• Fire Science and Engineering
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• v.15 no.1
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• pp.34-40
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• 2001

Fire extinguishing efficiency of mixed gaseous agents were investigated by the cup-burner test and predicting by the model of flame extinguishing concentration. The binary mixed agents that tested were carbon dioxide/HFC-23, carbon dioxide/HCFC-22, carbon dioxide/HFC-227ea, carbon dioxide/HFC-125, carbon dioxide/FIC-13I1, Hexafluoropropylene/HFC-23 and ternary mixed agents were carbon dioxide/HFC-23/HFC-l34a, carbon dioxide/HFC-23/HFC-227ea, carbon dioxide/HFC-23/HFC-125. A model which contains the flame extinguishing concentration and composition of pure components predicted the flame extinguishing concentration of mixture well. This model was superior when each component of the mixture exhibit physical fire extinguishing performance.

• Fire Science and Engineering
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• v.16 no.3
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• pp.77-83
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• 2002

We measured flame extinguishing concentration and flue gas composition in the n-heptane fuel cup-burner system using inert gas agents such as nitrogen, argon, carbon dioxide and their mixtures. The flame extinguishing concentration of binary gaseous mixture was well predicted by model which contains the flame extinguishing concentration and composition of pure components. The higher average specific gravity of the mixed inert gas agents, the more excellent flame extinguishing performance. And the structure of enclosed space also affects the fire extinguishing. The composition of carbon dioxide in the flue gas was decreased with increasing extinguishing agent used. Nitrogen monoxide production is not related with increasing nitrogen, but increased at rapid mass flow rate of air in the cup-burner.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.303-306
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• 2002

Liquid atomization by means of a spinning cup is widely used as a device for combustion, in cooling and spray drying. In this study, the blowing type rotary atomizer was experimental carried out the investigations on the characteristics of the blowing type rotary atomizer which is an air flow energy of blower instead of an electric motor most commonly used to a driven energy. The analysis on the rotary cup speed, air velocity with the blower conditions was performed and also the drop size was measured using LDPA. It was tried to analyzed on air-nozzle size and liquid flowrate as the result. It was found that the increase of the relative velocity between liquid and air improve significantly atomization liquid, and decrease of the liquid flowrate improved the maximum drop size though the mean drop size is really the same.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.148-150
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• 2008

Halon gas agent has been widely used as the extinguishing agent for B class and C class fires because of its excellent extinguishing power. But Halon was found to contribute to the ozone layer destruction, eventually Halon designated as one of ozone-layer-destroying materials in the Montreal Protocol in 1987, In this study, in the context of such researches, we measured the characteristics of flame concentrations of inert gaseous agents by Cup-burner method.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.71-76
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• 2012

The coflow velocity effect on the minimum extinguishing concentration(MEC) was investigated experimentally in heptane cup-burner flames. Various inert gases($N_2$, Ar, $CO_2$, He) were added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the MECs were increased with increasing coflow velocity for most inert gases except helium, but the higher coflow velocity induced the lower burning rates of heptane. This indicated that the increase of coflow velocity resulted in the decrease of fuel velocity evaporated from fuel surface, and hence the stain rate on the reaction zone was also decreased. In the case of helium as a additive, the extinguishing concentration was independent of the coflow velocity because the heat conductivity was ten times larger than the other inert gases and flow effect by a strain rate might be compensated for heat loss to the surroundings.

• Fire Science and Engineering
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• v.28 no.3
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• pp.34-42
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• 2014

The concentrations of inert gases ($N_2$, Ar, $CO_2$ and He) required to induce the flame instabilities such as swing, rotation, lifted and blow-out were measured in a cup burner nonpremixed flames for $CH_4$ and $C_3H_8$ fuels. Quantitative differences in the extinguishing concentration with fire suppression criteria (i.e. blow-out or onset of flame instability) were also examined. It was found that the difference in extinguishing concentration was increased with the appearance of lifted flame and the low extinguishing performance of inert gaseous. The maximum difference in extinguishing concentration with the suppression criteria was approximately 35% at the highest fuel velocity condition (1.3 cm/s) for the $C_3H_8$-air nonpremixed flame. It can be also expected that the extinguishing concentration by the criteria based on the onset of flame instability will provide the useful information from the viewpoint of the accurate and economical design concentration.

• Fire Science and Engineering
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• v.19 no.2 s.58
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• pp.69-74
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• 2005

A study of the utilization of inert gas generator(IGG) that generates a large amount of inert gas for the fire extinguishing equipment was performed. In this study, the fire extinction performance of gas generated from a 1GG which is implemented to a gas turbine was investigated. A simulated mixture gas of which composition is the same as that of the gas generated from ICG was used in all experiments. First, the extinction concentration was measured using a cup burner method. The extinction design concentration and the volume of extinction space was calculated by applying the obtained extinction concentration to a method recommended by NFPA 2001. In practical respects, the fire extinction performance of IGG-generated gas was confirmed through the fire suppression experiment within a $2m\times2m\times2m$ room.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.76-83
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• 2008

In the course of increasing in human and material damage caused by fire, it is an important research field to develop clean extinguishing agent which does no harm to global environment as well as has a good extinguishing efficiency. This research is a basic step to develop a new clean extinguishing agent. In order to get a satisfactory result, we tested fire extinguishing ability using nitrogen and Novec mixtures gas which are inert gas and new clean extinguishing agent. We used Cup Burner Test made by international standard ISO-14520 regulations of gaseous extinguishing agent ability test, and the fuels used in the test are n-heptane, methanol, ethanol, iso-propanol and 1-butanol. The experimental results of flame extinguishing concentration are n-heptane 6.54%, methanol 8.47%, ethanol 6.98%, isopropanol 6.10% and butanol 6.54% by pure Novec agent. So the finding is that a new clean agent, Novec has an efficient extinguishing ability in a state of gas. Also, in a test as to mixtures gas of nitrogen and Novec, it has a good result for minimum oxygen concentration is under 16%.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.21-25
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• 2009

Extinguishing limits of laminar ethylene/oxygen flames in both normal and inverse co-flow jet burner have been determined experimentally and computationally. An inert gas($N_2$, Ar, $CO_2$) was added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the physical aspect of inert gases was main mechanism for flame blow-out as same as cup burner test, but the flow effect should be considered to determine the extinction concentration. The numerical prediction was performed with modified WSR model and the result was in good agreement with the measurements. The experimental and numerical methods could be used for the assessment of various flame suppression agents such as minimum extinguishing concentration.

• Journal of the Korean Institute of Gas
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• v.11 no.3
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• pp.7-12
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• 2007

The search for a new fire-extinguishing agent with all the desirable properties of halon 1301 has not been successful. To study binary gaseous extinguishing agents instead, one has to determine the extinguishing concentrations for several compositions of a given chemical in an inert gas. This process is expensive and time consuming. The fire suppression efficiencies of gas mixtures of HFC 125 and HFC 227ea with nitrogen as total flooding agents were studied by cup burner method. It was shown that addition of small amounts of those extinguishants to nitrogen can enhance the suppression effectiveness of the inert gas. As expected, the degree of synergism was highest at low concentrations of the chemical. For each binary system, extinguishing concentrations of the pure compounds and one binary data were used to predict the extinguishing concentrations for the entire range of binary composition. The predicted values were very close to experimental data.