addressing the root cause of preventable injuries · the study of work and the relationship of work...
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Addressing the Root Cause of Preventable Injuries
Presented by: Misty J. Chapman
Ergonomic Consultants of Indiana 11595 N. Meridian Street Suite 140
Carmel, IN 46032 (317) 708 ‐ 4832www.eci‐in.com
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Musculoskeletal Disorders in the Workplace
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Musculoskeletal disorders, or MSDs, are injuries or illnesses to soft body tissue such as:
Muscles
Nerves
Tendons
Ligaments
Joints
Cartilage
Spinal Discs
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Sprains/Strains Injuries
1. Sprains:
‐ stretching or tearing ligaments
2. Strains:
‐ stretching or tearing tendons or muscles
Chart B. Distribution of sprain, strain, and tear cases requiring days away from work by selected event or
exposure and part of body, all ownerships, 2011
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Common Musculoskeletal Disorders (MSD’S)
• Carpal Tunnel Syndrome
• Muscle Strains
• Shoulder Pain & Soreness
• Elbow Tendonitis
• Plantar Fasciitis
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Who is at Risk? Repeat the same motion throughout their workday
Must do their work in an awkward position
Use a high force to perform their job
Repeatedly lift heavy objects
Combination of risk factors
Ergonomics
• Primary focus of an ergonomics program is the reduction of WMSD
• This is accomplished through the management of employee exposure to workplace hazards» Awkward postures» Forceful exertions » High rates of repetition
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Ergonomics (er'gõ nom'iks):
The study of work and the relationship of work to the physical and cognitive capabilities of people
Fitting the job (tools, tasks, and environment) to the employee, instead of forcing the worker to fit the job
Ergonomic principles derived from many areas, including:
Biomechanics
Physiology
Anthropometry
Industrial engineering
Safety
What is Ergonomics?
Fitting the Workplace to the Person
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Ergonomics
OSHA defines ergonomics as:
… the science of “designing the job to fit the worker, instead of forcing the worker to fit the job.”
Lathe Operator
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Normal guy
Perfect Lathe Operator
• Risk Factors inherent to
the Task
• Risk Factors inherent to
the Worker
• Risk Factors inherent to
the Environment
Occupational Ergonomics
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Why do Injuries Occur at Work?
• Job Design & set-up
• Job demands exceed employee capabilities
• Failure to account for human physiological
limitation
• Work stress (psychosocial factors)
• Failure to account for body size differences
One of many factors that contributes or creates an undesired outcome (MSD) and if eliminated would have prevented the
undesired outcome!
Have to start with analyzing Workplace Risk Factors!
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Risk Factors inherent to the Task
• In the picture, the worker is moving a box from the pallet to a dolly. Using the dolly eliminates forceful exertions needed to carry the box, but when he moves the box to the dolly, he is exposed to two risk factors: forceful exertions and awkward postures
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Ergonomic Risk Factors & Hazards for WMSD’s
Repetitive Motions
Awkward Postures & sustained
Forceful exertions
Pressure points (contact stress)
Vibration
Repetitive Motion
• Duration of task
• Frequency of task
• Speed of work or cycle time to do each cycle
• Productivity requirements
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Repetition
Repeating the same motions every few seconds or repeating a cycle of motions involving the affected body part more than twice per minute for more than 2 consecutive hours in a workday.
Using an input device, such as a keyboard and/or mouse, in a steady manner for more than 4 hours total in a workday.
