p9 - ergo - manual material handling.pdf
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Manual Material
Handling
Fact about MSDs
(Case study : British worker)
Fact about Manual Handling
(Case study : British worker)
Manual Material Handling (MMH)
Accident Cost &
Workday Lost
Injuries / Illness
Unsafe MH
Manual Material Handling SystemIn
div
idual
(W
ork
er)
• Physical
• Sensory
• Personality
• Experience
• Health
• Activity
Mat
erial • Load
• Dimension
• Distribution
of load
• Handles
• Stability of
load
Work
pla
ce
• Workplace
geometry
• Environment
• Frequency
Com
pan
y (Indus
try) • Teamwork
• Safety policy
• HSE people
• Shifting
• Insurance
support
• Personal
protective
equipment
Types of Manual Handling Task
Pulling/pushing Holding Carrying Lifting
The Revised NIOSH Lifting EquationLifting Task, defined as the act of manually grasping an object of definable size and mass with two hands, and vertically moving the object without mechanical assistance.
NIOSH : National Institute of Occupational Safety and Health
Persamaan NIOSH berlaku pada keadaan :
• Beban yang diberikan adalah beban statis, tidak ada penambahan ataupun pengurangan beban di tengah-tengah pekerjaan.
• Beban diangkat dengan kedua tangan
• Pengangkatan atau penurunan benda dilakukan dalam waktu maksimal 8 jam.
• Pengangkatan atau penurunan beban tidak boleh dilakukan saat duduk atau berlutut
• Tempat kerja tidak sempit.
Lifting Task Indicator
RWL (Recommended Weight Limit) adalah rekomendasibatas beban yang dapat
diangkat oleh manusia tanpamenimbulkan ciderameskipun pekerjaan
tersebut dilakukan secararepetitive dan dalam jangka
waktu tertentu.
LI (Lifting Index)digunakanuntuk mengetahui index pengangkatan apakahproses pengangkatan
menimbulkan resiko cideratulang belakang atau tidak.
Advantages of The Revised NIOSH Lifting Equation
Help identify potentially hazardous lifting jobs.
Help in design/
modification process.
Help prioritize evaluation of lifting tasks
Recommended Weight Limit (RWL)
LC : (Lifting Constanta) konstanta pembebanan
HM : (Horizontal Multiplier) faktor pengali horisontal
VM : (Vertical Multiplier) faktor pengali vertikal
DM : (Distance Multiplier) faktor pengali perpindahan
AM : (Asymmetric Multiplier) faktor pengali asimentrik
FM : (Frequency Multiplier) faktor pengali frekuensi
CM : (Coupling Multiplier) faktor pengali kopling (handle)
RWL = LC x HM x VM x DM x AM x FM x CM
1. LC (Load Constanta)
L (load weight) : weight of the object to be lifted (in pounds or kilograms), including the container.
LC 23 kg (230N) or 51 lbs
(acceptable to 75% of female population)
2. HM (Horizontal Multiplier)
H distance of the hands away
from the mid-point between ankles.
Measure at the origin & destination of lift.
HM (cm) = 25 / HHM (inch) = 10/ H
3. VM (Vertical Multiplier)
V distance of the hands above
the floor.
Measure at the origin & destination of lift.
VM (cm) = 1-0,003|V-75|VM (inch) = 1-0,0075|V-30|
VM = 1 – 0.00326 | V – 69 |
4. DM (Distance Multiplier)
D absolute value of the difference
between vertical heights at the destination and origin of the lift.
DM (cm)= (0,82 + (4,5/D)) DM (inch)= (0,82 + (1,8/D))
5. AM (Asymmetric Multiplier)
A (asymmetry angle) the location
of the load relative to the worker’s mid-sagittal plane, as defined by the neutral body position.
Measure at the origin & destination of lift.
AM = (1 - (0,0032 A))
6. FM (Frequency Multiplier)
F average number of lifts per
minute over a 15 minute period.
Duration is classified as :Short (1 hour)Moderate (1-2 hours)Long (2-8 hours)
See FM Table
7. CM (Coupling Multiplier)
C classification of the quality of
the hand-to-object coupling (e.g., handle, cut-out, or grip).
