• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.381-389
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• 2009

Confined spaces are inherently dangerous workplace and many fatal and nonfatal accidents have been reported. Even though these accidents occur in various kinds of confined spaces, there has rarely been reported on the health hazard agent, i.e., the types of gases and their concentration ranges. Therefore in this study, we evaluated several toxic and asphyxiating gas concentrations in various confined spaces. We surveyed 57 manholes, 3 sewage treatment plants, 2 yellow radish manufacturing companies and 7 barges to measure the concentrations of oxygen($O_2$), hydrogen sulfide($H_2S$), carbon monoxide(CO), ammonia($NH_3$). Lower Explosion Limits(LEL) and Volatile Organic Compounds (VOCs). Those four types of confined spaces occupies 56% of accidents during last 9 years in Korea. In 57 manholes, the concentration varied according to the types of manholes; rainfall and sewage, and by location; residential and industrial areas. Sewage manhole in industrial area was evaluated as the most hazardous than other types of manhole like rainfall manholes, residential sewage manholes. The highest $H_2S$ concentration and the lowest $O_2$ concentration at sewage manhole in industrial area were 300 ppm, 8.7% respectively. In 3 sewage treatment plants, $H_2S$ and $NH_3$ concentrations were reached up to the 500 ppm and 200 ppm respectively. Two yellow radish manufacturing companies showed the concentrations of 316 ppm, 505.2 ppm, 90 ppm and 15.7% for $H_2S$, CO, VOCs and $O_2$, respectively. Seven barges showed 15.9%~20.9% oxygen concentration. Gas species and concentration ranges varied by the types and location of confined spaces; CO, $H_2S$, $O_2$ could be hazardous in manhole, especially manhole connected to sewage plants. CO, $H_2S$, LEL, $O_2$, $NH_3$ should be controlled in sludge silo and sluge pumping confined spaces in sewage treatment plant. The activity of lifting out radish from the storage tank was evaluated more hazardous rather than the other activities in yellow radish manufacturing industry. The employers must conduct the survey to identify all possible confined spaces in their local workplace prior to performing the tasks. At the national level to reduce the accidents in the confined spaces, we suggest that systemic approach and active education program including possible hazards, standard operation procedures, ventilation plan, and personal protective equipment in confined spaces should be implemented.

• Journal of the Korea Safety Management & Science
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• v.18 no.3
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• pp.47-54
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• 2016

A confined space means places where the risk of damage to health caused by lack of oxygen or hazardous gases in inadequate ventilation conditions and the risk of fire and explosion caused by flammable substances. Asphyxiation accidents in a confined space occured every year and also occurred more than two people at the same time. In this study, we surveyed the domestic statistical data occurred the lack of oxygen in confined space for the last 10 years(2006-2015) and, analyzed the accident by industries sector, workplace size etc. 17 fatal work accidents that occurred in confined spaces in Korea between 2013 and 2015 were investigated and analyzed using the database of the KOSHA and suggested interventions to minimize asphyxiation accidents in confined spaces. This paper is expected to be used to establish interventions planning and training as a preventive measures in workplace having confined spaces.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.83-93
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• 2021

Objectives: 'Confined space' was only defined in the Safety and Health Regulations as a place where oxygen deficiency and hydrogen sulfide must be dealt with at the time of the initial enactment (1982). The danger of fire and explosion were added in 2003. We will compare and review the regulations related to confined space work under the current safety and health rules alongside regulations in other countries and prepare a plan to improve the system through enhanced clarity and execution. Methods: In a comparison of systems for the prevention of suffocation in confined spaces in major countries (Germany, United States, Japan) different concepts of the definition of confined spaces in different countries apparently due to differences in each country's legal implementation system, accident analysis methods, the status of safety and health implementation in workplaces, the precautions against actual confined space work, and the definition of confined spaces were found to be not much different between Korea and the other foreign countries. Results: In the case of Germany and the United States, a confined space is defined as a contextual concept rather than a place, so more careful attention is needed from operators or enclosed space managers as it is often necessary to judge the actual workplace. In the case of Korea and Japan, the interior of the place is mainly defined as a place, especially in the case of Japan, which concentrates on oxygen deficiency and hydrogen sulfide poisoning. Conclusions: For measures to improve regulations on the prevention of suffocation accidents in Korea, I would like to propose three major measures to improve the system in the rules on domestic industrial safety and health standards. It is necessary to prepare and provide a guide to ensure that the 18 types of confined spaces currently defined as confined spaces are clearly understood by field management supervisors or workers.

