• 한국안전학회지
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• 제35권2호
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• pp.111-117
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• 2020

When KS C IEC 60069-10-1(2015) standard is applied to estimate a hazardous area, the chart showing the relationship between a hazardous area distance and release characteristic is used as a guide to determine the extent of hazardous zones for various forms of release. Three release characteristic lines based on the three types of release as an unimpeded jet release with high velocity, a diffusive jet release with low velocity, and a release of heavy gases or vapours that spread along horizontal surfaces are given. As these characteristic lines have the low limit threshold, it is difficult to estimate the hazardous area distance when the value of release characteristic is under the low limit threshold. And KS C IEC 60079-10-1(2015) standard shows the concept for a zone of Negligible extent(NE) which can be considered as non hazardous area, but it is also difficult to apply the concept of a Negligible extent. The purpose of this paper is to suggest the guideline for the release characteristic to decide a hazardous area distance and the Negligible extent(NE) being considered as non-hazardous area when deciding a hazardous area distances by the KS C IEC 60079-10-1 standard.

• Safety and Health at Work
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• 제12권3호
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• pp.416-420
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• 2021

Hazardous area classification design is required to reduce the explosion risk in process plants. Among the international design guidelines, only IEC 60079-10-1 proposes a new type of zone, namely zone 2 NE, to prevent explosion hazards. We studied how to meet the zone 2 NE grade for a facility handling hydrogen gas, which is considered as most dangerous among explosive gases. Zone 2 NE can be achieved considering the grade of release, as well as the availability and effectiveness of ventilation, which are factors indicative of the facility condition and its surroundings. In the present study, we demonstrate that zone 2 NE can be achieved when the degree of ventilation is high by accessing temperature, pressure, and size of leak hole. The release characteristic can be derived by substituting the process condition of the hydrogen gas facility. The equations are summarized considering relation of the operating temperature, operating pressure, and size of leak hole. Through this relationship, the non-hazardous condition can be realized from the perspective of inherent safety by the combination of each parameter before the initial design of the hydrogen gas facility.

• 한국가스학회지
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• 제22권4호
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• pp.13-26
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• 2018

현재 KS Code 등 국내규정에서는 폭발위험장소의 범위를 계산하는 방법이 명확하게 나타나지 않아, 정확한 범위 선정을 위해서는 확산 모델링 해석을 이용하여야 한다. 본 연구애서는 대표적인 물질과 운전조건을 활용하여 확산 모델링에 비하여 간편하면서도 비교적 합리적인 폭발위험장소의 범위를 산정하는 방법을 제시하고자 하였다. 현재 시행되고 있는 국내외 표준을 바탕으로 폭발하한계(LFL, Lower Flammable Limit)까지 거리에 영향을 미치는 변수를 선정하였다. 총 16종의 인화성물질을 대상으로 물질변수, 운전변수, 기상조건에 대하여 모델링을 진행하였으며, 통계분석을 통해 영향을 미치는 변수를 선별하였다. 선별된 변수를 이용하여 폭발위험장소의 범위 선정을 위한 3단계 분류화 방법(3Step Classification Method)을 작성하였다.

• 대한안전경영과학회지
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• 제19권2호
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• pp.31-39
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• 2017

Classify of explosion hazardous areas must be made at the site where flammable materials are used. This reason is that it is necessary to manage ignition sources in of explosion hazardous areas in order to reduce the risk of explosion. If such an explosion hazard area is widened, it becomes difficult to increase the number of ignition sources to be managed. The method using the virtual volume currently used is much wider than the result using CFD(Computational Fluid Dynamics). Therefore, we tried to improve the current method to compare with the new method using leakage characteristics. The result is a realistic explosion hazard if the light gas is calibrated to the mass and the heavy gas is calibrated to the lower explosion limit. However, it is considered that the safety factors should be taken into account in the calculated correction formula because such a problem should be considered as a buffer for safety.

