New European directive for hearing protection

The European Directive 2003/10/EC on the minimum health and safety requirements regarding the exposure of workers (to the risks arising from physical agents (noise) arising or likely to arise from exposure) to noise and in particular the risk to hearing has entered into force on 15 February 2006.

This new directive reduces the limit of harmful sounds with 5 dB and contains the following limits for a daily noise exposure level timeweighted average of the noise exposure levels for a nominal eight-hour working day covering all noises present at work, including impulsive noise :

  • Where noise exposure exceeds 80 dB, the employer shall make individual hearing protectors available to workers.

  • Where noise exposure matches or exceeds 85 dB, individual hearing protectors shall be used.

This new directive introduces also the notion of Exposure Limit Values as follows :

  • Under no circumstances shall the exposure of the worker exceed the exposure limit values of 87 dB. When applying the exposure limit values, the determination of the worker’s effective exposure shall take account of the attenuation provided by the individual hearing protectors worn by the worker.
The individual hearing protectors shall be so selected as to eliminate the risk to hearing or to reduce the risk to a minimum.


    Wearing a double protection

The wearing of a double hearing protection (earmuffs plus earplugs) can be made necessary for executing particularly noisy works (120 dB and more). Studies have made evident that the attenuation made by such combined protection was lower than the sum of the attenuations provided by each one of them.

This is explained by the mechanicalacoustic coupling which exists between the devices but also more particularly for high frequencies, by a upper limit due to the passage of sound through bone conduction and which in some way short-circuits the protection, how high it might be. The maximum attenuations obtained during the tests of combining earmuffs and earplugs is around 40 dB.

Source : INRS, ND 1789-140-90