• Fire Science and Engineering
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• v.25 no.5
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• pp.128-133
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• 2011

The present study performs a series of 40 % reduced scale of ISO-9705 fire test to investigate the characteristics of heat flux on the floor level in terms of fire characteristics and location in the compartment. The heat flux was measured with Schmidt-Boelter type heat flux gauge at two locations on the floor level of inside and doorway side of the compartment. Different types of fuel - methane, heptane, toluene, ethanol, polystyrene - were burned in this test series. The measured heat flux inside of the compartment was relatively higher than that of front side as the heat release rate of fire and upper layer temperature increased. The difference of measured heat flux at inside and doorway side increased for high sooty fire. The present study shows that the heat flux distribution at lower layer greatly depend on the thermal radiation from fire and upper layer, not only the upper layer temperature but also various fire characteristics such as composition of combustion gases, soot concentration, ventilation condition and so on.

• Fire Science and Engineering
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• v.21 no.4
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• pp.52-58
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• 2007

The effect of stand-growing-stock characteristics of thinning area and non-thinning area on forest fire was studied in this work. 14 spots were selected from 3 counties such as Yangyang, Injae, and Gapyeong and on-the-spot investigations were performed to evaluate the effect of forest fire. The stand-growing-stock characteristics on the spots were analyzed through the height of tree, breast height diameter, clear length, mortality of branch, forest tree standing crop density, degree of closure, and shrub and grass cover degree. The relation between forest fire and the risk of spread of forest fire were analyzed from the analysis of the stand-growing-stock characteristics. It is considered from this work that the possibility of forest fire is decreased on the thinning area compared to the non-thinning area because of higher clearlength, lower number of tree, lower mortality of branch and higher shrub and grass cover degree.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.3
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• pp.127-131
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• 2005

Big fire such as mountain fire may cause the prevention of the functions of the overhead cables and insulators, which may affect the operation of the transmission lines. In the worst case, this kind of disaster may have a huge effect on the whole industry of a country. However, the study on the effect of the mountain fire on the transmission line is very rare. Therefore, in order to understand the effect of the mountain fire on the polymeric insulator for transmission lines, the author observed the deformation of the sheds of the polymeric insulators and the change of the discs of the porcelain insulators under fire, varying the ignition time using the artificial ignition testing equipment which simulates the mountain fire, and investigated the electrical and mechanical characteristics of the insulators after the ignition test. For the test, the miniature insulators made of polymeric material and porcelain have been utilized. As the result, the following conclusions were obtained. First, the porcelain insulator was degraded in electrical characteristics when the insulator was subjected to the fire for approximately 5 minutes; whereas, the polymeric insulator was not degraded though there were some damage on its sheds. Second, after 20 minute exposure to the fire, the polymeric insulator lost a lot of parts of sheds, but the electrical characteristics was lowered by around $20\%$, but the porcelain insulators were electrically degraded by more than $80\%$.

• Fire Science and Engineering
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• v.25 no.2
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• pp.88-94
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• 2011

Heat release characteristics of live fire load are an important parameter for performance oriented fire safety design of a building. While investigations have been carried out on the fire load and its burning behavior in office, residential and commercial buildings and so on, little effort has been paid for the rational treatment of fire load in bookstore. In this report, burning behavior of typical combustible objects in bookstore are studied by measuring heat release rates of bookshelf with book. Based on the results, it has reviewed fire safety when a fire accident occurs on the large bookstore and suggested peak heat release rate per burning surface, fire growth rate, etc of the live fire load required for fire safety design in bookstore.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1199-1204
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• 2004

Most overhead transmission lines in Korea run over the mountain; however, only little study has been made for the effect of mountain fire on polymeric insulator for transmission lines, though the study is significantly required, Therefore, in this study, the authors observed the deformation of the sheds of the insulator under fire, varying the ignition time using artificial ignition testing equipment, and investigated electrical and mechanical characteristics of the insulator through dry withstand voltage test, impulse flashover test and tensile load test. As the results of the tests, the following conclusions were obtained, First, when the insulator was subjected to the fire, the electrical characteristics were slightly reduced, but there was no change on the mechanical characteristics, Secondly, the sheds and sheath of the insulator were not non-flammable but less-flammable. These two results show the high mechanical stability and durability of the insulator under severe fire condition, though the electrical characteristics can be deteriorated as the time that the insulator is subjected to fire, goes by.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.9
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• pp.847-854
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• 2014

