• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.243-247
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• 2020

In the era of the fourth industrial revolution, safety of disasters is being emphasized above all else, and electric fires are most frequent during disasters, and human and property damage is very serious. In this paper, we propose a study that can determine the efficiency of evacuation and non-evacuation guidance due to the large difference in casualties depending on the traffic line in the case of fire. Evacuation guidance was assumed to be a situation in which adequate evacuation routes were guided by a recorded voice or a trained staff, and non-evacuation guidance was assumed to be a situation without anything. Evacuation simulations were carried out using a evacuation simulation tool called PATHFINDER and SIMULEX for the analysis of the efficiency of evacuation and non-evacuation guidance. As a result, the evacuation time was similar, but in the case of non-evacuation guidance, it was not guided to the safe zone, which could cause serious damage.

• Fire Science and Engineering
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• v.14 no.2
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• pp.21-32
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• 2000

In this study, reduced-scale experiments as the alternative to a real-scale fire test were conducted to understand fire properties in tunnel, and their results were compared with those of numerical simulation. The 1/20 scale experiments were conducted under the Froude scaling since smoke movement in tunnel is governed by buoyancy farce. A numerical simulations were on performed 3D unstructured meshes with PISO algorithm and buoyant plume models. Results showed that data was in reasonable agreement with the numerical data of smoke velocity, temperature distribution, and clear height.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1319-1324
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• 2007

Many researches have been performed to analyze the smoke movement in tunnel fires by using field model. Recently, FDS(Fire Dynamics Simulator) v.4, which is one of the field model and developed from NIST(National Institute of Standards and Technology), is widely used. In tunnel fires, FDS can show detail results in local point, but it has difficulties in boundary condition and taking long computing time as the number of grid increases. So, there is a need to use alternative method for tunnel fire simulation. A zone model is different kind of CFD method and solves ordinary differential equation based on conservation and auxiliary equations. It shows good macroscopic view in less computing time compared to field model. In this study, therefore, to confirm the applicability of CFAST in tunnel fire analysis, numerical simulations using CFAST are conducted to analyze smoke movement in longitudinal ventilation reduced-scale tunnel fires. Then the results are compared with experimental results. The differences of temperature and critical velocity between numerical results and experimental data are over $30^{\circ}C$ and 0.9m/s, respectively. These values are out of error range. It shows that CFAST 6.0 is hard to be used for tunnel fire simulation.

• Fire Science and Engineering
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• v.13 no.2
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• pp.3-11
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• 1999

New examination of a predictive model for the ISO 9705 room-corner test have been m made for materials studied by L S Fire Laboratories, Italy. The ISO 9705 test subjects wall a and ceiling mounted materials to a comer ignition source of 100 kW for a duration of 10 m minutes; if flashover does not occur this is followed by 300 kW for another 10 minutes. The m materials that did not stay in place during combustion because of melting, dripping, or d distorting were simulated by an adjustment to the material's total available energy. For m mat려als that remain in place the simulation model appears to do well in its prl어ictions. A l large-s떠Ie room test results 뾰 compar벼 with the m여el’s prediction also.

• KIEAE Journal
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• v.10 no.5
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• pp.87-93
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• 2010

The objective of this study is to verify the safety in case of fire and change of residential environment for different wall construction approaches in a stairways apartment house. In order to confirm that case_1, which is current case that most of wall is opened and the case 2, which upper part of wall is limitedly opened are compared and analyzed based on simulations of fire, escape and natural ventilation performance. The analysis reveals that possible escape time for case 1 was more than 600 seconds and for case 2 was 195 seconds. Since the escape times for both cases were over 128 seconds, it would be reasonable to assume that every resident would escape. The simulation results on natural ventilation performance shows the air change per hour of case 1 and case 2 were .19n/h and .16n/h and there was 1.2 times difference. However, the difference was too insignificant and it could be seen as that different approaches on wall construction would not significantly influence on natural ventilation performance.

