Your Economics of Ergonomics Playbook Jerome J. Congleton, PhD, CPE, PE 2016 Jerome J. Congleton Definition of Ergonomics Ergonomics: The study of the work to prevent and control injury and illness while improving wellness, productivity, quality, marketing, customer service, delivery and reducing turnover and costs. Anthropometric Design Design for the RANGE Adjustable car seat leg and arm length, seated eye height Headset (head diameter) Wristwatch band (wrist circumference) 1
Design for the RANGE Safe Lifting Height Elbow Rest Height (Standing) Anthropometric Design Design for the EXTREME Height - design clearance for tall people Reach -design to be reached by short people Design for the AVERAGE Public seating -designed to accommodate the median of the population in use Anthropometric Demonstration Knuckle Height (Standing) Elbow Rest Height (Standing) Hand Length/Grip Span Functional Reach Strength Hand Dynamometer Demonstration 2
Neutral Body Posture Researched in zerogravity environment of space A natural, open trunkthigh posture the human body assumes in a stressfree environment Periodic changes to and from the neutral posture promotes proper alignment of vertebrae, muscles, tendons and ligaments Benefits of Neutral Body Posture Better breathing, more open chest cavity Easier to rise out of the seat pan because the posture is a compromise between sitting and standing In neutral posture we have the most endurance, most resistance to injury/illness, least fatigue, and most strength Changing postures frequently is healthy and stimulates thinking Promotes blood flow Reduces fatigue and discomfort ASSESSMENT 3
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SOLUTIONS Condition Probable Cause How to Correct 1. Neck tension, tightness, upper back and shoulder discomfort 2. Hand, wrist and lower arm discomfort 1a. Head is too far forward during reading, writing, or viewing the computer/tablet screen. 1a. Elevate work surface, reading materials, and computer/tablet screen so as to keep the head and trunk relationship more vertical. 1b. Hands and arms not 1b. For typing tasks, adjust the armrests to supported while typing, inputting the correct height and angle to support the data, writing or using hands in weight of the arms and use palm rest or wrist manipulating or holding work. rest. 1c. Head is too far back during reading, writing or viewing computer/tablet screen. 1e. Head and neck are tilted in a 1e. Use headset. lateral direction holding the telephone between the shoulder and ear. 2a. The wrist is deviated in an unnatural position. 2b. Excessive application of force to keys. 1c. Tilt the seat and backrest forward so as to keep the head and trunk relationships more vertical. 2a. Set the keyboard and/or calculator to produce a neutral wrist position. 2b. Reduce excessive force through training and practice. Condition Probable Cause How to Correct 3. Lower back pain discomfort 3a. Lumbar curvature is not 3a. Bring backrest in further being maintained and supported. horizontally through in and out adjustment or tilting forward, and/or changing lumbar curvature via inflatable lumbar adjustment (if equipped). The backrest should be placed just slightly above the pelvis to provide support in the lumbar region (lower back). 3b. Major thigh muscle is pulling on the spine because feet are dangling or unsupported. 3b. Lower chair and/or use footrest so that the feet are supporting the weight of the legs only. Backrest should be placed slightly above the pelvis to provide support in the lumbar region. 3c. Increased disc pressure due 3c. Open up trunk/thigh angle to vertebrae not having towards the neutral position. equidistant spacing. This results in stretching the muscle, tendon and ligament systems. 5
4. Buttocks discomfort 4a. Sitting too far forward in the seat pan and not using the backrest. 5. Thigh discomfort Condition Probable Cause How to Correct 5a. Too much pressure on the thigh because chair is too high and legs are dangling. 4a. Open up the trunk/thigh angle towards the neutral position. 5a. Lower chair height so that feet are supporting feet and lower legs only. 5b. Too much pressure on the 5b. Sit forward in seat pan and popliteal area (soft tissue behind adjust backrest forward. the knee) from the seat pan. 6. Lower leg/foot discomfort 6a. Too much pressure in the 6a. Sit forward in seat pan and popliteal area (soft tissue behind adjust backrest forward. the knee). Circulation is restricted to lower leg and feet, putting pressure on the nerves to lower legs and feet. 6b. Infrequent posture changes in the feet and lower legs and feet. 6b. Utilize a well-designed footrest to promote movement and frequent posture changes. Sitting & Standing Stand/Sit Concept By standing for 2 hours throughout an average workday, you can burn 280 extra calories. In one year, that converts to roughly 20 pounds of weight loss. Results vary depending on body shape and metabolism. Raising desk heights from 30 to 40 and raising the chair to stool height allows users to easily and freely stand up to work periodically. A keyboard tray and monitor arm are also essential if an electric height adjustable desk is not available. Additionally, the extra 10 of storage under the 40 desk results in a 33% gain in cubic storage. 6
