When selecting hearing protectors, it is required to evaluate the level of internal noise levels. The attenuation values of the hearing protectors describe the attenuation capacity at different frequency levels (Hz). Hearing protector attenuation values can be found at Silenta´s website.

When selecting hearing protectors, besides the protector's attenuation value, you must know the level of external noise in your working environment. Based on the protector-internal noise level, the correct model is easy to select using the table below:

SNR (Single Number Rating or Simplified Noise Level Reduction) defines the typical level of noise attenuation in industry. H means high frequency (H), M stands for medium frequency (M) and L for low frequency attenuation (L).

Attenuation provided by various hearing protector models can be different in high and low frequency noises. Noise produced by an excavator or a compressor is typically low frequency noise, whereas lawn movers, for example, create medium frequency noise.

The noise level exposed to the ear can be calculated based on the SNR-value, subtracting the SNR value from the weighted sound pressure level of the object C.

The suitability of the hearing protector can also be roughly checked by subtracting the attenuation value of the protector M from the machine's noise level. The noise level exposed to the ear should be 75 to 80 dB. If noise is low frequency noise coming e.g. from a compressor, then use the L value.

The Silenta hearing protectors are tested in strict accordance with the standards EN 352.1:1993 (muff) or EN 352.3:1993 (helmet fitted). Testing is carried out at the Centre for Occupational Health, Laajaniityntie 1, 01620 Vantaa, Finland. ID #0403.