آنتروپومتری - Shahid Sadoughi University of
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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
Biomechanics
Force from a lifted load 10 times larger in
the spine
Most injuries on L4/L5
or L5/S1
Movements which cause injury:
Lifting
Pulling and pushing
Twisting
Carrying
Holding
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
Personal risk factors
Gender
Age
Anthropometry
Lift technique
Attitude
Strength
Training
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
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
NIOSH lifting equation
3 criteria for lifting:
1. biomechanical criterion:
2. Physiologic criterion
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
Acceptable for 75% of women and 99% of men
NIOSH lifting equation
Disqualifiers for Use
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
LC (load constant) = 23 Kg
HM (Horizontal Multiplier):
Location of hands from the midpoint between the ankles
HM = 25/H
VM (vertical multiplier):
Vertical location of the hands from the floor
VM = 1- 0.003|V - 75|
DM (distance multiplier):
Vertical travel between origin and destination
DM = (0.82 + 4.5/D)
AM (Asymmetric multiplier):
Angular displacement of the load from the
sagittal plane
AM = 1 – 0.0032A
FM (frequency multiplier): from table
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):
Good: 1
Fair: 0.95
Bad: 0.9
LI (lifting index) = Load/RWL
Reducing lifting hazards
1.
2.
3.
4.
5.
6.
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
Minimize reach and lift distances
• Keep off floor
• Work station design
Frequency
• Relax time standard
• Rotation
• Work-Rest allowances Minimize Weight
Mechanical aids
Carton capacity
• Balance contents
Convert
• Carry to push/pull
• Push over pull
• Use large wheels
•
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