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Ergo nomics

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First description/ writing……….

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• Every 15 seconds, a worker dies from a work-related accident or disease.

• Every 15 seconds, 151 workers have a work-related accident.

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What is Ergonomics

• Ergo – from the Greek word meaning work Nomos – from Greek word meaning natural laws

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Definition: Ergonomics (or human factors) is the

1. scientific discipline

2. understanding interactions -humans and other elements of a system,

3. Professional application of principles ( theories, data and methods) to design to optimize human well being & overall system performance.

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Objective:

• To improve the fit between the physical demands of the workplace and the employees

i.e, To achieve best mutual adjustment of man and his work for improvement of human efficiency and well being

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History of Ergonomics

o World Warso Aircraft, weapon design

o Cold Waro Nuclear power plants

o Todayo Industry, hospitals, offices,

product design

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History of Ergonomicso Industrial Revolution

o Steel industry (shovels)

o Henry Fordo Assembly line design

o Frank and Lillian Gilbreth o Micro-motion studies (i.e.

today’s surgical techniques)

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Ergonomics Today• More than Matching the job, work tools, and workplace to the

worker, but in all activities of day to day life and in recreation

sports and sleep.

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• In 1777 Bernardino Ramazinni wrote

– about work-related complaints in his book "De Morbis Artificum "

• In 1857- ergonomics word coined

– Term ‘Ergonomics’ was first coined by Wojciech Jastrzebowski

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• Early 19th century- ergonomic approach • Frederick W. Taylor was a pioneer

• World war II- Prompted interest in human-machine interaction

• 1970 – first act in the world - The Occupational Safety and Health Act of 1970 (U.S.)

Purpose to "assure so far as possible every working man and woman a safe and healthful working conditions to preserve human resources.“

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• 1857 – corrective ergonomics• 1990s –prospective ergonomics

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Ergonomic pioneers - Alphonse Chapanis • Psychological and Brain Sciences

at Johns Hopkins University in Baltimore.

• He was a founding father of ergonomics, the science of human factors in engineering design.

• Improving the safety of aircraft cockpits, • the design of the standard telephone

touchpad, • teleconferencing, safety labels, • colorblindness, night vision, • digitized speech and • human-computer interaction are just

some of the projects he pioneered in his lifetime.

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Ergonomic pioneers - John Karlin• John Karlin, father of human factors engineering

• John E. Karlin, a researcher at Bell Labs, studied ways to make the telephone easier to use. (Image from the NY Times, courtesy of Alcatel-Lucent USA)

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Ergonomic pioneers - Niels Diffrient (6 -9- 1928 to 8 -6- 2013)

• American industrial designer - focused mainly on ergonomic seating, • well known designs are the Freedom and Liberty chairs, manufactured

by Humanscale

Diffrient World Chair 2009, Liberty Chair 2004,Diffrient Task and Work Light 2002,Freedom Chair 1999,

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Ergonomics- concerns of ergo

Employee Concerns– Comfort

• No Fatigue• No Injuries

– Job satisfaction • Decreased boredom• Decreased stress• Reasonable workloads

Employer Concerns– Worker’s comp costs– Productivity – Errors– Products– Profit

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productivity and quality ∞ design

of working conditions.

One direct economical measure of

productivity—the costs of

absenteeism through illness—is

affected by working

conditions.

Design good = decrease sickness

absence = increased

productivity

Good workplace design

Less absenteeism

Increased productivity

Reverse is reverse

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So, Poor Ergonomics…..o Decreased efficiencyo Decreased productivityo Errors

Results of Poor Ergonomic Design

o Discomfort and fatigueo Injuries and accidents

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Musculoskeletal Disorderso Neckso Backs o Arm and hando Knee and foot

Results of Poor Ergonomic Design

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What Are Ergonomic Improvements?

Definition: Changes made to improve the “fit” between a job and the capabilities of the employees

performing it

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When you think about how to improve a workstation, remember this rule:

• If it feels right, it probably is right. If it feels uncomfortable, there is probably something wrong with the design, not the worker.

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Engineering Improvements

• Engineering improvements include rearranging modifying, redesigning, or replacing: • Workstations, • Equipment, • Tools, • Packaging• Reduce or eliminate existing hazards• Most effective strategy• Best time is when new facilities, processes, or work

procedures are being planned

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Administrative Improvements

• Reduce exposure to the hazard by controlling behaviors through design of safety rules and safe work practices and procedures

• Include changing work practices or the way work is organized

• Require continual management and employee compliance to ensure that the new practices and policies are effective

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Administrative Improvement Options

1. Providing variety in jobs

2. Adjusting work schedules and work pace

3. Providing recovery time (i.e., muscle relaxation time)

4. Ensuring regular housekeeping and maintenance of work spaces, tools, and equipment

5. Increase workforce & Reduce workload

6. Training in recognition of risk factors

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Safety Gear or Personal protective equipment

• Provides a barrier between the worker and the hazard source

• Reduces the duration, frequency, or intensity of exposure

• Includes gloves, knee and elbow pads, respirators, ear plugs, safety goggles, , aprons, safety shoes, and hats

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Examples of ergonomic improvements

1. Use good quality tools

2. Wear anti vibration gloves3. Lubricate tool regularly

1. Put shock absorber in vehicle

2. Use well designed seat in vehicle

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Benefits of ergonomics

• Reduced fatigue and discomfort• Helps to prevent injuries like MSDs• Improved quality of life • Improved comfort, morale and job satisfaction• Improved quality of work• Improved productivity and reduced workers’ compensation costs

and employee turnover• Reduced sickness absenteeism

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Role of the health and safety representative

• Ensure that ergonomics is used in the workplace.

