Vibration can enter the body through contact with vibrating machines or surfaces. This is known as segmental vibration exposure when it affects a body part like hands, or whole body vibration exposure when it affects the entire body. Segmental exposure is common in workers using hand tools and can cause damage to hands and arms. Whole body vibration in vehicle operators is linked to increased risks of disorders in various body systems. Vibration exposure is measured and limits are set to reduce health risks, with higher risks at levels exceeding daily exposure limits.

1. DR RAYJIV THEVENDRAM
MD, MCHS HOSPITAL MANAGEMENT & HEALTH
ECONOMICS

2. DEFINITION

4. VIBRATION
EXPOSURE
• Contact with a vibrating machine transfers vibration energy to an organ(s) of the
body. We know that vibration affects the organ in contact such as the hands. But we
do not fully understand how vibration may affect other parts of the worker's body or
only a selected particular organ. The effect of vibration exposure also depends on
the frequency of vibration. Each organ of the body has its own resonant frequency. If
exposure occurs at or near any of these resonant frequencies, the resulting effect is
greatly increased.

5. Segmental vibration exposure affects an organ, part or "segment" of the body.
The most widely studied and most common type of segmental vibration
exposure is hand-arm vibration exposure which affects the hands and arms.
Exposed occupational groups include operators of chain saws, chipping tools,
jackhammers, jack leg drills, grinders and many other workers who operate
hand-held vibrating tools.
• White finger (also known as "dead finger" ) - damage to hands causing
whiteness and pain in the fingers;
• Carpel tunnel syndrome (and other symptoms similar to occupational
overuse syndrome);
• Sensory nerve damage;
• Muscle and joint damage in the hands and arms (eg 'tennis elbow')

6. Whole body vibration energy enters the body through a seat or the floor, and
it affects the entire body or a number of organs in the body. Exposed groups
include operators of trucks, buses, tractors and those who work on vibrating
floors.
• Lower back pain (damage to vertebrae and discs, ligaments loosened from
shaking)
• Motion sickness
• Bone damage
• Varicose veins/heart conditions (variation in blood pressure from vibration);
• Stomach and digestive conditions;
• respiratory, endocrine and metabolic changes;
• impairment of vision, balance or both;
• reproductive organ damage.

7. We can feel vibrations and know that people might be
exposed to it. But we cannot determine if what we feel is
going to be harmful. For that, we must measure vibration
exposure.

8. • Vibration enters the body from the part of
the body or organ in contact with
vibrating equipment. When a worker
operates hand-held equipment such as a
chain saw or jackhammer, vibration affects
hands and arms. Such an exposure is
called hand-arm vibration exposure. When
a worker sits or stands on a vibrating floor
or seat, the vibration exposure affects
almost the entire body and is called
whole-body vibration exposure.

9. • Hand-arm vibration causes damage to hands
and fingers. It appears as damage to blood
vessels, nerves and joints in the fingers. The
resulting condition is known as white finger
disease, Raynaud's phenomenon or hand-arm
vibration syndrome (HAVS). One of the
symptoms is that affected fingers may turn
white, especially when exposed to cold.
Vibration-induced white finger disease also
causes a loss of grip force and loss of
sensitivity to touch.
• The health effect of whole-body vibration
(WBV) is poorly understood. Studies of drivers
of heavy vehicles have revealed an increased
incidence of the disorders of bowel and the
circulatory, musculoskeletal and neurological
systems.
This Photo by Unknown Author is licensed under CC BY-SA

10. • The risk of vibration induced injury depends on the average daily
exposure. An evaluation of the risk takes into account the intensity
and frequency of the vibration, the duration (years) of exposure
and the part of the body which receives the vibration energy.

11. • Your daily exposure to vibration is measured by a formula known
as an A(8) value. This is the average (A) exposure over an eight-
hour (8) day and takes into account the magnitude of the
vibration and how long you are exposed to it. The rate of
vibration of a tool or piece of machinery is measured in metres
(m) per second (s) – its movement per second.
• For hand-arm vibration (HAV), the daily ELV is 5 m/s2 A(8) and the
daily EAV is 2.5 m/s2 A(8).
• For whole-body vibration (WBV), the daily ELV is 1.15 m/s2 A(8)
and the daily EAV is 0.5 m/s2 A(8)

12. HAND-ARM VIBRATION EXPOSURE
CALCULATOR

13. USING THE HAV CALCULATOR
Step 1: Determine Vibration Magnitude in m/s²
- Measure in-use vibration magnitude with a vibration meter.

14. Step 2: Determine Exposure Duration
- Use a stopwatch to determine the average duration or the “trigger time” required
to perform the work task when using the tool being evaluated. Use maximum
production rates to determine the number of repetitions required per 8-hour shift. To
determine the Exposure Duration, multiply the number of repetitions required times
the average task duration or trigger time for each tool.
USING THE HAV CALCULATOR
Step 3: Enter Data into Calculator
1. Vibration Magnitude – r.m.s. acceleration value in m/s² for each Tool / Process.
2. Exposure Duration – total daily vibration contact time or “trigger time” for each
Tool / Process.

15. CALCULATOR OUTPUTS
1. The Exposure Points per hour is the rate at which exposure will rise at the
specified Vibration Magnitude. This point system is a simple alternative to
the A(8) value for describing and managing exposures in the workplace.
2. The Time to Reach EAV is the time required to reach the Exposure Action
Value(EAV) of 2.5 m/s² A(8).
3. The Time to Reach ELV is the time required to reach the Exposure Limit
Value(ELV) of 5 m/s² A(8).
4. The Partial Exposure is the vibration exposure, expressed in m/s² A(8) and
in exposure points, for each Tool / Process. It is calculated from
the Vibration Magnitude and the Exposure Duration.
5. Total Exposure Points is calculated from all the Partial Exposure point
values.

16. ACTION AND LIMIT VALUES
The Exposure Action Value (EAV) is equivalent to 100 points and
the Exposure Limit Value (ELV) is equivalent to 400 points.
• If the total exposure points value of 82, It is below the Exposure Action
Value (EAV) of 100 points, indicating that this task does not pose significant
risk of HAVS for most healthy employees.
• If the total exposure points value of 502, it exceeds the Exposure Limit
Value (ELV) of 400 points, indicating safe limits have been exceeded and
employees are at significant risk of developing HAVS. Controls should be
implemented immediately to reduce vibration magnitude exposure.
EXAMPLE OF RESULT

17. REFERENCES
1. Canadian Centre of Occupational Safety and Health
https://www.ccohs.ca/oshanswers/phys_agents/vibration/vibration_intro.html
2. Worksmart
https://worksmart.org.uk/health-advice/illnesses-and-injuries/work-
illnesses/vibration/how-vibration-measured
3. Ergoplus
https://ergo-plus.com/hand-arm-vibration-hav/