexion is limited, as in glove box manipulations.
23. Upper-arm Length: The subject stands with trunk erect, humerus, or upper arm, vertical, forearm horizontal. Upper-arm length is measured from the top of the acromial process to the bottom of the elbow. This measure is used to help define the level at which shoulder abduction or raising the elbows, may become necessary to do a task. For maintenance tasks through access ports, this measure becomes an important clearance requirement as well.
24. Shoulder Breadth: This value is measured across from the large muscles on the outer side of each upper arm in the shoulder region. It is used in determining whole body requirements for access ports, for instance.
25. Hip Breadth (Sitting): This distance is measured across the widest portion of the hips. It is used in determining seat widths and whole body access port clearances.

IV. MATERIAL USED: * Meter stick * Ruler * Protractor * Survey sheets * Data sheet * Ballpen * Wooden Chair
Height- 85 cm
Width- 50 cm
Sit pan- 37 cm
Sit pan to Arm rest- 23 cm
Arm rest length- 62 cm
Arm rest width- 26 cm

V. ANALYSIS OF DATA
The data shown in Table 3 which represents Male respondents refers to the average length of the live subject while sitting from Thigh Clearance Height which is 57.18cm; Elbow rest Height is 20.08 cm ;Mid shoulder Height is 58.18 cm ;Eye Height is 74.75 cm ;Sitting Height-Normal is 86.03 cm ;Functional Overhead Reach is 121.38 cm ;Knee Height is 56.6 cm ;Popliteal Height is 43.45cm;Leg length is 100.6cm ;upper leg length is 56.2cm; buttocks-to-Popliteal Length is 44.53cm ;Elbow-to-Fist length is 38.65cm; Upper arm length is 35.73cm ;Shoulder Breadth length is 42.1cm; Hip Breadth length is 33.43cm.

The data shown in Table 4 which represents Female respondents refers to the average length of the live subject while sitting ;Thigh Clearance Height is 57.18cm; Elbow rest Height is 20.08cm;Mid shoulder Height is 58.18cm ;eye height is 74.75cm;Sitting Height-Normal is 86.03cm ;Functional Overhead Reach is 121.38cm;Knee Height is 56.6cm;Popliteal Height is 43.45cm;Leg length is 100.6cm;Upper Leg Length is 54.63cm; buttocks-to-Popliteal Length is 42.69cm;Elbow-to-Fist length is 36.46cm; Upper arm length is 33.78cm;Shoulder Breadth length is 39.55cm; Hip Breadth length is 34.88cm;

The two set of data shows that the average length of each different anthropometric body parts from male to female are closely similar to each other as stated above.

VI. CONCLUSION AND RECOMMENDATION

According to table 5.1 and 5.2, most of our respondents, preferred to use plastic chairs rather than wooden chairs and metal chairs because when it comes to female, an above average of respondents says that they are not comfortable sitting in a wooden chair. When it comes to male, average respondents says that they are somehow comfortable and some are not. The researchers used wooden chairs as their sample chair in the experiment of measuring anthropometric body parts.

According to table 5.3 and 5.4, the data shows that the average length of the measured anthropometric body parts from male to female is closely similar to each other.

If possible, researchers would like to recommend replacing wooden chairs to plastic chairs which respondents says that they are more comfortable sitting there. The researchers also recommend to do waste segregation of plastic bottles for recycling and reuse to make ergonomically designed plastic chairs.