• Journal of the Korean Society of Safety
• /
• v.31 no.4
• /
• pp.55-63
• /
• 2016

A dust explosion is a phenomenon of strong blast wave propagation involving destruction which results from dust pyrolysis and rapid oxidation in a confined space. There has been some research done to find individual explosion characteristics and common physical laws for various dust types. However, there has been insufficient number of studies related to the heat of combustion of materials and the oxygen consumption energy about materials in respect of dust explosion characteristics. The present study focuses on the relationship between dust explosion characteristics of wood dust samples and oxygen consumption energy. Since it is difficult to estimate the weight of suspended dust participating in explosions in dust explosion and mixtures are in fuel-rich conditions concentrations with equivalent ratios exceeding 1, methods for estimating explosion overpressure by applying oxygen consumption energy based on unit volume air at standard atmospheric pressure and temperature are proposed. In this study an oxygen consumption energy model for dust explosion is developed, and by applying this model to TNT equivalent model, initial explosion efficiency was calculated by comparing the results of standardized dust explosion experiments.

• Korean Chemical Engineering Research
• /
• v.54 no.3
• /
• pp.367-373
• /
• 2016

Many of plastic powders handled in industry are combustible and have the hazard of dust fire and explosion accidents. However poor information about the safe handling has been presented in the production works. The aim of this research is investigated experimentally on explosive characteristics of various plastic powders used in industry and to provide additional data with safety informations. The explosibility parameters investigated using standard dust explosibility test equipment of Siwek 20-L explosion chamber. As the results, the dust explosion index ($K_{st}$) of ABS ($209.8{\mu}m$), PE ($81.8{\mu}m$), PBT ($21.3{\mu}m$), MBS ($26.7{\mu}m$) and PMMA ($14.3{\mu}m$) are 62.4, 59.4, 70.3, 303 and 203.6[$bar{\cdot}m/s$], respectively. And flame propagation velocity during plastic dust explosions for prediction of explosive damage was estimated using a flame propagation model based on the time to peak pressure and flame arrival time in dust explosion pressure assuming the constant burning velocity.

• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.154-154
• /
• 2011

최근 세계 각지에서 발생하는 대규모 터널 화재사고는 많은 사상자를 동반하고 이에 따른 경제적, 사회적 손실 또한 방대하게 진행되는 실정이다. 터널 구조물의 화재 특성상 외부에 쉽게 노출되지 않기 때문에 화재 발생 시 화재에 노출된 표층이 박리되거나 비산해서 단면결손이 생기는 폭렬 현상(explosive spalling)이 발생하게 된다. 이러한 폭렬 현상은 붕괴와 같은 대형 참사로 이어질 가능성이 크다. 따라서 본 연구에서는 터널 내 화재 발생 시 콘크리트 구조물의 폭렬에 의한 붕괴를 예방하기 위하여 이액형 상온경화 실리콘 고무와 인체에 무해한 친환경 첨가제인 펄라이트를 일정한 혼합비(5wt%, 10wt%, 15wt%, 20wt%)로 혼합하여 고성능 난연 복합체를 제조하고, 열적 특성과 난연 특성을 연구를 진행하였다. 열적 특성에 관한 시험으로 TGA를 측정하였으며, 난연 특성에 관한 시험으로는 화염 시험, 내화로 시험, 탄화로 시험을 진행하였다. 우선 TGA 시험은 $20^{\circ}C/min$ 승온 속도로 $800^{\circ}C$까지 실험을 하였고, 화염 시험은 제작한 시편과 gas torch($1200^{\circ}C$)의 화염 거리를 약 10cm로 하여 약 1시간 동안 시험을 하였다. 내화로 시험은 내화로 장치를 이용하여 RABT curve(5분만에 $1200^{\circ}C$도달 후 한 시간 동안 유지 후 냉각, 총 시험 시간 180분) 조건을 만족하는 환경에서 제작한 시편을 콘크리트에 부착하여 콘크리트의 내부온도를 측정하였다. 탄화로 시험은 탄화로 장치를 이용하여 $2^{\circ}C/min$ 승온속도로 $900^{\circ}C$까지 실험을 하여 외부 형태 변화를 관찰하였다. 각각의 시험 결과 TGA 열분해 결과 순수한 실리콘 고무보다 난연제인 펄라이트를 첨가했을 때 더 높은 온도에서 초기 분해 거동을 보였으며, 최종 잔류량은 80%를 보였고, 5 wt%의 펄라이트가 혼합된 시편의 최종 잔류량이 높은 것으로 보아 열분해에 가장 강한 조성임을 알 수 있었다. 화염 시험 결과 펄라이트가 혼합된 모든 시편에서 $300^{\circ}C$가 넘지 않은 결과를 보였다. 이는 제조된 복합체가 화염에 직접적으로 장시간 노출이 되어도 안전하다는 것을 알 수 있다. 내화로 및 탄화로 시험 결과 펄라이트가 15wt%와 20wt%가 첨가된 시편들보다 5wt%와 10wt% 첨가된 시편들이 고온에서 안정하다는 것을 보였다.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.10 no.2
• /
• pp.150-164
• /
• 2000

