• Fire Science and Engineering
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• v.29 no.2
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• pp.33-38
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• 2015

For the purpose of high-pressure and suction of fixed amount, the development of ultra-high pressure rotating helical gear positive displacement pump with no clearance had been proceeded. The CFD analysis was performed to verify the internal pressure and the discharge flow velocity of the pump. Accordingly, a flow analysis were performed by FVM technique and we were unable to obtain a successful result since the fluid domain is separated because the grid is not configured in a row in FVM flow analysis of the fully enclosed type without clearance. Because of these problems, the flow analysis was performed by MPS method which grid configuration is not needed and the internal pressure and the discharge flow velocity of the pump were confirmed through the MPS flow analysis. At 1,000 rpm rotation speed of the rotor, the minimum internal pressure of the pump was 19.5 bar, maximum pressure was 44.6 bar and average pressure was 33.9 bar. And the minimum discharge flow velocity was 64.5 m/s, maximum discharge flow velocity was 84.8 m/s and average discharge flow velocity was 76.1 m/s. Through this study, we could confirm that MPS method was more suitable than FVM method in terms of flow analysis with no clearance. In addition, the relationship of the flow velocity according to the change of ultra-high pressure rotating helical gear positive displacement pump could be identified through this study.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.649-658
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• 1997

When steel tube as a column is filled with concrete, it is common that the load-bearing capacities of CFST(Concrete Filled Steel Tube) column are increased substantially, And the CFST column can obtain a capacity of fire resistance without any additional detail on the surface of the steel tube for fire protection. In order to clarify the behavior of CFST column during fire occurrence, a theoretical study is performed, that is, a thermal analysis is used to find temperature gradient dependent on the time on the steel tube and the infilled concrete. N-M (axial force-moment) interaction curves are summarized under the consideration for time dependent variation. The material properties of concrete and steel in accordance with a temperature variation are referred to the existing general data. Thermal transient analyses are performed by finite element method through ANSYS and then these results are verified by comparing with the existing test results. On the basis of analytical results, load-carrying capacities (N-M interaction curves) are calculated by numerical analysis method.

• Journal of the Korea Safety Management & Science
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• v.10 no.4
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• pp.105-109
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• 2008

The purpose of this study is to distinguish the causes of broken glass on doors or windows when it is originally kept among the remains on the floor in fire site - whether it was broken due to heating or outer power-through test and characteristics of the broken plane including the pattern on the plane. Addition to it, the study tries to find characteristics to judge the point and direction of breakdown through the analysis of glass broken by outer power. With two assumed causes - a) breakdown due to heating and b) breakdown due to outer power-3 pieces of glass plates ($30cm{\times}30cm{\times}5mm$) were tested for each case, getting the results as following: First, for the glass broken due to the change of temperature, the broken plane is of slow and smooth curve without any pattern. Second, for the glass broken due to outer power, with the impact point as the center, the glass shows breakdown of radial type and the side shows breakdown of near-perpendicular type. The far the broken piece is from the impact point, the bigger the size is. The broken piece at the impact point is of long triangle type and the two long planes of the triangle shows semi-arc with the center of breakdown point and the other plane shows opposite pattern. Third, when glass that is damaged by outer power is heated, damaged forms and side patterns of the glass that is damaged by outer power are heated and disappeared.

• Fire Science and Engineering
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• v.15 no.1
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• pp.100-107
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• 2001

A Interior material, a main cause of fire-growth and generating toxic gas when it burns, should be dealt with great care in life safety design. Nonetheless, it has been used recklessly with undue attention to its contribution to fire in particular in entertainment occupancy and causes many victims in fire. Therefore, this study attempts to examine the current use of interior material in Korea and find out what to be improved and enhanced in terms of related regulations. Based on the comparison and analysis of the Korea regulation with those of advanced nations, suggestions are made for an effective and efficient improvement and complement to the current system. What can be suggested from this study are as follows. The use of interior material should be controlled under the unified regulation of fire-safety codes. Code should be set up so that the current construction enforcement should be applied in retroactive to those entertainment buildings that obtained a license prior to the implementation of the system certifying that the building is fire-resistant and fire-protective. The legislation should be made to control the fire-protection facilities of small-sized, underground entertainments. It should be obliged to present the blueprint displaying the use of interior material at the time of changing occupancy. Or, it should be compelled to report changes that go way without permit to the administrative office. A compulsory provision should be set up to have a fire-resistant performance to movable furniture. The classification index designating the fire hazard of interior material by flame spread rate and smoke toxicity and its test method should be established.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.189-199
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• 2019

In this study, behaviors of fire smoke in the operation of disaster prevention facilities (smoke damper, jet fan) in a tunnel-type structure (soundproof tunnel) were investigated numerically and results of the investigation were compared and analyzed. Through the simulation and analysis, it was found that there was a significant change in the patterns of fire smoke between the opening of the ceiling of a fire vehicle and the closing, and it was shown that the critical temperatures of PC and PMMA, main materials of a soundproof tunnel were not exceeded. In addition, the simulation of installation intervals of smoke dampers showed that the maximum temperature of a soundproof tunnel without smoke dampers was $552^{\circ}C$ while it reached $405^{\circ}C$ when smoke dampers were installed at the installation interval of 50 m. The simulation of the operation of a jet fan showed that the maximum temperature of a soundproof tunnel without a jet fan was $549^{\circ}C$ while it reached only $86^{\circ}C$ when a jet fan was operating. Therefore, it is highly expected that they could create a favorable environment for evacuation and protection of soundproofing materials, and it would be necessary to promote basic studies on tunnels serving various functions and purposes.

