ERGO Exam 1

cognitive ergonomics

- concerned with mental processes, such as perception, memory, reasoning, and motor response, as they affect interactions among humans and other elements of a system - process information - how ones perceives risk (stressors)

organizational ergonomics

- concerned with the optimization of sociotechnical systems, including their organization structures, policies, and processes - communication, design of working times, teamwork - extra/repetitive motions -> group of safety and health people with 1 manager (competition, bias)-> boss

Anthropometrics

- concerned with the physical sizes and shapes of humans - man measurements - meaning - differences between and among different populations

management commitment

- demonstrates the employer's belief that ergonomic efforts are essential to a safe and healthy work environment for all employees - key to success of any safety and health effort - assigning staff specifically to the ergonomics program to deal with concerns - establish goals -communicate programs importance - make resources available

Rule of thumb... who do we design for?

- design for smaller folks, or 5th percentile --- taller person will be able to reach as well - design for bigger folks of the 95th percentile --- something too big = smaller person can fit as well

Identifying Problem Areas: information gathering

- determine scope and characteristics of the hazard that is contributing to MSD ---research has highlighted a wide variety of ways employers can identify problem jobs or job tasks ---focus on those jobs where there is evidence that the job is a problem

identifying problem areas: sources of information

- employers could sue the following methods --- following up on employee reports of MSDs, symptoms, discomfort, physical fatigue or stress --- reviewing OSHA logs and other existing records, Work Comp claims --- conducting interviews or symptom surveys or administering periodic medical exams

fit the job to man

- ergonomic approach - fit/redesign to accommodate for majority of a population -suitable set of worker characteristics can be specified, around which the job can be designed- and that this can be done for any job design

Identifying Problem Jobs

- establish a procedure to encourage prompt and accurate reporting of signs and symptoms of MSDs by employees so that these symptoms can be evaluation and treated - RISK based assessment - undertake campaign to solicit employee reports of potential problems and suggestions for improving job operations/conditions

design for the 5th - 95th percentile?

- fits only 90% of people - 9/10, 90/100, 900/1000, etc

scientific management

- hardly a competent workman can be found who does not devote a considerable amount of time to studying just how slowly he can work and still convince his employer that he is going at a good pace - human nature (least amount of work t produce a good product) ---speed up process(short-cuts and skip breaks)

interfaces

- how we interact with a machine - holding back from performing job optimally - every time we use a tool or a machine we interact with it via an interface. we get feedback via an interface - the way the interface is designed determine show safely we use the machine

Hawthorne Experiments (ex. of employee involvement)

- human relations movement - 1924 - 1932 - Elton Mayo - Western Electric - purpose: examine effects of illumination on productivity ---perfect amount of lighting for workers to work the fastest in - concluded: not lights that made the impact but it was the fact that the employees were treated like humans (and not robots)

population differences

- if a piece of equipment was designed to fit 90% of the us male population, it would fit rough 90% of the Germans, 80% of Frenchmen,...... - need to be aware of who we are designing products for

employee involvement

- improve workplace conditions - benefits include: ---enhancing employee motivation and job satisfaction --- improve problem-solving capabilities ---increasing the likelihood that employees will accept changes in the job or work methods - safety committee, safety incentive plans, train employees on ergonomic assessments

Karl Marx

- increase specialization may also lead to workers with poorer overall skills and a lack of enthusiasm for their work - workers became more and more specialized and work becomes repetitive which lead to complete alienation from the process of production - worker is "depressed spiritually and physically to the condition of a machine

4 pronged approach

- industry specific guidelines - enforcement strategy - outreach and assistance - research

ergonomic program elements

- management commitment - employee involvement - identification of problem jobs - development of controls for problem jobs - training and education for employees - appropriate medical management

dynamic (functional anthropometry)

- measures distance when the body is in motion or engaged in a physical activity - reach - clearance - volumetric data

bell shaped curve

- more females of left because they are shorter - more males on right (taller)

using scissors

- neck pain looking down - hands doing repetitive cutting motion

Do we design for the average?

