Ergonomics -
Jobs Designed with People in Mind
1

What is Ergonomics?
• The size of people - anthropomety
• The strength of people - biomechanics
• The endurance of people - physiology
• The movement of people - kinesiology
• The environment for people - Industrial hygiene
• The information processing of people -
Psychology
2

What’s the objective?
• Error free performance
– Errors in perceptions
– Errors in decisions
– Errors in actions
3

How can problems be identified?
Injury Data
Interviews Observations
4

What type of injuries are seen?
• Muscle pain
• Joint pain
• Swelling
• Numbness
• Restricted motion
• Repetitive stress injury
• Repetitive motion injuries
• Cumulative trauma disorder
• Musculoskeletal disorder
5

What’s there usual diagnosis?
• Tendinitis
• Rotator cuff tendinitis
• Tenosynovitis
• Stenosing tenosynovitis
• Thoracic outlet syndrome
• Carpal tunnel syndrome
• De Quervain’s
• Herniated disc
• Tension neck
• Epicondylitis
• Cubital tunnel
• Guyon tunnel
• Gangilionic cyst
6

What are some common names?
• Trigger finger
• Bricklayers shoulder
• Carpet layers knee
• Pizza cutters wrist
• Tailors seat
• Gamekeepers thumb
• Cotton twisters hand
• Golfers elbow
• Tennis elbow
7

How are injuries and illnesses calculated?
# of injuries or illnesses
Total hours worked x 200,000
15 injuries
400,000 x 200,000 = 7.5
1
10
Fatality
Lost Time
300
600
Prevention
First Aid
Near Misses
8

Interviews
• Are there problem jobs??? - ask the worker
• Structured interviews
9

What’s the blueprint for a good ergonomic program?
• Commitment by Top Management
• Employee Involvement
• Written Program
• Review and Evaluation
10

What should the program include?
• Worksite analysis
• Hazard prevention and control
• Medical management
• Training and education
11

Work site analysis
• Identifies problem areas and risk factors
• Conduct worker surveys
• Perform analysis of tasks and positions that are problems
12

Hazard prevention and control
• Prevented by
– Design of task, job, or job site
• Corrected by using
– Engineering
– Work practice
– Personal protective equipment
– Administrative
• Some more effective than others
13

What are some examples of engineering controls?
• Mechanical devices
• Lift tables/adjustable workstations
• Push/pull carts
• Work bins
• Tool design
• Seating, wrist/foot rest, glare screens
• Floor mats
14

What do work practice controls involve?
• Proper work techniques
• Employee conditioning period
• Monitoring
15

What are the factors to consider when using PPE?
• Variety of sizes
• Proper fit, and safe design
• Back belts
16

Can administrative controls be used instead of engineering controls?
• Considered in conjunction with engineering controls
• Implemented where engineering controls not feasible
• Temporary, does not eliminate hazard
17

Examples include!
• Reducing # of repetitions
• Job rotation
• Frequent breaks
• Broadening job content
• Training on proper lifting procedures
• Decrease work pace
• Increase # of employees
18

What are the major components of a medical management program?
• Periodic walk-throughs
• Symptoms survey
• Identification of restricted duty jobs
• Health surveillance
• Early reporting of symptoms
• Medical care
• Accurate recordkeeping
• Periodic program evaluation
19

What training is required?
• General Training
• Job Specific
• Training for supervisors
• Training for managers
20

What are the benefits of videotaping a task?
• Record of job
• Offers detailed review
• Allows management to focus on task
Job
Safety
Analysis
21

What are the steps to take prior to taping the job?
Observe job
Plan the views Get permission
Describe job
22

How should the job be recorded?
• Use clock, and date
• Shoot upstream and downstream
• Whole body shots
• Zero-in on problems areas
23

What additional data should be considered?
• Weight of materials
• Amount of hand force used
• Hand tool or surface vibration
• Work organization
• Workstation design
• Environment - temperature, odors, etc.
• Height of worker
• Experience of worker and hours at work
• Worker modifications - both implemented and suggested
24