Source: OSHA
Repetitive Motion
Is often a concern in:
assembly tasks
sorting tasks
loading or off-loading materials
inventorying products
product stocking
software programming
telemarketing
customer service
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• Repetition:
– Use power tools when available
– Use shortcuts on keyboard
– Use ergonomic products (trackball)
– Change tasks, stretch, or take a break from repetitive tasks
– Follow job rotation policies where applicable – effective job rotations work alternate muscle groups between successive job functions
Ergonomic Tips to Minimize Repetition
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Awkward Postures
Positions that require more effort than others or that result in compression or stretching of the tissues in or around joints
Non-Neutral
Examples:Overhead Reaching
Twisting
Forward Bending
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ECI’s Guidelines ‐ Awkward Postures
Hands/Wrists Flexed ≥ 45°
Extended ≥ 45°
Ulnar Deviation ≥ 30°
Radial Deviation ≥ 30°
Elbows Elbow Extension ≥ 135°
Fully Rotated
“wings”
Shoulders Arm Raised ≥ 45°
Arm behind body
Shoulders Shrugged
Neck Flexed ≥ 30°
Extended
Twisted ≥ 20°
Sideways
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Awkward Postures – cont’d
BACK
Flexed ≥ 20°
Twisted ≥ 20°
Extension
Sideways
Unsupported (chair)
LEGS
Kneel
Unsupported
Partial Squat (45°)
Awkward Postures are caused by:
• Location of parts, equipment or tools
• Position of parts, equipment or tools
• Design of parts, equipment or tools
• Employee work habits (choice vs. design)
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BACK
• Flexed ≥ 20°• Twisted ≥ 20°• Extension• Sideways• Unsupported (chair)
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2010 IAOHN Conference
Proper Sitting Position
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PARTIAL Forward Bending
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• Flexed ≥ 45°
• Extended ≥ 45°
• Ulnar Deviation
• Radial Deviation
Risk Factors for the Hands and Wrists
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Wrist – Use straight wrist positions
Working with bent wrists decreases grip strength
Use tools that let you keep your wrist straight
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Neutral vs. Non‐Neutral
Common Keyboard Position
2010 IAOHN Conference 44
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ELBOWS
•Elbow Extension ≥ 135°•Fully Rotated•“wings”
Arms Away from Body
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Excessive Reaching
Move keyboard and mouse closer to you, adjusted to approximately elbow height.
ELBOWS IN
Elbows out andwrists bent
Are elbows relaxed and resting by the torso during keying or mousing?
Keyboard Position ‐ Arms by your side
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SHOULDERS
• Arm Raised ≥ 45°• Arm behind body• Shoulders Shrugged
Source: 40” horizontal repetitive reach for sander located on the side wall. In addition, the employee will reach for tools and parts resulting in elbow extension.
Raised Shoulders
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SHOULDER SHRUGGED & RAISED
NECK
• Flexed ≥ 30°• Extended • Twisted ≥ 20°• Sideways
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Forward Head
Your head weighs??
Forward head posture puts up to three times more force on the base of your neck
Headaches are associated with this posture
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Neck: Twist >20°
Forceful Exertions
Lifting bag weighing 50 lbs. Lifting manhole cover weighing 75lbs.
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Ergonomic Tips to Minimize Force• Use mechanical lift assists and carts
when available
– Avoid manually handling heavy objects (more than 35 pounds)
– Avoid carrying objects more than 100 feet
• Practice Proper Cart Handling
– Push instead of pulling
– Use both hands when pushing
– Stand directly behind the cart when pushing (avoid twisting your body)
– Maintain good control and limit speed
– Ensure cart is not overloaded
Pushing versus Pulling
• Force exerted by the body
– Type of wheels
– Types of bearings
– Type of surface
– Slope of surface
– Handle height
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Pushing versus Pulling
• Force exerted by the body
– Pulling force
• Flex spine
• Back muscles contracting > ⇑ compressive forces
Pushing versus Pulling
• Force exerted by the body
– Pushing force
• Abdominal muscles are more active
• Less compressive force
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Pushing versus Pulling
• Control options
– Keep forces low• Initial and peak
– Handle height between hip and shoulder
– Large wheels
• To ⇓ friction
– Slip resistant shoes
– Good housekeeping
– Good steering mechanism
– Incline surfaces < 2
Ergonomic Tips to Minimize Force• Use proper lifting techniques when
lifting– Examine the load and the
surrounding area– Bend knees when lifting a load– Look forward to keep back straight– Position the load close to the body– Maintain a firm grip on the load– Use smooth, controlled movements– Keep arms in front of body– Turn feet in direction of movement
to avoid twisting
Get help before performing tasks requiring excessive force
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A lift, hoist or other mechanical assistance
is unavailable
The object is heavier than you are capable
of lifting alone (typically more than 35
pounds)
The object is not heavier than what two
people are capable of lifting (typically less
than 60 pounds)
The object is awkward or oversized.
Any object that does not have its weight
equally distributed within the load.
Remember some objects are too heavy
or awkward to be handled with two
people
A Two‐Person Lift Is Appropriate When. . .
