The document discusses industrial hygiene and ergonomic controls. It defines ergonomics as fitting the workplace to the person to prevent injury. It notes that ergonomics can improve quality, health, and reduce costs. The document discusses engineering, administrative and personal protective equipment controls and emphasizes engineering controls as the preferred method. It also covers topics like anthropometry, common postures, ranges of motion and repetitive motions.
3. Ergonomics
VARIOUS AUTHORS DEFINE ERGONOMICS AS:
The study of man’s relationship with his or her
workplace.
Fitting the task to the person rather than forcing
him/her to adapt to the work environment.
Designing the workplace to prevent occupational
injury and illness.
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Slide 3
4. Ergonomics
VARIOUS AUTHORS DEFINE ERGONOMICS AS:
Discovering the capabilities and limitations of the
human body.
The art and science that addresses workers’ job
performance and well-being in relation to their job
tasks, tools, equipment and environment.
The study of the relationship between people and
machines or between employees and their
environment.
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5. Ergonomics
VARIOUS AUTHORS DEFINE ERGONOMICS AS:
The study of the interaction between the
worker and the process at the workplace.
WHAT OTHER DEFINITIONS
HAVE YOU HEARD?
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6. Ergonomics
ERGONOMICS PLAYS A ROLE IN APPROXIMATELY 50% OF
ALL WORKPLACE INJURIES. ERGONOMICS WILL HELP:
Improve quality.
Improve absenteeism.
Maintain a healthier work force.
Reduce injury and illness rates.
Acceptance of high-turnover jobs.
Workers feel good about their work.
Reduce workers’ compensation costs.
Elevate OSHA compliance to a higher level of awareness.
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Slide 6
7. Ergonomics
“It is estimated that in the United States,
97% of the money spent for medical care is
directed toward treatment of an illness,
injury or disability. Only 3% is spent on
prevention.”
Self-help Manual for your Back
H. Duane Saunders, MSPT
by Educational Opportunities
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Slide 7
8. Historical progression of WMSDs
(Work related Musculoskeletel disorders)
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Slide 8
9. Ergonomics
A Multi-disciplinary Approach
THINK ABOUT THE NUMBER
OF WAYS ERGONOMICS
IMPACTS OUR
DAILY LIFE!
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10. Ergonomics
A Multi-disciplinary Approach
FOR EXAMPLE!
The science of ergonomics is
critically important in the
continuing development of
the
AUTOMOBILE!
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11. Ergonomics
A Multi-disciplinary Approach
THE FOLLOWING DISCIPLINES HAVE PLAYED A ROLE IN
DEVELOPMENT OF THE AUTOMOBILE:
Economics
Sociology
Physiology
Psychology
Biomechanics
Physical Sciences
Management Philosophies
Engineering, Industrial Design
Safety & Health, Human Factors Engineering
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12. Program Implementation
IMPLEMENTATION OF AN ERGONOMIC PROGRAM REQUIRES:
Personal Interest
Dedication
Management Commitment
NOTE:
UNDERSTANDING AND SUPPORT FROM THE WORK FORCE IS
ESSENTIAL, WITHOUT IT THE PROGRAM WILL FAIL!
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13. Typical Applications
APPLICATIONS
Work station design
Tool selection and design
Office safety improvement
Video display terminals (VDT’s) safety
Back injury reduction and prevention
Manual material handling improvement
Cumulative trauma disorder (CTD) reduction
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14. Industrial Hygiene And
Ergonomic Controls
ENGINEERING CONTROLS 1st CHOICE
Work Station Design Tool Selection and Design
Process Modification Mechanical Assist
ADMINISTRATIVE CONTROLS 2nd CHOICE
Training Programs Job Rotation/Enlargement
Pacing Policy and Procedures
PERSONNEL PROTECTIVE EQUIPMENT LAST CHOICE
Gloves Wraps
Shields Eye Protection
Non-Slip Shoes Aprons
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15. Source of ergonomic
hazards
1. The work itself
2. The workstation
3. Workpiece / tools
4. Working environment
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16. Industrial Hygiene And
Ergonomic Controls
OCCUPATIONAL RISK FACTORS:
Occupational risk factors are defined as any attribute of a job or
task that we know increases the probability of injury or illness.