Where can I get additional information?
• Trade associations
• Venders
• Visits to other worksites
• OSHA field offices
• OTI
• Internet
25

G AL
* Find the problem and fix it, but don’t put Band-Aids on the symptoms!
26

Video Display Terminals
27

Introduction
• Have revolutionized workplace
• 25% use in 1984, versus 45%in 1993
• More than 18 million workers in jobs
• Along with use comes health effects
28

What are the components of a Video
Display Terminal?
• Display screen
– Shows what’s being processed.
• Keyboard
– Allows user to send information.
• Central processing unit
– Brains of computer
– Performs calculations, organizes data
29

What are some of the problems that come with their use?
• Eyestrain and irritation
• Symptoms can be from
– improper lighting
– glare from screen
– poor positioning of screen or copy material
• Adjusting physical and environmental settings
30

Fatigue and Musculoskeletal
Problems
• Operators are subject to various
MSD’s
• Injuries to muscles, joints, tendons, nerves
• Caused/made worse by work related factors
• Early symptoms include:
• If workers have problems
31

Lighting
• Direct so doesn’t shine into screen.
• Four factors must be controlled to avoid eyestrain.
– Quantity
– Contrast
– Direct glare
– Reflected glare
32

What are some of key areas of work station design?
• Proper design will reduce visual and (MSD) discomfort when the following are observed:
– Flexible sitting position
– Support for back, arms, legs, and feet
– Adjustable screens, keyboards, tables, and desks
– Proper chair height, and support for lower back.
– Use of document holders
33

How important are Chairs?
• Crucial factor in preventing back pain
• Majority of office workers spend most of time sitting.
• Comfortable for the task.
• Easy adjustments.
34

Chair Height
• Human body provides a starting point.
• Height from floor to point at crease behind knee.
• Sole of foot on floor or footrest.
• Allows good circulation
35

Seatpan Design
• Size and shape are two factors
• Slightly concave, rounded edge
• Distributes weight/prevents sliding
• Also consider angle.
• Options to include:
– back and forward tilts
36

Arm and Backrest
• Armrest, low, short enough to fit under worksurfaces.
• Backrest should support entire back.
37

VDT Design
• Separate, adjustable keyboards and screens.
• Top line no higher than user’s eyes.
• Screen and document holder same distance from eye.
– Preferred viewing ranges
38

Keyboard
• Detachable and adjustable
• Forearms, parallel to floor, elbows at side
• Wrist in line with the elbows
• Padded and detachable wrist rests
39

Mouse
• Operator’s side, arm close to body
• Straight line between hand and forearm.
• Upper arm not elevated/extended while in use.
• Pad or rest helps maintain straight wrists.
40

What are some work practices that may help employees?
• Frequent breaks
• Design jobs so employees can vary VDT task with non-VDT tasks
• Open and positive working relationships
41

Back injuries-
A painful problem
Ouch
!
42

What are the risk factors?
• Awkward posture
• Forceful exertions
• Repetitive motion
• Vibration
• Contact stress
43

What should I look at when analyzing the job?
• Look at the function
• Interview workers
• Break it into elements
– work station
– work methods
• Use checklist
• Interview supervisors
• Videotape
44

What are some of the controls can I use?
• Engineering
• Administrative
• Personal Protective Equipment (PPE)
45

Administrative controls!
• Temporary
• Do not eliminate hazard
• Must maintain practices and policies
46

Types to consider include!
• More rest breaks
• Job rotation
• Broadening of job content
• Training of proper lifting procedures
• Reduce overtime
• Decrease work pace
• Increase # of employees
47

After an injury, how soon should a worker return?
• As soon as possible
• Helps employee/employer
• Reduces cost
48

49

50

Ouch
!
51

1
10
300
Fatality
Lost Time
600
Prevention
First Aid
Near Misses
52

53

54

55

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