• 제목/요약/키워드: Leakage safety

검색결과 851건 처리시간 0.022초

A Study on Classification of Explosion Hazardous Area for Facilities using Lighter-than-Air Gases (공기보다 가벼운 가스 사용시설의 폭발위험장소 설정방안에 대한 연구)

  • Yim, Ji-Pyo;Chung, Chang-Bock
    • Journal of the Korean Society of Safety
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    • 제29권2호
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    • pp.24-30
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    • 2014
  • There have been controversies over whether explosion hazardous area(EHA) should be classified for facilities which use lighter-than-air gases such as city gas, hydrogen and ammonia. Two view points are confronting each other: an economic piont of view that these gases are lighter than air and disperse rapidly, hence do not form EHA upon release into the atmosphere, and a safety point of view that they are also inflammable gases, hence can form EHA although the extent is limited compared to heavy gases. But various standards such as KS, IEC, API, NFPA do not exclude light gases when classifying EHA and present examples of EHA for light gas facilities. This study calculates EHA using the hypothetical volume in the IEC code where the hole sizes required for the calculation were selected according to various nominal pipe sizes in such a way to conform to the EHA data in the API code and HSL. Then, 25 leakage scenarios were suggested for 5 different pipe sizes and 5 operating pressures that cover typical operating conditions of light gas facilities. The EHA for the minimum leakage scenario(25 mm pipe, 0.01MPa pressure) was found to correspond to a hypothetical volume larger than 0.1 $m^3$(medium-level ventilation). This confirms the validity of classifying EHA for facilities using lighter-than-air gases. Finally, a computer program called HACPL was developed for easy use by light gas facilities that classifies EHA according to operating pressures and pipe sizes.

A Study on the Threat Review to use Secure Smartphone Applications (안전한 스마트폰 앱 사용을 위한 위협 요소 검토 연구)

  • Choi, Heesik;Cho, Yanghyun
    • Journal of Korea Society of Digital Industry and Information Management
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    • 제16권1호
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    • pp.41-54
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    • 2020
  • In this paper, it will study various problems such as personal information infringement from when using various useful Apps in the Smartphone environment. It also researched the vulnerabilities Mobile Apps and the risks of personal information leakage when using Smartphone information to decrease threat and find solution. In the second chapter, it will check the existing Mobile App related Apps. In the third chapter, it will check the threats and major factors that caused by the leakage of personal information which related to the app. Then it will suggest solution and end with conclusion. This paper also looked at various problems that caused by illegal adverse effect from illegal personal information collection. Then it researched and made suggestion to make consideration on safety of personal information and privacy infringement that threat to personal information For safety of mobile banking, it proposed a safety method to separate and manage the code which has the core logic which required to run the App. For safety of direction App, when running the direction App, even if the information is collected, location information for unauthorized accessed will encrypt and store in DB, so that access to personal information is difficult. For delivery App environment, by using the national deliver order call center's representative phone to receive a telephone order then, the customer information is delivered to the branch office when it receive order and it will automatically delete information from the server when the delivery is completed by improving DB server of order. For the smart work app environment, the security solution operates automatically by separating and make independent private and work areas. Then it will suggest initialization for company's confidential business information and personal information to safe from danger even if loss.

A Study on Securing Safety of Evacuation through Smoke Control in Case of Fire at the Central Corridor Type Intelligent Buildings (중복도형 인텔리전트빌딩 화재시 연기제어를 통한 피난안전성 확보에 관한 연구)

  • Min, Se Hong;Lee, Jae Moon;Bae, Yeon Jun
    • Journal of the Korea Safety Management & Science
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    • 제17권2호
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    • pp.117-127
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    • 2015
  • This study investigated the smoke blocking and control systems for the safety of residents evacuation and for the prevention of smoke spread through the central corridor in the event of central corridor type of intelligent building fire. We offered additional ways of utilizing smoke ventilators and intake ventilation equipment and utilized CFD-based fire simulation program(FDS Ver.5.5.3) in order to analyze the effect. As a result, many differences in the smoke block effect, depending on the application of smoke ventilator and location of installation, was found. In addition, the result was found that larger effect was showed not in the case of application of smoke ventilator in central corridor only but application in fire room. The reason is that the smoke leakage is blocked primarily as air is flowed in the fire room through open door by operation of intake smoke ventilator in the public corridor and secondarily, the smoke leakage to the public corridor could be blocked as fire and smoke were released to the opened smoke ventilator continuously. Especially, the effect was maximized through complex interactions by applying smoke ventilator and intake ventilation equipment in corridor together rather than applying smoke ventilator and intake ventilation equipment independently. The proposed measure through this study shall be considered from architectural plan as one of ways for blocking from smoke spread to the central corridor in the central corridor type of intelligent building. In addition, flaws on regulation shall be established and supplemented.

