• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.376-377
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• 2011

최근 Mg, Mg-Al합금, Al은 전자제품의 케이스, 차량의 휠 등의 신소재로서 활용성이 높아 사회적 수요가 급격히 늘고 있다. 이러한 수요 증가와 함께 관련 사업장에서는 취급 과정에서 폭발사고 위험성이 높아지고 있는데, 2010년도에는 국내 사업장에서 금속 분진에 의한 폭발사고가 4건이 발생하여 인명 및 재산피해가 발생하였다. Mg-Al합금의 폭발사고로 사망 1명과 부상 2명이 발생하였으며, Al분진의 폭발사고는 3건이 발생하여 사망 2명과 부상 3명의 인명피해로 이어졌다. 사고조사를 통하여 사업장에서의 금속분진에 대한 위험인식이 매우 낮은 것이 유사 사고가 반복되고 있는 가장 큰 이유로 알려지고 있는데, 이는 금속분진에 대한 부족한 안전기술정보와 밀접한 관련이 있다. 본 연구에서는 Mg, Mg-Al합금, Al등을 취급하는 관련 사업장에서 폭발사고 예방대책을 위하여 활용할 수 있는 폭발특성에 관한 안전기술정보 제공을 목적으로 하고 있다. 보다 구체적으로는 사고 다발 금속분진에 대한 위험성 이해에 도움을 될 수 있도록 동일 입경분포 조건에서의 위험성을 정량적으로 평가하였으며, 이를 위하여 각 금속분진의 동일 입경 조건에서 최대폭발압력, 폭발하한계 등의 폭발위험성 데이터를 실험적으로 조사 하였다. 조사한 시료는 평균입경 200 mesh의 Al, Mg, Mg-Al(60:40 wt%)로서 입도분석기(Beckman Coulter LSI 3320)를 사용하여 측정한 결과 평균입경은 약 $155{\mu}m$로 나타났다. Al분진의 농도변화에 따른 폭발압력을 조사한 결과, 최대폭발압력(Pmax)은 7.9 bar였으며 최대폭발압력상승속도 (dt/dP)max는 농도 $1500[g/m^3]$에서 322 [bar/s]로 최대가 되었으며 폭발 하한계(LEL)는 $70[g/m^3]$가 얻어졌다. 반면에 순수한 Mg의 LEL은 $30[g/m^3]$였으며 Pmax는 6.4 bar, (dP/dt)max는 100 [bar/s]가 얻어졌다. 이러한 결과로부터 LEL이 낮은 Mg는 Al보다 연소성이 큰 것으로 나타났으며, Al은 화염을 유지하는데 필요한 최저 열분해 가스농도를 확보하는데 Mg보다도 고농도의 분진이 필요함을 알 수 있었다. 또한 Mg-Al(60:40 wt%)의 LEL은 $50g/m^3$이었으며 Pmax는 9.4 bar, (dP/dt)max는 472 [bar/s]가 얻어졌다. 이러한 결과로부터 Mg-Al(60:40 wt%)합금의 연소성을 살펴보면 착화하기 쉬운 정도는 Mg와 Al의 성분비에 의해 변화하지만 Mg와 Al의 중간 정도로 나타나는 반면, Pmax는 Mg 또는 Al의 단독 물질 성분보다도 매우 큰 것을 알 수 있었다. 본 연구를 통하여 단일 성분의 Mg와 Al보다도 Mg와 Al이 일정 비율로 구성된 Mg-Al합금의 경우가 화재폭발 위험성이 증가한다는 사실을 알 수 있었으며, 이와 같은 폭발위험특성 자료를 활용하여 분진의 보관, 취급, 폐기 등의 지속적 관리가 필요하며 사업장 특성에 적합한 안전대책을 통한 사고예방대책이 요구된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.5
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• pp.359-370
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• 2021

