• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.1
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• pp.1-22
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• 2012

This paper tried to verify whether the fixed fire fighting system (FFFS) that is installed in road tunnel improves evacuation performance or not. Verification was performed according to the Disaster Prevention Facilities Installation and Management Guide at Road Tunnel. Twenty seven different fire scenarios were set up for the verification and the cases that FFFS was installed were compared with the cases that FFFS was not installed. The result of the comparison showed that the average equivalent death was reduced in 26 cases out of 27 cases when water spray extinguishing system was installed. It was confirmed that the risk when was not installed was unacceptable in Hong Kong and the Netherlands. On the other hand, it was confirmed that the risk was reduced to as low as reasonably practicable (ALARP) when was installed. The cumulative frequency of average death in case with FFFS was compared against the frequency of death without FFFS: death of one or more is about 50 times less; 10 or more is about 100 times less; and the death of more than 100 is four times less. It was verified that FFFS makes improved conditions to escape from the fires in road tunnel.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.377-384
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• 2011

Although concrete is considered as fire proof materials, high strength concrete shows severe material and structural damages when exposed to fire. To understand such damages in high strength concrete structures, the effects of various design parameters and fire condition on the thermal behaviors of high strength concrete structures are investigated in this study. In order to achieve this goal, fire tests are performed on high strength concrete columns with different fire conditions and design parameters including cross sectional area, cover thickness, and reinforcement alignment. To investigate thermal behaviors, temperature distributions and amount of spalling are measured. In overall, the columns show rapidly increasing inner temperatures between 30~60 mins of the fire tests due to spalling. In detail, the higher temperature distributions are observed from the columns with the larger cross section and less cover thickness. Moreover, among the columns with same reinforcing ratio, larger number of reinforcements with the smaller diameter causes the higher temperature distribution. The findings from the experimental study allow not only understanding of thermal behaviors of high strength concrete columns under fire, but also guidance in revising fire safety design.

• Fire Science and Engineering
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• v.32 no.3
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• pp.51-59
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• 2018

Although a fire curtain plays an important role in preventing smoke from spreading to the auditorium in a theater fire, there has been insufficient research on fire curtains. In this study, to check the accuracy of numerical simulation, for previous experiments using a reduced scale model, a numerical simulation was carried out, and the results were compared with previous experimental data. The fire curtain effect was then predicted numerically. A Fire Dynamics Simulator (FDS) was used, and the natural exhaust vent sizes were set to ~10%, ~5%, and ~1% of the stage floor area. The smoke movement was visualized, and the mass flow rates and temperatures were measured and analyzed. In addition, the law of similarity was used to examine the influence of a fire curtain in a real scale theater fire. Without the fire curtain, the present numerical simulation results were in agreement with the previous experimental data within reasonable accuracy. Meanwhile, the fire curtain affects the mass flow rates through the natural exhaust vent and proscenium opening, as well as the start time of soot outflow to the auditorium. Overall, the present results can be used to develop a fire curtain system.

• Resources Recycling
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• v.20 no.1
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• pp.28-36
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• 2011

More than 50% of refractory materials generated from high-temperature melting furnace was not carbonized and could be recycled by adopting proper separation process. In the present work, the separation of refractory materials has studied by adopting color sorting technology to promote the recycling of waste refractory. Purity of the refractory materials was obtained with at 97.2%, color temperature of sorter light source 6,500K, which gives less interference of surrounding light source. Purity and separation efficiency were improved as size is setting bigger and lower conveyer belt speed. It is revealed that optimum conditions were color temperature 6,500K, conveyer belt speed 1,000 mm/sec, particle size -20 mm, etc. To improve purity and separation efficiency on below 10mm size, the resolution of should be fixed camera and it narrow recognition range. As a result of the study, color sorting technology could be used for separation of waste refractory materials and will contribute to promote the waste recycling.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.866-876
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• 2003

Experiments were performed for the real sized 12 reinforced concrete columns of 350${\times}$350${\times}$3350 mm with normal concrete in order to observe the fire-damaged behavior of these columns. Columns were heated according to the ISO heating curve. Main experimental parameters were: magnitude of axial load, heating time, cover thickness, and eccentricity. Effects of these parameters on the axial expansion and contraction, rotation, buckling, ISO fire resistance, and structural stability were experimentally quantified. It has been observed that the contraction rate of axial deformation was affected mostly by the duration of heating time and buckling of reinforcement or member by the magnitude of axial load, duration of heating time, cover thickness and eccentricity in order. Based on the experimental observations, ISO fire resistance criteria were qualiatively criticized.