Distribution of Ultraviolet Intensity and UV Leaking of Commercial UV Sterilizers Used in Restaurants (음식점에서 사용하는 자외선 살균소독기 내 자외선 강도 분포 및 자외선 누출)

  • Mok, Chul-Kyoon;Lee, Nam-Hoon
    • Korean Journal of Food Science and Technology
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    • 제40권2호
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    • pp.228-233
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    • 2008
  • Ultraviolet sterilizers (UVS) are widely used in restaurants, cafeterias and catering businesses in Korea. The proper application of UVS, however, is still questionable since no studies have clearly identified their efficacy and safety, while regulations and regulatory management systems are yet to be established. In the present study, the efficacy of UVS were investigated by measuring spatial UV intensity inside five commercially operated UVS. The operating safety parameters were also checked by measuring leaked UV intensity. The UV intensities were inversely proportional to distance from the UV lamp within 25 cm, and to the square of the distance exceeding 25 cm. The UV intensities in commercial UVS varied with the distance from UV lamp and the incident angle, highlighting efficacy and stability concerns. Notable leakage was detected through the door gaps of a studied UVS, which also brought about safety concerns. Allowable working distances for the UV leaking UVS were suggested based on international standards.

A Seasonal Risk Analysis and Damage Effects Assessment by Gas Leakage of Chemical Plant using 3D Scan and FLACS (3D 스캔과 FLACS를 활용한 화학플랜트 가스 누출의 계절별 위험성 및 피해영향 평가)

  • Kim, Jiyoung;Kim, Jiyu;Kim, Euisoo
    • Journal of the Korean Institute of Gas
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    • 제25권4호
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    • pp.1-9
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    • 2021
  • The process and facilities of modern chemical plants are becoming increasingly complex, there is possibility of potential risk. Internal chemicals generate stress concentration when operated due to turbulence, laminar flow, pressure, temperature, friction, etc. It causes cumulative fatigue damage, which can damage or rupture chemical facilities and devices. The statistics of chemical accidents found that the highest rate of occurrence was in summer, and in the last five years statistics on chemical accidents, leakage incidents make up a decent percentage of accidents. Chemical leaks can cause serious human damage and economic damage, including explosions and environmental pollution. In this study, based on the leak accident of chemical plant, the risk analysis, and damage effects assessment were estimated using a 3D scanner and FLACS. As a result, if chemicals leak in summer, the risk is higher than in other seasons, the seasonal safety management measures, and countermeasure were estimated.

Dispersion Model of Initial Consequence Analysis for Instantaneous Chemical Release (순간적인 화학물질 누출에 따른 초기 피해영향 범위 산정을 위한 분산모델 연구)

  • Son, Tai Eun;Lee, Eui Ju
    • Journal of the Korean Society of Safety
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    • 제37권2호
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    • pp.1-9
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    • 2022
  • Most factories deal with toxic or flammable chemicals in their industrial processes. These hazardous substances pose a risk of leakage due to accidents, such as fire and explosion. In the event of chemical release, massive casualties and property damage can result; hence, quantitative risk prediction and assessment are necessary. Several methods are available for evaluating chemical dispersion in the atmosphere, and most analyses are considered neutral in dispersion models and under far-field wind condition. The foregoing assumption renders a model valid only after a considerable time has elapsed from the moment chemicals are released or dispersed from a source. Hence, an initial dispersion model is required to assess risk quantitatively and predict the extent of damage because the most dangerous locations are those near a leak source. In this study, the dispersion model for initial consequence analysis was developed with three-dimensional unsteady advective diffusion equation. In this expression, instantaneous leakage is assumed as a puff, and wind velocity is considered as a coordinate transform in the solution. To minimize the buoyant force, ethane is used as leaked fuel, and two different diffusion coefficients are introduced. The calculated concentration field with a molecular diffusion coefficient shows a moving circular iso-line in the horizontal plane. The maximum concentration decreases as time progresses and distance increases. In the case of using a coefficient for turbulent diffusion, the dispersion along the wind velocity direction is enhanced, and an elliptic iso-contour line is found. The result yielded by a widely used commercial program, ALOHA, was compared with the end point of the lower explosion limit. In the future, we plan to build a more accurate and general initial risk assessment model by considering the turbulence diffusion and buoyancy effect on dispersion.

