PPE Catalogue CYMOT PPE CAT 2018 (Final) | Page 30

HEARING
PROTECTION
HEARING
PROTECTION
HEARING PROTECTION
Definitions:
SNR Single Number Rating European Union
NRR Noise Reduction Rating United States
SLC80 Sound Level Conversion Australia/New Zealand
NRR [Noise Reduction Rating] – This rating is used in the United States, and is accepted for use in a variety
of other countries. The NRR is an estimate of the amount of protection achievable by 98% of users in a laboratory
setting when hearing protectors are properly fitted. The current range of NRRs available in the U.S. market extends
from 0 to 33 decibels. Published by the U.S. Environmental Protection Agency in 1979,1 the NRR labeling requirement
is a standardized format for all hearing protectors distributed in the U.S. The chart showing mean attenuation values
and standard deviations at each of the seven test frequencies (from 125 Hz through 8000 Hz) is also part of the
labeling required by EPA.
SNR [Single Number Rating] – This rating number is used by the European Union and affiliated countries.2
Tests are conducted at independent testing laboratories, using test frequencies which are slightly different than those
used for the NRR rating. In addition to an overall rating, the SNR further rates protectors in terms of the particular
noise environments in which they will be used – H for high-frequency noise environments, M for mid-frequency,
and L for low-frequency. Note that the HML designation does not refer to noise level, rather the spectrum of the
noise. For example, a protector might be designated with SNR 26, H=32,M=23, L=14.The estimated attenuation
changes according to the noise spectrum of the environment in which the protector is to be worn.
SLC80 [Sound Level Conversion] – The SLC80 is a rating number used in Australia and New Zealand. 3 It is an
estimate of the amount of protection attained by 80% of users in well-managed hearing protector programs, based
upon laboratory testing of inexperienced users. Depending on the level of attenuation in the SLC rating, a classification
is assigned to a protector: a Class 1 protector may be used in noise up to 90 dB, a Class 2 protector to 95 dB, a
Class 3 protector to 100 dB, and so on in 5 dB increments. Packaging will often show the SLC80, followed by the
classification (i.e. SLC80 27, Class 5).
People should wear a hearing protector if the noise or sound level at the workplace exceeds 85 decibels
(A-weighted) or dBA. Hearing protectors reduce the noise exposure level and the risk of hearing loss.
If hearing protection is required, then a complete hearing conservation program should be implemented.
A hearing conservation program includes noise assessment, hearing protector selection, employee
training and education, audiometric testing, maintenance, inspection, record keeping, and program
evaluation.
The effectiveness of hearing protection is reduced greatly if the hearing protectors do not fit properly, if
they are worn only periodically, or if they are removed even for a short period of time. To maintain their
effectiveness, the hearing protection should not be modified. Radio/music earphones or headsets are
not substitutes for hearing protectors and should not be worn where hearing protectors are required to
protect against exposure to noise.
Select hearing protection that is:
• Correct for the job and provides adequate protection. Check the manufacturer’s literature.
• Compatible with other required personal protective equipment, or communication devices.
• Comfortable enough to be accepted and worn and most essential to meet a national safety standard.
• Appropriate for the temperature and humidity in the workplace.
• Able to provide adequate communication and audibility needs (e.g., the ability to hear alarms or
WHAT IS NOISE INDUCED HEARING LOSS?
Noise induced hearing loss is a permanent hearing impairment resulting from prolonged exposure to high levels of noise. It is important
to practice hearing conservation by using hearing protection to prevent noise induced hearing loss. Hearing protection includes ear
plugs and earmuffs that are designed to reduce the intensity or loudness of sound.
“Rule of Thumb” for determining the need for hearing protection
A good “rule of thumb” for determining if your work area or activity requires hearing protection is as follows. If you have difficulty
hearing or understanding a “normal” tone of voice at a distance of about three feet, noise levels are probably exceeding safe levels and
you should be using hearing protection.
Many activities and tools require the use of hearing protection. This includes, but is not limited to, lawn mowers, tractors, leaf blowers,
weed trimmers, chain saws, concrete saws, concrete/hammer drills, snow blowers, power saws, backpack vacuums, working near
running chillers, etc.
How much noise is too much?
85 Decibels (dB) - the “Action Level” where hearing protection is required.
90 dB - the OSHA, 8 hour average exposure limit.
100 dB - exposures longer than 15 minutes are not recommended.
110 dB - regular exposure of more than 1 minute risks permanent hearing loss.
What Are Hearing Protectors? How Effective Are They?
Hearing protection devices decrease the intensity of sound that reaches the eardrum. They come in two forms: earplugs and earmuffs.
Earplugs are small inserts that fit into the outer ear canal, To be effective they must totally block the ear canal with an airtight seal. They
are available in a variety of shapes and sizes to fit individual ear canals and can be custom made. For people who have trouble keeping
them in their ear, they can be fitted to a headband.
Earmuffs fit over the entire outer ear to form an air seal so the entire circumference of the ear canal is blocked, and they are held
in place by an adjustable band. Earmuffs will not seal around eyeglasses or long hair, and the adjustable headband tension must he
sufficient to hold earmuffs firmly around the ear. Earplugs must be snugly sealed so the entire circumference of the ear canal is blocked.
An improperly fitted, dirty or worn-out plug may not seal and can irritate the ear canal.
Properly fitted earplugs or muffs reduce noise 15 to 30 dB. The better earplugs and muffs are approximately equal in sound reduction,
although earplugs are better for low frequency noise and earmuffs for high frequency noise. Simultaneous use of earplugs and muffs
usually adds 10 to 15 dB more protection than either used alone. Combined use should be considered when noise exceeds 105 dB.
warning sounds).
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CYMOT Personal Protective Equipment
Hearing Protection
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