• Title/Summary/Keyword: respirator

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Protection against Aerosols by particulate Respirators and Fit Performance (방진마스크의 에어졸 방어효과와 밀착정도)

  • 한돈희
    • Journal of Environmental Health Sciences
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    • v.27 no.2
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    • pp.30-36
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    • 2001
  • This review begins with a brief expression of aerosol capture mechanism of fibrous filter(s) and performance of particulate removing respirators. The more complicated and detailed discussion is not included in this articles. Filtration efficiency and pressure drop are introduced as quality factor ( $q_{F}$) and the way in which filtration efficiency varies with particle size is discussed. Quality factors fro filters recently certified in USA were found to be very higher than those of filters made in Korea, China and USA filters certified with old certified standards. Electrically charged filters are widely used because they have high filtration efficiency and low pressure drop, but their efficiency decreases sharply at the condition occurring wet and oil mist. A discussion is given of respirator leakage through face seal and filter media with fit testing and total inward leakage testing. Since fit factor (FF) refers to the reciprocal of the fraction of the total air entering a respirator through face seal leakage , the degree of fitting performance for respirators is expected with FF. Because respirators made in Korea had generally lower FFs than respirators made in USA, it is necessary to develope respirators that fit properly for Koreans or establish regulations for fit testing.g.

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Adsorption Characteristics of a Respirator Cartridge for Organic Vapor Packed with Activated Carbon Fiber (활성탄소섬유가 충전된 유기가스용 방독마스크 정화통의 흡착특성)

  • Shin, Chang-Sub;Kim, Ki-Hwan;Kang, Young-Goo
    • Journal of the Korean Society of Safety
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    • v.15 no.2
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    • pp.84-91
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    • 2000
  • The adsorption characteristics of a respirator cartridge is affected by the kind of adsorbent, concentration of organic vapor, humidity and packing density of cartridge. In this study, activated carbon fiber(ACF) instead of activated carbon is used as a adsorbent of cartridges for the removement of organic vapor and the adsorption characteristics were examined. ACF made of cellulose showes high efficiency for the removal of carbon tetrachloride and the adsorption capacity was 0.569g/g ACF at 450 ppm. The relative humidity dose not affected to the adsorbed amount and Langmuir Isotherm was more adequate than Freundlich Isotherm for this adsorption phenomena.

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Development and Evaluation of a Teensy Microcontroller-based O2 Mass Flow Controller (Teensy 마이크로 컨트롤러 기반 산소 유량 제어기 개발 및 성능평가)

  • Yu, Min Sang;Jang, Yeonsook;Kim, Muhwan;Cho, Sungbo
    • Journal of Biomedical Engineering Research
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    • v.42 no.4
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    • pp.193-200
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    • 2021
  • Flowmeter and oxygen sensors are listed in COVID-19 essential medical devices. This article reports a Teensy microcontroller-based Oxygen mass flow controller (MFC), core part of the oxygen respirator or extracorporeal membrane oxygenation (ECMO). The developed MFC consisting of the microcontroller, MEMS flow sensor, and solenoid valve was able to accurately control 0 to 100 sccm of oxygen flow rate. The pressure of vacuum chamber increased proportionally to the flow rate (0.998 of Pearson correlation coefficient). The experimental results proved that the developed MFC exhibits comparable performance to a commercial MFC in accuracy, settling time, linearity with pressure, and repeatability of oxygen mass flow control. It is expected that this simple and cheap MFC is utilized for oxygen therapy against the severe acute respiratory syndrome coronavirus 2.

