Worksite Analysis
The worksite analysis is a systematic observation of your plant. You look for existing ergonomic hazards and look in areas where there is a potential for ergonomic hazards to develop. The objective of a worksite analysis is to recognize ergonomic hazards. You cannot develop an effective ergonomics program without first performing a worksite analysis. Before you begin the worksite analysis, do the following:
- Explain the analysis to line supervisors and production workers. Let them know the objective of the analysis, the extent of the analysis, and the required outcome.
- Get your workers involved. Form an ergonomics team and use the team members’ help to perform the worksite analysis. Be sure your ergonomics team understands ergonomics in the workplace.
- Gain an understanding of good work station design and learn to identify ergonomic hazards. Read this entire section of the application guide before you perform your worksite analysis.
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The following is a sequential overview of a worksite analysis as it relates to Whizard Trimmers:
- Try to meet with the plant manager and departmental supervisors and jointly make a commitment to ergonomic changes.
- Review your injury and illness records (OSHA 200 reports) from the past 12 months. Look for any jobs that had high numbers of injuries and used Whizard tools.
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- Involve health care providers in this step of the worksite analysis to ensure confidentiality of records.
- Meet with line supervisors to explain the ergonomic job hazard analysis (which includes a work station analysis) that you are going to perform.
Note: An ergonomic job hazard analysis is a strict observation of jobs that increase workers’ exposure to ergonomic hazards. The analysis helps you recognize hazards related to cumulative trauma. Work station analysis is part of the job hazard analysis.
- Identify any work positions or jobs that use Whizard tools and require an analysis of ergonomic hazards. Jobs and positions that expose workers to cumulative trauma or increase their exposure to ergonomic hazards are commonly due to poor work station design, but can also include any of the following:
- repetitive motions or prolonged activity
- standing in the same position for a prolonged time
- using excessive force with the hands
- awkward upper body postures (twisting wrists or reaching upward)
- cold temperatures
Jobs, work stations, or positions that show multiple risk factors are more likely to cause cumulative trauma disorders.
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Definitions
Flexing is when the wrist is bent in an extreme forward position, with the fingers extending downward.
Extending is when the wrist is bent in an extreme backward posture, with the fingers extending upward.
Ulnar deviation is when the wrist rotates toward the little finger, which takes the wrist out of its neutral position.
Radial deviation is when the wrist rotates toward the thumb, which takes the wrist out of its neutral position.
Static back posture occurs in a job where the worker stands in the same position with a bent back for long periods of time.
Winging is when the operator works with their elbows up and away from their body.
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- Decide the priority required for making ergonomic changes in the jobs that you identified as high-exposure jobs.
- Meet with the production workers to explain your plant’s commitment to ergonomic change. Distribute a comfort survey to the production workers. The survey can help you identify physical problems that might be associated with the jobs. Also, discussions with workers can help you identify ergonomic hazards.
- Involve an industrial engineer or maintenance supervisor to help you perform an ergonomic job hazard analysis. Observe the jobs that you classified as high-exposure jobs. While you observe those jobs, try to identify the problems associated with the injuries.
- Before you begin the work station analysis, inform the production workers about the ergonomic job hazard analysis and explain that you want to video them while they perform their jobs. Be sure they understand that you will not use the use of video as a job performance appraisal.
- View the video with the line supervisor and the industrial engineer or maintenance supervisor.
- Perform the work station analysis as explained in the remainder of this section.
Work station analysis is part of the ergonomic job hazard analysis. The following section explains how to conduct a work station analysis for work stations equipped with the Whizard Trimmers
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Using Our Checklist for a Work Station Analysis
The following pages provide and If…, And…, Then…checklist to use when you perform a work station analysis, which is part of the ergonomic job hazard analysis. Include these illustrated subjects in your work station analysis. The next section, Understanding the Principles of Work Station Design, provides some illustrated hazard recognition cases and some solutions for those hazards. Together, these sections provide you with a basic understanding of good work station design.
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Checking for Extreme Postures
If . . .
you observe the production workers performing their jobs,
And . . .
you notice any of the following body postures:
- extreme flexing or extending of the wrists
- ulnar deviation or radial deviation of the wrists
- raised shoulders
- static back postures
- elbows held up, away from the body (winging)
- reaches extending more than 18 inches or above shoulder height
- Winging, which reduces the worker’s leverage and applies more force to the hand and to the weaker muscles of the arm. Winging can cause increased exposure to hazards that can affect the elbow.