See CM Table
L i f t i n g I n d e x ( L I )
• Jika LI ≤ 1 tidak mengandung resiko cidera tulang belakang
• Jika LI > 1 mengandung resiko cidera tulang belakang.
LI = Load Weight / RWL
Let’s Try...!!!
Loading Punch Press Stock
O R I G I NLC = 51 lbs
HM = 10 / H = 10 / 23 = 0,43 inches
VM = 1 - (0,0075|V-30|) = 1 - (0,0075|15-30|) = 0,8875
DM= 0,82 + (1,8/D) = 0,82 + (1,8/(|15-63|)) = 0,8575
AM = 1 - (0,0032A) = 1 - (0,0032*0) = 1
FM = 1 (F<0,2 lifts/min; V<30 inches)
CM = 0,95 (Fair; V<30 inches)
RWL = 15,85 lbs
LI = L / RWL = 44/15,85 = 2,77
D E S T I N A T I O NLC = 51 lbs
HM = 10 / H = 10 / 23 = 0,43 inches
VM = 1 - (0,0075|V-30|) = 1 - (0,0075|63-30|) = 0,7525
DM = 0,82 + (1,8/D) = 0,82 + (1,8/(|15-63|) = 0,8575
AM = 1 - (0,0032A) = 1 - (0,0032*0) = 1
FM = 1 (F<0,2 lifts/min; V<30 inches)
CM = 1 (Good; V<30 inches)
RWL = 14,15 lbs
LI = L/RWL = 44/14,15 = 3,1
LIMITATIONS (1)
The equation does not apply in the following situations:
• Lifting/lowering with one hand
• Lifting/lowering for over 8 hours
• Lifting/lowering while seated or kneeling
• Lifting/lowering in a restricted work space
• Lifting/lowering unstable objects
• Lifting/lowering while carrying, pushing or pulling
• Lifting/lowering with wheelbarrows or shovels
• Lifting/lowering with high speed motion (faster than about 30
inches/second)
• Lifting/lowering with unreasonable foot/floor coupling
• Lifting/lowering in an unfavorable environment
LIMITATIONS (2)
Designing to avoid back pain
More importantly, NIOSH equation gives ways to reduce injury :
reduce horizontal distance
keep load at waist height
reduce distance to be travelled
reduce twisting
add handles
reduce frequency of lifts
LIFTING VARIABLES
LiftingTask
HHorizontalLocation
(10 – 25”)
VVerticalLocation(0 - 70”)
DTravel
Distance(10 – 70”)
AAngle of
Asymmetry(0 - 135˚)
CCoupling(1=good,
2=fair, 3=poor)
FFrequency(0.2 – 15 lifts/min.)
LAve. Load
Lifted(lbs.)
LMax. Load
Lifted(lbs.)
Work Dur.Duration
(1,2,8 hrs)
Origin 15 38 6 0 1 6 24 24 8
Destination 20 32 6 30 1 6 24 24 8
Calculate RWL, LI !!
This job task consists of a
worker lifting compact
containers full of copper
component parts from the
bottom shelf of storage rack
with both hands directly in front
of the body, and then placing on
a cart for transport to the
assembly line. For this analysis,
assume that significant control
of the object is required at the
destination. The containers are
of optimal design with
handholds. 2 lifts/minute over a
duration of 1–2 hours per day
Load weight = 12,5 lbs
LIFTING VARIABLES
LiftingTask
HHorizontalLocation
(10 – 25”)
VVerticalLocation(0 - 70”)
DTravel
Distance(10 – 70”)
AAngle of
Asymmetry(0 - 135˚)
CCoupling(1=good,
2=fair, 3=poor)
FFrequency(0.2 – 15 lifts/min.)
LAve. Load
Lifted(lbs.)
LMax. Load
Lifted(lbs.)
Work Dur.Duration
(1,2,8 hrs)
Origin 15 11 29 10 1 2 12,5 24 2
Destination 12 40 29 0 1 2 12,5 24 2
Calculate RWL, LI !!
Have an enjoy study and see you next week…
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