niosh lifting eqn.-ppt
Post on 03-Nov-2014
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SAMPLE CALCULATION
SAMPLE CALCULATION The measured task variables when the worker is lifting:-
Load to be lifted= 20Kg
H1(origin)= 40cm V1(origin)= 50cm A1(origin)=0
H2(dest.) = 43cm V2(dest.) =0 A2(dest.) =0
D(dist.)= 50cm F (freq.) = 4 Duration (hrs) =1-2
C(coupl.) = Poor
FOLOWING ARE THE MULTIPIERS:-
AT ORIGIN
HM= 25/H=0.63
VM= 1-(0.003|V-75|)=092
DM=0.82(4.5/D)=0.91
AM=1-(0.0032A)=1
FM (from table)=0.72 CM(from table)=0.9
AT DESTINATION
HM= 25/H=0.58
VM= 1-(0.003|V-75|)=0.78
DM=0.82(4.5/D)=0.91
AM=1-(0.0032A)=1
FM (from table)=0.72 CM(from table)=0.9
RESULTSRWL=LC * HM *VM * DM * AM *FM * CM
RWL(origin)=7.8Kg
RWL(dest.) = 6.1Kg
LI(origin)= Load/RWL=2.6
LI(dest.) =Load/RWL =3.3
As the Lifting Index is more than one which indicates that the worker must be having problem of Low Back Pain, thus the layout is to be redesigned by redesigning the task variables
REVISION OF THE UNSAFE RESULTS
THE RESULTS OBTAINED FOR THE ABOVE SAMPLE ARE UNSAFE. THUS WORKING LAYOUT IS REVISED BY REVISING THE TASK VARIABLES IN ORDER TO HAVE THE SAFER RESULTS i.e SAFE LOADING CONDITIONS OF THE WORKER.
SAMPLE CALCULATION The revised task variables when the worker is lifting:-
AT ORIGIN
Load to be lifted= 20Kg
H1(origin)=30cm V1(origin)=50cm A1(origin)= 0
H2(dest.) = 30 cm V2(dest.) =40 cm A2(dest.) =0
D(dist.)=10 F(freq.) =3 Duration(hrs)=1-2
C(coupl.)=Poor
AT DESTINATION
HM= 25/H=0.58
VM= 1-(0.003|V-75|)=0.9
DM=0.82(4.5/D)=1
AM=1-(0.0032A)=1
FM (from table)=0.79 CM(from table)=0.9
REVISED RESULTSRWL=LC * HM *VM * DM * AM *FM * CM
RWL(origin)=12.6Kg
RWL(dest.) =12.2Kg
LI(origin)=Load/RWL=1.5
LI(dest.) = Load/RWL=1.6
As the Lifting Index is not less than one ,but the layout of work has been revised so as to reduce the LI to maximum possible extent. Thus summarising the revisions made as mentioned:
CHANGES DONE IN THE TASK VARIABLES
The worker is advised to be closer to the Origin and destination points in order to increase the HM
Raising the height of the Destination Point in order to increase VM
Reducing the lifting frequency in order to increase the FM
Further the LI can also be reduced by reducing the Load to be lifted
SOFTWARE DEVELOPED
FEATURES
The software has been made in C++ Programming Language.
It is used to calculate the RWL & LI using NIOSH Lifting Equation.
The input given to the software are the values of Task Variables.
The output comprises of the Multipliers along with RWL & LI.
12
Start
Define variables involved
Initialize desired variables
Define various functions
Read input data i.e task
variables
B
Call functions for task multipliers
A
If Dur==1
B
Call function for freq. multiplier for V1
Call function for freq. multiplier for V2
C
If Dur==2
If Dur==3
YES
YES
NO NO
YES
YES
If Dur==1
If Dur==2
If Dur==3
YES
YES
NO NO
C
Display all the multipliers
Display RWL and LI
Compute RWL and LI
End
A
Stop
YES
NO
NO
THE RESULTS ALONG WITH THE
EXECUTION OF THE PROGRAMME
16
Enter the following data
Load to be lifted---
15
Horizontal Distance at origin---
50
Horizontal Distance at Destination---
45
Vertical Distance at Origin---
114
Vertical Distance at Destination---
0
Frequency i.e, Lifts per Minute---3Asymmetric Angle at Origin---15Asymmetric Angle at Destination---20What is the type of CouplingPRESS 1 for Good 2 for Fair 3 for Poor2
What is the Duration of Service
PRESS
1 for <=1 hour
2 for 1 to 2 hours
8 for 2 to 8 hours
2
---------------------------------------------
The Recommended Weight Limit(RWL1) at origin is 6.563798
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The Recommended Weight Limit(RWL2) at Destination is 5.97883
---------------------------------------------
The lifting Index at origin is 2.285262
----------------------------------------------
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The lifting Index at Destination is 2.508852
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MULTIPLIERS ARE AS UNDER
HM VM DM AM FM CM
0.50.8830.8594740.9520.791
0.555556 0.775 0.859474 0.9360.79 0.95
THANKS
21
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