• 한국안전학회지
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• 제34권4호
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• pp.22-31
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• 2019

The flammable liquid conductivity is an important factor in determining the generation of electrostatic in fire and explosion hazardous areas, so it is necessary to study the physical properties of flammable liquids. In particular, the relevant liquid conductivity in the process of handling flammable liquids in relation to the risk assessment and risk control in fire and explosion hazard areas, such as chemical plants, is classified as a main evaluation item according to the IEC standard, and it is necessary to have flammable liquid conductivity measuring devices and related data are required depending on the handling conditions of the material, such as temperature and mixing ratio for preventing the fire and explosion related to electrostatic. In addition, IEC 60079-32-2 [Explosive Atmospheres-Part 32-2 (Electrostatic hazards-Tests)] refers to the measuring device standard and the conductivity of a single substance. It was concluded that there is no measurement data according to the handling conditions such as mixing ratio of flammable liquid and temperature together with the use and measurement examples. We have developed the measurement reliability by improving the structure, material and measurement method of measuring device by referring to the IEC standard. We have developed a measurement device that is developed and manufactured by itself. The test results of flammable liquid conductivity measurement and the data of the NFPA 77 (Recommended Practice on Static Electricity) Annex B Table B.2 Static Electric Characteristic of Liquids were compared and verified by conducting the conductivity measurement of the flammable liquid handled in the fire and explosion hazardous place by using Measuring / Data Acquisition / Processing / PC Communication. It will contribute to the prevention of static electricity related disaster by taking preliminary measures for fire and explosion prevention by providing technical guidance for static electricity risk assessment and risk control through flammable liquid conductivity measurement experiment. In addition, based on the experimental results, it is possible to create a big data base by constructing electrostatic physical characteristic data of flammable liquids by process and material. Also, it is analyzed that it will contribute to the foundation composition for adding the specific information of conductivity of flammable liquid to the physical and chemical characteristics of MSDS.

• 한국안전학회지
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• 제19권4호
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• pp.69-73
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• 2004

The flash point is one of the most important combustible properties used to determine the potential for the fire and explosion hazards of industrial material and the fire point is the temperature of the flammable liquid at which there will be flaming combustion, sustained 5 seconds in response to the pilot flame. In this study, the flash point and fire point were measured to present raw data of the flammable risk assessment for alcohols, using Tag open-cup apparatus(ASTM D 1310-86). The measured values were compared with the calculated values based on 0.78 times stoichiometric concentration. The values calculated by the proposed equations were in good agreement with the measured values.

• 한국안전학회지
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• 제30권4호
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• pp.64-72
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• 2015

The purpose of this study is to study the safety of a small LPG storage tank with a capacity less than 3 ton when it is exposed to an external fire. First, simulation studies were carried out using ASPEN Plus and PHAST to demonstrate that overpressurization in the tank can be relieved by discharging the LPG through an adequately sized safety valve, but the release may lead to the secondary risk of fire and explosion around the tank. Next, the temporal variations of the temperatures of the lading and tank wall were obtained using AFFTAC, which showed that the tank wall adjacent to the vapor space could be overheated in about 11 min to such a point that the weakened strength might cause a rupture of the tank and subsequent BLEVE. The consequences of the BLEVE were estimated using PHAST. Finally, several practical measures for preventing the hazards of overheating were suggested, including an anti-explosion device, sprinkling system, insulation, heat-proof coating, and enhanced safety factor for tank fabrication. The effectiveness of these measures were examined by simulations using AFFTAC and ASPEN Plus.

• Architectural research
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• 제15권3호
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• pp.151-158
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• 2013

Offshore oil and gas process plants are exposed to hazardous accidents such as explosion and fire, so that the structural components should resist such accidental loads. Given the possibilities of thousands of different scenarios for the occurrence of an accidental hazard, the best way to predict a reasonable size of a specific accidental load would be the employment of a probabilistic approach. Having the fact that a specific procedure for probabilistic accidental hazard analysis has not yet been established especially for explosion and fire hazards, it is widely accepted that engineers usually take simple and conservative figures in assuming uncertainties inherent in the procedure, resulting either in underestimation or more likely in overestimation in the topside structural design for offshore plants. The variation in the results of a probabilistic approach is determined by the assumptions accepted in the procedures of explosion probability computation, explosion analysis, and structural analysis. A design overpressure load for a sample offshore plant is determined according to the proposed probabilistic approach in this study. CFD analysis results using a Flame Acceleration Simulator, FLACS_v9.1, are utilized to create an overpressure hazard curve. Moreover, the negative impulse and frequency contents of a blast wave are considerably influencing structural responses, but those are completely ignored in a widely used triangular form of blast wave. An idealistic blast wave profile deploying both negative and positive pulses is proposed in this study. A topside process module and piperack with blast wall are 3D FE modeled for structural analysis using LS-DYNA. Three different types of blast wave profiles are applied, two of typical triangular forms having different impulse and the proposed load profile. In conclusion, it is found that a typical triangular blast load leads to overestimation in structural design.

