Occupational hearing loss and prevention Hearing loss can be caused by occupational noise exposure in various industries such as construction, manufacturing, and military. Noise from sources like power tools, machinery, and weapons can damage hearing over time. Musicians are also at risk from loud music. Prevention methods include monitoring noise levels, conducting audiometric testing, raising awareness of noise hazards, and using hearing protection like earplugs and earmuffs. Hearing loss is cumulative and permanent damage can occur even from moderate noise levels with regular exposure over years. Employers should implement noise control measures and hearing conservation programs.

1. Occupational hearing loss and
prevention

2. Boiler makers and gunners were the predecessors
1510-1590
873
self inflicted hearing loss
Rock Musician Pete Townshead--- prompted by his
partial deafness and Tinnitus –formation ---H E A R
(Hearing Education and Awareness for Rockers in
1980’s)

3. High Risk of Noise Induced Hearing
Loss
• Industrial/Workplace
• Military
• Recreational Noise Exposure
• Musicians

4. Common Noise
Sources
 Waste extraction Fan
 Electric motor
 Air Compressor
 Assembly
machine
 Ultrasonic
welder

5. Music Induced Hearing Loss
• Hearing loss due to excessive,
unprotected exposures to loud
music
Listening to an MP3 player at full
volume for one hour a day is enough to
seriously damage people's hearing
Attending a rock concert

6. Florence Nightingale wasn’t exaggerating when she referred to
hospital noise as “abuse.”
Florence Nightingale wrote in
her 1859 book, Notes on
Nursing
she wrote, “Unnecessary noise is the most cruel abuse of
care which can be inflicted on either the sick or the well.”

7. World Health Organization’s recommendation of
35 decibels as a top measure of sound levels in
patient rooms.
medical and communications technologies -
major culprits behind increasing noise levels.
Communications devices like overhead pagers
and cell phones - monitoring and life-
sustaining equipment continually beeps and
whooshes around patients’ beds, occasionally
erupting into alarming warning signals

8. Non-Auditory Effects
• Annoyance
• Sleep Disturbance
• Attention
• Stress reactions

9. Cardiovascular problems
Endocrine problems
Exposure to sudden, unexpected
noise raises patient heart rates
and has been proven to have a
negative influence on patient
recovery times. Chronically high
levels of sound -tend to increase
blood pressure levels
Disrupt sleeping pattern
of the neonates

10. Auditory Effects
• Acoustic Trauma: Sudden hearing damage
• Tinnitus: Ringing in the Ears
• TTS:Temporary threshold shift
• PTS: Permanent threshold shift

11. NOISE INDUCED HEARING LOSS
Acoustic trauma- Sudden impulsive sound for
shorter duration-explossive blast injury

12. Progressive
Can be temporary or permanent
– Temporary Loss: Change in hearing after noise exposure but returns in time
– a temporary loss of hearing after exposure to sound---results in a temporary
shift of the auditory threshold known as a temporary threshold shift (TTS).
– Permanent Loss: Change in hearing after noise exposure but will NOT return
– The damage can become permanent (permanent threshold shift, PTS) if
sufficient recovery time is not allowed for before continued sound exposure

13. Hallowell Davis’ classic experiments in
the 1940s further linked the hair cell
damage to hearing loss and he also
reported cochlear neuron degeneration
and capillary vasoconstriction as a
consequence of hazardous noise
exposure.

14. minor bending of the stereocilia (inner ear) is
associated with temporary hearing loss and is
involved in auditory fatigue. Complete loss of
the stereocilia causes permanent hearing
damage

15. NIHL-Dependent on intensity ,duration
and type of noise expossure
The greater the intensity of the noise ,
the less expossure time required for
damaging effects
Impulsive noise ----physically break
hair cells with the potential for little or
no recovery
Steady state noise (factory noise)—
may temporarily stress the hair cells,
which then recover after a period of
rest

16. Sound Level
(dBA)
Permitted Duration per
Workday (hours)
Sound Level
(dBA)
Permitted Duration per
Workday (hours)
90 8.00 103 1.32
91 6.96 104 1.15
92 6.06 105 1.00
93 5.28 106 0.86
94 4.60 107 0.76
95 4.00 108 0.66
96 3.48 109 0.56
97 3.03 110 0.50
98 2.63 111 0.43
99 2.30 112 0.38
100 2.00 113 0.33
101 1.73 114 0.28
102 1.52 115 0.25
Table of Permissible Noise Exposure Limits

17. Why notch at 4 KHz

18. PREVENTION

19. Pre-employment & annual examinations
Audiometry
Designated Factory Doctor
Audiometric screening

20. Raising Awareness

21. Sound Level Meter and Noise Dosimeter
Noise monitoring
• noise dosimeters - document
the average noise exposure over
your working day
A personal noise indicator is a
warning device.It indicates if
your immediate exposure is
less than or greater than 85
dBA. It flashes green if the
sound level is under 85 dBA
and red when above 85 dBA.

22. Hearing
Protection Devices

23. Ear Muffs
Advantages
• More protection at higher
frequencies than earplugs
• Various NRRs available
• Durable, long lasting
• Can be fitted on hard hat
• Reusable
Some high-tech muffs can filter out certain
frequencies or have radios inside for
communication in high noise areas

24. Custom earplugs
– Common option for musicians
– More expensive but are custom
– Earmold Impressions
– Typically are more comfortable and can provide a
better seal
• Most companies have a choice of either 9, 15, or 25 dB filters on
earplugs

25. Foam Insert Earplugs
Advantages
• Inexpensive; disposable
• Can be custom molded for
individual worker
• Reusable plugs are available

26. Semi-aural Caps
Ear caps are like earplugs, except they do not
go into the ear canal, they only block it.
They are good for occasional use or for people
who find earplugs uncomfortable.
They are not as protective as earplugs or
muffs.
• Ideal for people going in and out of noisy areas

27. Buildings can be designed with suitable
noise absorbing material for the walls,
windows, and ceilings. Noise Barriers
pre-fabricated noise barriers-Block the noise
by building temporary barriers of plywood or
other on-site materials to keep the noise from
reaching

28. Soundproof doors and windows can be
installed to block unwanted noise from
outside.
Regulations should be imposed to restrict the
usage of play loudspeakers
acoustical insulation-Place wooden box
over the generator. Add fire-resistant
acoustical absorbing material (foam) inside
the box. If the generator sits on soil or
sand,that will help absorb some of the
noise.

29. Similar to automobiles, lubrication of the machinery
and servicing should be done to minimize noise
generation.

30. • It is cumulative like tobacco.
• One cigarette will not kill you and one day at work will not
make you deaf.
• Neither will two or three – but where is the line? It is easy
to say “one more exposure is not going to make any
difference.”