• Journal of the Ergonomics Society of Korea
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• v.36 no.3
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• pp.245-254
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• 2017

Objective: This study aims to investigate the effects of organizational support, risk perception and job satisfaction on safety consciousness in confined space works. Background: Confined space works are rated as hazardous works with high injury frequency and fatalities. But there were few researches for the occupational injury of the confined space workers. Method: Questionnaire survey targeting 236 workers working in confined spaces were carried out to construct the structural equation model on safety consciousness. The participants were all male workers, and they install and maintain or clean facilities mainly in the confined spaces. Results: A structural equation model for safety consciousness was proposed, and validated based on perceived organizational support, risk perception and job satisfaction factors. Perceived 'organizational support' contributed significantly to 'worker's safety consciousness' both directly and indirectly. Also, perceived 'worker's safety consciousness' was also affected by perceived 'job satisfaction' and 'risk perception'. In terms of magnitude of relationships, the direct effect of perceived 'job satisfaction' on 'worker's safety consciousness' was the greatest among the interrelationships among latent factors. Conclusion: Workers' safety consciousness can function as a leading indicator for safety and hazard prevention of workers. Application: The results can be used in developing safety prevention programs for confined space workers.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.113-131
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• 1997

This study was performed to evaluate the exposure levels of worker exposed to welding fume and metals in confined spaces of a shipyard. The airborne concentration of welding fumes and metal elements in confined spaces were compared with those in open working areas. Results of the study were as follows. 1. The geometric mean of welding fume concentration in a confined space was $16.6mg/m^3$, which contained $3.9mg/m^3$ Fe, $1.2mg/m^3$ Mg, $0.8mg/m^3$ Zn, $0.008mg/m^3$ Cu, $0.008mg/m^3$ Pb, $0.005mg/m^3$ Ni, $0.003mg/m^3$ Cr, $0.003mg/m^3$ Cd. The geometric mean of welding fume concentration in open working areas was $5.2mg/m^3$, which contained $1.1mg/m^3$ Fe, $0.3mg/m^3$ Mg, $0.3mg/m^3$ Zn, $0.004mg/m^3$ Cu, $0.008mg/m^3$ Pb, $0.005mg/m^3$ Ni, $0.003mg/m^3$ Cr, $0.0003mg/m^3$ Cd. The geometric mean of welding fume concentration in confined spaces was 3,2 times higher than that in open working areas. The geometric mean concentrations of such metals as Fe, Mg, Zn, or Cu within fume in confined spaces were 2-4 times higher than those in open working areas, while little difference made such metals as Pb, Ni, Cr, Cd. 2. In 32 samples out of a total of 39 samples (82.1%) collected in confined spaces, the concentrations of welding fume exceeded TLV. while so did 19 samples out of 33 samples (57.6%) in open working areas. As for the concentrations of metals in welding flume from confined spaces, Fe exceeded TLV in 14 out of a total of 38 samples (36.8%), Mn exceeded TLV in 23 out of a total of 38 samples (60.5%). As for the concentration of metals in welding fume from open working areas, Fe exceeded TLV in 3 out of a total of 34 samples (8.8%), Mn exceeded TLV in 6 out of a total of 34 samples (17.6%). Considering additive effect among metals, in 31 out of a total of 39 samples (79.5%) collected in confined spaces, the concentrations of welding fume exceeded TLV, while so did 14 out of 38 samples (55.6%) in open working areas. 3. In respect of base metal and welding type the concentration of total welding fume by $CO_2$ gas W./mild steel was the highest, followed by semiauto MMA/mild steel, then followed by TIG or $CO_2$ gas W./stainless steel. ; as for concentration of metal within fume, a decreasing order was Fe, Zn, Mn, and Pb in $CO_2$ gas W./mild steel and semiauto MMA/mild steel, but Fe, Mn, Cr, and Ni in TIG or $CO_2$ gas W./stainless steel. 4. In case of welding base metal covered by paint, contents of Zn within red paint chip and within gray paint chip were 14.0% and 0.08% respectively, which showed a little difference, while the airborne concentrations of Zn within fume during welding base metal covered red paint and gray paint were $1.351mg/m^3$ and $1.018mg/m^3$ respectively, which showed little difference. As for Pb, contents of red paint chip and gray paint chip were 0.14% and 0.08% respectively, and the airborne concentrations within fume during welding base metal covered red paint and gray paint were $0.009mg/m^3$ and $0.007mg/m^3$ respectively, both of which showed little difference.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.9
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• pp.1159-1164
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• 2018

