Noise is a problem present in many working situations. For this reason, different types of protections exist and it is therefore important to outline the criteria for selecting the best to ensure the most ideal protection for workers.
Current norms supply guidelines for determining which type of hearing protection is best for protecting hearing in different working situations. Art. 4 of Legislative decree 626/94 requires that the employer evaluate safety and health hazards during work in their company, identify ideal prevention and protection measures to safeguard worker safety and health and present a programme for actuating said measures.
According to results reported in said evaluation, the employer must supply hearing protections which respond to CE safety requirements as defined by norm EN 352 (EN 352-1 headsets, headphones, EN 352-3 headsets for helmets, EN 352-4 active headsets).
The evaluation of industrial noise is performed on the basis of Legislative decree 15/8/91 n. 277, which indicates that daily personal exposure by a worker, expressed in dB(A) and calculated over 8 hours a day, must not exceed 85 dB(A).
If said level is exceeded (>85 dB(A)), the employer must supply PPE (Personal Protection Equipment) to workers by means of a training programme. When the daily noise level exceeds 90 dB(A), workers are required to wear PPE as well as to receive adequate training.
Tables indicated for each article are expressed with average evaluations, symbolised with letters in decibels H, M, L which respectively express the average attenuation to high, medium and low frequencies. The value SNR is the average attenuation of the protector on all frequencies. Values H, M, L and SNR are obtained according to EN 24869-1, staring from presumed protection values (APVf) of the protector.
THERE ARE THEREFORE 3 METHODS FOR SELECTING THE HEARING-PROTECTIVE DEVICE ON THE BASIS OF ATTENUATION:
- octave band method
- H,M,L method
- SNR method
The latter and most used is calculated starting from the level of noise present in the environment, subtracting from it the SNR value of our protector and, if the result is less than 85 dB(A), we have the ideal protective device. What’s more, it is important to verify working environment and daily work characteristics to identify hearing-protective devices which offer a good comfort level.