• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.53-54
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• 2022

There is an increasing demand for prediction of asbestos concentration which has an fatal effect on human body. While demolishing asbestos, the dust scatters and makes workers be exposed to danger. Up to this date, however, factors that particularly influences have not considered in predicting asbestos concentration. Most of the studies could not quantify the distribution of asbestos. Also, they did not use nominal data on buildings as important factors. Therefore, this study aims to build an asbestos concentration prediction model by quantifying distribution of asbestos and using nominal data of buildings based on Artificial Neural Network (ANN). This model can give significant contribution of improving the safety of workers and be useful for finding effective ways to demolish asbestos in planning.

• Architectural research
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• v.13 no.2
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• pp.31-40
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• 2011

Asbestos have been used around the world by physical and chemical characteristics that are a reliable and cost-effective. But asbestos, once called the miracle of mineral, is now a quiet time bomb. Asbestos hazards have been studied and the government has pursued 'Comprehensive Measures for Asbestos Management' jointly with related departments. As a part of plan, Ministry of Environment is to introduce legislation 'Asbestos Safety Management Act' through Environment Announcement No. 2010-108. The same Act. 24 shows as follows. Minister of Environment or governor should do survey on the actual condition targeting rural buildings with slates and partly or fully fund to dissolve, remove asbestos slate which was used in each building. However, the local survey was only conducted by each municipality regionally. And there is no actual condition data by area, application and year, and there was no data on disposal costs concerning asbestos slate buildings In this study, discharge of asbestos slate was calculated per unit area and formula was developed with regression analysis. In addition, Demolition, dismantling, disposal costs were computed via a phone survey to disposal companies and then this study proposed standards for this.

• KIEAE Journal
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• v.11 no.3
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• pp.57-62
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• 2011

Asbestos have been used around the world because of reliable and cost-effective physicochemical characteristics. After incubation period about 15-40 years asbestos can cause various cancers, including malignant mesothelioma when inhaled into the air. These properties turned out, asbestos have been banned from using in developed countries. Also in Korea also, the use of asbestos was banned across the board by revision of Industry Safety and Health Act in February 2009. Therefore, the problem of asbestos is not when using. It is about dismantling, maintenance, and the final processing of asbestos waste. Asbestos Cement slates which is Widely distributed throughout the country as roofing materials has much scattering potential compare with inside materials. Also Ministry of Environment is planning to introduce legislation 'Asbestos Safety Management Act' through Environment Announcement and The same Act. 24 show as follows. Minister of Environment or governor should do survey on the actual condition targeting rural buildings with slates and partly or fully fund to dissolve, remove asbestos slate which was used in each buildings. Therefore, to solve these problems, database-building and necessity of management strategies have been continually arisen. So this study was performed. Its application value is very high in terms of its political, economic. Asbestos Cement Slates database could build to collect national registered building data and then using GIS, asbestos cement Slates distribution map were constructed in each province's cities and counties of the country. And this map by Application, construction was to visualize by application, construction of year. Through these results, information of Asbestos Cement Slates could visually inform to policy makers, asbestos dismantling and management contractor, and civilian and it would alleviate the gap of knowledge information. This is expected to be utilized by medium and long-term and effective plan for demolition and dismantling of asbestos cement Slates.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.405-411
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• 2020

Objectives: The objectives of this study were to investigate whether airborne fibers were released to the outside air from the asbestos removal area in buildings, and to confirm the existence of asbestos fibers in samples using transmission electron microscopy(TEM). Methods: A total of 1,295 samples was collected from inside and outside 155 asbestos removal areas. To investigate the release of asbestos fibers from the removal area, samples were collected at three locations, such as an entrance to change room, an exit of negative pressure unit(NPU) and perimeter areas. Samples were also collected in the removal area prior to and after removal activity. All samples were analyzed by phase contrast microscopy(PCM) and one-tenth of the samples was analyzed using TEM to discriminate asbestos fibers. Results: During the asbestos removal activity, 27(4.1%) of 662 samples collected outside the removal area showed airborne fiber concentrations equal to or in excess of 0.01 f/cc, the permissible emission standard of the Korean Ministry of Environment. Further, 111 samples were analyzed using TEM. The distribution of asbestos fiber concentrations was log-normal. It was found that 51 of 111 samples(46%) contained asbestos fibers. Conclusions: There is a potential risk of asbestos exposure among neighbors and the public outside the asbestos removal areas. It is recommended that the asbestos removal work be conducted strictly following the specifications required by government and/or professional organizations.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.165-175
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• 1996

Fourteen(14) large commercial buildings located in Seoul with friable sprayed-on surface insulation material on ceiling were investigated for fiber types in bulk material and for airborne fiber concentrations in buildings by transmission electron microscopy (TEM) in order to compare the results with those by polarized light microscopy (PLM) and phase contrast microscopy (PCM). The results were as follows: 1. Chrysotile asbestos was found in one bulk sample out of total 14 bulk samples collected. Glass fiber and mineral wool were the two major constituents of the bulk samples. 2. The Na-Mg-Si-Ca-Fe-Al ratios of the EDX spectra which were normalized with the Si peak were 0-1.0-10-8.3-4.0-4.0 in mineral wool and 0-5-10-21-0-0 in chrysotile asbestos, respectively. 3. Airborne fiber concentrations were log-normalcy distributed and the geometric mean (geometric standard deviation) fiber concentrations by TEM in the underground parking lots and inside buildings were 0.0048 f/cc(1.93) and 0.0040 f/cc(2.27), respectively with no statistical difference. In the outdoor ambient air, statistically significantly lower concentration of 0.0018 f/cc(2.04) was measured. 4. The TEM/PCM ratios of airborne fiber concentrations ranged 0.5 - 2.0 for 80 % of airborne samples analyzed, end the regression equation between TEM and PCM was PCM=-0.2724+1.1355(TEM) with the coefficient of determination $R^2=0.52$. The results of this study confirmed that the sprayed-on surface insulation material found in some commercial buildings may possibly be contaminated with asbestos fiber. Since statistically significant relationship of fiber concentrations measured by PCM and TEM inside buildings and ambient air was found, previous results by PCM in ambient air could be used to estimate the ambient fiber concentrations in knowing the ratio of TEM/PCM.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.174-183
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• 2015

