• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.454-465
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• 2020

Fire simulations were performed using the Fire Dynamics Simulator (FDS) software to examine the vent flow and temperature in the engine room of a small ship. A diesel fire with a heat release rate of 10 kW was targeted, and the effects of the ceiling duct location, side vent existence and nonexistence, and side vent size were investigated. The existence or nonexistence of the side vent and its size considerably affected the smoke behavior, mass flow rate through the vent, and temperature. When the side vent was not installed or was small, the smoke layer reached the floor in the engine room. In addition, as the side vent size increased, the mass flow rate through the vent increased with decreasing temperature value. However, the effects of the ceiling duct location on the smoke behavior, mass flow rate through the vent, and temperature seemed to be relatively minor compared to those of the side vent size. Therefore, to improve the fire safety of the engine room in a small ship, the side vent size is considered to be a more important design factor than the ceiling duct location.

• Fire Protection Technology
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• s.15
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• pp.28-38
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• 1993

This report is explain the nature of smoke and the principle of smoke detection. The object of this research is to understand the hazard of smoke and select the optimum smoke detectors, according to the types of smoke and the particle size of smoke produced by fire

• Fire Science and Engineering
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• v.30 no.1
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• pp.12-16
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• 2016

Propane fires of 1000 to 3000 kW in the ISO 9705 fire room were simulated using FDS to study the problem of decreasing temperature with increasing fire size. A criterion is proposed for under-ventilated fires. The computed temperature at 2000 kW and above was lower than that at 1500 kW. The heat release rate was limited by a lack of oxygen in the simulation. It was found that the heat release rate can therefore be a criterion for under-ventilated fires in simulations. Fires of 1700 kW and above in the ISO 9705 fire room are predicted to be under-ventilated.

• Journal of ILASS-Korea
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• v.11 no.4
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• pp.251-265
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• 2006

To prevent the ozonosphere from being destroyed by Halon, it is an urgent task to find out Halon replacement. As one of the replacements water mist have showed broad applications by its advantages: little pollution to environment (not destroying the ozone layer or bring green house effect), extinguishing fire quickly, consuming a small quantity of water and having little damage to the protected objects. The methods of generating water mist strongly influence fire suppression effectiveness, which determine the cone angle, drop size distribution, flux uniformity, and momentum of the generating spray. The traditional water mist nozzle included pressure jet nozzles, impingement nozzles and twin-fluid nozzles. All of them have more or less disadvantages for fire suppression. Therefore, many research institutes and corporations are taking up with innovations in mist generation. This article provided some recent studies in State Key Laboratory of Fire Science (SKLFS) of University of Science and Technology of China. SKLFS have investigated new methods of generating water mist (i.e. effervescent atomization and ultrasonic atomization). and self developed a series of nozzles and developed advanced DPIVS (Digital Particle Image Velocimetry and Sizing) technique. Characteristics of water mist (the distribution of droplet sizes, flux density, spray dynamics and cone angle) produced by these nozzles were measured under different conditions (work pressure, nozzle geometry, etc.) using LDV/APV and DPTVS systems. A series of experiments were performed to study the fire suppression effectiveness in different fire scenario (different kindsof the fuel, fire size and ventilation conditions). The fire extinguishing mechanisms of water mist was also discussed.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.87-93
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• 2021

Modern society shows rapid growth that is different from that of the development of existing technologies. The development of these technologies has led to the tendency of buildings to become dense, large and advancing. Regarding fire hazards, the possibility of large-scale fires causing fatal damage, due to the rapid spread of fire, increases. Therefore, for this reason, fire defense, i.e. detection and fire extinguishing facilities, in buildings are essential and well applied. But there are always limitations to that. Based on this reason, we would like to suggest the introduction of a new concept of a fire safety system. The method presented here is not only to use a single system for fire detection and fire extinguishing systems but to jointly use it in the environment and energy management fields within the building. However, an important step is required before introducing a system of these technologies. The fire extinguishing method proposed by this system is a method of extinguishing by blocking oxygen flowing into the space where the fire occurred. However, a sufficient basis is needed for this system to be applied in practice. Therefore, in this study, we intend to conduct a preliminary experiment to introduce the new concept of fire detection and extinguishing. The experiment used ethanol with a relatively simple combustion reaction and a high possibility of complete combustion. As a result, it was confirmed how the internal values changed during a fire using ethanol. Resultingly, we obtained the internal oxygen concentration and internal environmental changes according to the initial flame size. Lastly, the data accumulated in this study can be used as data for application in an automatic fire extinguishing system.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1773-1780
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• 2008

