LCD 제조공정 종사근로자의 극저주파자기장 노출특성 연구

Abstract

Objectives: The aim of this study is to evaluate exposure levels of the extremely low frequency magnetic fields(ELF-MF) radiated from various electric facilities in Liquid Crystal Display(LCD) manufacturing processes.

Methods: This study measured the exposure levels of personal and local ELF-MF for the electronic facilities installed in two LCD manufacturing companies. Samplers were installed around workers’ waist during working hours to identify personal exposure levels, and direct reading equipment were located at 3 cm, 10 cm, and 30 cm away from the surface of the electronic facilities to measure local exposure levels. Average and maximum(ceiling) values were calculated for personal and local exposure levels.

Results: Average and maximum of personal exposure levels for each worker were 0.56(mean) ± 0.02(SE) μT and 6.31 ± 0.75 μT, respectively. Statistical analyses of the study found that maximum of the personal exposure levels for engineers was significantly higher than that for operators since engineers spend more time near the electronic facilities for repairing. The range of maximum personal exposure levels was 0.50 ~ 43.50 μT and its highest level was equivalent to 4.35 % of ACGIH(American Conference of Governmental Industrial Hygienists) exposure limit value(1 mT). Maximum of local exposure levels was 8.18 ± 0.52 μT and the electronic facilities with higher exposure levels were roof rail and electric panel, which were not related to direct manufacturing. The range of maximum local exposure levels was 0.60 ~ 287.20 μT and its highest level was equivalent to 28.7 % of the ACGIH exposure limit value. Lastly, the local exposure levels significantly decreased as the measurement distance from the electronic facilities increased.

Conclusions: Maximum of personal and local exposure levels did not exceed the exposure limit value of ACGIH. However, it is recommended to keep the workers as far as possible from the sources of ELF-MF.