INAPPROPRIATE
1. Force - Including- Internal or External
2. Posture - Such as - Extreme Twisting or Bending
3. Repetition - Including- Muscle Group Overexertion
4. Insufficient Rest - Including- Muscle Group Overexertion
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17. Industrial Hygiene And
Ergonomic Controls
WORKSITE ANALYSIS IS DIVIDED INTO 4 MAIN PARTS:
1. Gathering information from available sources.
2. Conducting baseline screening surveys to determine which
jobs need a closer analysis.
3. Performing ergonomic job hazard analyses of those work
stations with identified risk factors.
4. After implementing control measures, conducting periodic
surveys and follow-up to evaluate changes.
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18. Industrial Hygiene And
Ergonomic Controls
TANGIBLE INDICATORS:
Accident Records
Production Records
Personnel Records
Employee Surveys
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19. WORKSITE ANALYSIS
Continued
SYMPTOM SURVEY
1. Note areas of pain
or discomfort!
2. What do you feel is
the source?
3. What environmental
changes would help?
4. What other feedback
can be gathered?
FRONT BACK
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20. INDUSTRIAL HYGIENE AND
ERGONOMIC CONTROLS
WHAT TANGIBLE
INDICATORS
WOULD BE MOST
USEFUL TO YOU?
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21. INDUSTRIAL HYGIENE AND
ERGONOMIC CONTROLS
INCIDENCE RATES: incidence rates for upper extremity
disorders and/or back injuries should be calculated by counting
the incidences of CTDs and reporting the incidences per 100 full
time workers per year per facility.
INCIDENCE RATE
(NUMBER OF NEW CASES (200,000 WORK HRS*) PER FACILITY
NUMBER OF HOURS WORKED/FACILITY/YR
200,000 = approximate annual work hours for 100 workers.
The same method should be applied to departments, production lines, or
job types within each facility.
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Slide 21
22. INDUSTRIAL HYGIENE AND
ERGONOMIC CONTROLS
• SAMPLE INCIDENCE RATE CALCULATION:
(Number of new cases (200,000 work hrs*) per facility
Number of hours worked/facility/yr
If you experienced 2 carpal tunnel cases last year, in a population of 100 employees.
What is the incidence rate?
2 X 200,000
IR =
100 X (50 X 40 hrs)
400,000 IR = 2 CASES OF CARPAL TUNNEL PER
IR =
200,000 100 PERSON-YEARS OF EXPOSURE
* 200,000 = approximate annual work hours for 100 workers.
* The same method should be applied to departments, production lines, or job types
within each facility.
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23. ANTHROPOMETRY
ANTHROPOMETRY:
The technology of measuring and
quantifying various human physical traits
such as size, weight, proportion, mobility
and strength.
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24. Anthropometry
Engineering
Anthropometry:
The application of anthropometric
data to equipment, workplace and job
design to enhance the
efficiency, safety and comfort of the
operator.
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Slide 24
25. Anthropometric
Measurements
• When designing products it is important to
remember that people come in many sizes
and shapes.
• Anthropometric data varies considerably
between regional populations.
• For example, Scandinavian populations tend
to be taller, while Asian and Italian
populations tend to be shorter.
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26. Anthropometric
Measurements
The relative sizes of different percentile humans.
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27. Anthropometric
Measurements
• It is common practice to design for the 5th percentile
(5th%) female to the 95th percentile (95th%) male.
• The 5th% female value for a particular dimension (e.g.
Sitting height) usually represents the smallest
measurement for design in a population.
• Conversely, a 95th% male value may represent the largest
dimension for which one is designing.
• The 5th% to 95th% range accommodates approximately
90% of the population.
• To design for a larger portion of the population, one might
use the range from the 1st% female to the 99th% male.
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Slide 27
28. Common Ranges Of
Measurements (For Office
Furniture Design.
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Slide 28
30. Common ranges of measurements
used in office furniture design.
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Slide 30
31. Common Workplace
Postures
There are common postures found in the
office environment that can be considered
when designing workplace products or
space.
• Standing
• Sitting
• Reaching
• Moving
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32. Standing
Desk height for a standing operator can range from 28 - 43“
(Grandjean, 1997) depending on whether the desk is for precision,
light, or heavy work.
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33. Sitting
• Knowing what parameters to design for while the user
is seated can help increase the comfort of the user.
• Common seated anthropometric measurements can
be seen in slide 17
• Spine and Lumbar
– Maintaining the neutral, or standing shape of the lumbar, or
lower spinal area, is important for comfort and posture.