• 한국안전학회지
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• 제29권2호
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• pp.24-30
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• 2014

There have been controversies over whether explosion hazardous area(EHA) should be classified for facilities which use lighter-than-air gases such as city gas, hydrogen and ammonia. Two view points are confronting each other: an economic piont of view that these gases are lighter than air and disperse rapidly, hence do not form EHA upon release into the atmosphere, and a safety point of view that they are also inflammable gases, hence can form EHA although the extent is limited compared to heavy gases. But various standards such as KS, IEC, API, NFPA do not exclude light gases when classifying EHA and present examples of EHA for light gas facilities. This study calculates EHA using the hypothetical volume in the IEC code where the hole sizes required for the calculation were selected according to various nominal pipe sizes in such a way to conform to the EHA data in the API code and HSL. Then, 25 leakage scenarios were suggested for 5 different pipe sizes and 5 operating pressures that cover typical operating conditions of light gas facilities. The EHA for the minimum leakage scenario(25 mm pipe, 0.01MPa pressure) was found to correspond to a hypothetical volume larger than 0.1 $m^3$(medium-level ventilation). This confirms the validity of classifying EHA for facilities using lighter-than-air gases. Finally, a computer program called HACPL was developed for easy use by light gas facilities that classifies EHA according to operating pressures and pipe sizes.

• 한국재난정보학회 논문집
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• 제20권1호
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• pp.47-59
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• 2024

연구목적: 인화성 액체의 누출형태에 따라 제조업 사업장 내 화재·폭발사고를 예방하기 위해 기존 폭발위험장소 구분도를 개선하여 점화원 및 가연물을 안전하게 관리할 수 있는 방안을 제안하고자 한다. 연구방법: 「KS C IEC 60079-10-1」를 사용하여 폭발위험장소를 계산했으며, 계산된 폭발위험거리를 3D로 폭발위험장소를 구현하였다. 또한, 3D를 통해 구현된 폭발위험장소 내 인화성 증기의 대기확산량을 계산하기 위해 「P-91-2023」 액체의 대기확산량 공식을 활용하였다. 연구결과: 폭발위험장소를 3D로 표현했을 때 평면도의 사각지대를 확인할 수 있었으며, 폭발위험장소 내 점화원을 즉각적으로 확인 가능하였다. 다음으로 가연물은 3D로 나타난 폭발위험장소 체적 내 LEL 도달시간을 계산했을 때, 폭발위험거리와 동일하게 위험도가 나타나지 않았다. 결론: 인화성 액체의 대기확산량을 고려하여 안전관리가 이루어져야 할 것으로 판단하였다. 따라서 사업장에서 현실적으로 시행할 수 있는 환기량으로 감지·경보가 필요한 농도값을 계산하는 방법을 제안하였다.

• Korean Chemical Engineering Research
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• 제55권1호
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• pp.40-47
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• 2017

가연성 분진이 제조 취급되는 공정에서의 분진폭발 위험성은 항상 존재한다. 그러나 산업현장에서 취급되는 분진에 대한 분진폭발 특성 정보는 아주 미흡한 실정으로 사업장에서는 화학사고 예방대책 수립에 어려움을 겪고 있다. 본 연구에서는 입도분포가 다른 두 종류의 다중벽 탄소나노튜브(MWCNT)에 대한 분진폭발 특성을 실험적으로 조사하였으며, NFPA 499 Code를 적용하여 MWCNT 제조 취급 공정의 분진폭발 위험장소 구분을 검토하였다. 그 결과 평균입도가 $124.2{\mu}m$인 MWCNT 1의 $P_{max}$, $K_{st}$, LEL, MIE, 및 MIT는 각각 6.3 bar, $56bar{\cdot}m/s$, $125g/m^3$, 1000 mJ 초과 및 $650^{\circ}C$ 초과로 나타났다. 평균입도가 $293.5{\mu}m$인 MWCNT 2의 $P_{max}$, $K_{st}$, LEL, MIE, MIT는 각각 6.2 bar, $42bar{\cdot}m/s$, $100g/m^3$, 1000 mJ 초과 및 $650^{\circ}C$ 초과로 나타났다. NFPA 499 Code에 따른 MWCNT 1, 2의 폭발강도와 점화감도는 각각 0.35와 0.01 미만으로 나타났기 때문에 MWCNT는 NFPA 499 Code에서 제시된 분진폭발 위험장소로 구분하여야 하는 가연성 분진으로 분류되지 않았다.

