Pollution Control Consultancy and Design

Acoustical Consultants (Noise and Vibration) - Sydney

Selection of appropriate personal hearing protectors (PHP)


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 actually appropriate in your particular case ?


Occupational noise assessment


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.

Occupational Noise