A Study of Network 2-Factor Access Control Model for Prevention the Medical-Data Leakage (의료 정보유출 방지를 위한 네트워크 이중 접근통제 모델 연구)

  • Choi, Kyong-Ho;Kang, Sung-Kwan;Chung, Kyung-Yong;Lee, Jung-Hyun
    • Journal of Digital Convergence
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    • 제10권6호
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    • pp.341-347
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    • 2012
  • Network Access Control system of medical asset protection solutions that installation and operation on system and network to provide a process that to access internal network after verifying the safety of information communication devices. However, there are still the internal medical-data leakage threats due to spoof of authorized devices and unauthorized using of users are away hours. In this paper, Network 2-Factor Access Control Model proposed for prevention the medical-data leakage by improving the current Network Access Control system. The proposed Network 2-Factor Access Control Model allowed to access the internal network only actual users located in specific place within the organization and used authorized devices. Therefore, the proposed model to provide a safety medical asset environment that protecting medical-data by blocking unauthorized access to the internal network and unnecessary internet access of authorized users and devices.

A Study on the Damage Range of Chemical Leakage in Polysilicon Manufacturing Process (폴리실리콘 제조 공정에서 화학물질 누출 시 피해범위에 관한 연구)

  • Woo, Jongwoon;Shin, Changsub
    • Journal of the Korean Institute of Gas
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    • 제22권4호
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    • pp.55-62
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    • 2018
  • There is growing interest in solar power generation due to global warming. As a result, demand for polysilicon, which is the core material for solar cells, is increasing day by day. As the market grows, large and small accidents occurred in the production process. In 2013, hydrochloric acid leaked from the polysilicon manufacturing plant in SangJu. In 2014, a fire occurred at a polysilicon manufacturing plant in Yeosu, and in 2015, STC(Silicon Tetrachloride) leaked at a polysilicon manufacturing plant in Gunsan City. Leakage of chemicals in the polysilicon manufacturing process can affect not only the workplace but also the surrounding area. Therefore, in this study, we identified the hazardous materials used in the polysilicon manufacturing process and quantitatively estimate the amount of leakage and extent of damage when the worst case scenario is applied. As a result, the damage distance by explosion was estimated to be 726 m, and the damage distance to toxicity was estimated to be 4,500 m. And, if TCS(Trichlorosilane), STC(Silicon Tetrachloride), DCS(Dichlorosilane) leaks into the air and reacts with water to generate HCl, the damage distance is predicted to 5.7 km.

Case Analysis of the Harmful Chemical Substances' Spill (유해화학물질 유출의 사례 분석)

  • You, Jisun;Chung, Yeong-Jin
    • Fire Science and Engineering
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    • 제28권6호
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    • pp.90-98
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    • 2014
  • Lately accidents of harmful chemical substance in korea were repeatedly replaying. We studied problems and preparation plan in 2008 years~2014 years through analysis cases of harmful chemical substance. Leakage of chemical substance's accident situation shows that leakage in the workplace is the most 10 cases, accounting for 58.6% is the largest proportion in 2009. Leakage according to explosion accounting for 50% (5 cases) in 2004, 25% (4 cases) in 2007 and 33.3% (4 cases) in 2011 has very irregular change. Therefore, A major cause of accidents is lack of safety management. Harmful chemical substance showed various aspects, high residual substance and non-visible characteristic so response and recovery was easy. And the second damage to move a distance causes environment pollution. So a mutual-assistance system and integrated system of related organization have to build and expert of chemical incident response and therapist of chemical substance response have to establish to do efficient and rapid response.

A Study on Durability Test of Check Valve for CNG Vehicles (천연가스 차량용 체크밸브의 내구성능에 관한 연구)

  • Kim, Chang-Gi;Lee, Sun-Youp;Cho, Gyu-Baek
    • Journal of the Korean Institute of Gas
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    • 제13권6호
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    • pp.15-20
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    • 2009
  • The number of compressed natural gas (CNG) vehicles have increased gradually by virtue of korea government's urban air quality improvement policy since 1998. Although the use of CNG as transportation fuel gives environmental benefits, there is a possibility of huge accidents from unexpected fire. Therefore, needs for the guarantee of safety are indispensible for the reliable operation of CNG vehicles. A check valve is a safety device which prevents leakage of the pressurized fuel charged in a fuel tank. Durability of this component should be guaranteed in spite of repeated operation. This research has performed durability tests of a CNG check valve regarding the repeated usage, extreme chattering, and the effect of compressor oil.Although a check valve used for CNG vehicle satisfies validation requirements in the test results, it has been found that problem in the function of leakage prevention in a check valve could take place in the case of prolonged exposure to compressor oil.

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