Transcript ergonomics-anikaharris

Ergonomics
The science of fitting the job to the worker
MULTIDISCIPLINARY
NATURE OF ERGONOMICS

Anatomy and physiology
 Engineering Psychology
 Engineering
 Medicine
 Anthropology
 Biomechanics
Benefits of Ergonomics

Decreased injury risk
 Increased productivity
 Decreased
mistakes/rework
 Increased efficiency

Decreased lost work
days
 Decreased turnover
 Improved morale
HISTORICAL PERSPECTIVE
Ramazzinni described posture and disease in 1700s
Before WWI labor surplus
During WWII labor scarce
WWII mass production of sophisticated equipment
Reading Errors
Control-Display Relations
EROGONOMIC CONCEPTS
Tool design
Workstation Design
Material handling limits
Visual and auditory task design
ENVIRONMENTAL FACTORS
Noise
Vision
Thermal
Chemical
PSYCHOLOGICAL STRESS

Machine Pacing
 Shift Work
 Morale
PHYSICAL

Posture
 Force
 Repetition
 Manual Materials Handling
TARGET REGIONS

Back
 Upper Extremities
 Lower Extremities
DESIGN AND DISEASE
POSTURE
DISCOMFORT
Standing
Legs, Feet, Back
Sitting
Neck, Back, Shoulders
Reaching
Shoulders, Upper Arms
Head Bent Back
Cervical Region
Trunk Bent Forward
Lumbar Region
STATIC EXERTIONS

Holding activities
 Carrying
 Standing
 Pushing and pulling
 Arms raised
EFFECTS OF STATIC
EXERTION
When effort greater than or equal to 60 percent MVC
blood flow almost completely interrupted.
15-20 percent MVC blood flow just about normal but
still is associated with pain.
MVC less than or equal to eight percent can probably be
maintained indefinitely.
WORKSTATION
GUIDELINES
Reduce static component and allow worker to use
optimal posture
Optimal posture usually at midpoint of limbs range of
motion
Avoid muscular insufficiency
Avoid forward reaches in excess of 16”
Elbows down close to the body flexor angle around 90
degrees
WORKSTATION
GUIDELINES (continued)
Sit-Stand preferred but rarely seen
Use gravity do not work against it
Avoid the need for excessive head movement
Avoid compression Ischemia
WORKPLACE INDICATORS
Performance deterioration…Engineering
 Quality Control problems
 Absenteeism and turn-over…Human
Resources
 Musculoskeletal disorders…OSHA Logs
WC reports
 Complaints of fatigue and discomfort

NIOSH LITERATURE SURVEY
(NIOSH 97-141)
In 1994 32% of LWD cases (705,800) were result of overexertion
or repetitive motion
367,424 Lifting 65% affected back
93,325 pushing/pulling (52%)
68,992 holding/carrying (58%)
92,576 repetitive motion, 55% wrist
83,483 NEC
GROWING AWARENESS OF CTDs
Year
Number of Repeated
Trauma Cases
Total Number of
Illnesses
1980
1981
1982
23,200
23,000
22,600
(18%)
(18%)
(21%)
130,200
126,100
105,600
1983
26,700
(25%)
106,100
1984
1985
1986
34,700
37,000
45,500
(28%)
(30%)
(33%)
124,600
125,400
136,800
1987
1988
72,900
115,400
(38%)
(48%)
190,200
240,900
TOP FIVE CTD INCIDENCE
INDUSTRIES BY RATE
1990
Meatpacking
Poultry Processing
Household Refrigerator/Freezer
Motor Vehicle and Car Body
Men’s and Boy’s Trousers and Slacks
TOP FIVE CTD INCIDENCE
INDUSTRY CLASSES BY
NUMBER
1990
Meat Products
Motor Vehicles
Men’s and Boy’s Furnishings
Miscellaneous Plastic Products
Aircraft and Parts
Types of Injuries






Muscle pain
 Repetitive motion
injury
Joint pain
 Cumulative trauma
Swelling
disorder
Numbness
 Musculoskeletal
Restricted motion
disorder
Repetitive stress injury
CUMULATIVE TRAUMA DISORDERS
A class of musculoskeletal disorders arising from repeated
biomechanical stress due to ergonomic hazards. Common
names for these disorders are:

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
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Carpal Tunnel Syndrome
Tendinitis
Tenosynovitis
Ganglion cyst
Tennis Elbow

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Trigger Finger
DeQuervian’s Disease
Thoracic Outlet Syndrome
Bursitis
Synovitis
Ergonomic Risk Factors