- Raised shoulders and winging, which often occur as a result of flexed wrists or ulnar deviation of the wrists. These postures can cause increased exposure to hazards that can affect the hands and wrists.
- Identify the reasons for the extreme postures. There could be several reasons for these body postures. The following pages illustrate some of these postures and help you identify the ergonomic hazards that can cause workers to use extreme postures. Also refer to the next section, Understanding the Principles of Work Station Design, for more information about recognizing the hazards of extreme postures.
Then . . .
The production workers are exposed to several ergonomic hazards, such as:
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Checking Work Station Height
If . . .
the work surface or product is above a worker’s waist level and the work surface has a raised edge that hinders the worker’s reach,
And . . .
the production worker assumes a posture with raised shoulders (especially on the side that holds the trimmer) in an effort to get above the product to make a cut,
Then . . .
the production worker is exposed to ergonomic hazards that can affect the back.
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Ergonomic Hazards
Both of these ergonomic hazards reduce the worker’s ability to reach the product:
- This works surface is too wide.
- The raised edge and the work surface are too high.
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- Design the height of the work station to fit the tallest production worker, with the work surface height set at least 44 inches high.
- Use adjustable stands to bring workers to their correct work station heights.
- Remove the raised edges from the work surfaces (edges can also be perceived as barriers).
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Corrected Design
Reducing the width of this work surface decreases the worker’s exposure to back injuries. Providing an adjustable stand brings the worker to the correct height at the work station.
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Checking Work Surface Depth
If . . .
work surfaces are too wide,
And . . .
production workers are forced to increase their reach lengths, possibly using a pinch grip to lift heavy product,
Then . . .
production workers are continuously using poor leveraging positions that can cause elbow, shoulder, and lower back injuries. Pinch grips expose workers to ergonomic hazards that relate to Carpal Tunnel Syndrome.
- Install work surfaces that are the correct width for the production workers and the jobs. Do not allow reach lengths over 18 inches.
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Checking Reach Lengths
If . . .
reach lengths are over 18 inches and hooks are not used to grasp the product,
And . . .
a production worker reaches for, then grasps, pushes, or pulls the product with force, or production worker grips the trimmer by the base of the handle,
Then . . .
the production worker is exposed to ergonomic hazards that can affect the back. Also, this is an unsafe grip that could potentially cause a worker to be cut. This grip also defeats the ergonomic benefits of the Whizard Trimmer.
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Ergonomic Hazards
The distance between this stand and the product forces the worker to lean and reach forward to perform the job. This posture exposed the worker to lower back strain
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- Move stands closer to the product or divert the product to the worker to reduce the length of the worker’s reach and reduce back stress.
- If you cannot change the product orientation, use hooks for grasping the product to reduce the stress on the worker’s back muscles
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Corrected Design
The stand was moved closer to the product. The worker can now maintain safe back posture while performing his job.
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Checking Reach Lengths
If . . .
the width of the work surface is too wide or the angle of the product is poor,
And . . .
the worker bends forward, raises the shoulder and elbow, and flexes the wrist to perform the job,
Then . . .
the production worker is attempting to compensate for poor work station design and product position.
- Use adjustable, angled work surfaces to change the product orientation. Angled work surfaces allow the worker to lower the shoulder and bring the elbows closer to the sides of the body. These adjustments reduce the length of the reach required for the job and reduce exposure to risk factors like wrist flexing.
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| This worker is cleaning neck bones at a cutting board that is 24 inches wide. To reach the product and perform her job, she leans forward at the lower back, raises her shoulder and elbow, and flexes her wrist. |
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- Poor work station heights, work surface depths, and poor angles of product position result in leverage problems for production workers. When the workers compensate for the problem, they increase their exposure to injury. Use adjustable work station stands and angled cutting boards to help reduce the ergonomic hazards.
