• Applied Chemistry for Engineering
• /
• v.29 no.6
• /
• pp.670-676
• /
• 2018

Experiments on combustion gases generation of untreated cypress specimens or treated with boric acid, ammonium pentaborate, and boric acid/ammonium pentaborate additive were carried out. Test specimens were painted three times with 15 wt% boron compound aqueous solutions. After drying, the generation of combustion gas was analyzed using a cone calorimeter (ISO 5660-1). As a result, comparing to untreated specimen, the smoke performance index (SPI) of the specimens treated with the boron compound increased by 1.37 to 2.68 times and the smoke growth index (SGI) decreased by 29.4 to 52.9%. The smoke intensity (SI) of the specimens treated with boron compounds is expected to be 1.16 to 3.92 times lower than that of untreated specimens, resulting in lower smoke and fire hazards. Also, the maximum carbon monoxide ($CO_{peak}$) concentration of specimens treated with boron compounds was 12.7 to 30.9% lower than that of untreated specimens. However, it was measured to produce fatal toxicities from 1.52 to 1.92 times higher than that of permissible exposure limits (PEL) by Occupational Safety and Health Administration (OSHA). The boron compounds played a role in reducing carbon monoxide, but it did not meet the expectation of reduction effect because of the high concentration of carbon monoxide in cypress itself.

• Fire Science and Engineering
• /
• v.21 no.2 s.66
• /
• pp.30-35
• /
• 2007

The flame retardancies by the addition of metal powder and flame retardant were evaluated to present as the fundamental data to decrease the fire hazard of polymers and life losses by suffocation and poisoning. For this study, the experiments of flame retardancy were conducted as follows : weight loss rate using thermogravimetric analysis, the measurement of the limiting oxygen index(LOI) and char yield. And smoke mass concentration and CO yield were measured. Acrylonitrile butadiene styrene containing metal powder and flame retardant reduced weight loss rate and increased LOI and char yield with the decreased smoke mass concentration and CO yield. It was found that the most effective complex was tricresyl phosphate-Mo complex.

• Environmental Analysis Health and Toxicology
• /
• v.24 no.1
• /
• pp.53-61
• /
• 2009

사람 기관지상피세포주인 BEAS-2B에 담배연기농축액(CSC)을 처리하여 유도된 1198 세포주는 대조군 세포주인 1799에 비해 현저하게 낮은 glutathione 농도와 낮은 glutamate-cysteine ligase(GCL), glutathione peroxidase(GPx), glucose-6-phosphate dehydrogenase(G6PD), catalase 효소활성을 보였다. 두 세포주를 포도당 존재 하에서 4시간 hypoxia 처리 후 reoxygenation 하면서 시간에 따른 세포의 항산화계 활성을 측정한 결과, 1799 세포주에서는 의미 있는 변화가 관찰되지 않은 반면, 1198 세포주에서는 hypoxia 처리에 의해 glutathione의 농도 및 GSH/GSSG 비와 G6PD 활성이 감소되었고, reoxygenation 기에는 GPx, glutathione reductase(GRd), G6PD, superoxide dismutase 활성이 감소되었다. 그러나 reoxygenation 2시간 이후에는 GRd와 G6PD 활성의 회복이 관찰되었으며, 그 결과 GSH/GSSG 비율이 회복되었다. 이 실험 결과는 CSC가 능력을 현저히 저하시킬 수 있음을 보여준다. Glutathione은 hypoxia-reoxygenation에 의한 산화적 스트레스 하에서 항산화제로서의 역할뿐 아니라, 세포 내 GSH/GSSG 비의 변화를 통해 산화적 스트레스에 대한 항산화계의 적응 반응 여부를 결정하는 중요한 인자로 작용할 것으로 보여진다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.483-490
• /
• 2019

Assessing the effect of forest fires and measuring the gas concentration around a fire has received little attention. Therefore, the concentrations of various gases in areas surrounding a fire need to be measured by the development of a suitable device. Unlike conventional portable devices, the AQS (Air Quality System) proposed in this paper is a portable instrument that measures five types of gases simultaneously, including CO, CO2, NOx, VOCs, and NH3, and has high durability through sensor protection algorithms. A PC-based program with an AQS connection was developed to monitor the real-time changes in the gas concentration. The reliability of the developed device was proven through a comparison of the results with other commercial gas analyzers. Measurements of the concentration due to indoor and outdoor fires were performed around a fire area to review the applicability and the predicted results were obtained.

