• Fire Science and Engineering
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• v.23 no.3
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• pp.67-72
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• 2009

This paper is for response feature of fire detectors not only to analysis response feature of fire detector, but also to observe flame spread of inside-building and fire enlargement by using the row house which is supposed to be broken up. Many kinds of popular detectors such as heat type detector(differential type, fixed temperature type, Analogue type)and smoke type(light scattered type, Analogue type, single alarm type) were installed in the house in order to check for the change of temperature by installing of thermocouples. As a result, smoke detectors are better than heat detectors when it comes to making effective fire-detect system in the row house.

• Architectural research
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• v.10 no.1
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• pp.1-11
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• 2008

A Steel column with damaged spray-applied fire resistive material (SFRM) may exhibit reduced structural performance due to the effects of elevated temperature during fire events. Thus, the fire load behavior of steel columns with removed or reduced SFRM needs to be examined to predict the structural damage by fire. FEM analyses were performed for the flange thinning removal models in which the SFRM was reduced as a constant strip in thickness at the top flange of the column. The temperature results for all models obtained from the heat transfer analyses were included as an initial condition in the FEM structural analyses. In this study, the results of analysis show that even small remnants of SFRM led to an effective reduction of temperature at any given fire duration, and improved significantly the axial load capacity of a column as compared to the complete removal cases of SFRM.

• Journal of the Korean Society of Safety
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• v.24 no.4
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• pp.17-21
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• 2009

The fire whirl occurring in the urban and/or wildland fire is generated by the instabilities of atmosphere. The fire whirl is a rare phenomenon, but highly destructive because it has high inhalation and lift force. In this study, experimental study is performed with oriental oak leaves, for investigating of the fire whirl characteristics occurred in wildland fire. As a result of experiment, the circulation intensity increases as increasing of the induced air velocity, and then the fire whirl occurs. Also, the heat release rate and flame height increase 22% and 18% in highest circulation.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.39-46
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• 2020

This paper recognizes the risk of ignition of air fryer (machine that can cook fried dishes with hot air without oil) that is far exceeding the sales rate of microwave ovens, which is necessary to modern household kitchen, and identifies fire risk through the operation principle of the process of heat transfer, and the main structure of the machine. The fire test that we conducted is to observe the risk of ignition of the machine due to the damage to the safety system and the possibility of igniting oil paper along with food, to experiment with the possibility of ignition due to blockage of the exhaust due to obstacles, and accumulation of oil stains on the hot wire, and to present the method of fire control and devise countermeasures.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1157-1166
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• 2021

In this study, a numerical sensitivity analysis was performed to determine the fire suppression time for a large number of water mist nozzles in a large fire compartment. Fire simulations were performed using FDS (Fire dynamics simulator) 6.5.2 under the same condition as the test scenario 5 of the International Maritime Organization (IMO) 1165 test protocol. The sensitivities of input parameters including cell size, extinguishing coefficient (EC), droplets per second (DPS), and peak heat release rate (HRR) of fuel were investigated in terms of the normalized HRR and temperature distribution in the compartment. A new method of determining the fire suppression time using FDS simulation was developed, based on the concept of the cut-off time by cut-off value (COV) of the heat release rate per unit volume (HRRPUV) and the cooling time by the HRR cooling time criteria value (CTCV). In addition, a method was developed to determine the average EC value for the simulation input, using the cooling time and cut-off time.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.59-65
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• 2000

The purpose of this study is to investigate the details of unsteady heat transfer in a heated fire door. This investigation is carried out numerically for two dimensional fire door which is composed of normal plasterboard and mild steel including air layer or heat shield. It is shown from the results that the recirculation occurs at the inner part of fire wall due to gravity force by temperature difference. The case I gives better adiabatic effect than the case II because temperature around the fire wall reachs at $230.96^{\circ}C$ in the case I and reachs at $450.37^{\circ}C$ in the case II.