- no because there are no people whose body dimensions are all at the 50th percentile - do not use 50th percentile to accommodate for majority of users - no consistent correlation (ex. short arms does not mean someone will have short legs)

reach envelop is influence by

- posture (can't reach as far when seated) - footbase - size of foot (bigger feet = reach farther) - weight in hands (as arms stretch out = less weight can hold) - type of grip (more control with pinch grip vs. power grip) - proximity to obstacles (if against the wall = can't reach as far) - highly specific to situations

reach considerations

- reach envelope (kinetosphere)

ergonomics

- relationship between the human and the product - man/woman to machine interface can be optimized for comfort and output

Anthropometrics

- science of using body measurements to make a product more comfortable or optimal for the user

importance of anthropometrics

- stadium seats - small to fit more people - cost benefit analysis - mazzerati - made in italy - harley davidson side cart - was big in japan - space between urinals - if too close, makes one uncomfortable to urinate

static (structural anthropometry)

- static (measures distance of bones between joint centers) - refers to naked person

Fitting the man to the job

- taylorism - philosophy for ergonomics - post WWII attempts to FMJ based on the idea that productivity or efficiency could be improved by selecting workers with the right aptitude for a particular job (pilots must have certain leg lengths)

physical stressors

- vibration, repetitive motions, excessive force

man working in snow

- weather (snow) causing footing to off making man working harder - wearing layers - restrict movement) - awkward posture - gloves - harder to grip axe - excessive force to have to hit tree - repetitive motion - swinging axe - sharpness of the blade - if dull one has to apply more force

zone of convenient reach

- workers can reach sitting or standing without having to lean forward - square root of (a^2 - d^2) = r - a = shoulder to grip length - d = vertical distance from shoulder to surface - r = radius of ZCR

cons of taylorism

- workers didn't like the control and change -peace work - repetitive motion - removed from entire process

development of control for problem jobs

-- design of piece-part in relation to larger system (sharp parts, slotted holes, wright of subsystems, packing design) -- design of workstation (layout, lighting, reaching, carrying) -- design of tools (weight correct type of power tools, end factors, vibration)

mouse and elbow location

-- elbow at 90 degree angle -- controlled mouse movements using elbow as pivot point

ways to carry out medical management

-- encourage early reporting of symptoms, ensure employees do not fear reprisal or discrimination -- prompt evaluation of MSD reports by health care providers -- making health care providers familiar with jobs (facility walk-throughs, JHAs, job descriptions)

visual problems

-- frequent complaints from VDT operators -- eye discomfort, eyestrain, burning, itching, irritation, blurred distance vision and aching

light sources should be oriented so that...

-- operator has no bright light source in field of vision while viewing the screen

Types of training

-- overall ergonomics awareness training- recognize general risk factors and familiar with process the facility uses to identify and control problem jobs -- targeted training for line supervisors and managers to recognize early symptoms of MSDs -- engineers to prevent and correct ergonomic hazards through equipment design, purchase, or maintenance

visual requirements

-- position of head is major determinate of posture of body -- looking downward more then 30 degrees, must tilt head forward ---> places a static load on neck muscles, displaces the COG causes a slumped position which the backrest or lumbar support becomes useless -- optimum position for placing object is 15 degrees on either side of straight ahead sight

When is a job considered repetitive?

-- when the duration of a task or a group of tasks (a cycle) is less than 30 seconds (ex: bundling harnesses) -- when cycles are longer than 30 seconds, and the worker is performing the same motion more than 50% of the cycle

wrist and hand location

-- wrist straight and neutral -- hand relaxed

Clearance Envelope

clear space below the workstation table

mouse placement for shorter people should be placed where?

closer location

picture of wheel

consider: what is the wheel made out of? castor material is best for the job, diameter of the wheel, maintenance, and path of travel - implement better light and handle of cart for easier use

ergonomics

covers all aspects of the job - physical stresses and environmental factors

medical management

emphasizes prevention of impairment and disability through early detection of injuries, prompt treatment, timely recovery for employee

What can be caused if monitor is too close or too far away?

eye strain and awkward position of head

mouse placement for taller people should be placed where?

farther location

static seated work

often people with bad backs gravitate toward sedentary work but it just makes it worse (lack of oxygen exchange with muscles)

temporal

time spent in a particular workstation and the extent to which the employee has the flexibility to adjust

Eyestrain is caused by...

too much light in the visual field of the operator and by reflections on the screen

anthropometer

versatile instrument suitable for measuring nearly any linear dimension of the human body

cone of sight

visual requirement kept within straight ahead line of sight to 30 degrees below and 15 degrees to right and left

Hazards of VDT use

visual, muscles (neck, shoulder, back, legs)

What are the three sets of requirements that influence workspace design?