This study was conducted at occupational health laboratories in Seoul and Gyunggi district area from December, 1999 to January, 2000. The main purpose of this study was to survey the actual condition of safety and health by questionnaire and checklist and to assess the performance of fume hoods and the airborne exposures to chemicals in the laboratories. The chemicals in the cabinet were not classified by hazardous properties and the compressed gases were not stored safely. The prevalences of laboratories having first aid kits, fire extinguishers, and safety showers were found to be 18%, 55%, and 9%, respectively. Most laboratory workers were not educated for safety and health. Also, there was no performance evaluation for hazards and risks. The fume hoods in laboratories had not been annually inspected by checklist and the face velocity had been checked more than one time in the previous year for only 18% of them. Five percent of fume hoods had the face velocity more than 4.0 m/sec and 17% had no capture performance. Detected organic solvents were methylenechloride, acetone, ethylbenzene, isopropanol, xylene, methylisobutylketone, trichloroethylene, and toluene. The concentrations of organic solvents were much less than the occupational exposure limits proposed by the Ministry of Labor in Korea. This study showed that the actual condition of safety and health was not appropriate for laboratory workers. It is recommended that laboratory workers should be educated for the treatment and storage of hazardous chemicals and compressed gases to improve the working environment of the occupational safety and health laboratories.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.1
• /
• pp.166-175
• /
• 2017

Hazardous volcanic activity will continue to occur in the ring of fire, a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur. and, because of rising populations, development pressures, and expanding national and international air traffic over volcanic regions, risks to life and property through exposure to volcano hazards continue to increase. During an eruption, volcanic contamination can reach and exceed the cruising altitudes of turbine-powered aircraft, among others, within minutes and spread over vast geographical areas within a few days. Volcanic ash can affect the operation of aircraft at aerodromes. Volcanic ash deposition at an aerodrome, even in very small amounts, can result in the closure of the aerodrome until all the deposited ash has been removed. In this study, air traffic information framework is presented along with algorithms to define affected routes, waypoints and airports using GIS geometry analysis.

• Journal of Preventive Medicine and Public Health
• /
• v.35 no.1
• /
• pp.72-75
• /
• 2002

