35 |
P a g e
OWNER’S
MANUAL
|
STARTRAC 263 4WD
–
8G
–
STAGE
–
V
•
How the risk is evaluated: The higher the sound level and exposure time, the greater the
noise risk will be:
•
LAeq: (Equivalent continues weighted level A): this is a sound level measurement that
considers noise fluctuations and the varying sensitivity of the ear to the frequencies: LAeq is
measured with a sound: level meter;
2.38
NOISE PATHOLOGIES
Damage to the hearing
Noise causes hyperdulia or deafness because it destroys the acoustic receptors, nervous cells
able to transform the mechanical sound vibrations into nervous impulses that, on reaching
the brain, determine the aural sensation. These receptors are irreplaceable if they are
destroyed and the resulting damage is irreversible: hyperdulia worsens if exposure to noise
continues and does not improve even if this terminates.
Moreover, it is also bilateral since it can be accompanied by annoying buzzing and whistling
sounds, and by intolerance to loud noise. The damage is insidious since it proceeds slowly
and unexpectedly: in the initial phase, when it is limited to a diminished ability to perceive
acute sounds (music, bells) or the spoken voice when there is a background noise, it can only
be detected by means of an audiometric test. Pulsating noises of great intensity lasting a
very short time are highly damaging since the ear is unable to actuate any physiological
protective measures in time. Hyperdulia from noise generally arises after several years of
exposure and depends on the PEL (risk almost null below 80 dBA) and on individual
characteristics. It is an incurable disease: the only efficacious means of protection against it is
prevention.
Other effects
Noise does not just determine aural sensation. For levels exceeding* 70dBA, it causes stress by
means of the cerebral integration centers and determines a specific neurovegetative reaction
responsible for effects that lead to cardio circulatory and gastro enteric diseases. Amongst
these, it is worthwhile noting: an increase in gastric acidity, a decrease in the heart rate, visual
range and reflex speed; a sensation of discomfort and weariness with an increased sense of
fatigue. These effects are dangerous because they also increase the risk of accidents.
Personal equipment to protect against noise
Individual protective equipment attenuates the sound energy
transmitted to the ear through the air. This equipment is used when
dangerous exposure cannot be avoided in any other way. There are
different types of devices with different attenuating capacities: helmets,
earmuffs, ear plugs (Fig.2-29). Helmets and earmuffs offer the greatest
protection, but they are bulky and inconvenient to wear. They are
therefore only of use for exposure to high noise levels but for short
periods of time (max. 2 hours).
Ear plugs are generally tolerated to a greater extent and are of
particular use in the case of lengthy exposure to noise of a lesser intensity. Always use
adequate individual protective equipment to safeguard the hearing when the personal daily
level of exposure to noise is 85 dBA or more. Consult the "specifications" chapter of this manual
in relation to tractor noise measured in instantaneous conditions in compliance with the laws in
force. Usage of above protection is advised in all conditions/ circumstances.
Fig.2.26
Summary of Contents for 263-4WD-8G-STAGE-V
Page 1: ...OWNER S MANUAL 263 4WD 8G STAGE V OWNER S MANUAL 263 4WD 8G STAGE V EDITION 210312...
Page 3: ...3 P a g e OWNER S MANUAL STARTRAC 263 4WD 8G STAGE V...
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