• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.313-322
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• 2019

Recently, there have been frequent occurrences of bridge fires. Fires in cable-supported bridges can damage and brake cables due to high temperatures. In this study, fire scenarios that can occur on cable-supported bridges were set up. In addition, based on the results of vehicle fire tests, a fire intensity model was proposed and cable heat transfer analyses were performed on a target bridge. The analyses results demonstrated that temperature rises were identified on cables with a smaller cross-sectional area. Furthermore, vehicles other than tankers did not exceed the fire resistance criteria. When the tanker fire occurred on a bridge shoulder, the minimum diameter cable exceeded the fire resistance criteria; the height of the cable exceeding the fire resistance criteria was approximately 14 m from the surface. Therefore, the necessity of countermeasures and reinforcements of fire resistance was established. The results of this study confirmed that indirect evaluation of the temperature changes of bridge cables under fire is possible, and it was deemed necessary to further study the heat transfer analysis considering wind effects and the serviceability of the bridge when the cable temperature rises due to fire.

• Journal of ILASS-Korea
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• v.17 no.2
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• pp.64-70
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• 2012

Water mist fire suppression systems which use relatively small droplets of water with high injection pressure are increasingly being used in wider applications because of its greater efficiency, low flooding damage and low toxicity. However, the performance of the system significantly relies on the water mist characteristics and it requires better understanding of fire suppression mechanism of water mist. In the present study, computational fluid dynamics simulations were carried out to investigate cooling performance of water mist in heated chamber. The gas phase was prepared with natural convection heat transfer model for incompressible ideal case and then the effects of water mist injection characteristics on cooling capabilities were investigated upon the basis of the pre-determined temperature field. For the simulation of water mist behavior, Lagrangian discrete phase model was employed by using a commercial code, FLUENT. Smaller droplet sizes, greater injection angles and higher flow rates provided relatively higher cooling performance.

• Fire Science and Engineering
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• v.34 no.1
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• pp.115-120
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• 2020

This study aimed to assist the improvement of organizational commitment and the preparation of an action plan regarding support from the organization by examining the effects of organizational culture types and perceived organizational support on firefighters' organizational commitment. To this end, 205 fire-fighting officers from the northern area of Gyeonggi-do were surveyed using the purposive sampling method. The results demonstrated that among organizational culture types, the perception of group culture, rational culture, and organizational support held by firefighters had a significant influence on their organizational commitment. Based on these results, this study suggested various support plans at the organizational level for stimulating group culture and rational culture among firefighters, and improving organizational commitment.

• Fire Science and Engineering
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• v.33 no.4
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• pp.152-162
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• 2019

This paper proposes improvement measures of a school safety education program by analyzing the factors affecting the cognition of school safety on the school safety transfer intention and their mediating effects. In summary, the satisfaction with the contents was represented as a variable with the greatest influence on the transfer intention followed in order by satisfaction with the instructor and satisfaction with the environment. On the other hand, satisfaction with the teaching method was not significant. In addition, the general cognition on school safety education showed that it has mediating effects on the relationship between the satisfaction with the school administrator safety education and the school safety transfer intention.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.114-115
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• 2019

When concrete is exposed to fire, the decomposition of Portland cement paste results in critical damage to the concrete structure of a building. Although the behavior of cement pastes after heating provides crucial information with respect to the reuse of the building exposed to fire, the recovery process of the damaged concrete structure has not yet been fully elucidated. In addition, research on appropriate additives such as carbon nanotube (CNT) has been increasing recently, however, investigation of CNT incorporated cement paste after decomposition of CNT by high temperature is not fully investigated. In this study, we investigated the physicochemical properties of CNT incorporated cement paste under different temperatures (200℃, 500℃ and 800℃). Also, the effects of different rehydration conditions (20℃ 60% RH and in water for different curing times) on the recovery of the paste were studied. The changes in tensile and compressive strength, surface observation of the specimens were characterized. In addition, the decomposition and formation of hydrates in the paste due to the heating process were studied using X-ray diffraction.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.792-797
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• 2013

4D film is just a film that made by adding some physical effects to 3D film or general film. In order to provide physical effects to the audience, the data that make the physical effect must be added to each frames. In this paper, we proposed a video detection system that can efficiently provide physical effects by assessing the present situation such as explosion scene, snowing scene. The proposed video detection system contains an algorithm for fire detection by using R color and $C_r$ value, and also an algorithm for snow detection by using RGB color model. The system constitutes in a MCU that from 8051 family. In the performance evaluations, the result shows that 91% of detection rate in case of fire and 25% of false detection rate in case of snow. Also the system is capable of providing physical effects automatically.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.33-39
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• 1999

In a compartment fire with openings, convective heat transfer consists of natural convection from the hot bodies and forced convection by airflow through the openings. The same finite volume method that was applied to pure natural convection in part I was utilized without modification to the square cavity with two openings. The objective of this study is to investigate effects of the openings on temperature distribution. Flow patterns, temperature distribution and heat transfer were compared for different Rayleigh numbers and with and without the openings.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.690-694
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• 2008

In this presentation, we study numerically an optimization problem of a fire fighting robot cooling system. The governing equation for the system is the unsteady heat equation with source term. We use a multigrid method for numerical solutions in three-dimensional space. We investigated the effects of various parameters and the results will be presented.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.113.1-113
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• 1996

No Abstract, See Full Text

• Fire Protection Technology
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• s.24
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• pp.17-22
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• 1998

The objective of this paper is to investigate the variation of orifice diameter in a straight pipe which can give equal-sampling rate. This can be utilized for designing orifice in air-sampling smoke detector. The elements which should be considered for designing orifices was presented and the calculation procedure was also given in this paper. The effects of pipe length, the number of orifices, fan pressure was decribed.