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1. Vibration at the Work Site
2.WHAT IS ERGONOMICS
Ergonomics has its origin in to Greek words
Ergon means work
Nomos means laws
-Ergonomics is the science of work which deals with the relationship between man and his working environment.
-It implies ‘Fitting the job to worker’.
Ergonomics has its origin in to Greek words
Ergon means work
Nomos means laws
-Ergonomics is the science of work which deals with the relationship between man and his working environment.
-It implies ‘Fitting the job to worker’.
3.ERGONOMICS IS MULTIDISCIPLINARY
Various disciplines are :-
1. Engineering: Design of work system suitable to
worker.
2. Physiology: Study of man and his working
environment.
3. Anatomy : study of body dimensions and relations for
work design.
4. Psychology : study of adoptive behaviour and skill of
people.
Various disciplines are :-
1. Engineering: Design of work system suitable to
worker.
2. Physiology: Study of man and his working
environment.
3. Anatomy : study of body dimensions and relations for
work design.
4. Psychology : study of adoptive behaviour and skill of
people.
5. Industrial hygiene : Occupational hazards and
workers health.
workers health.
4.FACTORS AFFECTING WORKING CONDITION
Occupational Safety and Health Elements
Fire Prevention and Protection Elements
Lighting and Ventilation Elements
Noise and Vibration Elements
Ergonomics Elements
Arrangement of Working Time
Occupational Safety and Health Elements
Fire Prevention and Protection Elements
Lighting and Ventilation Elements
Noise and Vibration Elements
Ergonomics Elements
Arrangement of Working Time
5.THE INTERNATIONAL STANDARD: ISO 2631
ISO 2631 was first published in 1974, with the purpose of giving “numerical values for limits
of exposure for vibrations transmitted from solid surfaces to the human body in the frequency range 1 to 80 Hz” (Griffin, 1990).
The standard was republished in 1978, 1982, 1985 and 1997, having undergone major revisions along the way.
The current version of ISO 2631,entitled “Mechanical vibration and shock – Evaluation of human exposure to whole-body vibration”
6.WHAT IS VIBRATION?
A simple vibrating system is represented by a weight suspended on a spring and set into an up and down motion
An object “vibrates” when it moves back and forth, up and down, or side to side, usually very rapidly.
The key terms used to describe this movement are “frequency” and “amplitude”.
ISO 2631 was first published in 1974, with the purpose of giving “numerical values for limits
of exposure for vibrations transmitted from solid surfaces to the human body in the frequency range 1 to 80 Hz” (Griffin, 1990).
The standard was republished in 1978, 1982, 1985 and 1997, having undergone major revisions along the way.
The current version of ISO 2631,entitled “Mechanical vibration and shock – Evaluation of human exposure to whole-body vibration”
6.WHAT IS VIBRATION?
A simple vibrating system is represented by a weight suspended on a spring and set into an up and down motion
An object “vibrates” when it moves back and forth, up and down, or side to side, usually very rapidly.
The key terms used to describe this movement are “frequency” and “amplitude”.
7.HOW VIBRATION EXPOSURE OCCURS
Vibration exposure occurs when a vibrating object, such as a machine, tool or surface, transmits vibration energy to a person's body. For this to occur, a part of the person’s body must either be in direct contact with the vibrating object, or another object that is itself making contact with the vibrating object, as shown in Figure
Vibration exposure occurs when a vibrating object, such as a machine, tool or surface, transmits vibration energy to a person's body. For this to occur, a part of the person’s body must either be in direct contact with the vibrating object, or another object that is itself making contact with the vibrating object, as shown in Figure
8.TYPES OF VIBRATION EXPOSURE
9.SEGMENTAL VIBRATION
Hand-arm vibration is the most common form of segmental vibration
HAV occurs when the hands and arms are exposed to vibration. Sources of vibration may include hand-held power tools or guiding materials, by hand, into a machine for processing.
