Assessment of Acoustic Noise Generated from Machines in a Mechanical Workshop Using 1-Octave Band Frequency Analysis

Abstract

Acoustic noise is one of the prominent occupational health hazards, particularly in manufacturing and process industries. Prolonged exposure to loud noise can cause noise induced hearing loss of the exposed personnel. Limiting the exposure to noise intensity within its permissible exposure limit is adopted as one of the administrative control measures to reduce the risk of hearing loss. However, frequency specific assessment of occupational noise exposure is limited. Here, we investigated acoustic noise generated from various machines during their operation in a mechanical workshop by recording equivalent continuous sound pressure levels. Further, we analyzed the frequency spectra of the noise to decipher the contribution of the 1-octave band frequencies to the total sound pressure level. The analysis revealed that the major contributing frequency bands to the total noise intensity are not same for different machine types. Cutting machines generate more high frequency noise, whereas Lathe, Drilling and Grinding machines generate mid frequency noise as a major contributor to the total noise intensity. Importance of frequency specific noise measurement for implementing suitable noise control measures was discussed.

Keywords: Noise assessment, Octave band analysis, occupational noise