| Summary: | 碩士 === 弘光科技大學 === 職業安全與防災研究所 === 105 === The major fastener manufacturing industries located in southern Taiwan, Tainan and Kaohsiung. Totally, it is over 20 thousands labors, and the production quantity is about 13-14％ among worldwide. The major production line includes wire drawing, forming, tapping/ threading, heat treatment, surface treatment, packaging and shipping.
The heat hazard result from the high temperature (700~900℃), that can make the steel to soften and can be cut easily in preventing the splintering. Meanwhile, the noise is also a serious problem and the exposure level of TWA8h achieve 95dBA, as well as the dose is about 200 %, those have over the PEL-TWA. The present study therefore aims to assess the noise exposure dose, noise map, and WBGT in 4 crew industries, and to collect the health examinations of hearing loss in the workers. The information can be integrated with the demographic data from the questionnaire interview and to assess association among noise exposure and hearing loss. Now we have finished the walkthrough survey and questionnaires interview, and the environmental monitoring were completed in 4 fastener manufacturing industries. Overall, 57 noise dose, 41 WBGTs have been assessed now. Meanwhile, 44 data of hearing loss test have been collected in the current study.
For the dosage evaluation of noise exposure in plant A, the average noise was 74±10%, and the TWA was 87.8±0.9dBA; the average noise was 67%, and the TWA was 86.8dBA in plant B; in plant C, the average noise was 92±42.6%, and the TWA was 88.7±3.37 dBA. In plant D, the average TWA was 95.0-101.8 dBA, and the TWA in packing area, surface treatment, forming, threading, heat treatment was all higher than PEL-TWA (90dB). The most high nose dose was detected in threading, that achieved to 512%.
In the hearing loss of the workers, in 4kHz, the average hearing loss in left and right ears was 28.8dB in plant B>25dB in plant D＞18.8dB in plant A, in 6kHz, the average hearing loss in left and right ears was 52.5dB in plant B>23.5dB in plant D＞21.5dB in plant A. But, the association cannot be calcified after adjusted confounding factor between exposure dose ad healing loss.
For heat exposure assessment, the major evaluation was in heat treatment area, and the result showed that no potential heat hazard was found after adjusting the work and rest ratio for each worker due to the WBGT was 26.45-28.68℃ in heat treatment and 27.23-27.95℃ in nodulizing/ annealing areas.
For suspected early noise hearing loss case tube should be strengthened, tracking on a regular basis to assess changes in hearing. Implement of workplace education and training, regular monitoring of health examination for safety and health management in order to reduce the risk of noise-induced hearing loss. Thermal hazards of WBGT measurements are non-hot jobs that although the working time is quite short but still has high temperature hazard risk, it is recommended that institutions can evaluate whether to increase the supply of labor to the cool or cooling air curtains heat formation to be improved.
The conclusive results from the data showed the noise exposure was the high potential hazard in fastener manufacturing industries. Therefore, we suggested that hazard monitoring should frequently be applied and health examinations in the workers should be done. The hazard education and personal protective equipment both also provide to preventing the hearing loss. Meanwhile, for suspected early hearing loss case should be tracking in preventing the further hearing loss. For thermal hazards of WBGT measurements, no potential thermal hazard was found in the current study. But, in quite short working time, high temperature was also detected in few times. It is recommended to increase the supply cooling air in heat treatment areas for avoiding the long-term occupational health risk.
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