Engineering Anthropometry

1. Engineering Anthropometry • 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 35-40th percentile • In Japan, I’d be in the 75-80th 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

2. 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.

3. 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.

4. Whole Body Scanner • Other sites: • http://www.industry.net/discussions/Features/caesar_measure.htm • http://www.af.mil/news/May1998/n19980520_980697.html • Whole Body Scanner

5. Engineering Anthropometry for Design • 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

6. 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

7. 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

8. 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 5th percentile of females to the 95th 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)

9. Design and Use of Anthropometric Data • Design Principles Discussion • Setting limits to 5th and 95th percentiles can eliminate a fairly high percentage of population • Bittner (1974) – looked at 5th and 95th 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

10. Design and Use of Anthropometric Data • General approach • 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 • 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

11. Percentile Covered • Herman Miller found that chairs theoretically designed to fit the 5th-percentile female to the 95th-percentile male actually fit far fewer people (Dowell, 1995a). Return: Source: Herman Miller Workplace Researchhttp://www.hermanmiller.com/research/essays/aeronessay2/essay2.html

12. Anthropometric Data - structural Source: OSHA Draft Ergonomics Standard (Appendix D)

13. Anthropometric Data - structural Source: OSHA Draft Ergonomics Standard (Appendix D)

14. Anthropometric Data - dynamic • Modeling Reach Distance Source: NASA

15. Anthropometric Data - dynamic Source: NASA

16. 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 reach zone Example from JACK Source: http://www.cis.upenn.edu/~hms/jack.html