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

Element B6 / 5

Basic Concepts

RMS Amplitude

Element B6 / 5

Occupational Vibration Exposure

Whole body vibration

Through floor structure, vehicle

HAV

Actual contact with source

Pneumatic drills, rotary tools, chain saws, grinding equipment

Element B6 / 5

Comfort Levels

Vibration may be amplified by up to 4

times by the resonance of a part of the

body

Element B6 / 5

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

Element B6 / 5

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”

Element B6 / 5

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