When the fire occur in the deeply underground subway station, the difficulties of passenger evacuation are expected because of many stairs to the exit. In this study, SOONGSIL-University station (7 line, 47m depth) is the one of the deepest subway stations of the each line in the Seoul metro. The numerical computational-simulation was performed for the fire driven flow in the subway station. Hot and smoke flow was analyzed from the simulation results. The proper plan of evacuation against fire was considered through the results. The fire driven flow was simulated using FDS code in which LES method was applied. The Heat Release Rate was 10MW and the ultrafast model was applied for the growing model of the fire source. The proper mesh size was determined from the characteristic length of fire size. The parallel computational method was employed to compute the flow and heat eqn's in the meshes, which are about 10,000,000, with 6cpu of the linux clustering machine.

• Journal of ILASS-Korea
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• v.20 no.3
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• pp.175-180
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• 2015

A series of sprinkler discharging tests was conducted to measure the droplet size and its distribution of residential fire sprinkler heads. Droplet sizes in sprinkler spray were measured using a laser diffraction method for the flush, circular and pendent type sprinkler head. In this study, the $D_{v,50}$ of the flush type sprinkler heads were ranged between $530{\sim}1040{\mu}m$ and those of circular and pendent type were $988{\mu}m$ and $916{\mu}m$, respectively. The measured cumulative volume distributions were followed by a combination of the log-normal and Rosin-Rammler distribution which is widely used in the computational fire analysis and the parameters of distribution function were obtained from the best fit line through the measured data.

• Fire Science and Engineering
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• v.33 no.6
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• pp.1-8
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• 2019

In this study, the effects of the characteristics of droplets of water spray on suppression of fire were analyzed numerically using fire dynamics simulator (FDS) 6.5.2. Additionally, the fire suppression characteristics by the water spray nozzle, including the extinguishing coefficient (EC), droplet size distribution function (SDF), median volumetric diameter (MVD), and droplets per second (DPS), were evaluated in terms of the decreasing normalized heat release rate (HRR) curve and cooling time. It was observed that with increase in the EC, the normalized HRR curve decreased rapidly, and the changing MVD affected the suppression of fire. In case of mono-disperse, the normalized HRR curve decreased slowly with the increase in DPS. On the contrary, in case of multi-disperse, the normalized HRR curve decreased rapidly even with a small increase in DPS.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.415-419
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• 2013

To mitigate forest fire damage, it is needed to concentrate suppression resources on the fire having a high probability to become large in the initial stage. The objective of this study is to develop the large fire judgement model which can estimate large fire possibility index between the fire size and the related factors such as weather, terrain, and fuel. The results of logistic regression equation indicated that temperature, wind speed, continuous drought days, slope variance, forest area were related to the large fire possibility positively but elevation has negative relationship. This model may help decision-making about size of suppression resources, local residents evacuation and suppression priority.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.16-21
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• 2017

The sprinkler system is a basic fire extinguishing system that uses water as an extinguishing agent. In order to evaluate the fire extinguishing performance of the sprinkler system, information such as the discharge angle, discharge speed, discharge pressure, flow rate, and water droplet size of the installed head are required. However, there is a lack of research on droplets size compared to other requirements. In this study, to evaluate the extinguishing characteristics of sprinkler system, the droplet size distribution was measured for various types of sprinkler heads actually used. The size of the droplet was measured using laser diffraction method. The 50% cumulative volume distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the Rosin-Rammler index value are presented. As a result of the fire simulation with FDS, it was confirmed that the performance difference occurs according to the water droplet size distribution even when the same amount of water is used. Therefore, the extinguishing performance of the sprinkler system should be evaluated considering the droplet size distribution according to the sprinkler head type.