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Corrected Design
An adjustable, angled work surface was installed at this work station. Using this work surface helps the worker easily reach the product, improves her leverage, reduces the flex of her wrist, and lowers her shoulder to a correct posture
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Checking Cutting Boards
If . . .
the product is positioned on a stationary cutting board,
And . . .
the production workers grasp, twist, and turn the product,
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| This worker is removing meat from a pork head. The position of the product and nature of this job forces the worker to maintain ulnar deviation and flex his wrist. Both ulnar deviation and flexing of the wrist are ergonomic hazards that can contribute to cumulative trauma disorders. |
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Then . . .
the production workers are exposed to ergonomic hazards, such as ulnar deviation and flexing of the wrists. These hazards increase the potential for DeQuervain’s disease or Carpal Tunnel Syndrome.
- Try positioning some cuts on slanted boards or rotating carousels to reduce the workers’ exposure to the risk factors associated with hazards mentioned above.
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Corrected Design
A wedge cutting board improves this work station by repositioning and elevating the product. Using this cutting board reduces ulnar deviation and flexing of the wrist.
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Checking Conveyors
If . . .
the product is presented to production workers on a moving conveyor,
And . . .
The production workers bend forward across the conveyor to reach the product, raising their elbows and flexing their wrists to perform the job,
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| These workers are removing chime bones. Even though the work surface is correct for their height, the position of the product forces them to bend their backs, raise their elbows, and flex their wrists to do the job. |
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Then . . .
the production workers are exposed to lower back strains and ergonomic hazards that affect the elbow and wrist.
- Orient the product to best suit the operation performed on the conveyor. This orientation reduces reaching and bending exposures and reduces exposure to ergonomic hazards of the elbow and wrist, without reducing the yield for the conveyor.
- When you position workers on both sides of a conveyor, take left and right handedness into consideration and allow the workers to make their cuts with the movement of the product into their downstream hands. This helps reduce the force required for the job.
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| With workers on both sides of the conveyor, the product was oriented parallel to the conveyor to help reduce the exposure to the ergonomic hazards that affect the elbow, wrist, and back. |
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Checking Conveyors
If . . .
product bins or vats are positioned behind or above conveyors,
And . . .
production workers throw the product to place it into the bin or vat,
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| This worker stands perpendicular to the line, so she must rotate to and from the conveyor to perform her job operations, exposing herself to back injuries. She crosses her left arm over the trimmer blade to throw the product into the vat behind the conveyor, exposing herself to shoulder injuries and laceration. |
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Then . . .
the product flow is poor and production workers are exposed to the following ergonomic hazards that can contribute to cumulative trauma injuries:
- Shoulder Stress
- Carpal Tunnel Syndrome
- Tendonitis
- Tensynovitis
- Back Stress
Poor product flow and the resulting injuries can potentially cost your plant double or triple the cost of the required engineering changes.
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| To improve the design, a conveyor was placed beneath the work surface. The worker drops the bones into the chute at the work surface and the conveyor moves the bones to the end of the line. This design eliminates the need to turn and throw, reducing the worker’s exposure to shoulder injuries and lacerations. |
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- Place trim and fat conveyors under the main conveyor lines and have production workers drop trim and fat through chutes placed near the work surfaces.
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| NOTE: Notice the hazards to the worker in image below. This example is from an actual pork neck bone operation: |
- The worker is standing perpendicular to the conveyor, causing her to turn and rotate on her lower back to retrieve the product from the conveyor, then rotate back toward the conveyor to throw bones into the vat. Both of these movements expose her to lower back injuries.
- She crosses her left arm over the trimmer blade to throw the bone into the vat, which exposes her to potential laceration.
- Throwing the bones causes increased exposure to shoulder injuries.
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| This worker stands perpendicular to the line, so she must rotate to and from the conveyor to perform her job operations, exposing herself to back injuries. She crosses her left arm over the trimmer blade to throw the product into the vat behind the conveyor, exposing herself to shoulder injuries and laceration. |
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Checking Conveyors
If . . .
the product is presented to the production workers on overhead conveyors or workers place trim or bones onto overhead conveyors,
And . . .
the workers reach above their shoulders to grasp and pull the product or to place trim or bones onto the conveyor,
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Then . . .
the production workers are exposed to ergonomic hazards that can affect the shoulders. The muscular structure of the shoulder is complicated and very sensitive when exposed to constant overhead lifting. Shoulder injuries are one of the most disabling in the industry.
- If the size of the product allows it, eliminate or lower overhead conveyors to below the height of the shortest worker’s shoulders. This helps reduce exposure to shoulder trauma.
- Install conveyors under the work surface so workers can push trim or bones into the chute on the work surface, then the conveyors can move it to the end of the line. This eliminates the need for the workers to reach overhead and place the trim or bones on the overhead conveyor.
