Task Analysis Tools

ERGONOMICS :: TRAIN-THE-TRAINER PROGRAM :: TASK ANALYSIS TOOLS

Task Analysis Tools


• Risk Factors

• Ergonomic Body Divisions

Review the Basics


• Force

• Frequency

• Posture

• Duration

• Contact Stress

• Environment

• Vibration

Risk Factors


• Upper Extremity

• Lower Extremity

• Trunk

Ergonomic Body Division


• Use OSHA 200/300 logs

• Accident Reports

• Workman’s Compensation info

• Employee Surveys

• Visual Cues

Recognizing a WMSD Problem


Body Part Discomfort Form and Rating Scale


• A narrative, quantitative and/or checklist system that provides a standardized evaluation of a job/task

• Tools based on biomechanical and physiological information compiled and calculated providing a relative risk of injury probability

• Can be specific for body region and/or risk factors

What is a Task Analysis Tool


• Provide guidance• Where to begin corrective actions• Helps direct efforts toward specific body

division, risk factors

• Involve employees• Employees can perform assessments

• Provide a level of measurement• Shows improvement of tasks• Baseline data

Why do we need these tools?


Two criteria for use:

• What are you trying to find out?• General vs. Specific information

• What limitations must be considered?• Various tools are only able to assess

specific body regions

How do we use them?


Checklists

• Easy to use

• Less time consuming

• Minimal training

• Very sensitive: One check, task must be considered

Types of Analysis Tools


Types of Analysis ToolsQuantitative

• Less sensitive

• More specific training

• Provide a relative risk assessment


Types of Analysis ToolsNarrative

• More formal training and experience required

• Provides specific areas for improvement

• Very time consuming


• Washington State Checklist (WISHA)

• NIOSH

• University of Michigan

Checklists


• Checklist system that identifies “caution or hazard zone jobs”

• Incorporates each of the risk factors including vibration and contact stress

• Has separate evaluation for heavy, frequent or awkward lifting

• Uses verbal cues to guide user through evaluation criteria

• Not generally left or right side independent

WISHA


• Does address combination of risk factors

• Great “first cut” ergonomic tool

• Draw Backs• High sensitivity: identify many jobs• Doesn’t separate frequency component

by body part

WISHA


• 3 basic sections• Entire body checklist• Lifting hazard section• Vibration hazard analysis

• Entire body checklist• Identify if a particular hazard exist as a

result of a risk factor for a body part• If a hazard exists then corrective action

is needed

Using WISHA


• Lifting hazard analysis

• Calculated weight limit is adjusted by:

• Compares the actual weight lifted to a calculated weight limit

• Actual weight lifted > Weight limit = Hazard exists

Using WISHA


• Vibration hazard analysis

• Compares the time an employee uses the machine to a pre-measured vibration value

• Plot time vs. vibration data on graph

• Intersection point indicates degree of hazard

• Vibration data: www.lni.wa.gov/wisha/ergo

Using WISHA


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• Job Strain Index

• Rapid Upper Limb Assessment

• ACGIH Threshold Limit Value – HAL

• Rapid Entire Body Assessment

• Rodgers Muscle Fatigue Analysis

• Snook Push/Pull Hazard Tables

Quantitative Tools


• Only evaluates hand, wrist and elbow (distal upper extremity)

• Assess task based on posture, frequency and force

• FORCE driven

• Doesn’t consider vibration or contact stress

• Index based on a relative risk (1-1053)• 7 considered hazardous

Job Strain Index


• Can assess right and left sides independently as well as worst case

• Used in meat packing, small part assembly, keyboarding and other highly repetitive hand motions

Job Strain Index


• Intensity of exertions (force)

• Duration of Exertion (% cycle)

• Efforts per minute

• Hand/wrist posture

• Speed of work

• Duration of task per day

Strain Index Elements


• Assign a value for each of the 6 elements

• Multiply each element = strain index

• Compare calculated value to decision threshold provided

• Decision Threshold• <3 safe• 3-5 uncertain• 5-7 some risk• >7 hazardous

Using the Job Strain Index


JHA/Work Methods



Videotaping Tips

• Announce the name of the job on the tape

• Tape 5 to 10 minutes for each task

• At least 3-4 cycles

• Start with whole body shots and then zoom in on problems areas

• Try different angles to get the best shot

JHA/Work Methods


Step 1: Breaking The Job Down

• List each step in order of occurrence

• Be sure to record enough information

• Can use Gilbreth’s terms to describe steps

• Can use video or photos

JHA/Work Methods


• Search• Select• Grasp• Reach• Move• Hold• Position• Inspect

• Assemble• Disassemble• Use• Unavoidable Delay• Avoidable Delay• Plan• Rest to overcome

fatigue

Gilbreth’s Table of Work Elements

JHA/Work Methods


Step 2: Identify the Hazards

• Look for Risk Factors in each job

• Repeat the job observation until all hazards identified• Video and photos can be especially helpful

• Consider abnormal activities and conditions

JHA/Work Methods


Step 3: New Procedure or Protection

• Can the job be performed in another way?

• Can you make physical changes to the job?

• Does the job have to be performed? Can it be done less often?

JHA/Work Methods


What does the worker need to know from this presentation?

Task Analysis Tools

Documents

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