• 한국안전학회지
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• 제8권2호
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• pp.39-43
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• 1993

The flash points of flammable liquids are a fundamental and important property relative to fire and explosion hazards. A new estimation method, based on statistics (mutiple regression analysis), is being developed for the prediction of flash points of pure flammable liquids by means of computer simulation. This method has been applied to alcohol liquids. The proposed method has proved to be the general method for predicting the flash points of alcohol liquids.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.629-637
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• 2017

식료품 가공 산업에서 분진폭발사고가 자주 발생하고 있으며 배관이나 장치 내의 화염전파에 의한 폭발피해가 증가하고 있다. 그러나 다양한 분체특성으로 인하여 활용 가능한 화재폭발특성자료가 적다는 문제가 있다. 사고발생 빈도가 높고 사회적 수요가 많은 설탕, 옥수수, 밀가루의 발화 위험성과 폭발특성을 실험적으로 조사하였다. 설탕, 옥수수, 밀가루 분진의 평균입경은 27.56, 14.76, $138.5{\mu}m$로 나타났으며 이러한 분체조건에서 열중량분석(TGA) 및 시차주사열량계(DSC)를 사용하여 발화온도를 조사하였다. 최대폭발압력($P_m$) 및 폭발지수는($K_{st}$) 각각 7.6, 7.6, 6.1 bar 및 153, 133, 61 [$m{\cdot}bar/s$]로서 분진폭발 위험성은 설탕이 가장 높고 밀가루가 가장 작았다. 또한 분진폭발 시의 화염전파로 인한 피해확대 위험성을 평가하기 위하여 분진화염전파의 소요시간을 계산하였으며 화염전파로 인한 폭발피해 위험성은 설탕, 밀가루, 옥수수 분진의 순으로 높았다.

• 대한조선학회논문집
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• 제54권4호
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• pp.294-300
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• 2017

The offshore installations and ships are the structures most likely to be exposed to hazards such as hydrocarbon fire and/or explosion. Developing proactive measures to prevent the escalation of such events thus requires detailed knowledge of the related phenomena and their consequences. $CO_2$ extinguishing systems are extensively used for fire accidents of on-and offshore installations because of outstanding performance and low cost. There is, however, the risk of carbon dioxide system which enumerates many of the fatalities by suffocation associated with industrial fire protection requirements. Therefore, the aim of this study is to perform the prediction of fire suppression characteristics of the carbon dioxide system in realistic enclosed compartment area of ships and propose $CO_2$ extinguish fire fighting system for preventing suffocation accidents during fire fighting. According to CFD calculations, it can be observed and assessed that various fire profiles with $CO_2$ and $O_2$ mole fraction in the target enclosed compartment area are applicable within the proposed system. Additionally, the design of fire safety system of ships and offshore installations can utilize ventilation system and/or layout arrangement through the proposed system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2280-2283
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• 1999

Close to high power radio/radar transmitters, there is a possibility that electrical sparks may occur at discontinuities in metallic structures. If these structures are in an area where flammable mixtures are present, there is a danger that fire or explosion may happen by these sparks. Voltage may be induced on these metallic structures by the radio-frequency transmitter. In this case, a person who comes into contact with these structure may be undergone a severe electrical shock. In this paper, assessment of the these hazards was investigated through experimental and evaluation for actual tower cranes near AM radio transmitters.

• 한국안전학회지
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• 제8권2호
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• pp.87-93
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• 1993

Many methods to assess hazards caused by the risks increased with the growth of petrochemical industry. The manual of International Atomic Energy Agency which was much more applied to quantitative analysis of the real situation and the CPQRA is introduced to verify the theoretical background of this manual. Than other methods, as a result, we can see that this manual, which is simple to use and requires a little information, shows similar results to those of calculation by numerical formula. Also, the program code of this manual was materialized and if it is possible to obtain adequate parameters to our circumstance, the manual will be quite useful in early risk analysis.

• 한국가스학회지
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• 제16권1호
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• pp.15-21
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• 2012

수소가스의 제트 누출에 의한 확산, 화재, 그리고 폭발에 의한 위험 범위를 분석하고, 안전거리 기준을 설정하기 위한 위험거리를 확산, 화재, 그리고 폭발에 대한 단순한 예측 식들을 제시하였다. 핀홀에 의한 누출과 같은 소량 수소가스 누출속도에 있어서 피해거리는 제트누출 확산에 의한 피해거리가 제트화재에 의한 피해거리보다 크며, 압력의 제곱근에 그리고 누출 홀의 직경에 비례하고 이는 수 십 미터에 이른다. 배관의 완전 파손 또는 저장 탱크의 큰 홀 발생과 같은 대량의 수소가스 누출속도에서는 제트화재의 피해거리가 개방공간의 가스운 폭발에 의한 피해거리보다 크며, 수 백 미터에 이른다. 수소충전소와 건물과의 최소이격거리 즉 안전거리 설정 기준을 대량 수소가스누출 사고시나리오를 기반으로 한다면, 도심지에 수소충전소는 안전거리 기준을 만족시키기 어려울 것이다. 따라서 대량의 수소가스 누출사고를 안전장치들을 통하여 예방하고, 안전거리 기준을 소량의 수소가스누출사고 기준으로 설정 할 수 있다. 그러나 대량누출 가능성이 있는 경우 학교와 병원 등 인구밀집 건물은 수 백 미터의 안전거리를 유지하여야 한다.