Ergonomic Tips to Minimize Force
Ergonomic Tips to Minimize Force
• Use the correct tools / powered tools for the task
– Powered tools tend to require less exertion to perform a task
– Ensure that the weight of a powered tool (and cording) does not create additional force issues
• Use only the amount of force necessary to complete the task
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Minimize Pressure Points
Contact: Forearm
Before
Minimize Pressure Points
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Contact: Fatigue MatContact: Hard Floor
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Treatment for Plantar Fasciitis
• ErgoMates: Anti-fatigue mat on the shoe. Protects the feet where you walk.
• Do calf stretches• Stretch calves before
getting out of bed.• Ice with water bottle!• Use golf ball to massage
heel. Roll heel over ball.
Ergonomic Tips to Minimize Contact Stress
• Select hand tools that conforms to the geometry of the hands
• Pistol grip & in‐line tools:– Recommended handle length: 5.0 inches– Recommended handle diameter: 1.0 to 1.5 inches
• Pliers & crimping action tools:– Recommended handle length: 4.0 inches (minimum)– Recommended handle span: 2.5 inches
• Avoid handles that end in the palm of the hand
4.0 inches
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Ergonomic Tips to Minimize Contact Stress
Avoid pressure on knees:– Avoid kneeling on hard surfaces for prolonged periods– Use knee pads when kneeling tasks are unavoidable
Avoid pressure on palms, wrists, and elbows: Use padding on hard or sharp surfaces
Change your position to eliminate the stress
Vibration
Using tools or equipment that typically have high vibration levels (such as chainsaws, jack hammers, percussive tools) for more than 30 minutes per day.
Using tools with moderate vibration levels (such as jig saws, grinders, etc.) for more than two hours per day.
Source: OSHA
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• Hand‐arm vibration measurements and analyses should be performed according to ANSI S3.34, ACGIH‐TLV, and NIOSH 89‐106 recommendations.
• Any and all vibration is hazardous.
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Vibration Values
Die Grinders Vibration Value (m/s2)
Dotco
12L2500-36
90 psi/23000rpm3.5
3M
20237
20,000rpm
< 2.5
Dynabrade - 52669
Straight-Line Die Grinder
1.9
Dotco - 52679
6” Straight-Line
Extension
4.2
Ergonomic Tips to Minimize Vibration & Torque
• To lessen vibration:– Pad tool handles with a soft compressible surface– Use vibration damping (gel filled) gloves
– Select tools (hammers and chippers) with built in damping systems (springs/hydraulics)
• To lessen torque reaction:– Use electric tools as opposed to air driven tools– Use pulse tools or auto‐shutoff tools
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Human Factors
• People are Different
• People have Limitations
• People have Predictable Reactions
Risk Factors inherent to the Worker
• Age ‐ 26% in the 45‐54 age category
• Gender
• Physical Activity
• Strength
• Athropometry
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Risk Factors inherent to the Worker
• Age ‐ 26% in the 45‐54 age category
• Gender
• Physical Activity
• Strength
• Athropometry
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Incorporate Movement: Treadmill Walkstation
Energy Expenditure• Aerobic activities
– Produce whole body fatigue• Fast paced: lifting, lowering, walking, climbing
• Repetitive lifting > overexertion injury
– Factors affecting aerobic capacity• Gender
• Age
• Physical fitness
• Nature of work
• Whole body
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Energy Expenditure: Control Options
• Effect of the workload
– Lifts versus trips• Fatigue versus spinal compression
• Lifting technique
• Efficiency
– Amount of work
– Endurance
• Work pace
– Heavier object
– Heavier body weight
• Lift versus lower
– Lower less energy
• Carrying location
– Center of gravity
Risk Factors inherent to the Worker
• Age ‐ 26% in the 45‐54 age category
• Gender
• Physical Activity
• Strength
• Athropometrics
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Different Shapes & Sizes
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Behavioral & Cognitive
• Daily time at workstations (personal vs. work)
• Design vs. User’s behavior
• Lack of "ownership" in personal safety on the part of the employee.
“IT WON’T HAPPEN TO ME!!!!”• Lack of adjustable furniture at some worksites
• Lighting
• Temperature
• Vibration & Shock
• Noise, etc.
Risk Factors inherent to the Environment
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Ergonomics Improvement Process
1. Analyze Issues
2. Identify root causes or source of problem
3. Identify Improvements
4. Justification of cost or improvements
5. Follow Up to verify improvements
Ergonomic Consultants of Indiana
11595 N. Meridian St., Ste 140
Carmel, IN 46032
(317) 708 ‐ 4832
Services: www.eci‐in.com
Ergo Products: www.myergoplace.com