Particle Filtration Efficiency Testing of Sterilization Wrap Masks

  • Chau, Destiny F.;O'Shaughnessy, Patrick;Schmitz, Michael L.
    • Journal of Preventive Medicine and Public Health
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    • v.54 no.1
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    • pp.31-36
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    • 2021
  • Objectives: Non-traditional materials are used for mask construction to address personal protective equipment shortages during the coronavirus disease 2019 (COVID-19) pandemic. Reusable masks made from surgical sterilization wrap represent such an innovative approach with social media frequently referring to them as "N95 alternatives." This material was tested for particle filtration efficiency and breathability to clarify what role they might have in infection prevention and control. Methods: A heavyweight, double layer sterilization wrap was tested when new and after 2, 4, 6, and 10 autoclave sterilizing cycles and compared with an approved N95 respirator and a surgical mask via testing procedures using a sodium chloride aerosol for N95 efficiency testing similar to 42 CFR 84.181. Pressure testing to indicate breathability was also conducted. Results: The particle filtration efficiency for the sterilization wrap ranged between 58% to 66%, with similar performance when new and after sterilizing cycles. The N95 respirator and surgical mask performed at 95% and 68% respectively. Pressure drops for the sterilization wrap, N95 and surgical mask were 10.4 mmH2O, 5.9 mmH2O, and 5.1 mmH2O, respectively, well below the National Institute for Occupational Safety and Health limits of 35 mmH2O during initial inhalation and 25 mmH2O during initial exhalation. Conclusions: The sterilization wrap's particle filtration efficiency is much lower than a N95 respirator, but falls within the range of a surgical mask, with acceptable breathability. Performance testing of non-traditional mask materials is crucial to determine potential protection efficacy and for correcting misinterpretation propagated through popular media.

Aerosol protection using modified N95 respirator during upper gastrointestinal endoscopy: a randomized controlled trial

  • Chawisa Nampoolsuksan;Thawatchai Akaraviputh;Asada Methasate;Jirawat Swangsri;Atthaphorn Trakarnsanga;Chainarong Phalanusitthepha;Thammawat Parakonthun;Voraboot Taweerutchana;Nicha Srisuworanan;Tharathorn Suwatthanarak;Thikhamporn Tawantanakorn;Varut Lohsiriwat;Vitoon Chinswangwatanakul
    • Clinical Endoscopy
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    • v.57 no.3
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    • pp.335-341
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    • 2024
  • Background/Aims: The coronavirus disease 2019 pandemic has affected the worldwide practice of upper gastrointestinal endoscopy. Here we designed a modified N95 respirator with a channel for endoscope insertion and evaluated its efficacy in upper gastrointestinal endoscopy. Methods: Thirty patients scheduled for upper gastrointestinal endoscopy were randomized into the modified N95 (n=15) or control (n=15) group. The mask was placed on the patient after anesthesia administration and particles were counted every minute before (baseline) and during the procedure by a TSI AeroTrak particle counter (9306-04; TSI Inc.) and categorized by size (0.3, 0.5, 1, 3, 5, and 10 ㎛). Differences in particle counts between time points were recorded. Results: During the procedure, the modified N95 group displayed significantly smaller overall particle sizes than the control group (median [interquartile range], 231 [54-385] vs. 579 [213-1,379]×103/m3; p=0.056). However, the intervention group had a significant decrease in 0.3-㎛ particles (68 [-25 to 185] vs. 242 [72-588] ×103/m3; p=0.045). No adverse events occurred in either group. The device did not cause any inconvenience to the endoscopists or patients. Conclusions: This modified N95 respirator reduced the number of particles, especially 0.3-㎛ particles, generated during upper gastrointestinal endoscopy.

