Special Methods for Selecting Hearing Protectors for Very Low Frequency Noise
Invited paper
BG Holz und Metall
Wednesday 3 june, 2015, 09:00 - 09:20
0.4 Brussels (189)
Abstract:
The standard procedure for selecting hearing protectors is the HML check or the HML method with the attenuation values for high-, middle- and low-frequency noise calculated according to EN ISO 4869-2. For low frequency noise normally the L-value is applied which is defined as the attenuation performance of the hearing protector for a noise with a spectral balance L<sub>C</sub>-L<sub>A</sub> of 10 dB. But at some workplaces noises can occur that have an even higher value of L<sub>C</sub>-L<sub>A</sub>, e.g. diesel locomotives, airplanes, ships.
The presentation gives examples of such noise characteristics and the performance of hearing protectors that can be expected for these situations. The different methods for selection are compared and referenced to the octave band method. For ear-muffs the structure of the muff leads to mechanical resonances that reduce the attenuation in the range of about 50 Hz. The question is addressed which types of hearing protectors are suitable for workplaces with such extreme low frequency noises.