Transcript آنتروپومتری - Shahid Sadoughi University of

Manual Material
Handling
A.H. Mehrparvar, MD
Occupational Medicine Department
Yazd University of Medical Sciences
Introduction
High prevalence of back disorders
 Absenteeism
 High cost
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Biomechanics
Force from a lifted load 10 times larger in
the spine
 Most injuries on L4/L5
or L5/S1
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Movements which cause injury:
 Lifting
 Pulling and pushing
 Twisting
 Carrying
 Holding
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Job Risk Factors
Weight of the Object
 Location (position of load and
worker)
 Frequency of Lifts
 Stability of the Load
 Hand Coupling
 Workplace Geometry Twisting/Stooping
 Environmental Factors
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Personal risk factors
Gender
 Age
 Anthropometry
 Lift technique
 Attitude
 Strength
 Training
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Safe lifting
Plan the load and path
 Keep the load as close as possible to the
body
 Load in a height between shoulder and tip
of fingers
 Avoid overhead lifting
 Avoid twisting, esp. during lifting
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Safe lifting
Broad base of support
 Keep the back in a straight line
 See ahead and avoid obstacles
 Avoid stooping into deep bins
 Use height adjustable platforms
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NIOSH lifting equation
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3 criteria for lifting:
1. biomechanical criterion:
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2. Physiologic criterion
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The largest compressive force between L5/S1
Maximum disc compressive force: 3400 N
Maximum aerobic work: 9.5 Kcal/min
A single lift ≤ 70% maximum
1 hour lifting ≤ 50% maximum
1-2 hours lifting ≤ 40% maximum
2-8 hours lifting ≤ 33% maximum
3. psychologic criterion
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Acceptable for 75% of women and 99% of men
NIOSH lifting equation
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Disqualifiers for Use
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One handed lifts
More than 8 hours
Seated or kneeling
Restricted work space
Unstable Objects
Carrying, pushing or pulling while lifting
High speed motion
Unreasonable foot/floor coupling
Unfavorable environment
NIOSH lifting equation
RWL = LC × HM × VM × DM × AM × FM × CM
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LC (load constant) = 23 Kg
HM (Horizontal Multiplier):
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Location of hands from the midpoint between the ankles
HM = 25/H
VM (vertical multiplier):
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Vertical location of the hands from the floor
VM = 1- 0.003|V - 75|
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DM (distance multiplier):
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Vertical travel between origin and destination
DM = (0.82 + 4.5/D)
AM (Asymmetric multiplier):
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Angular displacement of the load from the
sagittal plane
AM = 1 – 0.0032A
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FM (frequency multiplier): from table
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Maximum: 15 lifts per minute
1 hour: 15 lifts per minute
2 hours: 12 lifts per minute
8 hours: 10 lifts per minute
CM (Coupling multiplier):
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Good: 1
Fair: 0.95
Bad: 0.9
LI (lifting index) = Load/RWL
Reducing lifting hazards
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Using mechanical devices
Approximating the load to the worker
Reducing the height of destination
Reducing the frequency of lifting
Correcting the handles
Correcting the size of the loads
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Minimize reach and lift distances
• Keep off floor
• Work station design
Frequency
• Relax time standard
• Rotation
• Work-Rest allowances Minimize Weight
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Mechanical aids
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Carton capacity
• Balance contents
Convert
• Carry to push/pull
• Push over pull
• Use large wheels
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Pulling and pushing
Pushing better than pulling
 Area ahead of the load level and free of
obstacles
 Proper shoes
 Handles about hip height
 Two handles or two sets of handles or
adjustable handles
 Proper gloves
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