• Safety and Health at Work
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• 제7권1호
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• pp.6-11
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• 2016

Background: A permit to work (PTW) is a formal written system to control certain types of work which are identified as potentially hazardous. However, human error in PTW processes can lead to an accident. Methods: This cross-sectional, descriptive study was conducted to estimate the probability of human errors in PTWprocesses in a chemical plant in Iran. In the first stage, through interviewing the personnel and studying the procedure in the plant, the PTW process was analyzed using the hierarchical task analysis technique. In doing so, PTWwas considered as a goal and detailed tasks to achieve the goal were analyzed. In the next step, the standardized plant analysis risk-human (SPAR-H) reliability analysis method was applied for estimation of human error probability. Results: The mean probability of human error in the PTW system was estimated to be 0.11. The highest probability of human error in the PTW process was related to flammable gas testing (50.7%). Conclusion: The SPAR-H method applied in this study could analyze and quantify the potential human errors and extract the required measures for reducing the error probabilities in PTW system. Some suggestions to reduce the likelihood of errors, especially in the field of modifying the performance shaping factors and dependencies among tasks are provided.

• 한국정밀공학회지
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• 제33권5호
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• pp.333-339
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• 2016

In this paper, a fundamental experiment regarding the formation of porous 3D structures for personal safety products using 3D PPP (Porous Polymer Printing) was introduced for the first time. The filament was manufactured by mixing PP (Polypropylene) and CBA (Chemical Blowing Agent) with polymer extruder, and the diameter of the filament was approximately 1.75mm. The proposed 3D PPP method, combined with the conventional FDM (Fused Deposition Modeling) procedure, was influenced by process parameters, such as the nozzle temperature, printing speed and CBA density. In order to verify the best processing conditions, the depositing parameters were experimentally investigated for the porous polymer structure. These results provide parameters under which to form a multiple of 3D porous polymer structures, as well as various other 3D structures, and help to improve the mechanical shock absorption for personal safety products.

• 한국가스학회지
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• 제23권3호
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• pp.33-39
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• 2019

2010년대에 들어서 노후화된 공정으로 인하여 많은 공장들의 안전이 보장되지 않은 채로 가동되고 있다. 공정 및 설비의 노후화 문제를 근본적으로 해결하기는 어렵지만, 사전에 위험성 평가로 위험을 예방할 수있다. 본 연구는 CDU(Crude Distillation Unit)의 탈황 장비에 있는 배관에서 황으로 인한 부식을 타겟으로 지정하였고, API RP 581를 참고한 RBI(Risk Based Inspection)기법으로 위험성 평가를 실시하였다. RBI 기법은 Frequency와 Consequence의 조합으로 Risk를 표현하고, 이들을 바탕으로 Risk Matrix를 만든다. 본 연구는 배관의 Hole Size를 Small과 Medium으로, Frequency의 감도는 'Low'로 선택하여 진행하였다. 기준을 통해 만들어진 Risk Matrix를 참고하여 배관에서 황으로 인한 부식의 사고 위험성을 평가하고 향후 사고 방지 계획을 세울 수 있다. 또한 이와 비슷한 방법으로 노후화에 대한 예방을 한다면 보이지 않는 크고 작은 사고들도 예방 할 수 있다.

• 한국가스학회지
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• 제20권4호
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• pp.15-24
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• 2016

반도체 산업에서 많은 종류의 화학물질 사용으로 인한 독성물질 누출과 화학물질간의 혼화에 따른 화재 폭발 등에 의한 화학사고의 위험성이 증가하고 있다. 화학물질의 혼화에 따른 반응성을 평가하는데 실험적 방법이 가장 신뢰성 있지만, 모든 화학물질을 실험을 통하여 평가하는 것은 시간적, 비용적인 제한이 있다. 본 연구에서는 반도체 산업에서 주로 사용되는 공정가스의 위험성 추정하기 위해 미국 NOAA(National Oceanic and Atmospheric Administration)과 EPA에서 개발한 CRW(Chemical Reactivity Worksheet) 3.0 프로그램을 사용하여 공정가스의 반응성을 고찰하였다. 이들 연구 결과는 반도체산업의 공정가스의 혼화성에 따른 반응성 정보와 저장캐비닛의 가스 실린더 보관에 관한 KOSHA 기술지침 작성에 필요한 기초자료를 제시하고자 하였다.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2329-2333
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• 2022

Base metal corrosion forms a significant issue during the chemical decontamination of the primary coolant loop in nuclear power plants as it is directly related to the economic and safety viability of decommissioning. In this technical note, potentiodynamic evaluations of several base metals (304 stainless steel, SA106 Grade B carbon steel, and alloy 600) were performed to determine their corrosion behavior during the hydrazine (N₂H₄)-based reductive ion decontamination (HyBRID) process. The results suggested that N₂H₄ protected the surface of the base metals in the HyBRID solution, which is primarily composed of H₂SO₄. The corrosion resistance of the carbon steel was further improved through the addition of CuSO₄ to the solution. The corrosion rate of carbon steel in the H₂SO₄-N₂H₄-CuSO₄ solution was lower than that exhibited in an oxalic acid solution, a commonly used reaction medium during commercial decontamination processes. These results indicate the superiority of the HyBRID process with respect to the base metal stability.