Development of Korean Head forms for Respirator Performance Testing

  • Seo, Hyekyung;Kim, Jennifer Ivy;Kim, Hyunwook
    • Safety and Health at Work
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    • v.11 no.1
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    • pp.71-79
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    • 2020
  • Background: Protection from yellow dust and particulate matter is ensured by the use of respirators among the Korean citizens and workers. However, the manikins used to test the performance of the same were manufactured considering western facial specifications owing to which they do not represent Korean facial characteristics. Methods: Analysis of the data from the 6th 3D anthropometric survey of Koreans (Size Korea; 2010-2013) of 4,583 people aged 7 to 69 years was performed to obtain their facial dimensions. We subsequently clustered 44 facial measurements using Design X software, followed by the creation of the cluster centroid. Results: Three 3D head forms were developed-small, medium, and large, and their images were stored in ".stl" format for 3D printing. The facial widths and lengths of the three head forms were 127.1 mm × 90.6 mm, 143.2 mm × 104.0 mm, and 149.1 mm × 120.2 mm, respectively. Conclusion: We developed manikin head forms according to the facial dimensions of the Korean population, which was essential in evaluating respiratory protective equipment. These head forms can be used to test the performance of respirators considering the facial dimensions of the Korean population.

Characteristics of Hazardous Factors Regarding Chemical(Liquid Lime) Storage Tank Dredging Workers (약품(액상소석회) 저장조 준설 작업자의 유해인자 특성 평가 사례)

  • Je-Hun Kim;Ki-Youn Kim
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.34 no.1
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    • pp.1-7
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    • 2024
  • Objectives: The study was performed to investigate characteristics of hazardous factors regarding chemical(liquid lime) tank dredging workers by case survey. Methods: Field data such as working condition, MSDS and respirators applied to chemical tank dredging work were analyzed and the work environmental factors of noise and indoor air quality were measured to compare existing data with actual work situations. Results: No health hazards to workers due to working conditions were confirmed during dredging work inside the chemical storage tank. All air quality measurement data during dredging work satisfied the management standards, and there were no by-products. During dredging work, there was a significant change in noise depending on the type of work, but considering the noise reduction rate(NRR) of the earplugs worn by workers, there was no actual health hazard due to noise exposure. Conclusions: A fit test for respirator and the expiration date of the safety helmet should be observed to ensure an appropriate level of safety and health for dredging workers in the chemical storage tank.

Changes in The Amount of Air Respirator Consumed by Field Fire-fighting Activities (현장 소방활동에 따른 공기호흡기 소모량의 변화)

  • Jeon, Jai-In;Kong, Ha-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.93-98
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    • 2019
  • The purpose of this study was to identify and analyze the rate of change of air respirator consumption based on field fire fighting activities, The results of the experiment are as follows. The mean air consumption of the Five subjects was $15.56{\ell}/min$ when standing still, $32.43{\ell}/min$ when walking with normal pace, $43.07{\ell}/min$ when the fire hoses was expanded and arranged, $55.28{\ell}/min$ when climbing stairs, The situation of running up the stairs and hitting the hammer continuously increases to $127.14{\ell}/min$, which means that the consumption of air increases according to the energy consumption. Despite being the oldest, Experimental subject A was $13.23{\ell}/min$ when standing still, $29.33{\ell}/min$ when walking normally, and $41.08{\ell}/min$ when the fire hose was deployed and arranged. This is a result of familiarity with deep and slow breathing methods. The average respiratory use rate of subjects D was $63.58{\ell}/min$. The reason for this is that obesity seems to increase the air consumption, and it is considered that the physical strength is exhausted by the action of the hammer, which has a greater influence on the increase of air consumption. The subject E had significantly lower air respiratory use rate of $49.90{\ell}/min$. The reason for this is that the age of E is the youngest among the subjects, and it is presumed that it possesses strong physical strength.

Optimal Design of Permanent Magnetic Actuator for Artificial Respirator (호흡기용 영구자석형 자기 액츄에이터의 최적설계)

  • Park, Sang-Min;Hwang, Kyu-Yun;Kwon, Byung-Il
    • Proceedings of the KIEE Conference
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    • 2007.10c
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    • pp.59-61
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    • 2007
  • This paper proposes optimized actuator to obtain a improved position control ability and respiratory performance with reduced weight. Respiratory organ uses actuator and controls patient's respiratory air volume. Therefore, actuator decides respiratory performance. Redesign actuator using surface response method. Actuator that is reestablished through 3D-simulations searches whether have suitable characteristic to respiratory organ.

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