Duct slabs, which are used to build ventilation facilities in underground spaces with transverse ventilation system, need to secure fire resistance according to longitudinal and heavy vehicle traffic of tunnels. This study measured the temperature change at the construction joint of the precast fireproof duct slab which integrates fire resistance material and duct slab under the RWS fire scenario. As a result, it was confirmed that if there is no reinforcement of the construction joint, damage will occur in concrete inside the construction joint, leading to damage to the fireproofing layer. On the other hand, when one side of the construction joint was reinforced with fireproofing materials, it showed more than three times the fire resistance performance compared to when there was no reinforcement. At this time, cross-sectional losses of concrete and fireproofing layer were shown in blocks without reinforcement, but no damage was seen in the reinforced blocks.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.201-210
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• 2019

Recently, due to the efforts to mitigate traffic congestion and expansion of space efficiency, the construction of underground roads has been increased in big-scale cities. Since tunnels in the city have a higher chance for a fire leading to a great tragedy during a severe traffic jam than mountain tunnels, it is highly likely that it will be constructed as a tunnel, having a small cross section, for small vehicles. However, if they are constructed as such small-vehicle tunnels, it would be possible to reduce the design fire intensity while the concentration of harmful gases would increase due to a reduction in the small cross sectional area, led by a decrease in the tunnel height. In this study, behaviors of fire smoke by the installation interval and format of large-scale exhaust-gas ports were examined and compared in the analysis of temperatures and CO concentrations of a tunnel and its results were as the following. Although there were no significant differences in the smoke spreading distance between installation intervals, but in this study, 100 m was found to be the most effective installation interval. The smoke exhaustion performance was found to be excellent in the order of $4m{\times}3m$, $6m{\times}2m$, and $3m{\times}2m$ (2 lane) of the smoke spreading distance. Although there was no significant difference in the smoke spreading distance between formats of large-scale exhaust-gas ports, it was found that the smoke spreading distance was larger than other cases when it was $3m{\times}2m$ in the fire growing process. The analysis of smoke spreading distances by the aspect ratio showed that a smoke spreading distance was shorted when its the smoke spreading distance was found to be shorter when its traverse distance was relatively longer than its longitudinal distance.

• Fire Science and Engineering
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• v.24 no.2
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• pp.38-43
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• 2010

The purpose of this study is to secure the basis for judgment on the cause of an accident by analyzing the melting characteristics of a blade type fuse used for vehicles due to overload. In order to increase the reliability of the test, it was conducted by connecting the electrical system with conditions similar to those of an actual vehicle to apply the load. Carbonization pattern experiment of fuse by outside flame applied Korean Standard (KS). The fuse melted by the overcurrent showed a smooth cross-section while the test terminals, clear plastic body, etc., burnt out by the external flame was badly deformed. When 185% of the rated current (27.8A) was applied to a cable of 15A rated current onto which an over-capacity fuse (20A) was installed, the fuse melting time was 217 seconds. In addition, when a load current of 28.8[A] (139%) was applied, the fuse's test terminal and terminal blade were not burnt out although foam was observed on some parts of the plastic body. When a load capacity of 28.2[A] (141%) was applied to a cable of 15A rated current onto which an over-capacity fuse (30A) was installed, the fuse melting time was approximately 10 seconds. When a load current of 35.8[A] (119%) was applied, the fuse's test terminal and terminal blade were not burnt out, although some parts of the plastic body was swelled. However, it was observed that the switch terminal melted if approximately six minutes lapsed under such conditions. When a load capacity of 39.4[A] (131%) was applied to a cable of 15A rated current onto which an over-capacity fuse (30A) was installed, the fuse melted in approximately 69 seconds, and the test terminal and terminal blade were not burnt.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.15-29
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• 2005

