5_6206315222613890679 industrial eng.pptx

Industrial engineering

1. UNIT -2 Anthropometry By V.Kamala Assistant Professor Department of Industrial Engineering Anna University, Chennai

2. Anthropometry Measurement of human dimensions Description of the physical variation in humans by measurement; The measurement of the physical characteristics of the body. The design of all equipment must be considered in relation to both the size of the individuals who are going to use it and the movements with they can make without difficulty or strain

3. Used to study differences between groups Race Age Sex Body Type

4. People Are Different Age Differences Height Differences

5. Purpose First, to determine the size and shape of the equipment which a man is to use. To determine the space in which a man is to work. The dimensions which are required for these two purposes will not always be the same.

6. Types of anthropometry Structural (static) and Functional (dynamic) measurement

7. Structural Static dimensions are measurements taken when the body is in a fixed (static) position. They consist of skeletal dimensions (between the centers of joints, such as between the elbow and the wrist) or of contour dimensions (skin-surface dimensions such as height or seat breadth).

8. Functional Dynamic dimensions are taken under conditions in which the body is engaged in some physical activity. In most physical activities (whether one is operating a steering wheel, assembling a mousetrap, or reaching across the table for the salt) the individual body members function in concert.

9. Principles in the Application of Anthropometric Data The data should be reasonably representative at the population that would use the item. In many instances the population of Interest consists of "people at large’ implying that the design features must accommodate a broad spectrum of people.

10. Principles in the Application of Anthropometric Data Design for Extreme Individuals Designing for Adjustable Range Designing for—the Average

11. Design for Extreme Individuals Designing for the maximum population Value is the appropriate strategy when high value of some design feature should accommodate all (or virtually all) people. Sometimes there may be reasons for accommodating most, but not 100 percent of the population (e.g. it is not reasonable to have all doorways 9 ft (2.7 m) high to accommodate circus giants). Thus, it frequently is the practice to use the 95th and 5th percentiles of the distributions of relevant population characteristics as the maximum and minimum design parameters

12. Designing for Adjustable Range: Certain features of 'equipment or facilities can be designed so they can be adjusted to the individuals who use them. Examples are automobile seats, office chairs, In The design of such equipment, it frequently is the practice to provide for adjustments to cover the range from the 5th to the 95th percentile of the relevant population characteristic

13. Designing for—the Average: The use of average values in the design of certain types of equipment or facilities, is appropriate specifically when, for legitimate reasons, it is not appropriate to pitch the design at an extreme value (minimum or maximum) or feasible to provide for an adjustable range.

14. Design Principles Determine the body dimensions important in the design (e.g., sitting height as a basic factor in seat-to-roof dimensions in automobiles. Define the population to use the equipment or facilities. This establishes the dimensional range that needs to be considered (e.g., children, women, different age groups, etc.)

15. Design Principles Determine what principle should be applied (e.g., design for extreme Individuals, for an adjustable range, or for the average) When relevant, select the percentage of the population to be accommodated (for example, 90 percent, 95 percent) or whatever is relevant to the problem

16. Design Principles Locate anthropometric tables appropriate for the population, and extract relevant values. If special clothing is to be worn, add appropriate allowances (some of which are available in the anthropometric literature).

17. Design Principles Ergonomic designs must accommodate a range of user dimensions, typically from a 5th percentile woman to a 95th percentile man. This range will accommodate 9.5 out of 10 users

18. Basic Statistics If the measures are computed for data from a sample, they are called sample statistics I f the measures are computed for data from a population, they are called population parameters .

19. Percentile 50th percentile: the point in the data where 50% of the data fall below that point, and 50% fall above it.

20. 25th percentile scores for incoming freshmen:  1400 75th percentile scores for incoming freshmen:  1570 So, what does that mean? 25th percentile means that 25% of the accepted students made a 1400 or  below on the test. It also means that 75% of the accepted students scored  above  a 1400  75th percentile means that 75% of the accepted students made a 1570 or  below on the test and that 25% of the accepted students scored  above  a 1570

21. Work Place design - Standing Tibial height: This measure is important for manual materials handling. Items located between the tibial height and the knuckle height must usually be picked up from a stooped position. Knuckle height: This height represents the lowest level at which an operator can handle an object without having to bend the knees or the back. The range between the knuckle height and the shoulder height is ideal for manual materials handling and should be used.