• Your efforts to ensure that equipment and jobs are designed or adapted to fit workers will help to prevent a variety of health problems caused by poor working conditions.

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Six-point strategy for winning ergonomic improvements in the workplace

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Six point strategy1. Reach out to other workers • Distribute copies of information factsheets or leaflets at

work. • Listen to what others have to say about ergonomics-related

issues. • Write down the names and work areas of people who are

experiencing symptoms which you suspect may be caused by the non-application of ergonomic principles.

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Six point strategy2. Collect information to identify problem areas 3. Study the areas you suspect are a problem • Walk through any problem areas and review the work tasks. • Start thinking of solutions, such as raising tables, rotating

work, etc.

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Six point strategy4. Gather recommendations from: • the workers who are affected; • maintenance and repair workers; • the union health and safety department (if one exists); • other health and safety specialists.

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Six point strategy5. Push for necessary changes • Worker support (plus documentation) will give you the

necessary encouragement for winning health and safety contract language, grievances, or other agreements with management.

6. Communicate with workers • Two-way communication is important in building and

maintaining solidarity within the union.

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Occupational health vs ergonomics

Occupational health• Toxic stuff• Etiology & management

ergonomics• Workplace design• Work design• Productivity

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Ergonomics- a multidisciplinary Science

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ergonomics

GoalsPrinciplesMethods

Physical and physiological

aspects

Psychological aspects

Organizational aspects of work

Work system design

Design for everyone

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GOALS, PRINCIPLES, METHODS

GOALS, PRINCIPLES, METHODS

AIMANALYSIS OF ACTIVITIES, TASKS AND

WORK SYSTEMS

STANDARDISATIONS

CHECKLISTS

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Aims of ergonomics

aims

productivity quality

Safety and health

efficiency Reliability Job satisfaction

personal development

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Analysis

• WORKERS - what they bring to the job

• TOOLS - what they bring to the worker

• TASKS - what the worker must do

• ENVIRONMENT- the conditions surrounding the worker and the tool

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How Do I Start?

Identify problems– Complaints of discomfort– Symptom surveys– Near misses– Accidents– Injuries– Errors– High turnover

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Analysis of the task • data-based

analysis of the activity

an accurate determination of prototype

put into operation,

Then analysis of performance of the users

and on dysfunctional situations, such as

accidents or human error.

gathering of information

on

final corrections

increase the reliability

Increase usability of the completed

object.

• Eg. nuclear industry and the aeronautics industry serve as example: operational feedback involves reporting every incident that occurs. In this way, the design loop comes full circle.

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Standardization in ergonomics

• 1970• International organization for standardization• Recent concept

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Standardization in ergonomics- principles

• Tasks within performance range

• to prevent injury

• tasks and working conditions will not lead to impairments

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standardisation….

• Standardisation committee

• iSO-CEN collobaration (to avoid duplication of standards)

• Technical committee – sub committees

• Preparation of ergonomic standards-voting of prepared draft

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• standards on methods of anthropometric measurements,

• body dimensions,

• safety distances and access dimensions,

• the evaluation of working postures and

• the design of workplaces in relation to machinery,

• recommended limits of physical strength and problems of manual handling.

Fields of ergonomic standardization

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Checklist

• assessment • Job Components Inventory• ergonomic workplace analysis

• the checklists adopt one of two approaches, • (1) the job-oriented approach • (2) the worker-oriented approach

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Checklist- to assess ergonomic issues/considerations

• Organization, worker and the task• Mechanistic aspect

– Job Specialization– Skill Requirement

• Biological aspect• General Physical Activity• Manual Materials Handling (MMH)• Workplace/Workspace Design• Work Posture• Work Environment• NOISE• CLIMATE • LIGHTING• DUST, SMOKE, TOXICANTS• RADIATION

• VIBRATION• Work Time Schedule• Perceptual/motor aspect• Displays• Controls• Technical aspect• Machinery• Small Tools/Implements• Work Safety• Psychosocial aspect• Job Autonomy• Job Feedback (Intrinsic and Extrinsic)• Task Variety/Clarity• Task Identity/Significance• Mental Overload/Underload• Training and Promotion• Organizational Commitment

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PHYSICAL AND PHYSIOLOGICAL ASPECTS

• ANTHROPOMETRY• MUSCULAR WORK• POSTURES AT WORK• BIOMECHANICS• GENERAL FATIGUE - FATIGUE AND RECOVERY

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Anthropometry- measurement of people

• Physical characters of the body - defined, standardized and referred to a unit of measurement

• For fitting – equipment and work space to humans – tailoring clothes to the right size.

• Equipment and work space require linear measures of limbs and body,

• tailoring sizes are based mainly on arcs, girths and flexible tape lengths.

• Both systems may be combined according to need.

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Why Does it Matter? o Average size is not good enougho Need to consider reaches and clearances

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Who Should We Match?o Central 90 percento Disregard extreme body sizeso Try to fit males/females from 20-65 yrs

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The Golden Rule?

Design so the small woman can reach, and the large man can fit.

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What Rule to Use Here?Design so the small woman can

reach, and the large man can fit.

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What Rule to Use Here?Design so the small woman can reach, and the large

man can fit.

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Accommodating Reach • How low can we

place materials these workers have to reach?

• How high can a shelf be placed holding work materials?

Golden Rule: Place objects between knee and shoulder height.