Recently, Internet use is increasing in various fields. Especially in the sudden disaster area, the role of Internet of things that can continuously monitor is getting bigger. In this study, the characteristics of the confined space and the environmental hazards are examined, and the Internet of the object which is being commercialized will be reviewed. Accidents in confined spaces are very high compared to other places, and it is very difficult to predict accidents. Recently, various attempts have been made to prevent accidents in confined spaces using the Internet of things. Especially, it detects the various gases that can occur in the closed space using sensors and sends them to the workers in real time, so that the risk can be detected in advance to minimize the risk. In this paper, we propose an effective disaster prevention plan using the Internet of things through the case study of the Internet for the prevention of accidents in a confined space.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.590-602
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• 2019

Objectives: This study was conducted to prevent asphyxiation of firefighters during confined space rescue. The specific purpose was to identify the magnitude of the problem, identify the cause of the accidents, and suggest measures to ensure safety of confined space rescues. Methods: We collected data from National Fallen Firefighters Memorial, press releases, and other sources In order to identify the current situation of asphyxiation incidents among firefighters from 1945 to 2019. In addition, an incident investigation was conducted for each case, and the processes, causes, and control measures of the incidents were described as a narrative data entry. Results: Over the past 73 years, eight incidents involving firefighter in Korea have occurred. In these incidents, five firefighters were killed, and eight were injured. The confined spaces incidents occurred were water supply tanks, wastewater treatment tanks, pickling pits, septic tanks, and more. The causes were three cases of hydrogen sulfide poisoning, one of oxygen deficiency, one of carbon monoxide poisoning, and three unclassifiable asphyxiations. The people in need were all workers in various industries. Conclusions: The number of firefighters' deaths and injuries during rescues in confined spaces was severe and the risks have not been completely eliminated. By establishing and implementing a precise incident investigation system, according control measures should be initiatedin order to prevent a recurrence of the same type of disaster and reflected in the SOP. In particular, due to the high risk of occurrence at workplaces, cooperation between fire and rescue authority and relevant agencies such as the Ministry of Employment and Labor and the KOSHA should be strengthened.

• Proceedings of the Korean Society of Rheology Conference
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• 2002.05a
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• pp.21-24
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• 2002

• Macromolecular Research
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• v.11 no.5
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• pp.393-397
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• 2003

By applying a configurational-bias Gibbs ensemble Monte Carlo algorithm, priority simulation results regarding the conformation of non-dilute polyelectrolytes in solvents are obtained. Solutions of freely-jointed chains are considered, and a new method termed strandwise configurational-bias sampling is developed so as to effectively overcome a difficulty on the transfer of polymer chains. The structure factors of polyelectrolytes in the bulk as well as in the confined space are estimated with variations of the polymer charge density.

• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.1-11
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• 2017

Blast injuries in a compartment are investigated, and the effects of obstacles on blast injury are particularly analyzed by comparing injuries in the compartments with or without protruding obstacles inside. Even if blast pressure profile tends to be complicated in a confined space unlike in open field, it can be obtained in a relatively short time by using some empirical fast running models for simple confined spaces. However, a finite element method should be employed to obtain blast pressure profiles in a case with obstacles in confined spaces, because the obstacles heavily disturb blast waves. On the other hand, Axelsson SDOF(Single degree of freedom) model and ASII(Adjusted severity of injury index) injury level are employed to estimate blast injury in compartments, because the usual pressure-impulse injury criterion based on the ideal Friedlander waves in open the field cannot be applied to personnel in a confined space due to complexity of blast waves inside. In cases with obstacles, chest wall velocity was reduced by 26 to 76 percent(%) and the personnel injury in the compartment caused by blast was also reduced.