Sit/Stand Workstations Produc vity up to 17% Figures reflect employees comfort or lack of discomfort Figures reflect employees awareness of their own control over their wellness Positive Employee Feedback Appreciate the ability to adjust workstation to their specific needs Enjoy the opportunity to stand Human Factors & Ergonomics Society Proceedings, 1994 Initial Productivity Data 40% increase in productivity & $72M increased sales Sit/Stand Workstations Workstations are adjusted to a standing position an average of 3.6 times/day 23% standing and 77% sitting Discomfort ra ngs over 26% Work-related injury/illness by 28% Lost- me by 82% Associated costs by 95% Human Factors & Ergonomics Society Proceedings, 1994 7
Sit/Stand Workstations Stand Biased Workstations 8
Facilities Benefits Benefits of the stand biased workstation No power requirements Much simpler construction cost More storage underneath No cord damage or management issues Faster install, simple maintenance No pinch points from moving parts One simple keyboard mechanism can cover the 5 th - 95 th seated and standing heights Worker Benefits Major ergo benefits including : blood flow respira on and alertness risk of injury calorie burn to fight weight gain in adverse postural changes from poor sea ng A workstation and work environment DESIGNED for computer users, not modified for computer users Significant cost over adjustable sit/stand sta ons Design depths for easy viewing of a flat panel monitor Maintenance and Repair Produc vity Collabora on and Interac on Standing Fatigue: Strategies to Eliminate and/or Significantly Reduce Sit more Use anti-fatigue mats Use foot rails Wear good athletic cross training shoes Use gel inserts in good athletic cross training type shoes. Remember you may need to get shoes ½ to 1 size larger 9
Sitting Fatigue: Strategies to Eliminate and/or Significantly Reduce Stand more or even better move/walk Use sit/stand workstations Use good ergonomic chairs Change postures even while sitting from slightly reclined to sit/stand Light Reflective materials such as highly polished metals should be avoided Light sources should not be directly in the line of sight and should be probperly shielded to avoid cuasing discomfort Directional lighting should not be aimed or focused on computer monitors If the office has a window, computer screens should be oriented 90 to the window Diffusers or partitions should be used to break up direct light from overhead sources such as florescent lighting Maintain ambient light levels around 30 foot candles Task lighting for viewing documents should be at approximately 80 foot candles Direct Light 90% of the light is directed to a target, such as source documents. Image: www.adatalighting.com 10
Indirect Light 90% of the light is directed onto walls and ceilings and is reflected back into the room. Only need 40 65 foot-candles. Computer Monitors The monitor should be positioned to avoid glare by using: Tilt or swivel for displays Light diffusing surfaces such as polarized lens filters and glare screens Hoods to reduce direct glare from light reflecting off the screen High Luminance Sources Light in the peripheral field of the computer user should be avoided. Window luminance may be controlled by using: Drapes Shades Louvers Polarized solar film on windows Overhangs Trees, ornamental or shade Image by Blind Technique 11
Noise Study out of University of Sydney shows 50% of employees in openoffice plans and nearly 60% of employees seated at workstations with partitions cited the lack of sound privacy as the most frustrating aspect of their work environment Ambient sound pressure levels should not be greater than 55 DBA including noise generated by the user. Suggest enclosing at least a few offices, provide distraction-free areas to focus, install white noise machine Jerome J. Congleton, PhD, PE, CPE Professor Emeritus E-mail: ergo@tamu.edu Website: http://www.tamhsc.edu/ 12