• 한국산업보건학회지
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• 제17권3호
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• pp.254-260
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• 2007

Trichloroethylene(TCE) is widely used as a degreasing solvent in workplaces. TCE is primarily toxic to the nervous system, however, systemic disorder like Stevens-Johnson syndrome has been recently reported in small-scale factories, where the government has had limited information of chemical use. A survey was performed to investigate the actual condition of using TCE and to provide practical information to occupational health service agencies and professionals. This survey was carried out on 103 factories out of 430 factories which were conducted periodic work environment measurement for TCE. Degreasing was the most popular reason for using TCE in Korea, which reached to 94%. TCE was also used as a solvent for rubber in the coating or molding process, and adhesives in the bonding process. Metal fabrication was the most common as 23%, followed by assembling automobile parts (17%), and machinery (12%). Workers exposed to TCE during full-shift were 52% while 48% were exposed during short period of the shift or intermittently. Manual or semi-automatic work occupied 87% while automatic work was just 13%. Though automatic work by a closed system was generally lower exposed to TCE, compared to manual work, it can cause a high exposure when the maintenance system is improper. Semi-automatic work especially like open-top degreasing process can cause a high exposure when local exhaust system with condensing and refrigerating coils in the degreaser does not work well. In conclusion, the survey showed nationwide status of TCE exposure in various aspects. It can be used to monitor workplaces and workers exposed to TCE to prevent occupational diseases.

• 한국산업보건학회지
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• 제30권2호
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• pp.213-225
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• 2020

Objectives: In order to prepare measures to enhance construction workers' satisfaction with their working environment, the effects of working conditions and the mediating effects of safety and health information on workers' satisfaction with their working environment in the construction industry have been studied. The results of this study can be used as basic data for further studies in this field. Method: Data on 1,361 male construction workers from the 5th Korea Working Condition Survey (KWCS) were used for this study. The effects of working conditions were analyzed using SPSS 25.0 and the mediating effects of health and safety information were analyzed with SPSS PROCESS macro using the bootstrap method. Results: The safety and health management system and the self-determination of break time had a statistically significant positive effect on satisfaction with the working environment. Chemical and ergonomic risk factors had a statistically significant negative effect on satisfaction with the working environment. The provision of safety and health information, the mediating variable, had a statistically significant positive effect on satisfaction with the working environment. Therefore, it had a mediating effect between working conditions and satisfaction with the working environment. Conclusion: In order to enhance construction workers' satisfaction with their working environment, the above results suggest that the safety and health management system should be well established; self-determination of break times should be guaranteed; and chemical and ergonomic risk factors should be controlled. In addition, workers should be provided with necessary health and safety information related to their work. This study will be useful if these findings are used as basic data in further studies in related fields.

• 한국가스학회지
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• 제22권6호
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• pp.40-43
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• 2018

압력안전밸브의 열림고장과 닫힘고장은 서로 부분적으로 종속되어있다. 본 연구에서는 마르코프 프로세스 모델과 Weibull 분포 모델을 이용하여 두 가지 고장에 대한 신뢰성 모델을 구축하는 방법을 제안한다. 압력안전 밸브 모델은 알려진 열림고장 모델, 유도된 닫힘고장 모델, 최근 보고된 점검결과를 재현하는 동시고장 모델로부터 얻어진다. 제안된 방법은 부분적으로 종속된 다중 고장상태를 갖는 다양한 시스템의 정량적 위험성 평가로 확대 적용할 수 있을 것으로 기대된다.

• 한국화재소방학회논문지
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• 제34권1호
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• pp.89-102
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• 2020

인체 건강에 치명적인 위해를 가할 수 있는 독성 및 인화성 가스를 이용한 화학테러행위는 행위자인 테러범과 그 행위로 인한 피해자 간에 존재하는 현격한 정보의 비대칭성으로 인해 대다수의 선진국, 또는 국지적 분쟁을 겪고 있는 국가 및 지역사회에 대하여 중대한 안보위협이 되고 있다. 화학테러에 대한 대응기관의 대처방안은 크게 예방, 대응, 수습의 3단계로 나누어 볼 수 있고, 이 과정 중에서 화학테러의 피해 정도 및 피해 범위에 절대적인 영향력을 미치는 예방과 대응단계에 해당하는 각 전문대응기관과 요원들의 성공적인 임무수행을 위해서는 화학테러의 잠재적 대상이 되는 시설들에 대한 객관적이고 체계화된 취약성의 평가와 등급화가 무엇보다 중요하다. 본 연구에서는 기존 국내외의 화학테러관련 취약성 등급분류체계를 비교분석하고 현재 국내 등급분류체계의 개선방향에 대해 살펴보고 실제 국내 다중이용시설 표본에 대한 취약성 평가를 통해서 보다 과학적이고 체계화된 방법론을 제시하였다.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.373-384
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• 2016

The membrane-aerated biofilm reactor (MABR) is a promising municipal wastewater treatment process. In this study, two cross-flow MABRs were constructed to explore the carbon and nitrogen removal performance and bacterial succession, along with changes of influent loading shock comprising flow velocity, COD, and NH₄-N concentrations. Redundancy analysis revealed that the function of high flow velocity was mainly embodied in facilitating contaminants diffusion and biosorption rather than the success of overall bacterial populations (p > 0.05). In contrast, the influent NH₄-N concentration contributed most to the variance of reactor efficiency and community structure (p < 0.05). Pyrosequencing results showed that Anaerolineae, and Beta- and Alphaproteobacteria were the dominant groups in biofilms for COD and NH₄-N removal. Among the identified genera, Nitrosomonas and Nitrospira were the main nitrifiers, and Hyphomicrobium, Hydrogenophaga, and Rhodobacter were the key denitrifiers. Meanwhile, principal component analysis indicated that bacterial shift in MABR was probably the combination of stochastic and deterministic processes.