The paper presented a method of early fire detection based on the environmental characteristics inside the nacelle of wind turbine generator system(WTGS). The rising rates of the temperature and smoke density were used as the parameters for early fire detection. By considering the characteristics of temperature and smoke density of a nacelle, this method is very reliable and can minimize the possibility of a malfunction of fire detection. The performance of the method was tested through sets of experiments by using nacelle simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4809-4814
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• 2014

The aim of the present study was to estimate the prediction performance of a FDS (Fire Dynamic Simulator) to simulate the fire behaviors and suppression characteristics by operating a water-mist. Rosin-Rammler/log-normal distribution function was used to determine the initial droplet distribution of water-mist and the effects of its model constant were considered. In addition, the simulation models were validated by a comparison of the predicted fire suppression characteristics with water-mist injection pressures to the previous experiments, and the thermal flow behaviors and gaseous concentration variations were analyzed. The results showed that water-mists with the same mean diameter were affected by the characteristics of the droplet size distribution, which have different size and velocity distributions at the downstream location. The fire simulations conducted in this study determine the initial droplet size distribution tuned to the base of the spray characteristics measured by previous experiments. The simulation results showed good agreement with the previous measurements for temperature variations and fire suppression characteristics. In addition, it was confirmed that the FDS simulation with a water-mist operation supplies useful details on estimations of the thermal flow fields and gaseous concentration under water mist operation conditions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.10
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• pp.49-55
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• 2014

This paper is basic study for development of an advanced photoelectric type smoke detector that has high reliability by reducing the occurrence of nuisance alarms. This paper was attempted to distinguish optical characteristics of the typical fire smoke particle and non-fire smoke particle. According to UL 268 standards, three types of test fires (the paper, the wood and the flammable liquid) were used in this paper for measurement of the fire smoke particles, and the water vapor and the cigarette smoke that were known as the main cause of the nuisance alarms were also used for the non-fire smoke particles. A smoke detection chamber was created, which was equipped with one light source and several light sensors for enabling simultaneous detection of light extinction and scattering, respectively. This paper analyzes the optical characteristics of each smoke particle using this chamber.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.752-757
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• 2001

The characteristics of heat energy distribution on the fire-proof clay with microwave heating drying are numerically investigated using finite element method. The modelled regular hexahedron chamber$(50cm\times50cm\times50cm)$ filled with air consists of vertical heat source and sink walls, a fire-proof clay model, and adiabatic plates on the top and bottom walls. With different geometrical aspect ratios of the fire-proof clay model, the heat energy distribution is throughly investigated. The model gave a good prediction of the microwave heating characteristics of fire-proof clay. The optimal shape of the fire-proof clay for given chamber geometry and microwave power is analyzed.

• Fire Science and Engineering
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• v.29 no.4
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• pp.67-72
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• 2015

A series of fire tests was conducted to examine the fire characteristics of flaming and smoldering combustion of engineered wood products, which have been widely used for furniture and finishing materials in buildings. The engineered wood products of MDF, plywood, and chipboard were ignited by a radiant cone heater with incident heat flux of $50kW/m^2$. During the fire test, key parameters representing the fire characteristics such as the heat release rate, yield rate of combustion product, and effective heat of combustion were quantified in terms of thickness. The tests show two peak points of HRRPUA due to lateral fire propagation in the initial stage, followed by later fire penetration through the specimen thickness. The mass loss rate of flaming combustion was 5 times higher than that of smoldering combustion, while the CO yield rate of smoldering combustion was 10 times higher than that of flaming combustion. This study can contribute to the understanding of fire behavior of wood combustibles and provide useful data for fire analysis.