– Chairs can give appropriate and correct lumbar support.
– This seated lumbar support will help the spine maintain an S-
shaped curve similar to the spine’s shape when standing (as
seen in Figure 5.)
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Slide 33
35. Sitting
• Posture
– Correct seated posture is a continual debate with
ergonomic professionals.
– Some say that users need to have a 90-90-90 degree
placement for the elbow, hip, and knee joints,
respectively.
– Others feel that a variation in this placement is better, as
long as it does not lead to slouching or hunching over.
– A good seated posture is one that is comfortable and
does not put a lot of stress or strain on the user’s
buttocks, back, or arm muscles, and allows the user’s
feet to be on the floor.
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36. Reaching
• The workstation, and parts that go with
workstations (such as overhead storage and
pedestals), should allow the majority of
movement of the user’s body joints within
healthy zones.
• When designing products, consider how much
individuals will have to reach in order to
minimize awkward or unhealthy positions.
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Slide 36
37. Moving
• Users will move around in their environment to file
papers, answer a phone, or stretch.
• An occasional break from sitting is encouraged
because it helps to stimulate muscles, and increases
blood flow, which decreases fatigue.
• The space in a cubicle or desk area should allow the
chair to move around easily.
• Also, a wheelchair may need to turn around or move in
the office space, requiring a 60" diameter turning
radius and at least 36" of passage width
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38. Moving
• Chairs and other devices in the workspace can allow the user to
easily get up and move around without having to move armrests,
adjust other chair settings, or put undue stress on the body.
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39. Ranges of motion (ROM) for
different joints.
• Zone 0 (Green Zone)
Preferred zone for most movements.
Puts minimal stress on muscles and joints.
• Zone 1 (Yellow Zone)
Preferred zone for most movements.
Puts minimal stress on muscles and joints.
• Zone 2 (Red Zone)
More extreme position for limbs. Puts greater
strain on muscles and joints.
• Zone 3 (Beyond Red Zone)
Most extreme positions for limbs, should be
avoided if possible, especially with heavy
lifting or repetitive tasks.
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40. Repetitive Motions
• If repetitive tasks are necessary, minimizing the
number of continuous movements can help reduce the
risk of injuries.
• There is no specific number for minimum daily
repetitions.
• The factors affecting repetitive tasks include user’s
muscle strength, amount of force required, and type of
task.
• Decreasing the amount of force required to perform a
task will also lower the risk of pain and musculoskeletal
disorders.
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Slide 40
45. Wrist posture with
the keyboard
placed at different
positions, including
flat, positive, and
negative tilt
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Slide 45
46. When body joints are in
awkward postures, maximum
force produced decreases.
Muscle fatigue will occur
earlier when working in an
awkward posture instead of a
neutral posture.
Hand dynamometer
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47. Pinch grip & power grip
A power grip curls the
fingers toward the palm;
a pinch grip presses the
thumb against the
fingers of the hand or an
object, and does not
involve the palm.
The amount of force that
can be generated
depends on the type of
grip and the width of the
grip.
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48. Fatigue Failure
Endplate fractures usually occur through
repeated loading, by a process known as
fatigue failure
The vertebrae of the back can have multiple
sub-failures that are not visible but can result
in complete failure over time.
The number of cycles that lead to failure of
the vertebrae varies across the population.
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Slide 48
49. Moment Arms And Lifting
Principles
• Reduce the weight of the object being lifted.
• Keep loads close to the body when lifting.
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50. Moment Arms And Lifting
The length of the moment arm
and weight of the object both
affect the forces exerted by the
lower-back muscles.
The size and shape of the object
lifted or carried, existence of
barriers, and design of
workstations are all factors that
affect the moment arm of an
object being lifted or carried.