• Fire Science and Engineering
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• v.18 no.2
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• pp.1-6
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• 2004

In this study, numerical simulations were conducted to analyze an effect of the aspect ratio on smoke movement in tunnel fires using FDS 3.0. It was confirmed an application for tunnel fires in comparison with experimental results. The results showed relatively good agreement with experimental data within 1$0^{\circ}C$. Clear height of CFD by velocity distribution was about 3% higher than that of experiment. Smoke movement was confirmed by the analysis of temperature and velocity field. Results from variation of the aspect ratio showed good agreement with experimental data. The temperature at the vicinity of the fire source became lowly with the increase of the aspect ratio. But, decrease rate of the temperature was reduced by the decrease of the heat loss to the width direction.

• Fire Science and Engineering
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• v.24 no.5
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• pp.50-59
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• 2010

Four fire scenarios, as the cases of fire sizes of 2 MW and 5 MW, and no installation and activation of atrium fire shutter for dormitory building of Daegu 'D college', were developed and fire simulations were run using FDS (ver. 5.5.0) and Pathfinder 2009 programs. By assessing fire and evacuation, the effects of atrium fire shutter and vents on the smoke control of atrium were evaluated and this study also analyzed fire hazard and egress safety for occupants in the dormitory. Fire shutter's preventing smoke transport around atrium was much effective, but smoke layer descended down the design limit of smoke height and kept about 2 m height from the atrium floor in all cases because flow rate through vents was not enough. For the case of 5 MW fire and no fire shutter, fire hazard was higher due to visibility than temperature and allowable egress time to stairwell was short less than 5 seconds for the occupants on the floors of 4F to 7F. For total occupants, egress time out of main doorway was calculated about 136 seconds. It is sure that additional systems improving the performance of smoke control need to be installed for more safe evacuation.

• Fire Science and Engineering
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• v.33 no.5
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• pp.37-47
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• 2019

In the present study, the influences of the fire curtain and natural vent in a theater fire were investigated through the numerical simulation of a reduced-scale model of a theater fire using the Fire Dynamics Simulator (FDS). Based on a previous experimental study using the reduced-scale model, the 1/14 reduced-scale model and its conditions were constructed according to the law of similarity with a real-scale theater. Through a series of numerical simulations, the smoke movements were visualized, and the temperatures in the stage and auditorium, mass flow rate of the outflow through natural vent, and time at which smoke started moving toward the auditorium were measured and analyzed. The general trends on the effects of the fire curtain and natural vent during the theater fire predicted by the present numerical simulation were similar to the previous experimental results. For quantitative comparison of the present numerical simulation and previous experimental results, the mean percentage errors of temperatures in the stage and auditorium, and the mass flow rate of outflow through the natural vent were calculated. The present numerical simulation results showed good agreement with previous experimental results with reasonable accuracy.

• Fire Science and Engineering
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• v.23 no.4
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• pp.13-18
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• 2009

The main objective of the present study is to investigate smoke propagation in railway tunnels with rescue stations. In particular, based on measurement of HRR (heat release rate) for pool fires formed at different locations, the influence of fire source location on smoke behavior is examined. The fuel is n-heptane and pool fires are generated with a square length 4cm. With the use of MVHS (Modified Volumetric Heat Source) model for fire source, extensive numerical simulations are performed by using the commercial code FLUENT (Ver.6.3) Predicted smoke temperatures and smoke propagation are discussed. From numerical predictions, it is found that ventilation systems may be necessary in the railway tunnels because the smoke moves along the tunnel, and consequently it enters the non-accident tunnel. It is also confirmed that the cross-passage and fire protection wall systems contribute to control the smoke.

• Fire Science and Engineering
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• v.31 no.2
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• pp.52-60
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• 2017

Numerical simulations were performed to evaluate the habitability of an operator for a cabinet fire in the main control room of a nuclear power plant presented in NUREG-1934. To this end, a Fire Dynamics Simulator (FDS), as a representative fire model, was used. As the criteria for determining the habitability of operator, toxic products, such as CO, were also considered, as well as radiative heat flux, upper layer temperature, smoke layer height, and optical density of smoke. As a result, the probabilities of exceeding the criteria for habitability were evaluated through the sensitivity analysis of the major input parameters and the uncertainty analysis of fire model for various fire scenarios, based on V&V (Verification and Validation). Sensitivity analyses of the maximum heat release rate, CO and soot yields, showed that the habitable time and the limit criterion, which determined the habitability, could be changed. The present methodology will be a realistic alternative to enhancing the reliability for a habitability evaluation in the main control room using uncertain information of cabinet fires.