• Fire Science and Engineering
• /
• v.18 no.2
• /
• pp.12-19
• /
• 2004

The commercially available IG-541 extinguished agent composed of inert gases was developed for environmental protection. The extinguished agents were considered in terms of physical properties, efficient characteristic, environment, stability, and economical efficiency. The pure and mixture components of physical properties of $N_2$, Ar and $CO_2$ were chosen and compared. The physical properties of density, viscosity and surface tension of inert gases were plotted with the molar ratios of $N_2$/$CO_2$ and Ar/$CO_2$ in terms of a temperature. The extinguished agent in the composition of $N_2$, Ar and $CO_2$, 50/40/10 (mol %) showed relatively high density, low viscosity and moderate surface tension, therefore it was suitable for the alternative extinguished agents.

• Fire Science and Engineering
• /
• v.28 no.2
• /
• pp.14-19
• /
• 2014

A current standard exist only on the surface tension in the current domestic wetting agent technology standards, so it is difficult to the performance evaluation of the wetting agent through the standard. So this study presents the optimized performance evaluation methods by scale model experimental equipment in order to present techniques for performance evaluation of wetting agents. The purpose of this study is to investigate validity of experimental results of the self-designed scale model experiment equipment by a comparative analysis of experimental results of the NFPA 18 experiment and the experiment using the self-designed scale model experiment equipment. As a result of a comparative analysis of experimental results of the NFPA 18 experiment that evaluate only the permeation performance on the contton and the experiment using the self-designed scale model experiment equipment that evaluate the permeation performance and fire extinguishing performance on wood flour, the discrimination of the permeation performance was confirmed in both the NFPA 18 experiment and the self-designed scale model experiment equipment. And a result of self-designed experiment equipment have clear discriminatory more than NFPA 18 by internal temperature measurement using the thermocouples.

• Fire Science and Engineering
• /
• v.26 no.4
• /
• pp.55-62
• /
• 2012

The suppression mechanisms of carbon dioxide ($CO_2$) as a representative fire suppression agent were revisited using a counterflow diffusion flame which could be applied the concept of a local application system. To end this, the low strain rate $CH_4$/air counterflow diffusions with $CO_2$ addition in either fuel or oxidizer stream were examined numerically using detailed-kinetic chemistry. Radiative heat loss due to radiating gas species including $CO_2$ added was considered by the optically thin model (OTM). As a result, the critical $CO_2$ volume fractions in the oxidizer stream required to extinguish the flame were in good agreement with the experimental data reported in the literature, while somewhat under-prediction was observed with $CO_2$ added in the fuel stream. The surrogate agents were adopted to estimate the quantitative contribution with changing in global strain rate ($a_g$) on the flame extinguishment among pure dilution effect, thermal effects including radiation heat loss and chemical effect due to the $CO_2$ fire suppression agent.

• Journal of the Society of Disaster Information
• /
• v.18 no.3
• /
• pp.581-588
• /
• 2022

Purpose: This study is about offering ways of improving existing technical standards in order to propose how to deal with coal deep-seated fire and to increase effectiveness of wetting agent. Method: This study conducts infiltration experiment using eight tons of coal, three types of wetting agents and fire water. And this study analyzes domestic and international technical standards, overseas experimental cases. Result: It is found that two findings are identified; one is fire water cannot infiltrate into the coal due to high level of surface tension, and the other is three types of wetting agent can infiltrate into the coal to the depth of 5~25cm. Also, domestic wetting agent technical standards include measuring surface tension only and testing wood on extinguishing capacity test. On the other hand, this study found that deep-seated fire experiment using cotton, B-class fire test using heptane are used from abroad. Besides it is analyze that capillary rise test, sink test, contact angle measurement are conducted to increase effectiveness of wetting agent at the U.S. Bureau of Mines. Conclusion: Based on standards and cases of U.S. NFPA and Bureau of Mines, this study suggests that domestic technical standards should include adding a new test standard which measures infiltration directly.