Objectives : To evaluate the health hazards in the underground storage facilities of ginger roots. Methods : The authors reviewed the emergency rescue records from the Seosan fire department over the period Jan 1, 1996 to Aug 31, 1999. The atmospheres in 3 different underground storage locations were analyzed for $O_2,\;CO_2,\;CO,\;H_2S\;and\;NH_4$. Results : From the emergency records, we were able to identify 20 individuals that had been exposed to occupational hazards in the underground storage facilities. Among these 20 cases, 13 were due to asphyxiation (resulting in f deaths) and 7 were due to falls. In the first atmospheric tests, peformed on Feb 25, 1998, the O2 level inside the underground storage facility, located about $5{\sim}6$ meters below the surface, was 20.6% and the $CO_2$ level was about 1,000 ppm. CO, $H_2S\;and\;NH_4$ were not detected. In the second tests on Jul 6, 1999, measurements of the $O_2$ level at 3 meters below the surface in two different storage locations were 15.3 and 15.1%. And the $O_2$ levels inside the storage facilities were 12.2 and 12.1%. The $CO_2$ level was above 5,000 ppm (beyond upper limits of measurement). CO, $H_2S\;and\;NH_4$ were not detected. Conclusions : We conclude that asphyxiation in the underground storage facilities for ginger roots was not due to the presence of toxic gases such as CO, $H_2S\;and\;NH_4$, but rather the exclusion of oxygen by carbon dioxide was responsible for causing casualties. For the development of a hazard free working environment, safety education as well as improvements in storage methods are needed.

• Journal of the Korean Institute of Gas
• /
• v.15 no.2
• /
• pp.82-87
• /
• 2011

Heat transfer oils are used in applications such as heating systems of chemical plant, refinery heat exchange systems, gas plant process, injection molding systems, and pulp and paper processing. These oils are extremely stable and resistance to thermal and oxidative degradation. In the event of a spill or accidental release of heat transfer oils, it can be ignite easily when there is an ignition source. This paper discusses the flammability and thermal stabilities of new and used oils. The flammability of the oils are assessed by measuring changes in flash point and auto ignition temperature. The thermal stability of oils are evaluated by the thermal screening unit ($TS^u$) and the differential scanning calorimeter (DSC). From the experimental results, it is suggested to give fire hazard characteristics to safe precautions for the proper use and treatment of heat transfer oils.

• Journal of the Korean Institute of Gas
• /
• v.18 no.4
• /
• pp.35-43
• /
• 2014

Usage of the inorganic floor finishing material can be advantageous to overcome some problems of traditional organic-based floor finishing material used for hazardous material storage facilities. A spark can be produced by physical impact between the flooring and the flooring disposal equipment while removing the existing flooring. In order to prevent a fire hazard, which may be caused the spark, it is feasible that a construction can be implemented without removing the existing flooring. Moreover, the top coating material containing an antistatic agent is effective to prevent secondary damage caused by static electricity after finishing the construction of the flooring. Therefore, the inorganic floor finishing material of the this study is expected to be beneficial for safety management and economical aspect for inspectors.

• Journal of the Korea Safety Management & Science
• /
• v.20 no.3
• /
• pp.27-36
• /
• 2018

The steel pipe manufacturing industry deals with facilities and materials. Especially thermal facilities are close to vapor cloud explosion (VCE) and may cause secondary damage to facilities because they deal with corrosive substances such as hydrofluoric acid, sulfuric acid and acid, fire, explosion, leakage etc. It is in danger. In this study, hazard identification method was conducted using HAZOP techniques and quantitative risk analysis was conducted using e-CA, a program that supports accident impact analysis. Equipment in the influence range of ERPG - 3 was determined to be a facility requiring replacement. It was decided that neutralization is necessary using slaked lime. Based on the cost of loss, We presented the proper replacement which is the timing of the dangerous facility. As a result, It was ideal to replace the facilities with 20 years of heat treatment facilities, one year of hydrofluoric acid storage tank, 20 years of sulfuric acid storage tank, and 5 years of hydrochloric acid storage tank.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.9
• /
• pp.774-781
• /
• 2018

In this investigation, a gas gun is proposed driven by carbon dioxide gas and installed on a quadcopter-type small unmanned drone for the purpose of cattle vaccination, and we developed a launcher and its connection unit. The system consists of a commercial drone, a gas gun, a solenoid valve, and the remote communication controller, etc. The velocity of launched projectile is measured, and the full system is finally validated through ground test and flight examination loaded for the real aircraft. The feasibility is checked if this technology is applicable to various disease abatement and hazard mitigation in the fields of agriculture and fire-fighting with the present research and development.