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Measuring instruments-anthropometers

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Measurements of interest• 1.1 Forward reach (to hand grip with subject standing upright against a wall)• 1.2 Stature (vertical distance from floor to head vertex)• 1.3 Eye height (from floor to inner eye corner)• 1.4 Shoulder height (from floor to acromion)• 1.5 Elbow height (from floor to radial depression of elbow)• 1.6 Crotch height (from floor to pubic bone)• 1.7 Finger tip height (from floor to grip axis of fist)• 1.8 Shoulder breadth (biacromial diameter)• 1.9 Hip breadth, standing (the maximum distance across hips)• 2.1 Sitting height (from seat to head vertex)• 2.2 Eye height, sitting (from seat to inner corner of the eye)• 2.3 Shoulder height, sitting (from seat to acromion)• 2.4 Elbow height, sitting (from seat to lowest point of bent elbow)• 2.5 Knee height (from foot-rest to the upper surface of thigh)• 2.6 Lower leg length (height of sitting surface)• 2.7 Forearm-hand length (from back of bent elbow to grip axis)• 3/19/2014 Anthropometry

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Measurements of interest• 2.8 Body depth, sitting (seat depth)• 2.9 Buttock-knee length (from knee-cap to rearmost point of buttock)• 2.10 Elbow to elbow breadth (distance between lateral surface of the elbows)• 2.11 Hip breadth, sitting (seat breadth)• 3.1 Index finger breadth, proximal (at the joint between medial and proximal phalanges)• 3.2 Index finger breadth, distal (at the joint between distal and medial phalanges)• 3.3 Index finger length• 3.4 Hand length (from tip of middle finger to styloid)• 3.5 Hand breadth (at metacarpals)• 3.6 Wrist circumference• 4.1 Foot breadth• 4.2 Foot length• 5.1 Heat circumference (at glabella)• 5.2 Sagittal arc (from glabella to inion)• 5.3 Head length (from glabella to opisthocranion)• 5.4 Head breadth (maximum above the ear)• 5.5 Bitragion arc (over the head between the ears)• 6.1 Waist circumference (at the umbilicus)• 6.2 Tibial height (from the floor to the highest point on the antero-medial margin of the glenoid of the tibia)

Muscular work

• All occupational activities involve varying degrees of muscular work.

• Ergonomically acceptable Workload in Static, Dynamic, Manual Materials Handling, Repetitive Work to be determined , standardized and adopted.

• Prevent Muscular Overload

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four groups:

dynamic -forestry, agriculture and the

construction industry

Materials handling -

nursing, transportation and warehousing,

static - office work, the electronics industry and in

repair and maintenance tasks.

Repetitive work - food and wood-processing

industries

• It is important to note that manual materials handling and repetitive work are basically either dynamic or static muscular work, or a combination of these two.

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• Repetition work can be dynamic & can cause repetition injuries

• fatigue will ensue, working capacity is reduced, and recovery slows down.

• Peak loads or prolonged overload may result in organ damage

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Postures at Work

• Posture - the mutual organization of the trunk, head and extremities

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Posture and Movements

Posture and movements are influenced by

• The load- shape, stability, size, slipperiness

• Organization and environment- work force, overtime

• Personal factors- skills, clothing, illnesses

• A posture is

– source of musculoskeletal load

– related to balance and stability

– basis of skilled movements and visual observation

– source of information on the events taking place at work

From a safety and health point

• source of musculoskeletal illnesses

• low back diseases

• Musculoskeletal problems related to repetitive work postures.

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Low back pain• Low back pain (LBP) is a generic term for various low back

diseases– posture – physically heavy work

possible mechanisms

• Forward bending & twisted posture - ↑ load on the spine & ligaments

• Jerks and slipping, increase the loads on the back by a large factor.

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Recording and Measuring Working Postures

• Self-reporting questionnaires and diaries• Observation of postures• Computer-aided postural analyses

• Video is usually an integral part of the recording and analysis process. The US National Institute for Occupational Safety and

• Health (NIOSH) has presented guidelines for using video methods in hazard analysis (NIOSH 1990). 67

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• Postural supports in the workplace and on machinery, such as handles, supporting pads for kneeling, and seating aids,

• useful in alleviating postural loads and pain.

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Safety and Health Regulations concerning Postural Elements• The International Labour Organization published a Recommendation in 1967 on

– maximum loads to be handled. – The Recommendation is now outdated – served an important purpose in focusing attention on problems in manual material

handling.

• The NIOSH lifting guidelines (NIOSH 1981), as such, are not regulations either, but they have attained that status. The guidelines derive – weight limits for loads using the location of the load—a postural element—as a basis.

• International Organization for Standardization

• the European Community, ergonomics standards and directives contain matter relating to postural elements (CEN 1990 and 1991).

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Bio-mechanics

• Biomechanics is a discipline that approaches the study of the body as though it were solely a mechanical system

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equivalents

• bones : levers, structural members• flesh: volumes and masses• joints: bearing surfaces and articulations• joint linings: lubricants• muscles: motors, springs• nerves: feedback control mechanisms• organs: power supplies• tendons: ropes• tissue: springs• body cavities : balloons.

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• The main aim of biomechanics is to study the way the body produces force and generates movement.

• The discipline relies primarily on anatomy, mathematics and physics;

• related disciplines are – anthropometry (the study of human body measurements), – work physiology and – kinesiology (the study of the principles of mechanics and

anatomy in relation to human movement).

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principles

• Muscles come in pairs. • Muscles contract most

efficiently when the muscle pair is in relaxed balance

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• Applications– In designing tools and

equipment for optimum use and recommends healthy and safe posture, movement & force application direction-repetition for optimum results by experiments and research

• The optimum diameter of tool handles- 40mm

• The use of cutting-pliers• Seated posture• Screw-driving• Manual Material Handling

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Manual Material Handling

• manual handling includes lifting, lowering, pushing, pulling, carrying, moving, holding and restraining, and encompasses a large part of the activities of working life.

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• How much can be handled without damage to the body - biomechanical criterion.

• How much can be handled without overexerting the lungs - physiological criterion.

• How much do people feel able to handle comfortably? - psychophysical criterion.