22. Work Place design - Standing 3. Elbow height: This is an important marker for determining work height and table height. 4. Shoulder ( acromion ) height: Objects located above shoulder height are difficult to lift, since relatively weaker muscles are employed. There is also an increased risk of dropping items. 5. Stature: This is used to determine the minimum overhead clearance required to avoid head collision.

23. Work Place design - Standing 6. Functional overhead reach : This is used to determine the maximum height of overhead controls. 7. Functional forward reach : Items that are often used within the workstation should be located within the functional reach.

24. Work Place design - Sitting 8.Buttock-knee depth. This defines the seat depth for chairs and clearance under the work table. 9. Buttock- popliteal depth. This is used to determine the length of the seat pad. 10. Popliteal height . This is used to determine the range of adjustability for adjustable chairs. .

25. Work Place design - Sitting 11. Thigh clearance: Sitting elbow height and thigh clearance help to define how thick the table top and the top drawer can be. 12. Sitting elbow height : Sitting elbow height and popliteal height help to define table height 13 . Sitting eye height. Visual displays should be located below the horizontal plane defined by the eye height. 14. Sitting height. This is used to determine the vertical clearance required for a seated work posture. 15. Hip breadth. This is used to determine the breadth of chairs and whole body access for clearance.

26. Work Place design - Sitting 16. Elbow-to-elbow breadth. This is used to determine the width of seat backs and the distance between arm rests. 17. Grip breadth, inside diameter. This is used to determine the circumference of hand tools and the separation of handles. 18. Interpupillary distance. This is an important measure in determining the adjustability of eyepieces on microscopes.

27. Illustration of the anthropometric measures

28. Statistics Find Mean Find Std deviation? 5 th percentile = mean – 1.645 s.d 95 th Percentile = Mean + 1.645 s.d

29. 5 th and 95 th percentile Find 5 th and 95 th percentile for the following data? 23 29 28 18 27 25 29 22 30 32 33

30. WHY ANTHROPOMETRY? Anthropometry data are used to develop design guidelines for heights, clearance, grips, reaches of workplaces and equipment's for the purpose of accommodating the body dimension of the potential work force

31. In this manufacturing task, the operator is sitting on a chair with his or her hands at elbow level and manipulating objects 6 cm above the table height.

32. Anthropometry dimension Find the following dimension for 5 th percentile female and 95 th percentile male. the popliteal height buttock-popliteal depth Sitting elbow height Thigh clearance Table height adjustability seat height adjustability

33. Anthropometry dimension Seat height adjustability : 39.5 – 52.5 cm Table height adjustability: 51.6 -75.9 cm

34. Problem 2: Using the setup of the microscope workstation as shown in fig, calculate adjustability ranges for seat height, table-top height, and microscope eyepiece eye height (measures A, B, and C in Figure 8). Design for a 5th to 95th percentile female population. There are several assumptions: 1. There is no footrest. 2. The shoes are 4 cm high. 3. In the upper part of the body from the elbow height to the shoulder height there is a postural slump of 2 cm.

35. Problem 2 4. When looking into the microscope the operators bend the head forward about 30°,which moves the position of the eye downwards by 1.5 cm. 5. The hands are manipulating the focusing controls at elbow height. 6. The arms are horizontal and resting on the granite slab. 7. The table top is 3 cm high. There is also a 4 cm thick granite slab on top of the table to reduce vibration.

36. 5 th Percentile female A = Sitting Eye Height -2- 1.5 =67.5-2-1.5= 64 cm B= Popliteal height+ shoes +sitting elbow height- granite slab =35.5+4+18.1-4 =53.6 C= Popliteal height+ shoes =35.5+4 =39.5

37. Reference “Human factors in Engineering and Design” by Mark S.Sanders and Ernest J McCormick “A Guide to Human Factors and Ergonomics”- Martin Helander