• 한국가스학회지
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• 제22권4호
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• pp.27-31
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• 2018

폭발위험장소의 구분은 인화성 물질을 취급하는 사업장에서 비용 및 안전 측면에서 매우 중요하다. 위험장소의 반경에 따라 전기기계 기구의 방폭기기 설치 여부가 결정되기 때문이다. 2017년 11월 6일부터 KS C IEC-60079-10-1:2015가 발행되어 새로운 기준으로 적용된다. 기존의 기준과 새로운 기준에 대한 차이를 이해하여 적용하는 것이 중요한 시점이다. 누출량 계산식에 누출계수 및 압축인자가 추가되었고 증발 풀 누출량 계산식, 누출공 크기 적용, 폭발위험장소의 모양이 추가 적용되었다. 안전계수 K값의 범위도 변경되었다. 또한 위험장소의 반경에는 기존기준은 가상체적에 환기횟수를 적용하였지만 개정기준은 누출 특성 값을 이용하여 산정된다. 본 연구에서는 환기 및 희석의 관점에서 기존 기준과의 차이점을 살펴보고 위험장소의 반경에 미치는 영향을 검토하였다. 기존 폭발위험장소를 선정한 기준과 개정기준을 기준으로 적용하여 비교 및 분석을 실시하였다. 연구결과 환기 및 희석이 잘 된다하더라도 실질적으로 위험반경에 영향이 없을 경우가 발생함을 알 수 있었다.

• Safety and Health at Work
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• 제8권3호
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• pp.267-275
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• 2017

Background: The mining industry is known worldwide for its highly risky and hazardous working environment. Technological advancement in ore extraction techniques for proliferation of production levels has caused further concern for safety in this industry. Research so far in the area of safety has revealed that the majority of incidents in hazardous industry take place because of human error, the control of which would enhance safety levels in working sites to a considerable extent. Methods: The present work focuses upon the analysis of human factors such as unsafe acts, preconditions for unsafe acts, unsafe leadership, and organizational influences. A modified human factor analysis and classification system (HFACS) was adopted and an accident predictive fuzzy reasoning approach (FRA)-based system was developed to predict the likelihood of accidents for manganese mines in India, using analysis of factors such as age, experience of worker, shift of work, etc. Results: The outcome of the analysis indicated that skill-based errors are most critical and require immediate attention for mitigation. The FRA-based accident prediction system developed gives an outcome as an indicative risk score associated with the identified accident-prone situation, based upon which a suitable plan for mitigation can be developed. Conclusion: Unsafe acts of the worker are the most critical human factors identified to be controlled on priority basis. A significant association of factors (namely age, experience of the worker, and shift of work) with unsafe acts performed by the operator is identified based upon which the FRA-based accident prediction model is proposed.

• 한국안전학회지
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• 제31권5호
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• pp.49-53
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• 2016

The goal of this study is to analyze accidents occurred at experimental laboratory and to suggest hierarchical taxonomy applicable to prepare countermeasures reducing the experimental laboratory accidents. Recent 5 years accidents were analyzed and classified according to their primary cause, facility or human. Then in case of facility, the accidents were further classified whether they can be fixed by organization or by individual. In case of human factor, they were classified into physical, chemical, or biological to prepare precise measures. Depending on the adequacy of appropriate practice, several measures were suggested such as; whether to improve training of laboratory workers, or to improve training the system, or to improve or prepare practice substantially. A new taxonomy for laboratory accident was suggested complying other governmental agencies' classification such as KOSHA and KGS. Additionally, two kinds of possibilities were suggested such as possibility of major accident and possibility of disaster which can be defined as laboratory accident causing large scale of harmful consequence to residential area or environment by fire, explosion and/or toxic release of hazardous chemicals and/or microbiology.