- Direct the product toward the workers or correctly position the product for the workers before it reaches the work station to eliminate the need to reach, pull, or push the product.
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Checking the Positions of the Whizard® Trimmers
If . . .
the Whizard® Trimmer is positioned at the top of the product,
And . . .
a production worker bends the flex shaft at the base of the trimmer handle to position the trimmer to the product,
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| The Whizard® Trimmer is installed to accommodate only right-handed workers, so this left-handed worker must pull the flex shaft of her Whizard® Trimmer across her body to reach the product. This increases exposure to muscle stress and fatigue, and increases the force required to perform the job. |
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Then . . .
the left-handed production workers are exposed to muscle stress, muscle fatigue, and force, all of which are major contributors to cumulative trauma.
- The position of the motor and flex shaft affects the workers’ posture and the amount of force the workers use to perform their jobs. Position the motor and flex shaft according to the instructions contained in the technical manuals that accompanied each trimmer model that you are using.
- Hang the motor on a rail so you can adjust it for right or left-handed workers.
- Adjust the height of the motor so there is a gradual bend in the flexshaft from the trimmer to the motor when the trimmer is positioned at the top of the product.
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| The trimmer motor is hung so it can be adjusted for right-handed and left-handed workers and the bend in the flex shaft is positioned correctly. This design reduces exposure to the hazards as shown. |
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- Ensure that the trimmer’s range of motion does not result in extreme bending of the flex shaft. Refer to the Whizard® Trimmer installation instructions.
- Set up and follow a preventive maintenance program for the Whizard® Trimmers. Refer to the technical manuals that accompanied your Whizard® Trimmers.
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Checking the Positions of the Whizard® Trimmers
If . . .
the yoke on the trimmer is turned,
And . . .
the motor cannot swivel, so the worker pulls the end of the flex shaft during the job,
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Then . . .
the worker is exposed to increased muscle stress, muscle fatigue, and force.
- The motor of the Whizard® Trimmer is designed to swing in the yoke. The yoke allows the motor to swing when a worker reaches the end of the usable length of the flex shaft during a job.
- Position the motor of the Whizard® Trimmer so it swings toward the work station when the production worker pulls on the flex shaft.
- Movement of the motor in the yoke helps reduce muscle stress, muscle fatigue, and force required to continually pull the flex shaft.
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Checking for Pinch Grips
If . . .
you observe a production worker performing a job,
And . . .
the worker uses a pinch grip to grasp or pull the product,
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Then . . .
the production worker is exposed to the ergonomic hazards that can lead to Carpal Tunnel Syndrome.
- Train workers to use safe grips when grasping or pulling the product, or use hooks or fixtures to hold the product stationary.
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Checking Lighting
If . . .
the lighting in the work area is inadequate,
And . . .
production workers bend their faces close to the product,
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Then . . .
the production workers are exposed to the ergonomic hazards that can affect backs.
- Use a light meter to measure the amount of light at the work surface (you can purchase an inexpensive light meter in most camera shops). The USDA recommends at least 50 footcandles of light at the work surface; however, some jobs that require fine cuts might need 75 to 100 footcandles of light. Increase lighting according to the job needs. Adequate lighting can also improve cut accuracy and yields.
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Understanding the Principles of Work Station Design
If you have a good understanding of work station design, you can conduct a more effective and accurate work station analysis. The following pages explain the principles of a safe work station design, which can help reduce exposure to ergonomic hazards. These pages also illustrate the hazards of, and solutions to, poor work station design. Before you perform your work station analysis, read the following sections of this application guide:
- Using Our Checklist for a Work Station Analysis
- The Hazards and The Solutions, described on the following pages
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After you complete your work station analysis, come back to The Solutions for those hazards you encountered and include those solutions in your ergonomics program. Since each plant is different, we cannot give examples of exposures to the ergonomic hazards that can occur in your particular plant. However, if reducing exposure to injuries in your plant seems difficult, we recommend that you start by doing the following:
- Getting commitment from upper management
- Reading this entire section of the applications guides/li>
- Using videotape to observe problems and record the results of ergonomic changes
- Involving an experienced person who can help conduct the analyses
- Asking some hazard recognition questions like:
--“Have we had an injury on this job?”