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Recommendations Handling weight

Reduce lifting– Lifting equipment – Job redesign

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Manual Materials Handling o Golden rule

– Eliminate lifts o When you can’t

– Keep it off the floor– Reduce lifts

• Conveyors, dollies• Adjust work flow

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Making a Difference

If they have to lift, teach them how!– High risk groups first– Then campus-wide

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How Should You Lift?

Stoop

Squat Semi-squat

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Stoop

o Can get close to loado Less effort and energy

than squattingo Fast

….but it increases strain on low back

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Squat

Limits strain on low back

….but it is difficult to keep load close

….requires increased effort and energy

….and it is inefficient

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Semi-Squat Lift

o Less work o Preferred for lifting

heavy objects on occasional basis

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Squat and Semi-Squat Lifts

o More protective of backo Preferred by injured workers

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There are no “right” or “correct” ways to sit, stand or lift....

However, there are more and less demanding ways!

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Keep It Simple o Staggered stance o Keep it close

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Keep It Simple o Build a Bridge o Feet first

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Ergonomics principles during heavy physical work

Stand close to objects and feet slightly apartKeep back straight

Use both hands and grip with whole hand

Place feet in walking position Take help of others

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Threblig approach

• Therbligs are 18 kinds of elemental motions • the study of motion economy in the workplace. • analyzed by recording each of the therblig units for a process, • results used for optimization of manual labor by eliminating unneeded

movements.

• The word therblig was the creation of Frank Bunker Gilbreth and Lillian Moller Gilbreth, American industrial psychologists who invented the field of time & motion study. It is a reversal of the name Gilbreth, with 'th' transposed

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Recommendations for heavy work

1. Reduce the weight of the load

2. Make the load easier to handle

3. Use storage techniques to make handling materials easier

4. Minimize the distance a load must be carried

5. Minimize the number of lifts required

6. Minimize twisting of the body

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Recommended Weight Limits

• impossible to state a weight that will be “safe” in all circumstances

• National Institute for Occupational Safety and Health (NIOSH) in the United States has adopted 23 kg as a load limit in 1991

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Lifting

• The maximum weights recommended by the International Labour Organization are:

• Men: occasionally 55 kg., repeatedly 35 kg. • Women: occasionally 30 kg., repeatedly 20 kg.

Under continuous research

• Do not lift anything if you have backache. • Once the pain has gone, start lifting with caution and gradually

practise.

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Lighting

• daylight - provide an outside view.

• Light colours for walls and ceilings when more light is needed.

• Light up corridors, staircases, ramps and other areas

• indirect lighting • Sit at right angles to windows

and at least 3 feet away • Adjust desk lamp or task light

to avoid reflections

• Light up the work area evenly to minimize changes in brightness.

• Provide local lights for precision or inspection work.

• Full-Spectrum fluorescent mimic natural light but cost more.

• Age - 20 vs 65 yrs

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Lighting• Computer screens /other workstations may need to be repositioned to eliminate glare

• Anti-glare screens

• Adjust drapes or blinds to reduce glare.

• limit reflected glare, by painting medium or dark color to wall and not have reflective

finish.

• Monitors in relation to glare

• monitor’s brightness should match the room-

• Adjust the brightness control close to the mid-range

• set a higher contrast, the better.

• Do this more than once a day if the light changes in the room.

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Temperature• Elevated temperatures

and humidity can be harmful.

• Low temperatures can reduce finger flexibility and accuracy

• affected by several factors including type of work, clothing and heat sources, and amount of airflow.

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Premises

• Protect workers from excessive heat.

• Isolate or insulate sources of heat or cold.

• Install effective local exhaust systems that allow efficient and safe work.

• Improve and maintain ventilation systems to ensure good workplace air quality.

• Provide enough fire extinguishers within easy reach and be sure that workers know how to use them.

• Recycle wastes to make better use of resources and protect the environment.

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Noise

• Excessive noise levels above 90 decibels (dBA) and noise peaks above 100 decibels cause – headaches and – increases blood pressure,– muscle tension and – fatigue.

• High exposure over a long period of time causes deafness and other audiological disorders.

• Short term exposure causes irritability and distraction.

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Manage noise & Hazardous substances

• Isolate or cover noisy machines or parts of machines.

• Choose electric hand-held equipment that is well insulated against electric shock and heat.

• Ensure safe wiring connections for equipment and lights.

• Label and store properly containers of hazardous chemicals to communicate warnings and to ensure safe handling.

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watch

fatigue

• Neurophysiological interpretation of fatigue

• Inhibition and activation

• Clinical fatigue• Preventive Measures

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Physical/mental capability, preexisting conditions, etc

Noise, temperature, humidity etc

• Heavy, Frequent, or Awkward Lifting

• Pushing, Pulling or Carrying Loads

• Working in Awkward Postures

• Hand Intensive Work• Repetitive motions• Forceful exertions• Vibration

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Preventive Measures• attention to general working conditions and the

physical environment at the workplace & ergonomic improvements

– correct arrangement of hours of work, – provision of adequate rest periods – suitable canteens , rest rooms; – adequate paid holidays – ensuring that seats, tables and work benches are of suitable

dimensions – correctly organized. Work flow– noise control, – air-conditioning, heating, ventilation and lighting

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Preventive Measures• Monotony and tension may also be alleviated by

– a controlled use of color and decoration in the surroundings,

– intervals of music and – sometimes breaks for physical exercises for sedentary

workers.

• Training of workers and in particular of supervisory and management staff also play an important part.

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PSYCHOLOGICAL ASPECTS

• MENTAL WORKLOAD• VIGILANCE• MENTAL FATIGUE

Mental Workload• Time pressure• Qualification and training• Abstract thinking• Emotion management• Coping with daily stress • Stress management skills-

commmunication skills• Self motivation and motivational skills• Teaching ability-learning ability• Physical health

• Management skills• Appropriate task assignment

Findings in this area led to the technique of health and personality promoting task design (Hacker 1986).