• Fire Science and Engineering
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• v.15 no.2
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• pp.6-12
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• 2001

The objective of the present work is to examine the cooling effect of a water fire extinguishing agent containing NaBr(30%, w/w). The carbon steel and teflon were used as a hot solid. The temperature on the hot solid surface ranged from $70^{\circ}c$ to $116^{\circ}c$ and water droplet size was 2.6 mm in the experiments. It is suggested that regardless of the hot solid material, the indepth temperature of the case of NaBr solution is lower than that of pure water and the variation of indepth temperature of teflon is higher than that of carbon steel. Regardless of the hot solid material, the time averaged heat flux of the case of pure water is higher than that of NaBr solution. the apparent evaporation time of the case of pure water is shorter than that of NaBr solution.

• Fire Science and Engineering
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• v.30 no.1
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• pp.1-5
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• 2016

Cases of cardiac arrests due to cardiovascular ailments have increased recently., portable Current portable resuscitators which can be automatically supply oxygen operated by the pressure of supplied oxygen without manual or electronic actuators are now widely used in emergency worldwide. However, reductions in Pressure drop characteristics through the extended use of this type of resuscitator, however, is are not well-known described. This paper describes the reduction in pressure loss drop performance of the various holes in within the flow control disc of with various hole size of the portable resuscitators using on breathing resistance through the CFD simulation, and suggests the an optimum optimal design of the hole shapes for the minimization of alteration in order to minimize this pressure drops.

• Journal of ILASS-Korea
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• v.22 no.4
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• pp.175-184
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• 2017

The numerical investigation on the effects of water-mist characteristics has been carried out for the fire suppression mechanism. The FDS are used to simulate the interaction of fire plume and water mists, and program describes the fire-driven flows using LES turbulence model, the mixture fraction combustion model, the finite volume method of radiation transport for a non-scattering gray gas, and conjugate heat transfer between wall and gas flow. The numerical model is consisted of a rectangular enclosure of $L{\times}W{\times}H=1.5{\times}1.5{\times}2.0m^3$ and a water mist nozzle that be installed 1.8 m from fire pool. In the present study, the parameters of nozzle for simulation are the droplet size and the spray velocity. The droplet size influences to fire flume on fire suppression more than the spray velocity because of the effect of the terminal velocity. The optimal condition for fire suppression is that the droplet size and the spray velocity are $100{\mu}m$ and 20 m/s respectively.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.1984-1989
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• 2008

In this study, fire simulations were performed to analyze the characteristics of the fire driven flow and the effects of the platform screen door on the smoke flow in the station, when the fire occurred in the center of the platform. Soongsil Univ. station (line number 7, 47m in depth underground) was chosen which was the one of the deepest underground subway stations in the Seoul metro, SMRT. The parallel computational method was employed to compute the heat and mass transfer eqn's with 6 CPUs of the linux clustering machine. The fire driven flow was simulated with using FDS code in which LES method was applied. The Heat release rate was 10MW and The Ultrafast model was applied for the growing model of the fire source. The 10,000,000 structured grids were used.

• Fire Science and Engineering
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• v.32 no.3
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• pp.134-139
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• 2018

Extremely fine particles seriously affect people and are becoming a social problem. Conventional methods using the type of beta ray absorption are difficult to have real-time measurements and miniaturization for the acquisition of fine dust. In this paper, a light scattering method was used. The sensors were configured internally with semiconductor laser diodes for miniaturization, low cost and lightweight. The use of the FFT method makes it easier to separate fine dust according to size compared to conventional light scattering sensors. Bluetooth communication also allows the connection, monitoring and control of devices using smart phones.