Post on 04-May-2018
transcript
A Simplified Method for A Simplified Method for Analyzing Variable Lifting JobsAnalyzing Variable Lifting Jobs
Rick Goggins, CPEWashington State Department of Labor and Industries
Overview
Need for simplified analysis method
Proposed data collection and analysis method
Case study–Simplified method (Lifting Calculator)–NIOSH Lifting Equation
NIOSH Lifting Equation
Many limitations15-minute observation suggestedMeasurement errors–Horizontal distance–Frequency–Asymmetry–Coupling
Not well suited for variable (multi-task) lifting jobs
A simpler method would be nice
Simplified method
NIOSH LE Lifting CalculatorDesigned for practitioners“Serious” analysis toolRequires precise measurementsRecommend analyzing 10 to 15 lifts for variable jobs
Designed for layperson
Quick screening tool
Allows estimation
Analyze 3 lifts for variable jobs
Washington State Lifting Calculator
Based on NIOSH LE, but with Lifting Index of 1.5-2.0More discrete categories rather than continuous measurementsDoes not take into account:–Destination of lift–Distance component–Coupling component
Analyzing Multi-Task Jobs
Different weights / different locations
Analyze three lifts:
Worst-case lifts:
1. Heaviest object lifted (posture only) 2. Most awkward lift (posture only)
and
3. Most common type of lift (use frequency and duration of all lifts)
Simplified Method in Use
Data Collection– Interview–Records Review –Observation
Interview
Gain understanding of job as wholeDetermine typical work pace, objects handledDetermine factors that can change load weights, frequency of liftingFind worst case scenarios
Review Records
Sources of Data–Shipping records–Production data–Pick sheets–Work expectations
Review Records
Objective data to determine frequency and duration of lifting
Select typical and worst case lifts
Determine which lifts to observe during next phase
Observation
Representative samples of typical and worst case lifts
Determine work pace, work/rest cycles, multiple lifts
Observe/measure lifting postures
Note constraints, obstructions, storage practices
Case Study Lumberyard Order Picking
Interview Findings
Busiest time in summer
Typical busy day will fill around 25 orders
Customers occasionally help with lifting
Most common lifts are of dimensional lumber
Heaviest objects are timbers, most awkward lifts are from below racks
Lifts to Analyze
What is the most awkward lift you do? (which zone)
Records Review Findings
Handwritten sales slips from typical busy day
Number of each item lifted
Weight of each item
Total = 120 lifts per day (~ 1 hour)
DJ
Lifts to Analyze
Most common and heaviest lift
Yardman lifting distribution
0
24
6
8
1012
14
161820
17.5 18 20 22 24 25 30 32 36 40 44 47 48 50 53 54 56 58 60 65 67 90 103
150
Weight
Num
ber o
f lift
s
70
Observation
Will lift multiple items at one time (50 – 60 pounds per lift)
A lot of storage below knee level
Lifting in short bursts @ 2 to 3 lifts per minute
1 hour per day
Lifts to Analyze
Most common lift:– 47 pounds– Below knees– Mid distance– Twisting < 45
degrees– Frequency = 2 to 3
lifts per minute– Duration = 1 hour
per day
Lifts to Analyze
Heaviest lift:• Below knees• Close distance• 90 pounds• Twisting < 45 degrees
Most awkward lift:• Below knees• Far distance• 70 pounds• Twisting > 45 degrees
Analysis ResultsWash. State Lifting Calculator
Actual weight Weight limit
Most common liftHazard 47 lbs. 45 lbs.
Heaviest liftHazard 90 lbs. 70 lbs.
Most awkward liftHazard 70 lbs. 30 lbs.
Analysis ResultsNIOSH Lifting Equation
HM VM DM FM AM CM
Most common liftRWL = 22 lbs.
LI = 2.2
0.63 0.93 0.97 0.91 0.94
1.0 1.0
0.92
0.901.0
1.0 0.840.50
0.90
Heaviest liftRWL = 38 lbs.
LI = 2.3
0.93 0.90
Most awkward liftRWL = 15 lbs.
LI = 4.6
0.87 0.90
CLI = 4.8
Analysis Results
Lifting Calculator resulted in weight limits about 2x those of NIOSH LEBoth methods identified need for changesBoth methods would result in same priority for changes
Potential Solutions
BetterOK
Better Best
Post Solution Analysis ResultsWash. State Lifting Calculator
Actual weight Weight limit
Most common liftAcceptable 35 lbs.
(per person)70 lbs.
Heaviest liftAcceptable 45 lbs.
(per person)90 lbs.
Most awkward liftAcceptable 70 lbs. 90 lbs.
Post Solution Analysis ResultsNIOSH Lifting Equation
HM VM DM FM AM CM
Most common liftRWL = 39 lbs.
LI = 0.8
1.0 0.93 1.0 0.91 1.0
1.0 1.0
1.0
1.01.0
1.0 1.00.83
0.90
Heaviest liftRWL = 44 lbs.
LI = 1.0
0.96 0.90
Most awkward liftRWL = 38 lbs.
LI = 1.8
1.0 0.90
CLI = 1.9
Conclusions
Simplified method requires pre-screening, less observation
Looking at combination of typical and worst case lifts gives good indication of hazards
NIOSH LE and Lifting Calculator give similar results when goal is analysis for change
Thank You