• Title/Summary/Keyword: Noise contribution ($L_{ex,24h,i}$)

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Noise Exposure Level Measurements for Different Job Categories on Ships (선박의 담당업무에 따른 소음노출레벨 측정에 관한 연구)

  • Im, Myeong-Hwan;Choe, Sang-Bom
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.6
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    • pp.875-882
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    • 2021
  • To minimize occupational noise induced hearing loss, it is recommended that workers should not be exposed to noise levels exceeding 85 dBA for over 8 h. In the present study, noise exposure levels were measured for seven workers based on their tasks on a training ship. The A-weighted noise exposure level (Lex,24h) was measured by taking into account the A-weighted equivalent continuous sound level (LAeq,i), duration (h) and noise contribution (Lex,24h,i) from the workers' locations. Results are thus obtained for different job categories as follows: officer group Lex,24h=56.1 dB, navigation crew Lex,24h=58.9 dB, navigation cadet Lex,24h=62.0 dB, ship's cook Lex,24h=64.3 dB, engine cadet Lex,24h=91.1 dB, engineer Lex,24h=91.1 dB, and engine crew Lex,24h=95.1 dB. It was determined that the engineers, engine crews, and engine cadets in charge of machinery must wear hearing protection devices. By wearing hearing protection devices when working in highly noisy engine rooms, it is estimated that the noise expose levels could be reduced by the following amounts: engineer Lex,24h=23.1 dB, engine Crew Lex,24h=24.4 dB, and engine cadet Lex,24h=21.5 dB. Moreover, if the no. 2 lecture room and mess room bottom plates in the cadets accommodations were improved to the 64 mm A-60-class floating plates, then further reductions are possible as follows: navigation cadet Lex,24h=4.3 dB and engine cadet Lex,24h=1.8 dB.