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51. Ergonomic Risk Factors
PERSONAL RISK FACTORS
1. Age
2. Gender
3. Attitude
4. Training
5. Strength
6. Work Method
7. Anthropometry
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Slide 51
52. Ergonomic Risk Factors
JOB RISK FACTORS
1. Weight of load
2. Location/size of load
3. Frequency of the Task
4. Duration and pace of cycle
5. Stability of load
6. Coupling of load
7. Travel distances of worker
8. Reach distances of worker
9. Symmetry between worker and the object
held
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Slide 52
53. Ergonomic Risk Factors
JOB RISK FACTORS
10. Static work posture
a) Standing
b) Sitting
11. Work platforms or stairs
12. Torso flexion (bending)
a) Mild (up to 45 degrees)
b) Severe (greater than 45 degrees)
13. Work heights (too high or too low)
14. Floor surfaces (wet, smooth, vibration)
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Slide 53
54. Ergonomic Risk Factors
JOB RISK FACTORS
15. Environment
a) Hot (sweat, reduced grip, fatigue)
b) Cold (gloves reduce grip by as much as 30%)
16. Lighting
a) posture problems (because of inability to see)
17. Noise/vibration
a) Frequency very important
b) Can amplify through the body
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Slide 54
55. Ergonomic Risk Factors
WHAT ARE THE
PRIMARY RISK
FACTORS
ASSOCIATED WITH
YOUR JOB?
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Slide 55
56. Job And Task Analysis
UNIT LOADS:
DEFINED AS:
The unit to be moved or handled
at any one time.
THE CONTAINER, CARRIER, OR SUPPORT USED
TO MOVE MATERIALS MUST BE INCLUDED AS PART OF THE
UNIT LOAD.
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Slide 56
57. Job And Task Analysis
FACTORS AFFECTING UNIT LOADS
The material to be utilized
The quantity of material to be handled
The susceptibility of the material to damage
The number of times the unit load is handled
The receiving, storing, shipping, and handling methods
The environmental conditions to which the load is exposed
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58. Job And Task Analysis
DESIGNING THE UNIT LOAD
Optimize the weight of the load
Reduce the size of the load
Insure stability of the load
Optimize load coupling
- HAND TO LOAD
- FOOT TO FLOOR
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59. Job And Task Analysis
DEFINITION OF TERMS:
Fundamental Movements or acts
“ELEMENT”
- Search - Inspect
- Select - Assemble
- Grasp - Disassemble
- Reach - Delay (unavoidable)
- Move - Delay (avoidable)
- Hold - Plan
- Position - Rest (overcome fatigue)
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Slide 59
60. Job And Task Analysis
DEFINITION OF TERMS:
The time required to complete one sequence of tasks
sub- tasks, or elements.
“CYCLE”
Example:
1. Assemble new box
2. Put bottles in box from conveyor
3. Stack boxes on pallet
4. Go to step 1
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61. Job And Task Analysis
TASK ANALYSIS
Identify the job to study
Collect the data
Evaluate the data
Formulate control measures
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62. Job And Task Analysis
IDENTIFYING THE JOB TO STUDY
Accident investigations
Accident statistics
Complaints & operator feedback
Production bottlenecks, high errors
High employee turnover jobs
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Slide 62
63. Job And Task Analysis
COLLECTING THE DATA
Direct observation
Video tape
Action photographs
Documentary accounts
Accident statistics
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Slide 63
64. Job And Task Analysis
EVALUATING THE DATA
Task description
Sub-task description
Element description
Risk factor/hazard identification
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65. Job And Task Analysis
FORMULATING CONTROL MEASURES
Application of ergonomic principles
Corrective action for non-compliance
Eliminate or reduce exposure
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66. Job And Task Analysis
TASK ANALYSIS FORM
TASK DESCRIPTION - Action Being Performed
LEFT HAND - Usage
RIGHT HAND - Usage
FREQUENCY - Usually per minute
NOTES - Supporting information
POSTURE - Acceptable to extreme
FORCE - High, Medium, Low
DURATION - Length of Stressor
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67. Job And Work Station Design
GOOD JOB DESIGN
REDUCES Discomfort, Fatigue, Aches & Pains
Injuries & Illnesses, Work Restrictions
AVOIDS Absenteeism, Turnover, Complaints,
Poor Performance, Poor Vigilance
ABATES Accidents, Production Problems,
Poor Quality, Scrap/Rework
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Slide 67
68. Job And Work Station Design
GOOD JOB DESIGN
EMPLOYEE:
PREVENTS Economic Loss, Loss in Earning Power,
Loss in Quality of Life, Pain & Suffering
EMPLOYER:
PREVENTS Economic Loss, Loss in Expertise,
Compensation Costs, Damaged Goods
& Equipment
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Slide 68
69. Job And Work Station Design
DESIGN CONSIDERATIONS
Design for the Range-of-Motion of the Worker
Design for the Field of Vision of the Worker
Design out Extreme Ranges-of-Motion
Reduce Force in Job Accomplishment
Reduce the Frequency of Motions Required
Reduce the Duration of a Specific Task
Design to Provide Adequate Support to Back, and Legs
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Slide 69
70. Job And Work Station Design
DESIGN CONSIDERATIONS
Incorporate Adjustable Work Surfaces
Design Delivery Bins to Accommodate Various Heights
Design Delivery Bins to Accommodate Various Reaches
Design Work Platforms with Ranges-of-Movement
Incorporate the use of Mechanical or Powered Assists
Incorporate the use of Suspension Devices for Tools
Incorporate the use of Floor mats to Reduce Leg Trauma
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Slide 70
71. Job And Work Station Design
THE BOTTOM LINE
Do not design for the average!