--“What kinds of injuries have occurred on this job?”
--“What could have caused the injuries?”
- Asking some experimentation questions, like:
--“If we position the product at another angle, will we eliminate flexing of the wrist but still maintain the quality and yield we need to make a profit?”
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| Simple, practical solutions are usually the best and easiest to maintain. |
Fitting the Work Station to the Worker: The Hazards and Solutions
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The Hazard:
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| Some work stations force workers to use postures of extreme flexing, extending, ulnar deviation, and radial deviation of their wrists. The worker shown in Figure 17A uses these postures due to the poor design of the work station. |
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The work station is too high for the height of this worker and the flex shaft of the Whizard® Trimmer dips below the work surface. This forces the worker to life the flex shaft and bend it again at the base of the trimmer handle as she reaches up to the product (notice her raised shoulder). The edge of this work surface is so high that the worker rests her arms on it as she works. As the worker reaches over the raised edge of the work surface to the product, the right wrist flexes and rotates toward the little finger, causing ulnar deviation of the wrist. These postures and forced movements increase the worker’s exposure to the ergonomic hazards that can contribute to cumulative trauma injuries.
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This work station design causes several problems:
- The height of the work surface and the raised edge make the worker adjust the position of her body to accommodate the height of the work. Notice how the worker raises her shoulder and uses ulnar deviation and a flexed wrist?
- The flex shaft dips below the work surface, so the worker pulls it upward to the product and bends it again at the handle. This causes increases exposure to muscle stress, muscle fatigue, and the force she applies to the trimmer handle.
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The Solution:
Design work stations that permit the worker’s body joints to remain as close as possible to their neutral positions (refer to the worker’s posture in the image below). Keeping the joints close to their neutral positions allows the worker to use maximum muscle strength.
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Design work stations with shoulder height, elbow height, and waist height set to the 95th percentile for the tallest worker. Bring the other workers up to their correct working height by using adjustable stands. The following percentile statistics were collected from a group of workers (in standing positions) consisting of 50% males and 50% females. This design intends the maximum forward reach to be 18 inches.
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Shoulder
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Elbow
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Waist
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Inches
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Percentile
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Inches
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Percentile
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Inches
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Percentile
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48.4
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5th
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38.0
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5th
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37.4
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5th
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54.4
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50th
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42.0
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50th
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40.9
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50th
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59.7
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95th
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40.9
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95th
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44.7
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95th
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In this work station design, the worker stands on an adjustable work station stand that brings her to the correct working height. Notice that her back is straight, her shoulders are square with her body, her elbow is close to her side, and her wrist is comfortable (these postures are close to their natural positions). Also notice that the flex shaft gradually bends from just above the top of the product up to the motor, which means that the motor is hung at the correct height.
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The Hazard:
Extreme body postures are major contributors to cumulative trauma disorders. It is very important to set the correct work station height based on the trimmer position at the top of the product, not just to the work surface. If the elbow, when held at a ninety degree angle, is below the top of the product, the worker must adjust his body to the height of the work. This causes extreme postures of the shoulder, elbow, and wrist.
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The worker in the image below presses the shank of the ham against the work surface to secure it during the job. In doing this, the worker elevates his shoulder, wings his elbow out from his body, and flexes his wrist to adjust to the height of the top of the ham. These postures expose this worker to the ergonomic hazards that can lead to cumulative trauma injuries.
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Notice how this worker uses his left hand to press the shank of the ham against the work surface to secure the ham during his job? He is adjusting his posture to the height of the ham, which causes him to raise his shoulder, wing his elbow, and flex his wrist. These extreme postures are risk factors that can lead to cumulative trauma injuries.
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The Solution:
Improving work station design includes training production workers in safe job techniques. Training and education about working safely and recognizing ergonomic hazards can help production workers feel in control of their jobs, raise the worker’s morale, and keep them safe and healthy while they perform their jobs. Simple changes in work technique cost you only training time, but can save you the costs associated with many injuries and can improve your yields.
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The production worker in figure to the right is still removing fat from hams, but he was taught a simple change in work technique. Notice how he lifts the shank of the ham with his left hand to adjust for the height and contour of the ham? Now the shank of the ham lies in the palm of his hand, while his shoulders maintain a more even position, his elbow is closer to his side, and his wrist is closer to a neutral position. He has significantly reduced the ergonomic hazards associated with his postures in the image to the right.
