Analysis on the spectrum characteristics of noise hazards in metal products industry / 中国职业医学

ABSTRACT

{L-End}Objective To analyze the spectrum characteristics of noise hazards in the metal products industry. {L-End}Methods A total of six metal product industries were selected as research subjects using stratified sampling method. The noise intensity (A/C-weighted) and noise spectrum (Z-weighted) of workplaces and job positions were detected. The characteristics of the noise spectrum of each job position were analyzed using the difference between equivalent continuous C-weighted sound pressure level (LCeq)-equivalent continuous A-weighted sound pressure level (LAeq), the dominant frequency of the noise spectrum, and cluster analysis methods. {L-End}Results The workplace noise and job position noise of 11 main noise positions in the metal products industry were exceeded national standard, with incidence of 69.2% and 78.1%, respectively. The average of normalization of equivalent continuous A-weighted sound pressure level to a normal 40 hours working week exceeded the national standard in 100.0% of hydraulic workers, welders, and ultrasonic cleaning workers. The result of spectrum analysis showed that the noise in the metal product industry was mainly broadband. The noise of the collision welder position was classified as low-frequency broadband noise, while the noise of the painter position was classified as low-frequency narrowband noise. The noise spectrum characteristics of other positions were similar and classified into one category, all of which were broadband noise. Among them, numerical control lathe workers, welders, threaders, machinists, and cutters were exposed to high-frequency broadband noise, while press workers were exposed to mid-frequency broadband noise, and grinders, hydraulic workers, and ultrasonic cleaning workers were exposed to low-frequency broadband noise. The detection rate of binaural high-frequency hearing threshold improvement among workers was 61.7%, and there was no statistical correlation between the detection rate of binaural high-frequency hearing threshold improvement and the noise level intensity of each spectrum. {L-End}Conclusion The level of noise hazards in the metal products industry is severe. Effective engineering control measures and hearing protection measures should be implemented based on the spectral characteristics of noises.