• Fire Science and Engineering
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• v.32 no.3
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• pp.76-87
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• 2018

This study describes the damage effects modeling for a quantitative prediction about the hazardous distances from pressurized chlorine saturated liquid tank, which has two-phase leakage. The heavy gas, chlorine is an accidental substance that is used as a raw material and intermediate in chemical plants. Based on the evaluation method for damage prediction and accident effects assessment models, the operating conditions were set as the standard conditions to reveal the optimal variables on an accident due to the leakage of a liquid chlorine storage vessel. A model of the atmospheric diffusion model, ALOHA (V5.4.4) developed by USEPA and NOAA, which is used for a risk assessment of Off-site Risk Assessment (ORA), was used. The Yeosu National Industrial Complex is designated as a model site, which manufactures and handles large quantities of chemical substances. Weather-related variables and process variables for each scenario need to be modelled to derive the characteristics of leakage accidents. The estimated levels of concern (LOC) were calculated based on the Gaussian diffusion model. As a result of ALOHA modeling, the hazardous distance due to chlorine diffusion increased with increasing air temperature and the wind speed decreased and the atmospheric stability was stabilized.

• Fire Science and Engineering
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• v.30 no.2
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• pp.81-86
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• 2016

Recently, frequent traffic congestion has occurred in domestic urban roads. As a solution for downtown traffic congestion in domestic urban roads, plans for great depth underground double-deck tunnels have been made. Great depth underground double-deck tunnels that have been planned for passenger cars, has the structure of a network type; the entry of vehicles is carried out in the underground space. In these network great depth underground double-deck tunnels, the cross section and the height of the tunnel are smaller than the general road tunnel, and the smoke of a fire will propagate faster than the evacuation of tunnel passengers by the action of the traffic-ventilation and casualties are expected. Therefore, in the present study, an attempt was made to prevent the delay system for fire smoke diffusion at the time of a fire in a domestic network great depth underground double-deck tunnel according to the area of the tunnel block during the operation of the delay system for fire smoke diffusion to analyze the effects of reducing the inflow velocity. When the area of the tunnel block was not less than 50%, the effect of reducing about 21% of the wind speed acting on the tunnel was significant. If the area is more than 50%, the diffusion rate of fire smoke was reduced by approximately 21%, which will be useful for a safe evacuation.

• Journal of Korean Society of Forest Science
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• v.62 no.1
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• pp.43-52
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• 1983

The purpose of this study was to measure the changes in soil properties and forest vegetation after surface fire, which had occured on June 5, 1983 in Mt. Gwanag, Kyunggi-do. Moisture content, organic matter and acidity of soil increased just after the fire and then dropped down up to those of unfired areas as time goes. Also total nitrogen, available phosphorous exchangeable base had the similar trend to moisture, organic matter and acidity. Most of the exchangeable bases in surface soil except for sodium were higher than those in sub-soil. No changes in soil texture by the fire were found. Increasers, decreasers, invaders and neutral species could be classified according to the relative importance value of each species. Species diversity was reduced just after the fire and increased gradually afterward. Diversity in the southeast slope was higher than that in the southwest slope. Due to the fire, evenness of woody plants decreased continuously while that of herbs increased. Species similarity was shown greater at fired areas than at unfired areas.

• Fire Science and Engineering
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• v.31 no.6
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• pp.8-15
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• 2017

Most fire victims succumb to smoke inhalation, and fire smoke toxicity from interior materials is increasing with increased use of plastics. Large amounts of hazardous effects of smoke are related to deposition of smoke particles in respiratory tracts, and deposition characteristics are influenced by size distribution of particles. Thus, it is essential to know the size distribution of smoke particles from plastics for hazard analysis of fire smoke. In a recent study, it has been shown that size distributions of smoke particles from PP are different from wood in many aspects. In order to know whether other plastics show the same characteristics as PP, size distributions of smoke particles from four plastic materials (LDPE, PA66, PMMA, and PVC) were measured in real time under each fire type with various temperature and oxygen supply. In this study, smoke particles from different plastics were generated uniformly by using steady-state tube furnace method provided in ISO/TS 19700. Their size distributions were measured by using an electrical low pressure impactor (ELPI). Results of measurements showed that size distributions of smoke particles from these four plastic materials were similar to those from PP in many aspects. However, they were distinctively different from those of wood.

