Engineering Anthropometry the study of human body dimensions

Engineering Anthropometry – the study of human body dimensions Imagine you are positioning an emergency "rip cord" on a train. How high up should you put it? So people can reach it! is the obvious (and correct) response. One way to arrive at an answer is to ask your friends to give it a try. But to get values that are in any way robust (especially if the product is to be used by different nationalities), it is necessary to turn to the science of anthropometrics. Example: I’m 68 inches tall In USA/UK, I’d be in the 35 -40 th percentile In Japan, I’d be in the 75 -80 th percentile Links to look at: Anthropometry Resource Center People with Disabilities Dates back to ancient Egypt Cubit (~52 cm) – based on human dimensions (distance from elbow to tip of longest finger) Large scale anthropometrical surveys are expensive and time consuming Typically do specialized surveys on key dimensions Dept. of Biomedical, Industrial, & Human Factors Engineering 1

CAESAR Research Project CAESAR: A 3 -D anthropometric research project that will generate technologically advanced data on the size and shape of the modern human body. The companies supporting this $6 million project include: Boeing, Caterpillar, GM, John Deere, Levi Strauss, Magna Interior Systems Engineering, Navistar, Sears, Transport Canada, Visteon, Case Corp. Ford, Jantzen, Johnson Controls, Lee Company, Lockheed Martin Aeronautical, Mitsubishi Motors, Nissan Motors, Sara Lee Knit Products, and Vanity Fair, Inc. Collecting the measurements of 10, 000 people, ages 18 to 65, at eight sites in the U. S. and in Europe. Expected to be completed Fall 2000. Dept. of Biomedical, Industrial, & Human Factors Engineering 2

Wright-Patterson (USAF) Involvement The tests will use equipment from Cyberware, (Monterey, Calif. ) that was originally developed for a Wright-Patterson Air Force Base program called Computerized Anthropometric Research and Design (CARD). The Air Force used it to develop a means of determining if its clothing and tools were the most effective size and shape, and that pilot stations within aircraft were the most efficient possible. Dept. of Biomedical, Industrial, & Human Factors Engineering 3

Whole Body Scanner Other sites: http: //www. industry. net/discussions/Features/caesar_measure. htm http: //www. af. mil/news/May 1998/n 19980520_980697. html Whole Body Scanner Dept. of Biomedical, Industrial, & Human Factors Engineering 4

Engineering Anthropometry for Design Clothing Workspace Environment Equipment, tools, & machinery Consumer product design Design Idea Accommodate the body characteristics of the population Universal operability is 90 -95% of the population Build in adjustment to meet objectives Some dimensions only require one set of dimensions Example: 95% reach Dept. of Biomedical, Industrial, & Human Factors Engineering 5

Measurement Devices Calipers – spreading and sliding Anthropometer – rods with one fixed Tapes – measure circumferences and contours Simple scales – weight Cones and boards with holes – grip circumference and finger size Photographic Electronic scanners Dept. of Biomedical, Industrial, & Human Factors Engineering 6

Human Variability Is there a Average Human? Humans vary in dimensions based on Gender Ethnic groups Nationalities Etc. Over 300 anthropometric measurements on the body It is hard to say that any one person is 50%-tile on all measurements Factors affecting Anthropometric data Age – body dimensions begin to increase with age and then decrease around 40 Gender – men are generally larger than women at any given percentile and body dimensions except hips and thighs Ethnic differences cause further differences Body Position Posture affect size Clothing – clothing adds to body size plus restricts movement Dept. of Biomedical, Industrial, & Human Factors Engineering 7

Design and Use of Anthropometric Data Design for the Extreme -- An attempt to accommodate all (or nearly all) of the population Design for the maximum – if maximum value accommodates all (e. g. , height of door, escape hatch in airplane) Design for the minimum – if minimum value determines if all are accomodated (e. g. , distance to control button from the operator (reach); amount of force to press a button) Design for Adjustable Range – design to accommodate all (e. g. , office chairs, desk height, key board height) Range typically is 5 th percentile of females to the 95 th percentile of males in relevant characteristics Design for the Average – there is no average human There are times when the average may be acceptable (e. g. , counter height at grocery store) Dept. of Biomedical, Industrial, & Human Factors Engineering 8

Design and Use of Anthropometric Data Design Principles Discussion Setting limits to 5 th and 95 th percentiles can eliminate a fairly high percentage of population Bittner (1974) – looked at 5 th and 95 th percentiles on 13 dimensions Would have excluded 52% of population instead of 10% implied by percentiles Why? – body measurements are not perfectly correlated Short arms short legs To derive composite measures taking into account imperfect correlations requires regression analysis Dept. of Biomedical, Industrial, & Human Factors Engineering 9

Design and Use of Anthropometric Data General approach 1. Determine body dimensions important in the design Example: chair popliteal height (lower leg length), seat depth (buttock to popliteal length) hip breadth, midshoulder sitting height (back height), elbow height, lumbar height lumbar depth 2. 3. 4. 5. 6. 7. Define population (e. g. , adult - male, adult - female, children) Determine what principle should be applied Select % of population to be accommodated Locate anthropometric tables appropriate for the population If special clothing worn – add allowances Build prototype and test using representative tasks Anthropometric data Structural dimensions – taken in standard & still positions Functional dimensions – obtained in various work postures Dept. of Biomedical, Industrial, & Human Factors Engineering 10

Percentile Covered Herman Miller found that chairs theoretically designed to fit the 5 th-percentile female to the 95 th-percentile male actually fit far fewer people (Dowell, 1995 a). Return: Source: Herman Miller Workplace Research http: //www. hermanmiller. com/research/essays/aeronessay 2/essay 2. html Dept. of Biomedical, Industrial, & Human Factors Engineering 11

Anthropometric Data - structural Source: OSHA Draft Ergonomics Standard (Appendix D) Dept. of Biomedical, Industrial, & Human Factors Engineering 12

Anthropometric Data - structural Source: OSHA Draft Ergonomics Standard (Appendix D) Dept. of Biomedical, Industrial, & Human Factors Engineering 13

Anthropometric Data - dynamic Modeling Reach Distance Source: NASA Dept. of Biomedical, Industrial, & Human Factors Engineering 14

Anthropometric Data - dynamic Source: NASA Dept. of Biomedical, Industrial, & Human Factors Engineering 15

Software Mannequin (Humancad, Melville, NY) and Jack (Center for Human Modeling and Simulation, University of Pennsylvania, Philadelphia, PA) enable designers to determine the best digital Example from JACK reach zone Source: http: //www. cis. upenn. edu/~hms/jack. html Dept. of Biomedical, Industrial, & Human Factors Engineering 16