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vigilance

• The concept of vigilance refers to a human observer’s state of alertness in tasks that demand efficient registration and processing of signals

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vigilance

• Low overall vigilance in all aspects from beginning.

• Gradual decline over a period

• Studied by percent of faulty products

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Low vigilance - causes• sleep deprivation, which is “de-arousing”.

• depressant drugs like benzodiazepines or alcohol and stimulant drugs like amphetamine, caffeine or nicotine.

• With respect to age, vigilance performance increases during childhood and tends to decline beyond the age of sixty.

• Physical and mental diseases

• Lack of training/ education/ motivation/ supervision

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Improving vigilance• frequent short breaks, • job rotation, • job enlargement or job enrichment.

• Introduction of variety can be as simple as having the inspector himself or herself getting the material to be inspected from a box or other location

Mental fatigue

• Symptoms of mental fatigue

• perception: reduced eye movements

• information processing: extension of decision time, action slips, decision uncertainty, blockings, “risky strategies” in action sequences, disturbances in sensorimotor coordination of movements

• memory functions: prolongation of information in ultrashort-term storages , disturbances in the rehearsal processes in short-term memory, delay in information transmission in long-term memory and in memory searching processes.

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Prevention of Mental Fatigue

• 1. Changes in the structure of tasks. – Technology assistance (monitoring by robots- x-ray/ by alarm

on malfunction or faulty product identification)• Designing • Information processing • Human-centered technologies to reduce the mental effort

– Well-balanced coordination of different levels of regulations – Training workers in goal-directed action

• 2. Introduction of systems of short-term breaks during work.

• 3. Sufficient relaxation and sleep117

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ORGANISATIONAL ASPECTS OF WORK

• WORK ORGANISATION• SLEEP DEPRIVATION

Work Organization• Problems with organization are primarily

attributable to continuous attempts at implementing the latest technology in unsuitable organizational structures

• qualifications of employees• Use of Technology

– Insufficient technology– Unsuitable technology.– Excessively complex technology

• training is too frequently regarded as a cost factor to be controlled and minimized, rather than as a strategic investment

• From the Task to the Design of Socio-Technical Systems

• The Concept of Complete Task

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Work Organization• Design of Production Systems-

computer/ human centered

• Use of Technology– Insufficient technology– Unsuitable technology.– Excessively complex technology

• From the Task to the Design of Socio-Technical Systems

• The Concept of Complete Task

• Participatory – democratic Vs non-participatory

• Vertical – doing by order and non-participatory and non-expressive

• Participatory in decision making and ergonomically compatible- horizontal

• Organic(human centered) vs non-organic(technology oriented-robotic)

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• Though participatory is fruitful further research is still on……121

Sleep Deprivation

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• Effects• Declining performance

• Solution• Increasing flexibility in work schedules in combination with better job

design

• general conclusion is that we should minimize night sleep deprivation by selecting appropriate work schedules

• facilitate recovery by encouraging individually suitable sleeps, replacement sleeps and a sound night-time sleep in the early periods after sleep deprivation in good environment of long rest period to allow recovery.

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WORK SYSTEM DESIGN

• WORKSTATIONS• TOOLS• CONTROLS INDICATORS, PANELS• INFORMATION PROCESSING AND DESIGN

Workstation-A Workstation Design Processcollection of user-

specified demands

prioritizing of

demands

transfer of demands into (a)

technical specifications and

(b) specifications in user terms

iterative development of the workstation’s

physical layout

physical implement

ation

trial period of

production

full production

evaluation and identification

of rest problems.

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The collection of the user-specified demands should meet a number of criteria

• Openness. • Non-discrimination. • Development through dialogue. • Versatility. The process of collection of user-specified

demands should be reasonably economical and not require the involvement of specialist consultants or extensive time demands on the part of the participants.

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Ergonomics principles at Workstation

•Consider ergonomic factors like head height, shoulder height, arm reach, elbow height, hand height, leg length, and hand and body size while designing a workstation

25 cm50 cm

100 cm

160 cm

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Musculoskeletal load variables

• muscular force demand• working posture demand• time demand.

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The cube model

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Where Should one Look?

Offices and Telecommuters

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Where Should one Look?

Laboratories

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Where Should one Look?

Hospitals

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Where Should one Look? Facilities

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Where Should one Look? Shops

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Where Should one Look?

Grounds

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Where Should I Look? o Housekeepingo Diningo Housing o Student stores

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What Can Ergonomics Do?

• ↓ discomfort• ↓ accidents and injuries• ↑ accuracy• ↑ efficiency• ↑ satisfaction• ↑ job retention

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What Should I Look For?

Awkward posturesRepetitionForce

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A Workstation Design Example: Manual Welding

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• On the basis of the results of the first stages of the design process, a welding workplace (figure 3) was implemented. Assets of this workplace include:

• Work in the optimized zone is facilitated using a computerized handling device for welding objects. There is an overhead hoist for transportation purposes. As an alternative, a balanced lifting device is supplied for easy object handling.

• The welding gun and grinding machine are suspended, thus reducing force demands. They can be positioned anywhere around the welding object. A welding chair is supplied.

• All media come from above, which means that there are no cables on the floor.

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• The workstation has lighting at three levels: general, workplace and process. The workplace lighting comes from ramps above the wall elements. The process lighting is integrated in the welding smoke ventilation arm.

• The workstation has ventilation at three levels: general displacement ventilation, workplace ventilation using a movable arm, and integrated ventilation in the MIG welding gun. The workplace ventilation is controlled from the welding gun.