• Fire Science and Engineering
• /
• v.22 no.3
• /
• pp.300-304
• /
• 2008

The flame retardancy was evaluated to present as the fundamental data to decrease the fire hazard of polymers and life losses according to the addition of clay. The combustion characteristics were examined to increase flame retardancy and to decrease smoke yield of epoxy by the addition of clay such as montmorillonite in this study. For this study, the experiments of flame retardancy were conducted the measurement of the limiting oxygen index (LOI), char yield, and smoke density. As MMT concentration increased, LOI and char yield increased. This result showed that the flame retardancy of epoxy/MMT composite was improved. On the contrary, smoke density increased.

• Fire Science and Engineering
• /
• v.22 no.3
• /
• pp.201-207
• /
• 2008

In this study, three Dimensional CFD simulations were carried out to investigate the effective smoke extraction system in bi-directional road tunnel fires using FLUENT. Characteristics of transverse system with big size extraction port or with uniform extraction port, semi-transverse system and longitudinal system for smoke extraction system were analyzed. Air velocity, port size, and operating method were used with variable. Distributions of smoke spread, CO was analyzed. As a result, the transverse ventilation system with big size port was found to be more effective than the uniform ports for bi-directional road tunnel.

• Tunnel and Underground Space
• /
• v.24 no.4
• /
• pp.308-315
• /
• 2014

In this study, reduced scale experiments were carried out to evaluate the effect of external wind in a road tunnel fire. Experiments were conducted in a $1.1m{\times}0.5m{\times}50.4m$ tunnel. 4.5 litter gasoline was used as a fuel. Temperature, oxygen and carbon monoxide concentration were measured. Smoke reaching time to the tunnel exit was affected by the external wind. When a fire was fully developed, wind effect is reduced compared with the early stage of a fire. CO concentration was reached at more than 1,500 ppm.

• Fire Science and Engineering
• /
• v.19 no.1 s.57
• /
• pp.80-86
• /
• 2005

In this study effects of the natural wind and the forced smoke ejection by operating the exhaust fan are studied numerically to examine the flow characteristics of the smoke and heat generated from a fire on the platform of an underground subway station. Three different situations, including 1) the case with no natural wind and no exhaust fan operation, 2) the case with natural wind but no exhaust fan operation and 3) the case with no natural wind but exhaust fan operation, are considered for the numerical analyses. The numerical results show that the natural wind causes a rapid spread of the fire along the tunnel resulting in rapid spread of the smoke and heat over the platform which affects the escape. The operation of the exhaust fan also results in the rapid spread of smoke and heat over the platform, but the time required for reaching the safe escaping height of the smoke layer with the exhaust fan operation is much longer than that without the exhaust fan operation. The numerical results also show that the required capacity of the exhaust fan becomes larger when the effect of the natural wind is included.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2015.07a
• /
• pp.67-68
• /
• 2015

선상에서의 승객들의 보행속도, 운항 중 피난특성, 피난시 연기농도가 미치는 영향 등 선박에서의 피난상황을 해석하는 데 필요한 몇몇 연구가 수행된 바 있다. 그러나 정전 조건에서 승선자의 피난성능에 관한 연구는 미비하여, 이론적 혹은 실험적 연구가 수행된 사례를 찾아보기 어려운 상황이다. 이에 이 연구에서는 선박에서의 인적안전피난해석 프로그램인 Maritime EXODUS를 활용하여 승선자의 분포특성을 고려한 세 가지 시나리오에 대한 피난시간을 예측 비교하였다. 이 연구에서는 선행된 운항훈련선의 선내 정전조건보행실험에서 취득한 피실험자 보행속도 결과를 반영하였다.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2150-2151
• /
• 2011

본 논문에서는 분전반 내에서 전기화재가 발생할 경우 화염전파와 연기화염의 전파 특성, 연기의 진행방향, CO가스농도의 위치, 내부 온도분포 등을 통해 전기화재의 사전예방과 화재대응 운영시스템 등에 활용하고자 수치해석 등의 시뮬레이션을 수행하였다. 시뮬레이션 결과 화재가 발생한 경우 온도보다 CO가스가 분전반 상부에 빠르게 전달됨을 확인하였고, 시뮬레이션 결과는 분전반 화재예방을 위한 센서의 선택과 설치위치 선정 등에 활용될 것이다.