Hand-arm vibration is the most common form of segmental vibration
HAV occurs when the hands and arms are exposed to vibration. Sources of vibration may include hand-held power tools or guiding materials, by hand, into a machine for processing.
10.A person’s exposure to hand-arm vibration and the health impacts of exposure can be influenced by many factors, such as:
the temperature of the area the person is working in.
whether or not the person is wearing gloves.
how the tool is gripped
the frequency and amplitude of the vibration
how long and how often exposure occurs
the temperature of the area the person is working in.
whether or not the person is wearing gloves.
how the tool is gripped
the frequency and amplitude of the vibration
how long and how often exposure occurs
11.Hand-arm vibration exposure can happen in many different jobs such as:
building and maintenance of roads and railways
construction and demolition
maintenance of parks and groundskeeping
forestry
foundries
heavy engineering
manufacturing concrete products
building and maintenance of roads and railways
construction and demolition
maintenance of parks and groundskeeping
forestry
foundries
heavy engineering
manufacturing concrete products
12.SOURCE OF SEGMENTAL VIBRATION
POWERED HAMMERS
CHISELS
CHAIN SAWS
GRINDERS
RIVETERS
BREAKERS
DRILLS
SHARPENERS
SHAPERS
VEHICLES
WORKING PLATFORM
POWERED HAMMERS
CHISELS
CHAIN SAWS
GRINDERS
RIVETERS
BREAKERS
DRILLS
SHARPENERS
SHAPERS
VEHICLES
WORKING PLATFORM
13.DISORDERS ASSOCIATED WITH HAV
Tingling or numbness in the fingers or toes
Blanching (whitening due to lack of circulation) of fingers. Recovery from blanching
attacks is accompanied by acute pain
and flushing.
Reduced sensitivity to pain,
touch and temperature.
In later stages, hands become
numb and fingers appear
blue/black. Gangrene is possible.
Tingling or numbness in the fingers or toes
Blanching (whitening due to lack of circulation) of fingers. Recovery from blanching
attacks is accompanied by acute pain
and flushing.
Reduced sensitivity to pain,
touch and temperature.
In later stages, hands become
numb and fingers appear
blue/black. Gangrene is possible.
14.WHOLE BODY VIBRATION EXPOSURE
Whole body vibration occurs when a person stands or sits on a vibrating vehicle, machine or surface.
The vibration is transmitted through supporting surfaces such as the standing person’s feet, the buttocks of a seated person, and the supporting areas of a
Whole body vibration occurs when a person stands or sits on a vibrating vehicle, machine or surface.
The vibration is transmitted through supporting surfaces such as the standing person’s feet, the buttocks of a seated person, and the supporting areas of a
15.TYPICAL SOURCES OF WHOLE BODY VIBRATION
16.EFFECT OF WHOLE BODY VIBRATION
Sea, air or land vehicles cause Motion Sickness when the
vibration exposure occurs in the 0.1 to 0.6 Hz frequency range.
Studies of bus and truck drivers found that occupational
exposure to whole-body vibration could have contributed to a
number of circulatory, bowel, respiratory, muscular and back
disorders.
Studies show that whole-body vibration can increase heart rate, oxygen uptake and respiratory rate, and can produce changes in blood and urine.
Sea, air or land vehicles cause Motion Sickness when the
vibration exposure occurs in the 0.1 to 0.6 Hz frequency range.
Studies of bus and truck drivers found that occupational
exposure to whole-body vibration could have contributed to a
number of circulatory, bowel, respiratory, muscular and back
disorders.
Studies show that whole-body vibration can increase heart rate, oxygen uptake and respiratory rate, and can produce changes in blood and urine.
17.Removing or Reducing Vibration by Isolation and Damping
Isolation alters the pathways between the machine and the person, by reducing the vibration arriving at the person.
Example: Shock Absorber on a Car.
Damping is a method of converting vibration into a small amount of heat. The vibration is absorbed by the gloves or tape and heat is generated from the dampened motion.
Example: Anti-vibration gloves, or Taping the handles of Vibrating tools.