• Korean Journal of Remote Sensing
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• v.35 no.6_2
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• pp.1083-1093
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• 2019

The purpose of this study is to detect the burned area change by direct burning of tree canopies and post-fire mortality of trees via analyzing satellite imageries from the Korea multi-purpose satellite-2 and -3 (KOMPSAT-2 and -3) for two large-fires over the Goseong-Sokcho and Gangneung-Donghae regions in April 2019. For each case, the burned area was compared between two dates: the day when the fire occurred and 15-18 days after it. As the results, within these two dates, there was no substantial difference in burned area of sites whose severities were marked as "Extreme", but sites with "High" and "Low" severities showed significant differences in burned area between the two dates. These differences were resulted from the lagged post-fire browning of canopies which was detected by images from in-situ observation,satellite, and the unmanned aerial vehicle. The post-fire browning started after 3-4 days and became apparent after 10-15 days. This study offers information about the timing to quantify the burned area by large fire and about the mechanism of post-fire mortality. Also, the findings can support policy makers in planning the restoration of the damaged areas.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.11a
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• pp.3-8
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• 1995

An experimental investigation was conducted in order to figure out the multiple fire effects on the combustion efficiency and fuel properties of the solid fuel ramjet. Pure HTPB and metallized $B_4$C/HTPB fuel were studied. Fuel property effects were analyzed by using differential scanning calorimetry, The thermal or mechanical properties of the fuel grain were not affected and the combustion efficiency was a little increased.

• Fire Science and Engineering
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• v.32 no.2
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• pp.102-109
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• 2018

This study examined the effects of the risk generation factors on the public service motivation and a vocational calling of fire service officers during their work. This is based on the assumption that the risk generation factors of firefighters in their organization should be related to the effectiveness of the organization by affecting the psychological capital of the individual. For this study, the survey was conducted on fire service officers who participated the official training session in Kyuunggi and Seoul area and analyzed the data collected by the regression analysis and t-test analysis. As a result, the higher the perception of generation factors, the higher the level of public service motivation and vocational calling. In addition, there was a significant difference between a high risk generation factor perception group and low risk group regarding the perception level of public service motivations and vocational callings. These results show that there is a need to provide more field-based training opportunities for firefighters who can recognize the risk generation factors better.

• Fire Science and Engineering
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• v.33 no.3
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• pp.138-142
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• 2019

By securing golden time, this study analyzed the effects of an emergency vehicle priority system in Cheongju, North Chungcheong province. Until the scene of a fire is reached, severe obstacles in the street, such as traffic congestion, cars coming forward, non-cooperative vehicles etc., are significant. To solve these problems of road obstacles, it is essential to adopt an emergency vehicle priority system. From April 2017 to June 2018 (1 year and 2 months, 426 days), the dispatch time and date, fire truck moving distance and required time, traffic signal control section and pass time, and shortening time, were measured. This study selected 140 cases consisting of five heavy traffic and frequent dispatch routes out of 293 cases. The effects of the emergency vehicle priority system were excellent. Overall, it took 3 min 3 s to pass 1 km on an uncontrolled traffic signal section. On the other hand, it took 1 min 23 s to pass 1 km on the same section that was controlled. The shortening time to pass 1 km was 1 min 40 s, showing a 45.4% reduction. This means that the 15 min driving time can be reduced to 6 min and 49 s. From this result, an emergency vehicle priority system should be implemented nationwide as soon as possible.

• Fire Science and Engineering
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• v.31 no.2
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• pp.1-8
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• 2017

A sandwich panel is a composite material composed of a double-sided noncombustible material and insulation core which is used in the inner, outer walls, and roof structure of a building. Despite its excellent insulation performance, light weight and excellent constructability, a flame is brought into the inside of the panel through the joint between the panels, melting the core easily and causing casualties and property damage due to the rapid spread of flame. The current Building Law provides that the combustion performance of finishing materials for buildings should be determined using a fire test on a small amount of specimen and only a product that passes the stipulated performance standard should be used. This law also provides that in the case of finishing materials used for the outer walls of buildings, only materials that secured noncombustible or quasi-noncombustible performance should be used or flame spread prevention (FSP) should be installed. The purpose of this study was to confirm the difference between the dangers of horizontal and vertical fire spread by applying FSP, which is applied to finishing materials used for the outer walls of buildings limitedly to a sandwich panel building. Therefore, the combustion behavior and effects on the sandwich panel according to the application of FSP were measured through the construction to block the spread of flame between the panels using a full scale fire according to the test method specified in ISO 13784-1 and a metallic structure. The construction of FSP on the joint between the panels delayed the spread of flame inside the panels and the flash over time was also delayed, indicating that it could become an important factor for securing the fire safety of a building constructed using complex materials.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.9-15
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• 2012

The ignition characteristics in a confined axisymmetric coflow $CH_4$ jet were investigated numerically with the Fire Dynamics Simulator(FDS). The $CH_4$ fuel stream was diluted with main combustion product gases, such as $O_2$, $N_2$, CO, $CO_2$, and $H_2O$, and the mixed fuel stream was heated up to the sufficient temperature where a supplying fuel stream can be ignited. For the calculation of chemical reaction in the simulation, a 2-step global finite chemistry model was considered. Boundary condition for confined wall was optimized by investigating the effects of wall temperature on the ignition characteristics of fuel stream. In addition, the effects of composition of diluents in the fuel stream and fuel stream temperature on the ignition of fuel steam were investigated. The ignition characteristics of $CH_4$ stream with diluents were very sensitive to the wall temperature, composition of diluents in the fuel stream and fuel stream temperature.