• There are noise-absorbing wall elements on three sides of the workplace.

• A transparent welding curtain covers the fourth wall. This makes it possible for the welder to keep informed of what happens in the workshop environment.

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Additional variables

• precautions to reduce risks for accidents• specific environmental factors such as noise,

lighting and ventilation• exposure to climatic factors• exposure to vibration (from hand-held tools

or whole body)• ease of meeting productivity and quality

demands.

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tools

• Nature of grip• Power• Pinch• pencil

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• Grip thickness• Grip strength and hand span

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• Handles• Shape• Grip surface and texture• Length• Weight and balance• Significance of gloves• Handedness• Significance of gender• Special consideration

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• Pliers and cross lever tools• Knives• Hammers• Screwdrivers and scraping tools• Saws and power tools

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Ergonomic principles while using hand tools

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Controls indicators panels

• Sitting• Standing• Foot operated controls• Selection of controls• Preventing accidental operations• Data entry devices• Displays• Labels• warnings

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sitting

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Ergonomic guidelines for sitting work

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Ergonomics principles during sitting position

Bending forwardNo wrist support

No foot rest

Back straight and supported

Wrist supported and straight

Foot supported

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chair1. Provides lumbar support.2. Height can be adjusted.3. Width is appropriate for the individual using the chair.4. Backrest is adjustable.5. Seat depth – well-fitted or adjustable.6. Adjustable or removable armrests.7. Five-prong base.8. Breathable fabric.9. Well-fitted – small, medium or large chair

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Computer ergonomics

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• Use detachable mouse• Use tilt• Use keyboard• Very frequent breaks in

laptop use is advised

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Computer & Desk Stretches (Approximately four minutes)

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Ergonomics principles during standing position

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• A chair, footrest, a mat to stand on, and an adjustable work surface are essential components for a standing workstation.

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Foot operated controls• Sitting posture

• Locate pedals underneath the body, slightly in front, – so that they can be operated with the leg in a comfortable position. The total horizontal

displacement of a reciprocating pedal should normally not exceed about 0.15 m. For rotating pedals, the radius should also be about 0.15 m. The linear displacement of a switch-type pedal may be minimal and should not exceed about 0.15 m.

• Pedals should be so designed that the direction of travel and the foot force are approximately in the line extending from the hip through the ankle joint of the operator.

• Pedals that are operated by flexion and extension of the foot in the ankle joint should be so arranged that in the normal position the angle between the lower leg and the foot is approximately 90°; during operation, that angle may be increased to about 120°.

• Foot-operated controls that simply provide signals to the machinery should normally have two discrete positions, such as ON or OFF. Note, however, that tactile distinction between the two positions may be difficult with the foot.

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Selection of Controls• Selection among different sorts of controls must be made according to

the following needs or conditions

– Operation by hand or foot

– Amounts of energies and forces transmitted

– Applying “continuous” inputs, such as steering an automobile

– Performing “discrete actions,” for example, (a) activating or shutting down equipment, (b) selecting one of several distinct adjustments, such as switching from one TV or radio channel to another, or (c) carrying out data entry, as with a keyboard.

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controls preferred

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Some examples of "detent" and "continuous" controls

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Ergonomics principles during using controls

Poor control positionGood control position – lowered palm buttons can allow arms to be lower than shoulders and provide safety

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Preventing Accidental Operation

• Locate and orient the control so that the operator is unlikely to strike it or move it accidentally in the normal sequence of control operations.

• Recess, shield or surround the control by physical barriers.

• Cover the control or guard it by providing a pin, a lock or other means that must be removed or broken before the control can be operated.

• Provide extra resistance (by viscous or coulomb friction, by spring-loading or by inertia) so that an unusual effort is required for actuation.

• Provide a “delaying” means so that the control must pass through a critical position with an unusual movement (such as in the gear shift mechanism of an automobile).

• Provide interlocking between controls so that prior operation of a related control is required before the critical control can be activated.

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Data entry devices

• All controls can be used• One key one character• Rows-columns• Separate numeric tabs• Pushbutton types• Keyboard keys• Angulation, gaps, resurface

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Displays• Displays provide information about the status of equipment.

• Displays may apply – to the operator’s visual sense (lights, scales, counters, cathode-ray

tubes, flat panel electronics, etc.), – to the auditory sense (bells, horns, recorded voice messages,

electronically generated sounds, etc.) or – to the sense of touch (shaped controls, Braille, etc.).

• Labels, written instructions, warnings or symbols (“icons”) may be considered special kinds of displays.

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• The four “cardinal rules” for displays are:

– Display only that information which is essential for adequate job performance.

– Display information only as accurately as is required for the operator’s decisions and actions.

– Present information in the most direct, simple, understandable and usable form.

– Present information in such a way that failure or malfunction of the display itself will be immediately obvious.

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• The selection of either an auditory or visual display depends on the prevailing conditions and purposes. The objective of the display may be to provide:

• historical information about the past state of the system, such as the course run by a ship

• status information about the current state of the system, such as the text already input into a word processor or the current position of an airplane

• predictive information, such as on the future position of a ship, given certain steering settings

• instructions or commands telling the operator what to do, and possibly how to do it.

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• A visual display –– is most appropriate if the environment is noisy, the operator

stays in place, the message is long and complex, and especially if it deals with the spatial location of an object.

• An auditory display – is appropriate if the workplace must be kept dark, the

operator moves around, and the message is short and simple, requires immediate attention, and deals with events and time.

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Types

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color

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warnings

• Warnings

• Ideally, all devices should be safe to use. • It is preferable to have an “active” warning, • sensor that notices inappropriate use,

combined with • an alerting device that warns the human of an

impending danger.

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• Use warning signs that workers understand easily and correctly.