The worker uses an improved work technique that allows him to adjust his posture for the height and contour of the product. This change in work technique reduces the worker’s exposure to the ergonomic hazards of extreme postures.
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The Hazard:
Another hazardous posture to look for is the forward lean. If a worker leans forward from the lower back to reach for the product, the problem is probably the work station height or the product orientation. If the work station is too low, the worker is exposed to back injuries. If the product station is too low, the worker is exposed to other ergonomic hazards. Look at the worker below. The worker is removing chime bones from pork loins. The top of the working surface is too low for this worker’s height, so he leans forward from his lower back to perform his job. In an attempt to improve his reach to the product, the worker holds his trimmer at the base of the handle, resulting in extreme ulnar deviation of his wrist. Also, notice the position of his index finger on the trimmer handle. Applying pressure to the trimmer handle with the index finger indicates that the worker does not have adequate control of the trimmer. He is increasing the muscle stress, muscle fatigue, and force used during his job. The position of the conveyor and the orientation of the product cause another hazard. With thisconveyor position, a loin could drop from the conveyor and hit the hand the worker uses to hold the trimmer, exposing the worker to the possibility of laceration. This worker leans forward and uses unsafe work techniques to compensate for incorrect work station height and poor product orientation.
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The Solution:
Follow guidelines outlined in this section of the application guide to set correct work station heights for all workers.
- Use adjustable stands to bring workers to the correct working heights.
- Look at product orientation to identify any ergonomic hazards associated with the position or orientation of the product to the worker.
- Use slanted work surfaces, wedged cutting boards, and conveyors of the correct heights to help reduce the workers’ exposure to ergonomic hazards.
The figure below shows the same worker removing chime bones from the pork loins, but his work station is redesigned. This work station design allows the product to feed from the conveyors to the back, left-hand side of the work surface, eliminating the possibility of lacerations caused by a loin falling onto the worker’s trimmer hand. The raised work surface accommodates the worker’s correct working height and the slanted surface of the table reduces the worker’s reach to the product. The slanted surface also helps reduce the worker’s exposure to ulnar deviation and lower back injuries.
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This work station is now redesigned to allow the product to feed from the conveyor to the back, left-hand side of the work surface. The work surface was raised and slanted to improve the worker’s reach to the product. Notice how the worker now keeps his wrist in the neutral position and his back straight?
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The Hazard:
Often the most obvious, and most easily corrected, ergonomic hazards are overlooked, such as the hazards illustrated in Figure 20A. The worker in Figure 20A forces her toes against the toe board of her work station in an attempt to get closer to the product. She still cannot get close enough, so she bends from the lower back to perform her job and increases her exposure to back injury. The flat work surface and the length of the product also increase her exposure to lower back injury.
NOTE: If the toe board was not part of this work station, the worker might move forward to reach the product, allowing her toes to hang over the edge of the stand. This posture causes poor balance, which makes it difficult for the worker to maintain correct body posture during the job.
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This worker is at risk for lower back injuries. She forces her toes against the toe board as she leans forward to reach a long cut of meat, which is presented on a work surface that is too deep for her reach.
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The Solution:
The simple work station corrections in diagram below shows reduce this worker’s lower back stress and lower her risk for back injury. The foot rest that was added to the work station allows the worker to put her foot up or to place her foot under the edge of the work surface. This enables her to get close to the product while maintaining correct body posture. An adjustable, slanted work surface, also added to the work station, helps straighten the worker’s back and adds leverage to the cut. The construction of the slanted surface does not add distance between the worker and the product, but reduces the reach required for her job.
The work station design now uses simple solutions, like a foot rest and an adjustable, slanted work surface. These changes enable the worker to get close to the product and improve her posture during the job.
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The Hazard:
The worker in figure to the right is removing eye lids in a pork operation. The worker reaches and bends forward from the lower back to reach the product. This static back posture exposes the worker to lower back injury and increases his potential of falling from the work stand. This poor work station design exposes the worker to lower back injury and can increase his potential of falling.
The Solution:
In the improved work station design in Figure 21B, the work stand is closer to the hog. The worker can now stand upright with his arms close to his body, reducing his exposure to lower back injury. A hand rail was also added to prevent the worker from falling. Sometimes simple solutions, like moving this worker closer to his work and adding a hand rail, can easily reduce exposure to ergonomic hazards.
