|
KMID : 0895420010110030190
|
|
Journal of Korean Society of Occupational and Enviromental Hygiene
2001 Volume.11 No. 3 p.190 ~ p.197
|
|
|
An Assessment of Noise Exposure by Job and Dosimeter Parameters Setting in Automobile Press Factory
|
|
정지연/Jeong, Jee Yeon
박승현/이광용/이나루/유기호/박정선/정호근/Park, Seunghyun/Yi, GwangYong/Lee, Naroo/You, Ki Ho/Park, Junsun/Chung, Ho Keun
|
|
|
Abstract
|
|
|
Noise-induced hearing loss(NIHL) was the highest rate(43.5％∼58.5％ from 1996 to 1998) of positive findings through specific medical program in Korea. There were much more NIHL at workers of automobile manufacturing factories than other manufacturing factories.
The specific aim of the present study was to determine the noise exposure of automobile press lines, according to their job titles, press line types(auto, semiauto), dosimeter parameters setting. There were a total 11 press lines sampled at a automobile manufacturing company. Among those press lines, 10 press lines were autolines with acoustic enclosure, one semiauto press line was no aucostic enclosure
Noise exposure data were sampled for an work shift using noise dosimeter, which recorded both time-weighted average(TWA) and 1-min average.
The mean OSHA TWA(Korea TWA with threshold 90) was 80.7 ㏈(A) ±4.7 ㏈(A) for leader, 82.8 ㏈(A) ±4.5 ㏈(A) for pallette man. 76.7 ㏈(A) ±4.3 ㏈(A) for press operators, 76.6 ㏈(A) ±5.6 ㏈(A) for crane operators, 77.1 ㏈(A) ±2.8 ㏈(A) for forklift drivers, whereas the mean NIOSH TWA was 88.9 ㏈(A) ± 1.7㏈(A) for leader, 89.6 ㏈(A) ±21.㏈(A) for pallette man, 86.7㏈(A) ±1.8㏈(A) for press operators, 88.5 ㏈(A) ±2.0 ㏈(A) for crane operators, 87.7 ㏈(A) ±1.0 ㏈(A) for forklift drivers. While L10 for NIOSH TWA samples was 84.8 ㏈(A) ∼ 87.3 ㏈(A), L10 for OSHA TWA samples was 69.5 ㏈(A) ∼ 77.4 ㏈(A). L10 means that the TWA for 90％ of the samples exceeded L10.
Among OSHA TWA(Korea TWA with threshold 90) samples for pallette man, 7.7 ％ exceeded 90 ㏈(A), the OSHA permissible exposure level, but OSHA TWA samples for the other job titles didn´t. Among NIOSH TWA samples, the samples over 85 ㏈(A), the NIOSH recommended exposure limit, was 100％(leaders), 83.3 ％(operators), 97.4％(pallette man), 100％(forklift drivers), 91.7 ％(crane operator). The results of One-way random effects analysis of variance models shows that the difference between job titles was significant by OSHA TWA(p<0.05), but not significant by NIOSH TWA(p>0.05). NIOSH TWA samples were significantly higher than OSHA TWA samples(P<0.05).
Regression analysis was used to obtain relationships between OSHA TWA samples and NIOSH TWA samples. In this case the coefficient of determination = 0.09, which shows the high degree association between two methods. Regression equation, NIOSH TWA = 0.552 * OSHA TWA + 42.13 ㏈(A), shows that if OSHA TWA is known, NIOSH TWA can be predicted by the equation. The mean TWA difference between threshold 80dBA and 90dBA was significant(p<0.01).
While the TWA noise exposures were 7.7％ above the Korea(OSHA) PEL, they were more than 83.3％ over NIOSH REL. Automobile workers were exposed to noise level that could be potentially damaging to their hearing. It found that their approximately 25％ excess risk of hearing loss even if a worker is protected to the PEL in according to NIOSH study. So these data demonstrate the need of engineering control for noise reduction of press line and comprehensive hearing conservation programs for whole workers(press operator, crane operator, forklift driver). The Noise measurement criteria of Korea has no definition about threshold value. So I suggest that we should set the threshold set the threshold value by law.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|