Post on 15-Mar-2021
Element B6 / 5
Element B6 / 5
Vibration
Vibration
CVWR
Control of Vibration at Work Regs 2005
Vibration
Oscillating motion of a particle or body about a fixed point
Hand Arm Vibration
Mech vibration transmitted to hands and arms during work
activity
Mechanical Vibration
In a piece of m/c or vehicle as a result of its operation
Element B6 / 5
Basic Concepts
Described in terms of amplitude of
vibration
Amplitude may be measured as amount of
displacement, velocity, or acceleration relative to the
fixed point
Similar to noise
Freq measured in Hz
Displacement measured in metres
Velocity measured in metres per second (ms1)
Acceleration – rate of change in velocity – metres per
second squared (ms2)
Element B6 / 5
Basic Concepts
OHS – most interested in acceleration
Exposure limits – CVWR –
Magnitude of acceleration
Peak Amplitude
Max excursion of the wave from zero to highest point
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Basic Concepts
RMS Amplitude
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Occupational Vibration Exposure
Whole body vibration
Through floor structure, vehicle
HAV
Actual contact with source
Pneumatic drills, rotary tools, chain saws, grinding equipment
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Comfort Levels
Vibration may be amplified by up to 4
times by the resonance of a part of the
body
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Vibration Dose
Dose =
Magnitude of vibration and exposure time
Below action level – risk of harm unlikely
Dose – over 8 hr period
Equal vibration energy
Vibration of given magnitude for given time is equally hazardous
as half magnitude for twice the time.
HSE
Ready reckoner to calculate exposures and relative dose
Element B6 / 5
Whole Body Vibration
WBV
Human response depends on resonance of body
Impinges on all organs
Vehicle seats, farm vehicles, heavy equip, ships,
planes
Most common complaint is back pain (lower)
May also be down to bad posture, bad diet, stress (traffic)
Rest periods play complex role in overall performance
Element B6 / 5
Whole Body Vibration
At Risk Groups
Drivers of mobile machines
Tractors, FLT, quarry, earth moving
Sit or stand on vibrating equipment
Fast boats, rough seas; compaction, hammering,
punching machines; railway vehicles; helicopters
Lack of maintenance
Increases likelihood
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Hand-Arm Vibration
HAV
Specific effects of intense vibration to hands and
arms are long term damage to soft tissues, bones,
joints
Raynauds Phenomenon (Vibration White Finger)
Form of HAVS – usually hand tools
Symptoms progressive
No cure or treatment
Fingers throb in cold
Intermittent tingling and numbing
Continued exposure – “dead finger”, “hot aches”
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Hand-Arm Vibration
Stockholm Scale
Classification of HAVS
Separate grading for each hand
HAVS
Most common with low freq vibrations
Element B6 / 5
Hand-Arm Vibration
At Risk Groups
Hand held power tools
Chain saws, grinding, polishing, riveting, etc
Road breakers; pedestal grinders
Construction, civil eng
Forestry
Chain saws
Foundries
Heavy eng, fabrication, metal working
Mines, quarries
Shoe manufacture – pounding machines
Element B6 / 5
Hand-Arm Vibration
At Risk Groups
Hand held power tools
Chain saws, grinding, polishing, riveting, etc
Road breakers; pedestal grinders
Construction, civil eng
Forestry
Chain saws
Foundries
Heavy eng, fabrication, metal working
Mines, quarries
Shoe manufacture – pounding machines
Element B6 / 5