Reducing Exposure to
Carpal Tunnel Syndrome
The Hazard:
Most of the information published about Carpal Tunnel Syndrome in our industry cites flexed and deviated wrists as the main cause of the disease. However, in 1978 Armstrong and Chaffin, of the University of Michigan, researched Carpal Tunnel Syndrome in sewing machine operators. The study shows that the following operators experiences Carpal Tunnel Syndrome:
- 56% of the operators who used the pinch grip during their jobs
- 42% of the operators who held their wrists in neutral positions
- 28% of the operators who used extended wrists during their jobs
- 24% of the operators who used flexed wrists during their jobs
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Production workers in the meatpacking industry use a pinch grip to place bones, meat, and trim onto conveyors. Carpal Tunnel Syndrome of the opposite hand can possibly be caused by using the pinch grip to pull the product from the conveyor line, to grasp the product during the job, then to place the product onto a conveyor or into a bin. The cost of one case of Carpal Tunnel Syndrome that keeps a production worker from returning to work can exceed $150,000. If the production worker is off the job for six to ten weeks, the company loses a trained worker, spends more money to train a new worker, and also risks additional expenses due to other cases of Carpal Tunnel Syndrome.
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The Solution:
Design production lines to accommodate safe work flow. Train workers to use hooks or use a better method of grasping the product. Reducing the exposure to Carpal Tunnel Syndrome can help maintain a stable, well trained work force and save your company money.
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A Summary: Taking Advantage of Strength Postures
If you notice that workers’ postures include raised shoulders, bent backs, or flexed wrists, the workers are trying to adjust their body postures by positioning themselves to their work. These adjustments increase the workers’ exposure to ergonomic hazards by concentrating most of the force on the weaker muscle groups of the hands, arms, and shoulders.
If workers are reaching above their shoulders to overhead conveyors and bins, or are reaching over 18 inches (46 cm) to grasp the product, they are increasing their exposure to shoulder injuries. Reaches like these are common causes of cumulative trauma disorders.
The main objective of any job design is to use the strongest muscle groups to perform the job. Each illustrated example in this section showed you how to make adjustments that can reduce the workers’ exposure to the ergonomic hazards that contribute to cumulative trauma injuries.
Plan to make the required engineering changes to improve the work station designs in your plant. Remember, adjustable stands help spread the workloads over the production workers’ strongest muscle groups. Conveyors installed under the main line can carry trim, fat, and bones after production workers feed the product to the conveyor through chutes installed close to their working hands. Work surfaces of the correct depth eliminate the need to reach over 18 inches (46 cm) to the product.
Engineering changes are not always expensive, especially when compared to the cost of one injury, which can easily be double the cost of the required stands or conveyors. The expenses of permanent medical disabilities and reduced yields are far more than the costs of implementing the required changes at your work stations. If the work station designs are correct, the production workers can take advantage of their natural strength postures, which helps reduce exposure to cumulative trauma injuries.
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Performing Your Work Station Analysis?
During your work station analysis, look at the design of your work stations to determine the risk factors present when the production workers use the Whizard® Trimmers. While many factors can influence ergonomic safety, work station design is probably one of the strongest influences.
Bettcher Industries, Inc. studied the designs of work stations and how they affected the use of the Whizard®Trimmers. We found that poor work station design can easily defeat the ergonomic benefits of a well-designed tool. The work station analysis is a simple technique that can do the following for your plant and its production workers:
- Identify ergonomic hazards associated with the jobs and your present work station designs
- Identify the best work techniques for a job and for training new production workers for that job
- Recommend solutions to help reduce exposures to the ergonomic hazards associated with the jobs and work station designs
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Now you are ready to perform the worksite and work station analyses for your plant. Use this section of the application guide to remind you of some of the ergonomic hazards that are most common in our industry. Look for these and other ergonomic hazards during your worksite analysis.
Other work station hazards that are not described in this application guide might exist in your plant. Use the methods of analysis that are described in this guide, such as videotaping and talking to production workers, to be sure that you address all the ergonomic hazards that are present at your work stations. Also refer to the OSHA guidelines for more detailed information about performing worksite analyses.
For More Information
To read more on this important topic, here are is a few link to consider:
Worker Safety in the Meat and Poultry Industry Fact Sheet
www.workersafety.org
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