Noise Reduction Ratings, or NRR’s, are units of measurement that are used to
help determine the usefulness of hearing protection devices and to minimize
sound exposure inside a workplace or working environment. These ratings are shortened to Db, a term used
to categorize the power or density inside a sound. Ear plugs are made at
different levels to accommodate for high sound exposure and ratings. Hearing
protection equipment has to be tested and accepted by the American NationalStandards Institute (ANSI),
and also has to be in compliance with
the Occupational Safety and Health Administration (OSHA). The Noise Reduction Rating is rated on a
positive sliding scale that justifies the higher the number, the more
capability of the device for noise reduction.
The Noise Reduction Rating is calculated by taking the noise
exposure of the environment in decibels, subtracting by seven, then dividing by
two. For example, if you are working in an environment where the noise of
exposure is 90db and you are wearing ear plugs with an NRR of 33dB, the
calculation would be 33-7 = 26. 26/2 = 13. That means your new noise exposure
level would be 77db. Multiple reduction devices can be worn at the same time to
reduce your exposure.
Standard Threshold Shift, or STS, is the occupational
noise exposure standard. It is known as a change in hearing threshold, relative
to the baseline audio of the employee. It equates to a hearing loss of 10db or
more at 2000, 3000, and 4000 hz or Hertz, in either ear. Over time, someone
with STS will eventually have a hard time understanding people talking to them
and have a hard time generally hearing other sounds in their atmosphere. Through
aging, Standard Threshold Shift usually occurs naturally. Technically not
naturally, but through the course of life. Having hands on jobs increases your likelihood
of hearing damage because you are exposed to loud sounds on a more regular
basis for longer amounts of time over the course of your career, jumpstarting
hearing loss. This is why older people have a tougher time hearing than younger
people do.
an exchange rate is the increase of decrease in decibels
corresponding to twice or half the noise fdon.e this rate is used to calculate
the time that an employee is allowed to be in a particular environment. OSHA
uses an exchange rate of 5db. For example, if the exchange rate is 5db, 90db
produces twice the noise dose that 85 db produces when the exposure is
constant.
To best illustrate different sounds, I decided to measure
both high and low noise environments. I
first measured the floor in my apartment, because I was the only person home
and it was very quiet. For the high noise environment measurement, I used the
Pigskin Bar on Court street while I was working one night. The screenshots for
both are attached below. Potential adverse effects that may occur by staying in
the Pigskin for extended amounts of time, and those would be temporary hearing
loss and possibly permanent hearing loss.
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