• Title/Summary/Keyword: Extinguishing concentration

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Recommendation of an Occupational Exposure Limit and Legal Control Following an Acute Hepatotoxicity Incident from HCFC-123 (HCFC-123의 급성 독성간질환 발생 사례에 따른 노출기준 및 법 관리 필요성 권고)

  • Lee, Kwon Seob;Jo, Ji hoon;Choi, Bo Kyung;Lee, Hye Lim;Byeon, Sang Hoon
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.28 no.1
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    • pp.80-90
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    • 2018
  • Objectives: This study was performed to propose a domestic occupational exposure limit(OEL) following a health hazard assessment, calculation of a non-carcinogenicity reference concentration worker($RfC_{worker}$) value, and examination of international agencies' exposure limits. It also recommends legal management within the Occupational Safety and Health Act for HCFC-123, which caused an acute hepatotoxicity incident. Methods: An acute hepatotoxicity incident due to the fire extinguishing agent HCFC-123 was investigated. Toxicological hazard and health hazard classifications were examined and a non-carcinogenicity $RfC_{worker}$ value was calculated for HCFC-123. An OEL and the necessity of legal management were recommended as well. Results and Conclusions: An OEL for HCFC-123 of 10 ppm($62.5mg/m^3$), which considered the $RfC_{worker}$ value, 5.56 ppm, produced in dose-response assessment and the exposure level of 19.1-20.9 ppm measured as an eight-hour TWA(time-weighted average) in the incident place, is recommended. HCFC-123 is urged to be included as a chemical requiring legal management in the Occupational Safety and Health Regulations. In addition, it is recommended that a peak exposure of ACGIH be adopted in the Notice of the Ministry of Employment and Labor.

Characteristics of sulfur hexafluoride hydrate film growth at the vapor/liquid interface (기상/액상 계면에서의 SF6 하이드레이트 필름 성장거동 연구)

  • Kim, Soo-Min;Lee, Hyun-Ju;Lee, Bo-Ram;Lee, Yoon-Seok;Lee, Eun-Kyung;Lee, Ju-Dong;Kim, Yang-Do
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.2
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    • pp.85-92
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    • 2010
  • $SF_6$ gas has been widely used in many industrial fields as insulating, cleaning and covering gases due to its outstanding arc-extinguishing and insulating properties. However, global warming potential of $SF_6$ gas is 23,900 times more than that of $CO_2$ and it remains in the air during 3,200 years. For these reason, technological and economical effects could be expected for the separation of $SF_6$ from gas mixtures by hydrate forming process. In this study, we carried out morphological studies for the $SF_6$ hydrate crystal to understand its formation and growth mechanisms. $SF_6$ hydrate film was initially formed at the interfacial boundary between gas and liquid regions, and then subsequent dendrite crystals growth was observed. The dendrite crystals grew to the direction of gas region probably due to the guest gas concentration gradient. The detailed growth characteristics of $SF_6$ hydrate crystals such as nucleation, migration, growth and interference were discussed in this study.

An Experimental Study on a Discharge Pressure, Flow Rate and Foam Discharge Concentration through the Nozzle According to the Foam Suction Nipple Diameter (노즐 구경에 따른 포 수용액의 압력과 유량 및 농도 변화에 관한 실험적 연구)

  • Jang, Kyung-Nam;Lee, Maing-Ro;Park, Bong-Rae;Yun, Ki-Jo;Baek, Eun-Sun
    • Fire Science and Engineering
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    • v.29 no.2
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    • pp.84-91
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    • 2015
  • The purpose of this study is to suggest the reasonable model of the caliber in suction nozzle, the pressure of suction nozzle, and the flow rate about foam system of line proportioner type using in the pumpcar. To test this, the experimental study was accomplished on the ground of the standards for the Performance Certification and Product Inspection of Foam Fire-extinguishing Chemical Mixing Machine. Aqueous Film Forming Foam in 3% and pipe type air foam nozzle with line proportioner FE 40 type were used. Test result showed that the pressure of suction nozzle within the limits between 0.25 MPa and 0.35 MPa was appropriate when the caliber in suction nozzle is 4 mm. Also, the pressure of suction nozzle within the limits between 0.45 MPa and 0.60 MPa was appropriate in the higher pressure than 4 mm when the caliber in suction nozzle is 5 mm.