Do not design for yourself!
The large must be able to fit!
The small must be able to reach!
Design for a range!
Design for adjustability!
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Slide 71
72. Job And Work Station Design
WHAT ADDITIONAL
DESIGN
CONSIDERATIONS
CAN YOU THINK OF
FOR WORK
STATIONS?
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Slide 72
73. Job And Work Station Design
DESIGN CONSIDERATIONS
Consider the Gender and Age of Users.
The Specific Use of the Tool Is Critical.
Contact Manufactures for Their Assistance.
Make Informed Decisions Before You Buy.
Don’t be Fooled by Misleading Advertising.
Any Other (than its intended) Use Negates Possibly All
Benefits and May Prove to be Detrimental to an Ergonomic
Program.
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Slide 73
74. Job And Work Station Design
REMEMBER
A TOOL WHICH IS CALLED AN
“ERGONOMIC TOOL”
IS ONLY AN ERGONOMIC TOOL
WHEN IT IS USED FOR ITS INTENDED
PURPOSE
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Slide 74
76. Tool Design And Selection
Tools come in endless variety, the next few slides
provide some considerations to think about.
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Slide 76
77. Tool Design And Selection
HANDLE CONSIDERATIONS
Criteria consideration
Diameter - avoid one size fits all
Hand fit - avoid grooves and contours
that cause pressure points
Handle - non-conductive
Material - textured to avoid slip or twist
- Consider thickness
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Slide 77
78. Tools whose handles
are sized and
shaped to
complement the
hand, require less
effort to use, thereby
reducing the muscle
fatigue that leads to
discomfort.
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Slide 78
79. Tool Design And Selection
HANDLE CONSIDERATIONS
Criteria consideration
Orientation - accommodates straight wrist?
Span - not too large to grasp easily?
Grip strength - consider powered tools when
operator has difficulty with
forces or high repetition!
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Slide 79
80. Adjustability in tools, or
multiple tool designs, is
important because it
allows for neutral postures
to be adopted
When selecting or
purchasing a
tool, consider the ability of
the tool’s handle to be
adjusted in multiple
positions to keep the wrist
in a neutral posture
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Slide 80
81. Tool Design And Selection
GUARDING CONSIDERATIONS
Criteria consideration
Pinch points - pinch and nip points covered?
- Stopper to avoid closing fingers?
Exhaust - pointed away from hand and body?
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82. Tool Design And Selection
FREE HAND CONSIDERATIONS
Criteria consideration
Free hand use - jigs and fixtures to hold work
- Fixtures can even hold tool
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Slide 82
83. When purchasing heavy power tools, consider features that allow the
tool to be held with both hands.
When operating heavy tools, take advantage of features that allow for
greater control of the tool and less fatigue.
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Slide 83
84. Tool Design And Selection
STORAGE OF TOOL BETWEEN CYCLES
Criteria consideration
Between cycles - suspend if frequently grasped or
released
- Consider workstation or waist
mounted holster
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85. Tool Design And Selection
POWER TOOLS
Criteria consideration
Center of - should be near fist
Gravity - avoid nose-heavy tools
Weight - support or counterbalance
if over two pounds
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Slide 85
86. Tool Design And Selection
POWER TOOLS
Criteria consideration
Trigger location - placed with grip so digits
don’t have to reach
Trigger tension - light enough to avoid fatigue,
heavy enough to avoid
accidental activation
Size - preferably large enough to
span multiple fingers
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Slide 86
87. Tool Design And Selection
POWER TOOLS
Criteria consideration
Power - torque and speed should be adequate
to match fastening requirements
Hose connection - swivel connection reduces “moment”
created by dangling hose
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Slide 87