• Fire Science and Engineering
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• v.30 no.1
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• pp.104-110
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• 2016

Positive displacement pumps with high pressure and water capacity are used large fires in various high-rise buildings. This study provides information for a performance approval standard of fire pumps for fire trucks based on centrifugal pump standards enacted in 2012. An experiment was conducted with a positive displacement pump for three levels of performance from the approval standard (V-1, 2, and 3). The efficiency of the pump was included in the reference, which requires the approval of 65% performance, the same as a centrifugal pump. The water pressure is between 1.5 and 2.5 MPa, and the required flow rate was established as at least $0.31m^3/min$ and up to $3.0m^3/min$. A relief valve was added to adjust the shut-off pressure due to the structural characteristics of the positive displacement pump. A strainer was also installed to prevent damage to the inside of the pump due to foreign matter. However, the strainer includes a difference from the positive displacement pump to operate without a vacuum pump and the centrifugal pump. This is due to the additional approval standard portion of the positive displacement pump, which is expected to be selected for more variety of fire-fighting equipment and proactive responses to fire suppression in a high-rise buildings and large fires. In conclusion, this approval standard was enacted in January 2016.

• Fire Science and Engineering
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• v.33 no.1
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• pp.121-129
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• 2019

In Korea, life safety assessment through simulation are mandatory in performance-based design. Generally, there are three types of methods for simulation-based life safety assessments: the non-coupling method that compares available safe egress time (ASET) and required safe egress time (RSET) at a specific point through conducting fire and assessment simulations independently; the semi-coupling method that compares fire and evacuation simulation results by overlaying the result screens; and the coupling method that compares the results of fire effect simulation to an evacuation simulation. Of these methods, all designers in South Korea have used the only non-coupling method. In the non-coupling method, it is important to determine the location of a specific point to compare ASET and RSET. However, without any defined regulation, setting the location is determined based on the designer's experience and knowledge. The number of specific locations and the locations themselves differ with each designer, which can produce contrasting results in a life safety assessment. Therefore, this study conducted a life safety assessment based on the three methods (non-coupling, semi-coupling and coupling) and compared each of the results. Furthermore this study suggests a improvement way in particular for the computer simulation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.293-310
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• 2020

The purpose of this study is to present the most effective smoke exhaust mode by comparing the quantitatively evaluated risks according to the smoke exhaust mode when a train fire occurs in a subway platform. Therefore, applying the typical subway platform as a model, train fire scenarios are developed with the evacuation start time and location of the fire train for each exhaust mode. The fire accident rates (F) are calculated and the number of fatalities (N) was quantitatively estimated by fire analysis and evacuation analysis for each scenario. In addition, the F/N curve compared with the social risk assessment criteria and the following conclusions were obtained. In the event of a train fire at the subway station platform, the evacuation must start up within 600 s in maximum to ensure the evacuees' safety. To secure evacuation safety, it is advantageous to operate the HVAC system of the platform in the air-supply mode at station without TVF. Comparing the F/N curve for each exhaust mode with the social risk criteria, it turned out that the risk significantly exceeds the social risk criteria in case of no mechanical ventilation. As a result, this paper shows that the ventilation mode in which TVF are exhausted and HVAC system is operated in the pressurized mode are the most effective smoke exhaust mode for ensuring evacuation safety.

• Fire Science and Engineering
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• v.30 no.4
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• pp.39-45
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• 2016

The optimal design of an air curtain nozzle installed at exits, such as fire doors, was determined in order to block the flow of smoke into safe zones. Smoke is the greatest cause of loss of life during the fire. To block the flow of smoke, the airflow must be expelled uniformly without eccentricity from the slits in the air curtain nozzle installed on the upper part of the opening. In order to accomplish this, factors such as air inflow volume, shape of the internal slits, and thickness of the external slits were considered as variables in this study, and a numerical analysis was performed under various conditions. This led to the selection of a final shape which led to the finalization of a design shape. The final shape was manufactured as a prototype and the results were compared and verified with the results of the numerical analysis. The relative error of the numerical analysis results was less than 1%, and the average speed of all the slits was tested, exhibiting a highly consistent tendency.

• Journal of Hydrogen and New Energy
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• v.30 no.3
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• pp.243-250
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• 2019

In this study, to ensure the safety of the packaged hydrogen refueling system, the improvement plan was derived by using 3-dimensional CFD program (FLACS). We also confirmed the effectiveness of risk reduction and the suitability of safety standard. By ventilation performance evaluation according to the position of the vent, it demonstrated that the vent should be installed at the ceiling to safely ventilate without stagnation of the leaked gas. In case of ventilation system according to KGS standard, risk situation could be resolved after about 5 minutes in the worst leaked condition. The result showed that jet fire and explosion inside the packaged system could affect the surrounding facilities. This proves that the standard for installing flame detectors, emergency shut down system and protection wall is appropriate.