Truck Shipment Safety Information, which is a part of the development of NERIS is divided into Optimal Route Guidance System and Emergency Response System. This research is for establishing an advance warning system, which aims for preventing damages(fire, explosion, gas-escape etc.) and detecting incidents that are able to happen during transporting hazardous materials in advance through monitoring the position of moving vehicles and the state of hazardous materials in real-time. This research is peformed to confirm the practical possibility of application of the advance warning system that monitors whether the hazardous materials transport vehicles move the allowed routes, finds the time and the location of incidents of the vehicles promptly and develops the emergency system that is able to respond to the incidents as well by using the technologies of CPS, CDMA and CIS with testing the ability of performance. As the results of the test, communication accuracies are 99$\%$ in freeway, 96$\%$ in arterial, 97$\%$ in hilly sections, 99$\%$ in normal sections, 96$\%$ in local sections, 99$\%$ in urban sections and 98$\%$ in tunnels. According to those results, the system has been recorded a high success rate of communication that enough to apply to the real site. However, the weak point appeared through the testing is that the system has a limitation of communication that is caused in the rural areas and certain areas where are fewer antennas that make communication possible between on-board unit and management server. Consequently, for the practical use of this system, it is essential to develop the exclusive en-board unit for the vehicles and find the method that supplements the receiving limitation of the GPS coordinates inside tunnels. Additionally, this system can be used to regulate illegal acts automatically such as illegal negligence of hazardous materials. And the system can be applied to the study about an application scheme as a guideline for transporting hazardous materials because there is no certain management system and act of toxic substances in Korea.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.618-622
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• 2017

Gasoline is a widely used product as a source for energy in homes, the automotive industry, and for industrial power generation, and it is also a product with a high risk of fire and explosion. In this study, to examine the risk for explosion for gasoline, PG, MG and RG, which are categorized according to octane number, were used as test specimens to measure their explosion limit according changes in oxygen concentration. The explosion limit for 21% oxygen concentration in air were confirmed to be 1.5~10.9%, 1.4~8.1%, and 1.3~7.6%, respectively, and the MOC for each of the test sample were confirmed to be 10.9%. The explosion limit measured in the test performed in this study confirmed between a 1.2%~7.6% wider explosion limit for the currently accepted MSDS for gasoline, and therefore it is considered that the results of this study can provide significant reference for preventing fires and explosions for process used gasoline.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.191-196
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• 2019

In the case of urban railway facilities, the power supply should be maintained for the safe movement of passengers in communication facilities, disaster prevention facilities and boarding area security because of the confusion when power supply is cut off due to the nature of public transportation. In addition, considering that the number of trains is running on the urban railway line, it is necessary to operate at least 30 minutes for the bus stop and at least 1 hour for the communication and disaster prevention facilities. Therefore, it is essential to supply emergency power source to maintain stable operation of induction lamp and smoke exhaust system because main power is cut off in order to prevent further spread due to fire in case of the history of urban railway section or vehicle fires. Recently, UPS(Uninterruptible Power Supply) function to prevent power outage in emergency, emergency power generation combined with ESS function which saves electricity at nighttime price time, A hybrid power storage system with a UPS function.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.451-462
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• 2011

The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume with scaled-model and simulation when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250 m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1157-1163
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• 2015

The purpose of this study is to reveal the effects of the number of users and their spatial distribution on the evacuation time in a road tunnel in the event of a fire. An agent-based evacuation model was implemented using Netlogo following the ODD protocol. The proposed model illustrates how the evacuation behavior of one can hinder others across different evacuation environments. Simulations show that evacuation time increases with the number of users when they are randomly located in a road tunnel.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2101-2108
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• 2008

Most of train fires which occur in usual cases do not grow up significantly on a large scale enough to bring about casualties and harmful damages. However, the consequence of some train fire accidents can be devastating disaster so that it would be even recorded in history in unusual cases. Accordingly, such a probability of fire disaster cannot be ignored in aspect of the railway safety assesment. A scale of injury and damage is very difficult to predict and analyze. Because it is depend on various factors, i.e. fire load, burning period, facilities, environment condition, and so on. Thus, a prediction of fire load could be understood as a one methodology to estimate railway safety assesment. The summation method which is one of them is used to evaluate the overall fire load by assuming that sum of heat release rate per unit area or mass of each composite material equals the total. However, since the train fire is classified into a compartment fire in under-ventilation condition. The summation method do not estimate a fire load completely. In this journal, Various methods to predict fire load are introduced and evaluated. Especially the fire simulation tool FDS(Fire Dynamics Simulator)which is based on the CFD(Computational Fluid Dynamics) is introduced, too. Through the FDS simulation, numerical analyses for the fire load and flame spread are performed. Then, these results of the simulation are validated through the comparison study with the experimental data. Then, limitations and approximations including in simulation process are discussed. The future direction of research is proposed.