• Fire Science and Engineering
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• v.26 no.1
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• pp.74-79
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• 2012

This study is described for development of the stand-alone smoke and heat detector (SASHD) according to the revised in 2011 type approval and performance inspection code for detector. The main improvement of the revised regulation is source. CMOS microcontroller with nano watt technology is use for development of the workable SASHD over 10 years. The low-power SASHD is developed by using the power-saving sleep mode of microcontroller, by making the low-power source voltage checker, heat detector and smoke detector. The stand-alone detector is developed by smoke and heat detector type for reduce false fire alarm. User can choose type of work between the heat detection mode and smoke & heat detection mode. The SASHD can communicate with each them using RS-485 communication supported from microcontroller. So, this study can develop the SASHD that is able to alarm more wide area when fire occurs and reduce a flash fire alarm.

• Fire Science and Engineering
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• v.33 no.5
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• pp.55-60
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• 2019

The occurrence of fire in rack-type warehouses may either lead to the warehouses getting entirely burned up or collapsing. This can be attrubuted to the high height of rack-type warehouses, in which combustibles are generally vertically stacked. These characteristics make it difficult to detect a fire early; because detectors are installed on the ceiling, these fires cannot be extinguished at an early stage. In this study, the flow of heat and smoke generated by a fire in a rack-type warehouse was analyzed using a fire dynamic simulator. Through this analysis, the optimal installation conditions of fire detectors for the early detection of fire in rack-type warehouses were confirmed. The analysis results confirmed that complex detection of heat and smoke is required for the early detection of fire in rack type warehouses. Furthermore, it was found that fixed temperature detectors are not suitable for these warehouses, resulting in the need to install heat-smoke hybrid detectors at every three rack levels.

• Coupled systems mechanics
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• v.9 no.2
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• pp.163-182
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• 2020

Coupled thermo-mechanical analysis of reinforced concrete slab at elevated temperatures from a fire accounting for nonlinear thermal parameters is carried out. The main focus of the paper is put on a one-way continuous reinforced concrete slab exposed to fire from the single (bottom) side as the most typical working condition under fire loading. Although contemporary techniques alongside the fire protection measures are in constant development, in most cases it is not possible to avoid the material deterioration particularly nearby the exposed surface from a fire. Thereby the structural fire resistance of reinforced concrete slabs is mostly influenced by a relative distance between reinforcement and the exposed surface. A parametric study with variable concrete cover ranging from 15 mm to 35 mm is performed. As the first part of a one-way coupled thermo-mechanical analysis, transient nonlinear heat transfer analysis is performed by applying the net heat flux on the exposed surface. The solution of proposed heat analysis is obtained at certain time steps of interest by α-method using the explicit Euler time-integration scheme. Spatial discretization is done by the finite element method using a 1D 2-noded truss element with the temperature nodal values as unknowns. The obtained results in terms of temperature field inside the element are compared with available numerical and experimental results. A high level of agreement can be observed, implying the proposed model capable of describing the temperature field during a fire. Accompanying thermal analysis, mechanical analysis is performed in two ways. Firstly, using the guidelines given in Eurocode 2 - Part 1-2 resulting in the fire resistance rating for the aforementioned concrete cover values. The second way is a fully numerical coupled analysis carried out in general-purpose finite element software DIANA FEA. Both approaches indicate structural fire behavior similar to those observed in large-scale fire tests.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.2
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• pp.137-145
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• 2023

This paper presents the effects of fire-resistant materials on the temperature and vertical deflection of a composite beam exposed to fire through nonlinear thermo-mechanical analysis. The fire was modeled using the standard fire curve proposed in American Society for Testing and Materials (ASTM) E119. Fire-resistant materials were modeled by reducing the heat transfer coefficient from the air layer to the beam. The temperature and vertical deflection of the uncoated composite beam were measured using a laboratory fire test, and the results of the structural fire analysis were verified through comparison with experimental results. By introducing the fire-resistance effect, the reduction in the temperature and deflection of the beam for the ASTM E119 standard fire can be reasonably estimated. Based on a case study of the heat transfer coefficient, the fire-resistant effect on the thermo-mechanical response of a composite beam in the event of a fire is presented.