Activities such as operating a fork lift truck, rotary buffer or ride-on scrubber drier can cause fatigue, insomnia, headaches and shakiness with symptoms similar to those that many people experience after a long car or boat trip.
After daily exposure over a number of years, these same whole-body vibrations can result in a number of health disorders affecting your entire body including permanent harm to internal organs, muscles, joints and bone structure.
The risks linked to long-term exposure to strong or high frequency vibrations depends on the type of stress experienced, whether this is skeletal or muscular, or even to the vascular and nervous systems.
There are two main classifications of vibration:
Hand-arm vibrations (common to rotary buffers, walk-behind scrubber driers and ride-on machines)
Whole-body vibrations (specific to ride-on machines)
1. Hand-arm vibrations: ISO 5349-1
It is well known that vibrating hand tools and therefore exposure to high frequency vibrations interfere with blood circulation (vascular effects) and nerves signals (neurological effects – sometimes resulting in partial paralysis of the thumb’s radial nerve), thereby causing a tingling sensation, loss of feeling, numbness and a characteristic blanching or whitening of the affected parts of the hand-arm system known as “white-finger”.
Exposure to the vibrations of heavy tools (the most typical example being the pneumatic drill) may damage the osteo-articular system (resulting in arthrosis or bone decalcification).
It is important therefore to consult the Use and Maintenance booklet for any piece of equipment being utilised to see the level of vibrations transmitted to the hand-arm system.
Check the level of vibrations transmitted to the hand-arm system (expressed in m/s²) and, if possible, choose the one with the lowest level. The level of vibrations should be measured in compliance with ISO 5349-1.
2. Whole-body vibrations: Jolts ISO 2631-1
The whole-body vibrations of a person are commonly called ‘jolts’. When these are very strong or prolonged, they may lead to spinal problems mainly relating to bone and muscular disorders.
Vibration energy waves, much the same as noise, are transferred from the energy source – a hand tool or vehicle – into the body of the exposed operator. This is then transmitted through the body tissues, organs and skeletal systems of the individual before it is dampened and dissipated.
The symptoms of whole-body vibration are not so readily recognisable and are often mistaken for other unrelated conditions and ailments. The health outcomes are non-specific and can be difficult and extremely expensive to identify, manage and control.
These factors should not detract from the fact that employees, and in particular professional drivers, can suffer debilitating ill health effects from whole-body vibration exposure.
The most common medical conditions experienced through long term exposure to whole-body vibrations are:
- Spinal column complaints are perhaps the most common issues associated with the long-term exposure to whole-body vibration, where the back is especially sensitive to the 4-12Hz vibration range
- Digestive system issues are often observed in persons exposed to whole-body vibration over a long period of time. This is associated with the resonance movement of the stomach at frequencies between 4 and 5Hz
- Cardiovascular system effects resulting from prolonged exposure to whole-body vibration at frequencies below 20Hz. These result in hyperventilation, increased heart rate, oxygen intake, pulmonary ventilation and respiratory rate.
Fortunately the human body can tolerate certain levels of vibration energy but when exposed over a long period of time it begins to deteriorate and fail causing a disruption in the body’s natural processes and systems.
The health effects experienced by employees vary considerably and factors such as situation, age, lifestyle (smokers), posture, ergonomic design and resonance all have an influence on the ill health effects of the vibration exposure.
The problems may be caused through the incorrect position of the operator (resulting from bad machine use habits) or a machine design that fails to take into account the basic principles of ergonomics.
The onus is on the employer to know the vibration exposure that their workforce is exposed to, including the magnitude of vibration, distribution of the motion within the body, and the frequency, direction and duration.
Check the level of whole-body vibrations (expressed in m/s²) in the machine Use and Maintenance booklet and, if possible, choose the one with the lowest level. The level of vibrations should be measured in compliance with ISO 2631-1. Ensure the machine EC declaration states that it has been designed in compliance with directive EN 12100, and that the principles of ergonomics have also been applied.
The level of hand-arm vibrations of Comac scrubber driers, sweepers and single disc rotaries is certified by an accredited laboratory to offer the highest reliability of the declared values.