자동차 조립공정에서 공기압력식 진동공구의 국소진동평가

백남원,김선술 한국산업위생학회 1996 한국산업보건학회지 Vol.6 No.1

This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (P$gt;0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. 1n this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 ㏈ (7.94 × 10^(-6) m/s²) at 1,000 ㎐. Slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

통계학적 방법에 의한 공기중 유해물질농도의 평가

백남원 가톨릭대학 산업의학센타 산업의학연구소 1977 韓國의 産業醫學 Vol.16 No.1

産業場의 騷音에 關한 調査硏究

白南園 서울大學校 保健大學院 1968 公衆保健雜誌 Vol.5 No.1

Increasing mechanization and speeding up of industrial processes are often accompanied by increased noise. A study was carried out to find out noise levels in various plants in Korea from May I to September 30, 1967 and the results were as follows: 1) Shipbuilding plants produced the highest noise levels ranging from 92 to 126 phon and printing plants had the lowest noise levels of 57 to 94 phon. The levels at automobile industries were in the range of 81 to 117 phon, those at coal mines, 97 to 115 phon, at steel industries, 86 to 113 phon, at refining industries 85 to 110phon. at paper mills, 82 to 99 phon and at china wares, 90 to 98 phon. 2) As for the noise levels produced by various types of machines, those of air hammers were the highest 117 phon and those of carving machines were the lowest with a range of 80 to 83 phon. The levels of drilling machines ranged from 114 to 115 phon, those of air grinders, 112 to 113 phon, of rolling mills, 103 to 110 phon, of circular saws, 104 to 105 phon, of blast furnaces, 102 to 110 phon and those of cutting machines, 103 to 105 phon. 3) According to the octave band analyses, the noises of air harmers, drilling machines, cutting machines, air grinders and circular saws showed the high frequencies, those generated by rolling mills, shapers, sewing machines, dryers and spinning frames had the middle frequencies, and those by blast furnaces, heating furnaces and electric machines were in the low frequency category. 4) According to calculation based on the noise rating system proposed by the International Organization for Standardization (ISO), the allowable exposure times were less than 10 minutes in the cocking processes of shipbuilding plants and no hazadous noises were found throughout the printing plants.

下水의 再利用

白南園 가톨릭대학산업의학센타 산업의학연구소 1973 韓國의 産業醫學 Vol.12 No.2

수동식 시료채취기의 사용현황

백남원,Baek, Nam-Won 대한산업보건협회 2001 산업보건 Vol.163 No.-

'석면노출기준 20배 강화'의 의미

백남원,Baek, Nam-Won 대한산업보건협회 2001 산업보건 Vol.164 No.-

교실의 채광, 조명 및 소음관리

백남원 韓國學校保健學會 1991 韓國學校保健學會誌 Vol.4 No.1

중소기업 도금공정에서의 6가 크롬 폭로에 관한 연구

백남원,정희경 한국산업위생학회 1993 한국산업보건학회지 Vol.3 No.2

This study was performed at eleven small-sized plating factories located in Seoul, Incheon, Ansan, and Taejeon from July 21 to October 6, 1992. The major objectives of this study were to evaluate worker exposure to hexavalent chromium and local exhaust ventilation (L.E.V.) systems at the chromium plating operations. The most suitable L.E.V. systems for chromium plating tanks were designed as examples for recommendation to the industry. The results are summarized as follows. The range of chromium plating operations investigated included decorative, hard, and black chromium plating on several kinds of parts. Most of plating tanks were not equipped with proper control methods against emission of hexavalent chromium mists and workers were not wearing appropriate personal protectives. The airborne hexavalent chromium concentrations showed an approximate lognormal distribution. The geometric means of both personal and area samples were within the Korean and ACGIH standards, 50 ㎍/㎥. However, in comparison with the NIOSH criterion, 1 ㎍/㎥, the geometric means of personal samples at two factories and the geometric means of area samples at two factories exceeded it. The geometric means of personal and area samples of high exposure groups (above the NIOSH criterion) were 7 and 27 times higher than those of low exposure groups (below the NIOSH criterion), respectively. The L.E.V. systems of high exposure groups were improperly designed, and the factory with the highest exposure level had no L.E.V. systems at all on chemical etching process. Whereas at factories of low exposure groups, mist control methods such as mist suppressants, tank cover, and/or auxiliary L.E.V. systems were added to L.E.V. systems. The evaluation of L.E.V. systems showed that there was no chromium plating operation satisfying the ACGIH criteria for capture velocity, slot velocity, and exhaust rate simultaneously. To increase performance of L.E.V. systems, it must be designed to minimize the impact of boundary layer separation. Push-pull ventilation hood and downward plenum ventilation hood were suggested for the Korean industry.

일부 신나의 구성성분과 공기중 증발에 관한 연구

백남원,조경이 한국산업위생학회 1997 한국산업보건학회지 Vol.7 No.2

For twelve solvent thinners, evaporation rates of components were investigated and models to estimate the actual concentration have been evaluated. Also, the current ACGIH TLVs (Threshold Limit Values) for the concentration of organic mixtures have been adjusted. The results of this study are summarized as follows : 1. Airborne concentrations of solvent thinner components were related to their respective vapor pressure (r=0.96). On the other hand, there was no significant relation between the concentrations in the air of the thinner compounds and the original amount in liquid form. 2. Airborne concentrations of each chemical were estimated by temperature at 8.5 1, 16.7 1 and 31.5±2℃ with an air velocity of 1.5 m/s. The concentrations were increased by increasing temperature (p$lt;0.05). The percentage of concentrations were proportionate to their respective percentage of vapor pressure. Among the chemicals studied, n-butyl acetate, n-butyl alcohol, m-xylene, p-xylene and o-xylene showed a clear relationship to temperature. 3. Airborne concentration of each chemical was estimated by air velocity at 0.05, 1.50 and 2.50 m/s, with a constant temperature at 17±2℃. The concentrations were increased by increasing air velocity (p$lt;0.05). The percentage of concentrations were proportionate to their respective percentage of vapor pressure. Among the chemicals studied, n-butyl alcohol, m-xylene and p-xylene showed a clear relationship to velocity. 4. In estimating the concentrations of solvent thinners by temperature and air velocity. ACGIH TLVs for mixtures tended to be larger than the values obtained by ACGIH exposure index. It shows that ACGIH TLVs for mixtures are not adequate for evaluating the airborne concentration of thinners and other organic mixtures. 5. The evaporation rate of the thinners were compared to the theoretical equations of Hummel, Braun and Mackay. The Hummel and Braun methods were close to exposure index but Makay's showed an underestimated value. In order to see the accuracy of each three models, the SSE (Error Sum of Squares) calculated for Hummel's was 1.73, being the closest to the actual values. 6. Present ACGIH TLVs for mixtures are not appropriate evaluate industrial environments. In this study, a correction of TLVs using vapor pressure of respective components was suggested. In order to evaluate the corrected TLVs a paired t-test was performed. There was no significant difference between the exposure index and the concentration corer suggested TLVs (p$gt;0.05). Thus, this corrected TLVs seem appropriate in order to evaluate actual industrial workplaces organic chemical concentration in the air.

망간중독

백남원 가톨릭대학산업의학센타 산업의학연구소 1974 韓國의 産業醫學 Vol.13 No.4