Objectives: The objective of this study is the estimation of factors influencing airborne fiber concentrations by means of an observation survey of asbestos-containing materials in buildings. Methods: Forty-five samples were collected from four commercial buildings by NIOSH Method 7400 and classified according to current condition, potential activity, construction year, and operations and maintenance(O&M). Results: Airborne fiber concentrations by current condition(classified as good, fair and poor) were significantly different(p<0.05). Concentrations by potential activity were significantly different among groups(p<0.05), and those from the low activity group were higher than those from the middle activity group. Based on construction year, airborne fiber concentrations from the decade of the 1990's were higher than those from the 1960's. When O&M status was considered, airborne fiber concentrations from 1960's buildings were lower than those buildings not operated and maintained(p<0.01), because dust generation was influenced by O&M status. It was found that airborne fiber concentrations were related to current condition and potential activity via regression analysis, but the coefficient of determination was low. Also, correlation analysis showed that the higher the potential activity, the more current condition is worsened, but the relationship was not significant(r=-0.455, p>0.05). Conclusions: Airborne fiber concentrations in asbestos-containing buildings had weak relationships with current condition and potential activity.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.434-441
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• 2014

This study is purposed to measure airborne asbestos concentrations at demolition sites and surrounding areas of asbestos containing buildings in Seoul and examine whether the measurement results correspond with allowable exhaust standard for asbestos of the Asbestos Safety Control Act. The airborne asbestos concentrations for 37 sites were below the detection limit ($7fiber/mm^2$) in 101 (35%) out of 288 samples. The whole average airborne asbestos concentration in 37 sites was $0.003{\pm}0.002f/cc$(max 0.0013 f/cc) and almost the whole airborne asbestos concentrations were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act. So possibility of asbestos exposure is not yet a major concern at current levels for sites demolished of asbestos containing buildings in Seoul. Looking at each sampling point, the average airborne asbestos concentrations in boundary line of site, entrance of sanitation, around the workplace (in), around the workplace (out), negative pressure units, storage area for waste, outlet for waste and residential area of residents were respectively $0.002{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.005{\pm}0.004f/cc$, $0.005{\pm}0.003f/cc$ and $0.003{\pm}0.002f/cc$. As a result, all sampling points of study were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.99-100
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• 2022

As the danger of exposure to the asbestos has been revealed, the importance of demolition asbestos in existing buildings has been raised. Extensive body of study has been conducted to evaluate the risk of demolition asbestos, but there were confined types of variables caused by not reflecting categorical information and limitations in collecting quantitative information. Thus, this study aims to derive a model that predicts the risk in workplace of demolition asbestos by collecting categorical and continuous variables. For this purpose, categorical and continuous variables were collected from asbestos demolition reports, and the risk assessment score was set as the dependent variable. In this study, the influence of each variable was identified using logistic regression, and the risk prediction model methodologies were compared through decision tree regression and artificial neural network. As a result, a conditional risk prediction model was derived to evaluate the risk of demolition asbestos, and this model is expected to be used to ensure the safety of asbestos demolition workers.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.49-50
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• 2023

Asbestos is a building material that has been actively used because of its excellent durability and heat resistance until 2009, when it was found to be a first-class carcinogen and prohibited in Korea. Currently, asbestos dismantling is an essential process in demolition of old buildings. Workers are likely to be exposed to asbestos in the process of dismantling and removing them, which causes various occupational diseases, suggesting related laws and work standards to ensure the safety of asbestos dismantling process. Accordingly, prior studies have been conducted to analyze the level of asbestos exposure and influencing factors occurring during work, but most of them are mainly concerning health issue while research on process risks considering field characteristics and safety aspects of the work processes is still insufficient. Therefore, this study aims to derive the process risks affecting the safety of workers based on the survey results of asbestos dismantling companies, and further proposed a cost calculation model taking those risks into account.

• Journal of the Korean Society of Safety
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• v.35 no.2
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• pp.61-66
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• 2020

As asbestos-containing buildings are getting older, asbestos deconstruction works are increasing. As a result, accident risks such as falls, cuts, electric shocks, and suffocation are increasing. Existing studies are mostly about health management and institutional policy research and there is little research on work risk. So workplace risk assessments that are easily applicable in the field are required to be applied. Sealing is the first process of asbestos deconstruction and is the first step to ensure worker's safety. Job Safety Analysis(JSA) and Checklist were used to identify the risk factors and to calculate the level of the risk. By comparing the two risk assessment tools, it was figured out that the JSA is appropriate for the initial process and change of work procedure while Checklist is appropriate for repetitive work. Because the sealing process is sort and simple, it is unlikely to cause serious injury. But since the risk of falling and cuts are exist, safety education and supervision are necessary to maintain a safe working environment.