Pollution Control
Consultancy and Design

Personal Hearing Protectors
 

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and quite often forgotten business philosophy that the most effective form of advertising is to satisfy our clients.
 

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We not only pinpoint,
we also effectively resolve
engineering problems.
 



Do you realize that of a huge range of personal hearing protectors
(earplugs and earmuffs) that has been available on the market today,
only few protectors may be appropriate in your particular case ?



The specification of personal hearing protectors (printed on boxes containing protectors) usually provides information
on noise attenuation in a table that shows:

  1. MEAN (noise attenuation) and STANDARD DEVIATION, in octave band spectra from 125 Hz to 8000 Hz; and
     
  2. SOUND LEVEL CONVERSION for 80% of the population (SLC80).
     

Quite often in practice, the SLC80 is contentedly used by employers to assess the appropriateness of protectors,
e.g. if an employee is exposed to the LCeq,8h of 93 dB(C) and the SLC80 of a protector is 23, an employer believes
that the employee wearing this protector is exposed to the LAeq,8h of only 70 dB(A) [i.e. 93-23].

It may not be the case !
The selection (verification of appropriateness) of personal hearing protectors MUST BE MORE SOPHISTICATED,
if you care for your employees and if you wish to prove that the protectors that you provide for your employees
are adequate indeed (e.g. during proceedings of workers' compensation claims).

The proper selection of personal hearing protectors should be:
-   based on site-specific spectra of noise (frequencies of noise) your employees are exposed to;
-   better that those for 80% of the population (after all, protection for 80% of the population means
    that one of your five employees may not be protected adequately)

Our rigorous selection of personal hearing protectors is based on:
1.    actual (measured on your site) spectra of noise; and
2.    statistically valid for practically the entire range of the population.

 
Measurement Inside Real Ear (MIRE)
In cases of very high/dangerous levels of noise [LAeq exceeding 90 dB(A) and LCPeak exceeding 130 dB(C)],
Pollution Control Consultancy and Design (PCCD) recommends/offers Measurements Inside Real Ear (MIRE).

MIRE is a high-tech, advanced noise measurement that allows to assess the effectiveness of earmuffs
in a particular location/situation, for a particular person !!!

The photographs below show small microphones of our unique, Class 1, Dual-channel, Acoustical Dosimeter
Svan SV 102A that are used during a MIRE:



 

Disposable Ear-Plug Fitting Instructions

It is important to make sure that your ear-plugs are inserted and fit properly, or you will not get the full benefit of
their noise attenuation. 
 Inserting earplugs

Before fitting any ear-plugs, make sure your hands are clean! 
Hold the ear-plug between your thumb and forefinger. Roll and compress the entire ear-plug to a small, crease-free cylinder. 
While still rolling, use your other hand to reach over your head and pull up and back on your outer ear. This is important! 
This straightens the ear canal, making way for a snug fit.  Sometimes it helps to hold your mouth and throat open whilst
inserting the earplugs.

Insert the ear plug and hold for a few seconds. This allows the ear plug to expand and fill the ear canal. 

When properly inserted, the ambient sound level should drop way down as the earplugs expand.  You'll feel like the "world's
closing in on you" as some have mentioned.  If you can cup your hands over your ears and the noise seems to decrease,
your ear plugs are probably not fitted properly. Remove and refit following instructions. 

Always remove ear plugs slowly, twisting them to break the seal. If you remove them too quickly, you could damage your ear drum!  Foam ear plugs are disposable and are not supposed to be re-used.