Noise exposure of workers and the correct use of the hearing protection device

Occupational noise exposure in the workplace is linked with a range of negative effects on human health. Many researchers agree that the noise-induced hearing loss is the second most common form of sensorineural hearing deficit, after the illness of age-related hearing loss. An extended exposure to occupational noise can generates devastating disability that is potentially 100% completely preventable. The hearing deficit begins at the higher frequencies and it develops gradually as a result of chronic exposure to excessive sound levels. In order to avoid these negative effects on the worker's health and to stop further progression of the damage, italian law establishes strict limits, with the aim that the effective exposure of a worker may overpass the limit values of LAeq = 87 dBA and Lpeak = 140 dBC. After the risk assessment, particularly at noisy workplaces, the employers generally provide workers the hearing protection devices (HPDs), but the employment of this device results to be useless if it is not used correctly. This study aims to the analyze the correct use of hearing protection devices (HPDs), to determine how his position can influence the noise damping and consequently the worker's noise exposure dose. The experimental campaign consists of different measures of the same noise source realized on many subjects with the same HPD type. The results obtained for different types of subjects point out that the use of the protection device can be useless if insertion procedure in the worker's ear is wrong.