• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.573-581
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• 1997

Much activity is occurring throughout the world with respect to the implementation of new concepts and technology for fire detection and fire suppression applications. Obvious advances include tangible detection and suppression improvements, and also new methods and approaches such as performance based codes and standards. Examples of tangible advances include addressable detection systems, wireless detection technology, halon alternatives, water mist systems, advanced sprinkler technology, and so on. Examples of new approaches and methods include a revitalized focus on disaster planning and the need for a total fire protection plan. The concept of performance based codes and standards for the design and installation fire detection and suppression systems will be explored in detail.

• Fire Science and Engineering
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• v.16 no.3
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• pp.32-38
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• 2002

The synthesis of $CF_3$I and $C_2F_5I from $CF_3Br$ was studied for the reuse of $CF_3Br$ which is abolished to save the ozone layer of the earth. Reaction experiments were carried out in experimental scale synthesis equipment with catalysts, such as CuI, Kl, $K_2$$CO_3$, KF metal salt/active carbon and alumina support at $400~600^{\circ}C$. Main products of reaction were $CF_3i$ and $C_2F_5I$ with small amounts of $C_2F_5I$, $CF_4$, $CF_2Br_2$ by-products. 7.5wt% KI and $K_2CO_3$over activated carbon catalysts show the highest yield of $CF_3$I and 7.5wt% CuI over alumina catalysts show the highest yield of $C_2F_5i$. And optimal reaction temperature was about $500^{\circ}C$.

• 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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.939-944
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• 2018

Clean fire extinguishing agents refer to chemical that can replace Halon 1211 and Halon 1310 according to the Montreal Protocol fermented to protect the Earth's ozone layer. In Korea and abroad, system standardization and performance evaluation of clean fire extinguishing agents are being carried out. This paper proposes an optimal nozzle shape by modeling and numerical analysis of various nozzle shapes based on general clean fire extinguishing system. The ejection speed of the nozzle can be improved by studying three - dimensional modeling of the nozzle for two shapes, Type A and B. Flow analysis was performed on the two types of nozzles and the gas velocity and pressure distribution were measured with different nozzle diameters. It was confirmed that the jetting speed was changed at the nozzle outlet according to the number and diameter of the nozzle holes. The flow rate increased with increasing the pressure regardless of the nozzle hole diameter. Based on the results obtained from the experiment, the K-factor value was deduced. Finally, a nozzle with a 12-hole structure with a 5-mm nozzle hole was proposed.

• Fire Science and Engineering
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• v.19 no.2 s.58
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• pp.29-36
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• 2005

We carried out discharge and fire extinguishing tests of new inert gas clean agent, which consists of $92\%$ nitrogen and $8\%$ carbon dioxide, as an alternative of Halon that is banned by Montreal Protocol to protect the ozone layer of the earth. Discharge and fire extinguishing tests were performed in $27m^3$ and $190m^3$ rooms with piping which allows gaseous agent to transport from storage to test rooms. We confirmed that it took less than regulation time, 60 seconds for the discharge of over $95\%$ initial charged amounts. Discharge test variables were piping length and orifice size. Fire extinguishing tests verified that this new inert gas clean agent is suitable for both n-Heptane fire and deep seated fire of wood crib.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.05a
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• pp.21-29
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• 2002

With regard to the personnel safety and other safety when the gas suppressants are discharged into the area where occupants exist, the short term and long term effects to the health of people are discussed mainly with the Carbon dioxide agent and Halon Replacement agents system. To gain the benefits of CO2 extinguishing systems while minimizing risk to people serious attention must be given to personnel safety in the design, installation, and maintenance of CO2 systems. Training of personnel is essential. A major factor in the use of a clean agent fire suppressant in a normally occupied area is toxicity. While all halocarbon agents are tested for long-term health hazards, the primary endpoint is acute or short-term exposure, The primary acute toxicity effects of the halocarbon agents described here are anesthesia and cardiac sensitization. For inert gases, the primary physiological concern is reduced oxygen concentration.

• 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.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.4
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• pp.387-397
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• 2014

This work aims at estimating global warming potentials (GWP) of $CF_3Br$ and HFC-134a among green house gases. It has been reported that they have much higher GWP than $CO_2$ in the atmosphere. $CF_3Br$, halon 1301 which is well known to be a fire extinguisher, as one of the bromine-containing halons has been banned since 2003 due to destruction of ozone. HFCs, a kind of chiller which replaced chlorofluorocarbons (CFCs) are one of greenhouse gases regulated by the Kyoto Protocol. In this study, we produced GWPs of $CF_3Br$ and HFC-134a by calculating a life time and measuring an absorption cross section to obtain a radiative forcing (RF). Their absorption cross sections were measured by using Fourier-transformed infrared spectroscopy (FTS) with a gas cell filled with their certified reference materials at room temperature. As a result, the RFs of $CF_3Br$ and HFC-134a were 0.32 and $0.168Wm^{-2}ppb^{-1}$, respectively and the GWPs were calculated as 7989, 6076, 3903 for $CF_3Br$ and 3855, 1300, 656 for HFC-134a for the time horizon of 20, 100, 500 years, respectively. Overall, uncertainty of the estimated GWPs can be estimated to be about 2.6%. Our results were compared with those proposed by the previous studies (IPCC, 2007; WMO, 1999).

• Fire Science and Engineering
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• v.15 no.4
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• pp.41-48
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• 2001

Halogen-based fire suppressing agents have been the most effective fire suppressants and widely used for flammable liquid and electric fire. However they have environmental problems causing stratospheric ozone depletion and globe warming. As a substitution of halon, fire suppression system using fine water mist is one of an effective fire suppressant. Suffocating and cooling effects of water mist are increased by the evaporation characteristics because it has droplet size less than 1,000 $\mu{m}$ and very large surface area. In this study, the extinguishing characteristics of fire was measured with changing of water mist droplet size, flow density; discharge pressure, and fire size. As a result, the extinguishing time of pool fire was shortened with the increase of flow density and in case of low flow density less than 0.5$\pm$0.05 ml/$\textrm{cm}^2$ . min, the extinguishing time was shortened with the increase of droplet size. The cycling discharge was effective for $\eta$-heptane pool fire, and total amount of water mist required to extinguish fire was reduced to a quarter compare with continuous discharge.

• Fire Science and Engineering
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• v.24 no.6
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• pp.54-60
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• 2010

An experimental study has been carried out to determine the flow rate for a feasible N2 generator to extinguish the fire, and this study analogized the correlations to determine the flow rate for $N_2$ generator considered an Oxygen concentration, protected enclosure, discharging pressure and discharging time. We manufactured simple protected enclosure for analyzing fire-extinguishing performance of the $N_2$ generator. As a $N_2$ gas is exhausted on protected enclosure, a various of Oxygen concentration is measured to analyze fire-extinguishing performance experimentally. The correlations determined as an uncertainty analysis for the Oxygen concentration deviations of the theoretical and experimental value. The analogized correlations is Q = (21 $\times$ V)/($O_2+{\zeta}{\cdot}P$)-V. In case of $300m^3$ protected enclosure, 0.8 MPa discharging pressure and $40m^3$/min $N_2$ flow rate, the Oxygen concentration is decreased below 15% within 3 minutes.