Repetition
 Awkward posture
 Forceful exertion
 Static posture

Mechanical contact
stress
 Temperature
 Vibration
PSYCHOSOCIAL FACTORS
LA TimesHETA 90-013-2277
NIOSH PUBS 1-800-356-4674
US West HETA 89-299-2230
PSYCHOSOCIAL FACTORS
(continued)
Significant Findings
Fear of being replaced by computers
Enlarged Jobs
Uncertainty about job future
Work pressure
Lack of co-worker support
Lack of productivity standard
Lack of participation in decision-making
Perception management not value ergo
Ergonomic Controls

Engineering
 Administrative
 Work Practices
CONTROL TECHNOLOGY

Tool redesign
 Workstation redesign
 Job methods
 Early detection
 Job rotation
 Machine pacing
 Medical surveillance
REDUCTION OF
REPETITION
Task Enlargement
Mechanization
Automation
REDUCTION OF EXTREME
JOINT MOVEMENT
Altering tool or controls
Workstation Design
Moving the Worker
REDUCTION OF FORCE
Reducing the force
Spreading the force
Better mechanical advantage
ADMINISTRATIVE CONTROLS
HAZARD PREVENTION AND
CONTROL

Rest-pause
 Increase number of employees
 Job rotation
 Physical conditioning
 Relief personnel
 Medical management
MATERIALS HANDLING
Lifting/Lowering
Pushing/Pulling
Carrying
Weights and Forces
Frequency of activities
Load Center of Gravity
JOB RISK FACTORS
Weight lifted
Position of load center of gravity
Frequency
Posture
Torso Flexion
Twisting
Arms extended
JOB DESIGN
Can reduce one-third of compensable LBP
Minimize reach and lift distances
Keep off floor
Work station design
Frequency
Relax time standard
Rotation
Work-Rest allowances
JOB DESIGN (continued)
Minimize Weight
Mechanical aids
Carton capacity
Balance contents
Convert:
Carry to push/pull
Push over pull
Use large wheels
TRAINING
Focus on awareness and avoidance
Get object as close to body as possible
Planning
Use of handling aids
Back Schools
Strength and fitness important
WORKPLACE USE OF BACK BELTS
NIOSH 94-122

Insufficient Data that belts significantly
reduce trunk loading
 Insufficient data that wearing reduces risk
of injury based on IAP and EMG
 May strain cardiovascular system
 Insufficient data that discontinuation of use
increases risk among healthy workers
NIOSH does not recommend as tool for prevention
ORGANIZATIONAL
INFLUENCES
Wage Systems
Quality Control
Management-Labor Relations
Machine-paced versus Self-paced work
Rest Breaks
Overtime
Shift Work
RECOMMENDATIONS

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
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1. Identify Team Members
2. Identify problem jobs
3. Survey Employees
4. Develop Plan of Action
5. Select most feasible
6. Implement on small scale
7. Train
8. Measure response
9. Wider application or goto 4
10. Goto 2
REDESIGN EFFORT
Based on job analysis
Employee Feedback
Anthropometry
Fitting Trials (Prototyping)
Monitoring and Measurement
REMEMBER WORKSTATION
DESIGN GUIDELINES
Design where hands spend most of time
Normal reach envelope
Elbow height
Edge compression
Limit forward reaches to 16!
WORK SITE ANALYSIS

Review OSHA 200 log
 Employee interviews
 Performance Data (turnover, etc.)
 Video analysis of identified hazardous
positions
Ergonomics Program
Elements

Management
leadership and
employee participation
 Hazard information
and reporting

Job hazard analysis
and control
 Training
 MSD management
 Program evaluation
REFERENCES
Applications guide for the revised NIOSH lifting equation
NTIS PB94-176930 (703) 487-4650
NTIS PB91-226274 Scientific Documentation
Elements of Ergonomic Programs
NIOSH 97-117
1-800-35-NIOSH
Musculoskeletal Disorders and Workplace Factors
NIOSH 97-141
Work Practices Guide for Manual Lifting
NIOSH 81-122
$12.00
REFERENCES (continued)
Cumulative Trauma Disorders: A Manual for MSDs of the Upper
Limbs, Putz-Anderson
Fitting the Task to the Man, Grandjean
Taylor and Francis
1-800-821-8312
Methodological Limitations in the Study of VDT use and UEMDs
Gerr, Marcus, Ortiz, American J. Ind. Med. 29:649-656 (1996)
Ergonomics: The Study of Work, OSHA 3125,www.OSHA.gov
Dan Ortiz, Georgia Tech
www.oshainfo.gatech.edu
(404) 894-8276