Avaliação espectral do ruído de soldagem GMAW nas variações MIG/MAG: bases para exposição ocupacional e seleção de protetores auditivos por banda de frequência
Avaliação espectral do ruído de soldagem GMAW nas variações MIG/MAG: bases para exposição ocupacional e seleção de protetores auditivos por banda de frequência
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DOI: https://doi.org/10.22533/at.ed.8089222601049
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Palavras-chave: ruído ocupacional; soldagem MIG/MAG; soldagem GMAW; espectro sonoro; bandas de 1/3 de oitava; proteção auditiva; metrologia acústica.
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Keywords: occupational noise; MIG/MAG welding; GMAW welding; sound spectrum; one-third-octave bands; hearing protection; acoustic metrology.
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Abstract: This paper discusses the need to broaden occupational noise assessment in welding operations beyond global A-weighted sound pressure levels. Although LAeq, noise dose and normalized exposure level are essential for comparison with legal and technical criteria, these parameters alone do not fully describe the spectral distribution of acoustic energy and do not allow verification, by frequency band, of hearing protector adequacy. The proposed technical-methodological approach focuses on gas metal arc welding (GMAW) in its MIG/MAG variants, integrating occupational exposure, octave-band or one-third-octave-band spectra, hearing protector attenuation curves and audiometric frequencies of occupational interest. The literature on acoustic monitoring of welding shows that the sound produced by the electric arc contains relevant information on process stability and operating conditions, often represented by time-frequency spectrograms. However, for occupational hygiene and hearing protector selection, the priority domain is frequency versus sound pressure level. The distinction between spectrum and spectrogram is therefore incorporated as a central conceptual element. The paper proposes a pilot-study protocol including LAeq, LCpeak, band spectra, background noise, welding process parameters and estimation of the protected-ear sound pressure level. As a contribution, the study builds a bridge between acoustic metrology, occupational audiometry and safety engineering, with future application to the production of original field data in welding workshops.
- Murilo Alves do Amaral