visual, postural, temporal

other considerations

- anthropometic data is not universal

using a cutting knife

- awkward positions - dullness of the knife can add more force to the user

Data

- better living conditions = larger body size - many industrialized countries have witnessed an increase in population size over the last 150 years = better diet, sanitation, immunization, etc. ---trend has slowed in the US, Britain, and Northern Europe - mean stature of males/females has increased by 1 inch ( since 1960) - NASA, military, CDC

devision of labor

- break up the task not doing one task by yourself (start - finish) - Adam Smith wanted a qualitative increase in productivity (making of pins) *minute = efficiency SOP is best way - specialization of workers on their single sub-tasks led to greater skill and greater productivity on sub-tasks than would be achieved by the same number of workers each carrying out the original broad tasks - mental mutilation - workers became ignorant and insular as their working lives are confined to a single repetitive task (warned against this)

physical ergonomics

- concerned with human anatomical, anthropometric (measurements), physiological and biomechanic (use the body to reduce strain) characteristics as they relate to physical activity - working postures, materials handling, repetitive movement workplace layout - work with people of all sizes and accommodate with majority of population - find ways to fight human nature

Ergonomic event timeline

- 1986 NIOSH designed lifting practice - 1990 meat packing (heavy saw vibrations), voluntary guidelines - 1991 first loss (general duty clause) - 1995 no ergonomic standard passed (costly and hard to change led to slower production) - 2000 1910.900 (Clinton signs into law final rule) - 2001 bush repealed ergonomic final rule - 2002 Chao 4 pronged approach (failed to distinguish job related and non-job related injuries, pay for injuries that didn't occur/result from work, step to achieve compliance) - 2003 guidelines for nursing homes - 2004 guidelines for grocery stores and poultry processing - 2008 guidelines for shipyards

shovel study

- 21.5 pounds/day - increase 16-59 tons production - increased efficiency - optimal worker

Pig Iron

- 47 tons/day - carry at a certain pace with breaks at certain times - work harder and moved work closer (reduce amount of steps made) - faster and more efficient

history of ergonomics

- Fredrick Taylor - Taylorism - work study (gilbreths - sought to eliminate any wasteful movements and concerned with human comfort)

voluntary pushpack

- NY Times article - compliance is voluntary. the labor department is not ordering packing companies to adopt the new guidelines, which will be sent to them in the next few days

Pepperride Farm

-OSHA cited them for 389 repetitive motion injuries and lifting injuries - penalty was 1.7 million and they contested -> charges were reduced to 309,000 - OSHA could not prove a concrete solution

identifying problem areas: job analysis

Analyzing the job to identify ergonomic hazards present in job can involve a variety of activities, including: -- observing workers performing the task -- interviewing workers -- measuring work surface heights or reach distances -- videotaping the job/ taking pictures -- biomechanical calculations (muscle force required) -- administering special questionnaires

Z score application

Z = X-X(mean)/standard deviation

What is ergonomics?

an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely - aka biotechnology, human engineering, human factors

contact stress

anytime you are compressing a nerve

Monitor should be approximately an _______ length away

arm's

the wrist is naturally curved _______ from any contact surface

away

Recommendations on work/rest schedules (NIOSH)

break should be taken after 2 hours of continuous VDT work and breaks should be given more frequently as visual, mental or muscular burdens increase

The Paradox of medical management is...

good that you keep incident rates low but also good that the worker is healthy and goes to get checked out

where should the mouse be placed?

in line with shoulder

goniometer

instrument used to measure angles

supination

inward rotation

workspace layout- function

item with similar functions should be closest together

nomos

laws

The top of the monitor screen is approximately ______ with the _____.

level, eyes

Ergon

means work

workspace layout- importance

most important items should be central and closest

pronation

outward rotation - awkward

Where should VDT screen be oriented?

perpendicular to windows

Rule of thumb for flexion and extension reductions

pinch grip cannot exceed 8lbs and power grip 25lbs, but then subtract reductions for any deviations

workspace layout- normal posture

position items to be accessible from a normal posture

workspace layout- frequency-of-use

position most frequently use items in sequence-of-use- position items in optimal locations for sequence of use

postural

position of hands, arms, and feet

bright light source is behind operator can...

produce glare or reflections on screen

Taylorism

pros - speed up production and lower cost - broken up by tasks with less thinking - control workers - assembly line followed - organized efficiency for all types of industries - decrease inaccuracy/human error

radial deviation and ulnar deviation

radial- when hand goes toward the thumb ulnar- when hand goes towards the pinky

Training

recognizing and filling different training needs is an important step in building an effective program