Isolation alters the pathways between the machine and the person, by reducing the vibration arriving at the person.
Example: Shock Absorber on a Car.
Damping is a method of converting vibration into a small amount of heat. The vibration is absorbed by the gloves or tape and heat is generated from the dampened motion.
Example: Anti-vibration gloves, or Taping the handles of Vibrating tools.
18.REDUCTION AT SOURCE
Reduce Speed of Tool
Reduce Weight and Power Needed to Drive The Tool
Change Type of Tool
- E.g. Reciprocating Engine to Rotary or Electric Motor
Tool Maintenance
Mount Equipment on Springs or Compression Pads
Use Materials That Generate Less Vibration
Reduce Speed of Tool
Reduce Weight and Power Needed to Drive The Tool
Change Type of Tool
- E.g. Reciprocating Engine to Rotary or Electric Motor
Tool Maintenance
Mount Equipment on Springs or Compression Pads
Use Materials That Generate Less Vibration
19.REDUCTION AT TRANSMISSION
Provide Cushion to Act as A Vibration Isolator in a Seated Task
Example : Vehicle Seats
Provide Anti-Fatigue Mats for
Standing Operation
Design Tools to Reduce Vibration
Transmitted to The Hand
Counterweight Tools to Minimize Gripping Required to Operate Them
Dampening Materials and Gloves are Usually More Effective For Higher Frequencies
Provide Cushion to Act as A Vibration Isolator in a Seated Task
Example : Vehicle Seats
Provide Anti-Fatigue Mats for
Standing Operation
Design Tools to Reduce Vibration
Transmitted to The Hand
Counterweight Tools to Minimize Gripping Required to Operate Them
Dampening Materials and Gloves are Usually More Effective For Higher Frequencies
20.PROCESS MODIFICATION
Changes in Any Aspect of Process to Eliminate Need for Vibrating Tools or Equipment
Using Mechanical Aid (Chucks, Clamps) to Hold for Vibrating Tools or Equipment
Reduces Time or Intensity of Exposure
Robotics
Automation
Substitution of Materials
Example : Use Plastics For Hard material
Changes in Any Aspect of Process to Eliminate Need for Vibrating Tools or Equipment
Using Mechanical Aid (Chucks, Clamps) to Hold for Vibrating Tools or Equipment
Reduces Time or Intensity of Exposure
Robotics
Automation
Substitution of Materials
Example : Use Plastics For Hard material
21.WORK MODIFICATION APPROACHES
Limit Numbers of Hours
Reduce Number of Days Per Week
Rotate Between Vibrating and Non-Vibrating Tool Tasks
Schedule Maintenance Breaks
Limit Numbers of Hours
Reduce Number of Days Per Week
Rotate Between Vibrating and Non-Vibrating Tool Tasks
Schedule Maintenance Breaks
22.PURCHASING HAND TOOLS
Purchase hand tools which are
ergonomically designed:
Lower weight
Tool grip is:
appropriate for angle of application
correct size for the user
dampened with rubber, foam, or tape
isolated from the motor
Purchase hand tools which are
ergonomically designed:
Lower weight
Tool grip is:
appropriate for angle of application
correct size for the user
dampened with rubber, foam, or tape
isolated from the motor
23.POSITIVE EFFECTS
Vibration Effects on Humans are not necessarily Negative
- Music
- Ultra-Sound Treatment
- Relaxation
- Weight Removal Machine
Vibration Effects on Humans are not necessarily Negative
- Music
- Ultra-Sound Treatment
- Relaxation
- Weight Removal Machine
24.CASE STUDY : Construction Whole Body Vibration
SPOT the Ergonomic Hazard
Sitting for prolonged periods of time with whole body vibration increases the risk of developing low back injuries. Heavy construction is an industry that exposes workers to these risks.
SPOT the Ergonomic Hazard
Sitting for prolonged periods of time with whole body vibration increases the risk of developing low back injuries. Heavy construction is an industry that exposes workers to these risks.