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Passive warnings• label attached to the product • instructions for safe use in the user manual. • passive warnings rely completely on the human user to recognize an existing or

potential dangerous situation, to remember the warning, and to behave prudently.

• Labels and signs for passive warnings – must be carefully designed by following the most recent government laws and regulations,

national and international standards, and – the best applicable human engineering information. – text, graphics, and pictures—often graphics with redundant text. – Graphics, particularly pictures and pictograms, can be used by persons with different cultural

and language backgrounds, if these depictions are selected carefully. – users with different ages, experiences, and ethnic and educational backgrounds, may have

rather different perceptions of dangers and warnings.

Therefore, design of a safe product is much preferable to applying warnings to an inferior product.

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Ergonomic design is the application of this body of knowledge to the design of the workplace (work tasks, equipment, environment) for safe and efficient use by workers.

Good ergonomic design makes the most efficient use of worker capabilities while ensuring that job demands do not exceed those capabilities.

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Information processing and design

• Sensory input – clear understandable• Mind-processing- education / training/

vigil/warning• Output – motor capabilities• Feasible Design

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DESIGN FOR EVERYONE

• FOR SPECIFIC GROUPS• CULTURAL DIFFERENCE• ELDERLY WORKERS• WORKERS WITH SPECIAL NEEDS

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Designing for specific groups

• By using– The literature of research results.– Direct observation of the disabled person at work

and description of his or her particular work difficulties.

– The interview. – Questionnaires. – Physical measurements.

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Cultural differences

• Definitely taken into account in ergonomic design

• Sikhs with turban

• Definition of culture is way of life- complex to explain

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ageing

• Slow process in industry

• Addressed by– reduction in extreme stresses, using all possible

strategies for work organization, and – continuous efforts to increase skills, – efficient and less expensive when they are taken

over the long term and are carefully thought out in advance.

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Workers with special needs

• modification of the task• modification of a tool• design of new tools or new machines

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assessment• 1. Personnel

– Absence. Will the disabled worker have a satisfactory attendance record?– Is it likely that extra costs may be incurred for special task instruction?– Are personnel changes called for? Their costs must be considered also.– Can accident compensation rates be expected to increase?

• 2. Safety

– Will the job being considered for the disabled worker involve safety regulations?– Will special safety regulations be involved?– Is the work characterized by a considerable frequency of accidents or near accidents?

• 3. Medical

– As regards the worker whose disability is being examined with a view to his or her re-entry into the workplace, the nature and seriousness of the incapacity must be assessed.

– The extent of the disabled worker’s absence must also be taken into account.– What is the character and frequency of the worker’s “minor” symptoms, and how are they to be

dealt with? Can the future development of related “minor” illnesses capable of hampering the worker’s efficiency be foreseen?

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• Consider the easy access to and use of equipment and facilities for disabled workers, taking account of their particular needs.

• Make the tasks assigned to pregnant women comfortable and individually adjustable

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Global fatalities - ILO• Health and safety at work: > 2 million people

die each year from work-related diseases.• > 3 lakh people die each year from

occupational accidents.• > 150 million non-fatal work-related diseases

per year.• > 300 million non –fatal occupational

accidents per year.

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Occupational risk factors such as the

following, contribute markedly to

global illness and injury:

• 37% of back pain

• 16% of hearing loss

• 13% of Chronic Obstructive Pulmonary

Disease (COPD)

• 11% of asthma

• 9% of Trachea, bronchus lung cancer

• 8% of injuries

• 2% of leukemia

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India

• As per Director General of Factory Advisory Services & Labour Institutes [DGFASLI] there are 300,000 registered industrial factories and more than 36500 hazardous factories employing 2046092.

• Approximately 10 million persons were employed in various factories.

• The current burden of accumulated occupational diseases in India is estimated to be at around 18 million cases.

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Indian Statistics

• Rates of fatal injuries – >110 per 100,000 workers

• Rates of non-fatal injuries – >300 per 100,000 workers

• Cases of injury with lost workdays:

Fatal case – >2000

Non-fatal case – >6000

Cases of temporary incapacity – >3000

(Source – Labour statistics database by ILO)

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Work-related Injuries and Disorders

• Work related musculo-skeletal disorders are most common• Also known as:

– Repetitive Strain or Stress Injury (RSI)– Cumulative Trauma Disorder (CTD)– Overuse Syndrome

• Occupational disorders of the soft issues like muscles , tendons, ligaments, joints & nerves

• Usually occur slowly over time due to repetitive injuries to the soft tissues and nervous system

• Symptoms of WMSD: Discomfort, Pain, Numbness, Tingling, Burning, Swelling,

Tightness, loss of flexibility

• Risk of injury depends upon: Duration, Frequency & Intensity of exposure or combinations

of risk factors

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• Repetition

• Forceful Exertion

• Direct Mechanical Pressure

• Static Posture

• Inadequate Recovery Time

• Awkward Posture

• Environmental Stressors

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What Causes These Injuries?

Risk Factors

Repetition

Forceful Exertion

Direct Mechanical

Pressure

Static Posture

Inadequate Recovery

Time

Awkward Posture

Environmental Stressors

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• MSDs occur when the physical capabilities of the worker

do not match the physical requirements of the job

Prolonged exposure to ergonomic risk factors can cause

damage to a worker’s body and lead to MSDs

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Injuries Common sites CauseBursitis knee, elbow,

shoulderKneeling, pressure at the elbow, repetitive shoulder movements

Carpal tunnel syndrome wrist Repetitive work with a bent wrist. Use of vibrating tools.

Epicondylitis Elbow Repetitive work, often strenuous

Ganglion Back of hand or wrist

Repetitive hand movement

Osteo-arthritis Any joint Awkward liftting, pulling, pushing

Tendonitis Any site Repetitive movementsTenosynovitis Any site Repetitive movements, often

nonstrenuousTension neck or shoulder Neck or shoulders Sustained awkward posturesTrigger finger Fingers Repetitive movements.

Excessive gripping

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Evaluation of the jobDoes your job require you to: • Repeatedly bend and twist your wrists? • Repeatedly twist your arms? • Repeatedly hold your elbows away from your body? • Repeatedly use a pinch grip? • Repeatedly reach or lift things above shoulder level? • Repeatedly use a tool that vibrates?

(Analysis questionnaire)

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• Repeatedly use your hand to apply force? • Repeatedly twist or flex your back? • Repeatedly lift objects from below knee level? • Repeatedly work with your neck bent?

All of the above are “risky positions” that can lead to the development of repetitive strain injuries.

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Ergonomics - organisations

• Formed in 1946 in the UK, the oldest professional body for human factors specialists and ergonomists is The Institute of Ergonomics and Human Factors, formally known as The Ergonomics Society.

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National Ergonomics Month

• In 2003, the Human Factors and Ergonomics Society (HFES) designated October of every year to be National Ergonomics Month (NEM).

• The purpose of NEM is to focus on promoting human factors/ergonomics to corporate executives, students, and the general public by providing information and services to the community

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World Day for Safety and Health at Work

• The ILO celebrates it on the 28 April to promote the prevention of occupational accidents and diseases globally.

• It is an awareness-raising campaign intended to focus international attention on emerging trends in the field of occupational safety and health and on the magnitude of work-related injuries, diseases and fatalities worldwide.

•In 2014, the theme of the World Day for Safety and Health at Work is: safety and health in the use of chemicals at work

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International Ergonomics Association

• Is a federation of ergonomics and human factors societies

from around the world.

• The mission of the IEA is to elaborate and advance

ergonomics science and practice, and to improve the quality

of life by expanding its scope of application and contribution

to society.

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Ergonomic Checkpoints

• International Ergonomics Association (IEA)+ the International

Labour Office (ILO)

• 132 realistic and flexible solutions to ergonomic problems

applicable across a whole range of workplace situations like

Materials storage and handling, Hand tools , Machine safety,

Workstation design, Lighting, Premises , Control of hazardous

substances and agents, Welfare facilities and Work organisation

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Ergonomics in India

• In the early sixties,

• Industrial Physiology division of the Central Labour Institute,

Mumbai, under the Ministry of Labour, Govt. of India,

• evaluated the work loads of different occupations and

Acceptable Work Load for Indian industrial workers was defined.

• Anthropometry of the Indian population was also studied in

detail.

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• The first teaching

• Department of Physiology, University of Calcutta in 1971,

• post-graduate science course in Work Physiology and

Ergonomics.

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• The National Institute of Occupational Health, Ahmedabad

was established in 1966 under the Ministry of Health and

Family Planning, Govt. of India,

• Occupational Physiology division - extensive research in

thermal stress and comfort, agricultural ergonomics, and

women workers.

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• The All-India Institute of Hygiene and Public Health, Kolkata,

an institute aimed at developing health manpower ,

• Research in ergonomics, focus being on load carrying and

the occupational stress of pulling a hand-pulled rickshaw.

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• Incorporated in curriculum at the Industrial Design Centre of

the Indian Institute of Technology Bombay (IITB), in the year

1979 at the post-graduate level,

• Later in Indian Institutes of Technology Delhi, Guwahati, and

Kanpur.

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• Ergonomics has always been a part of Defence research

• The Defence Institute of Physiology and Allied Sciences (DIPAS) – including nutrition of soldiers, – load carriage and distribution in infantry soldiers, – thermal comfort.

• Research – performance in extreme environments,– development of a protective mechanism against noise induced hearing

loss and – evaluation of thermal protective clothing.

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• The earliest reports of

enterprise-level

ergonomics in India are

from the Hindusthan Lever

works and Tata Steel.

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• The public-sector Bharat

Heavy Electricals Ltd. (BHEL),

Tiruchirapalli, - first in Indian

industry to introduce in-house

Ergonomics unit in 1983,

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Organisations in India

Indian Society of Ergonomics

• 1983

• only professional body representing ergonomics / human factors

professionals in India.

• Affiliated to the International Ergonomics Association (IEA) and

nominates members to its committees.

• Members -wide variety of fields, including physiology, psychology,

occupational health, industrial safety, and engineering, reflecting the

multi-disciplinary nature of the subject.

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Overview of the development of ergonomics

Ergonomics research in India (past 50 yrs)

• physical work capacity, work stress of different occupation

• the diverse anthropometry of the people of this region

• load carrying – mainly in the unorganized sector

• improvement of working conditions in adverse

environments, including hot and humid environments

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• certain aspects of agriculture (upon which most rural people

still depend) including high profile areas like tea cultivation

• low-cost improvements for some traditional and unorganized

sectors

• product design

• women at work; and recently,

• the electronics and information technology (IT) sectors.

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BASIC ERGONOMIC PRINCIPLES

• work in neutral postures• reduce excessive force• keep everything in easy reach• work at proper heights• reduce excessive motions• minimize fatigue and static load• minimize pressure points• provide clearance• move, exercise, and stretch• maintain a comfortable environment

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Welfare facilities

Provide:

• Provide & maintain good changing, washing and sanitary facilities

to ensure good hygiene and tidiness.

• Drinking facilities and hygienic eating areas

• Rest facilities for recovery from fatigue.

• Easy access to first-aid equipment and primary healthcare facilities

at the workplace.

• Clearly mark areas requiring the use of personal protective

equipment.

• Ensure regular use of personal protective equipment by proper

instructions, adaptation trials and training.

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THANK YOU