25. ASSESS the Risk
Health and Safety Committee Assessment – The Manitoba Labour’s:
Ergonomic Guideline contains a checklist that can be used to score tasks for ergonomic risks, refer to Appendix A for details. The characteristics of this equipment operation task scored 8. A score over 7 indicates a hazardous task.
The main risk factors includes posture, whole body vibration and duration of the task.
Technical Assessment - Whole body vibration was measured on a CrawlerTractor:
The readings were 0.11m/s2 in the z (up/down) direction. This is less than the 0.315m/s2 standard for an eight hour per day exposure.
Health and Safety Committee Assessment – The Manitoba Labour’s:
Ergonomic Guideline contains a checklist that can be used to score tasks for ergonomic risks, refer to Appendix A for details. The characteristics of this equipment operation task scored 8. A score over 7 indicates a hazardous task.
The main risk factors includes posture, whole body vibration and duration of the task.
Technical Assessment - Whole body vibration was measured on a CrawlerTractor:
The readings were 0.11m/s2 in the z (up/down) direction. This is less than the 0.315m/s2 standard for an eight hour per day exposure.
26.Worker Consultation - Workers considered vibration from the equipment and road building to be a part of the job. Low back discomfort was inevitable.
Standards and Guidelines - Standards and guidelines indicate that the vibration in this task is not a hazard, however, individual susceptibility should to be taken into consideration.
Standards and Guidelines - Standards and guidelines indicate that the vibration in this task is not a hazard, however, individual susceptibility should to be taken into consideration.
27.FIND a Safer Way
In order to accommodate workers with existing or previous low back issues, a gel anti-vibration seat pad was purchased.
In order to accommodate workers with existing or previous low back issues, a gel anti-vibration seat pad was purchased.
28.RESULTS
Direct Cost of Improvements - $298 for a gel anti-vibration seat pad.
Worker Health Benefits - Manitoba Labour’s ergonomics checklist score was reduced from 8 to 7 due to a reduction in exposure to whole body vibration. The whole body vibration was reduced from 0.11m/s2 to 0.02m/s2 or a reduction of over 80%.
Quality and Efficiency Outcomes - Two workers noted that their sore lower back was better at the end of the day which resulted in a reduction of at least two lost days. When skilled workers are absent then productivity suffers. The benefits of this solution could easily equal its cost if one lost day was reduced.
Direct Cost of Improvements - $298 for a gel anti-vibration seat pad.
Worker Health Benefits - Manitoba Labour’s ergonomics checklist score was reduced from 8 to 7 due to a reduction in exposure to whole body vibration. The whole body vibration was reduced from 0.11m/s2 to 0.02m/s2 or a reduction of over 80%.
Quality and Efficiency Outcomes - Two workers noted that their sore lower back was better at the end of the day which resulted in a reduction of at least two lost days. When skilled workers are absent then productivity suffers. The benefits of this solution could easily equal its cost if one lost day was reduced.
29.OTHER OPTIONS
Refurbishing the old seat with a brand new anti-vibration seat.
Purchasing a cheaper sponge/foam cushion with unknown anti-vibration properties.
Refurbishing the old seat with a brand new anti-vibration seat.
Purchasing a cheaper sponge/foam cushion with unknown anti-vibration properties.
30.Industrial Engg. And Production Mgt.
- by MARTAND TELSANG
Best Practices – Vibration at the Work Site manual by Government of alberta
www.abcsafetymart.com/ergonomics-back-supports.html
www.nexgenergo.com/ ergonomics/vats.html
www.egronomics.about.com/od/vibrationsyndorm
www.science.nasa.gov
- by MARTAND TELSANG
Best Practices – Vibration at the Work Site manual by Government of alberta
www.abcsafetymart.com/ergonomics-back-supports.html
www.nexgenergo.com/ ergonomics/vats.html
www.egronomics.about.com/od/vibrationsyndorm
www.science.nasa.gov
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