• International journal of advanced smart convergence
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• 제12권4호
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• pp.378-385
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• 2023

The importance of wearing respiratory protective equipment has been highlighted even more during the COVID-19 pandemic. Even if the suitability of respiratory protection has been confirmed through testing in a laboratory environment, there remains the potential for leakage points in the respirators due to improper application by the wearer, damage to the equipment, or sudden movements in real working conditions. In this paper, we propose a method to detect the occurrence of leak holes by measuring the pressure changes inside the mask according to the wearer's breathing activity by attaching an IoT sensor to a full-face respirator. We designed 9 experimental scenarios by adjusting the degree of leak holes of the respirator and the breathing cycle time, and acquired respiratory data for the wearer of the respirator accordingly. Additionally, we analyzed the respiratory data to identify the duration and pressure change range for each breath, utilizing this data to train a neural network model for detecting leak holes in the respirator. The experimental results applying the developed neural network model showed a sensitivity of 100%, specificity of 94.29%, and accuracy of 97.53%. We conclude that the effective detection of leak holes can be achieved by incorporating affordable, small-sized IoT sensors into respiratory protective equipment.

• 한국산업보건학회지
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• 제20권4호
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• pp.225-235
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• 2010

This study was aimed to assess the status of working environment, health care management status and cause of exposure in manufactories using dimethylformamide (DMF). For the purpose, airborne concentration of DMF in the workplaces and N-methylformamide (NMF) in worker's urine were measured with job type and process. In addition, management of local exhaust ventilation system (LEV) and personal protective equipment (PPE) was evaluated at 35 work places (107 workers) located in Busan and Gimhae area. Mean DMF concentrations in work places by job type and process were of high level measured in printing and record media reproduction (5.23 ppm) and flaking process (2.48 ppm). Workers in adhesive job were measured a large amount of urine NMF (21.59 mg/${\ell}$). 98.1% of DMF handling workers were provided respirators, but 67.3% of those workers used them. The main reasons for not using respirators were inconvenience and difficulty of breathing. Airborne concentrations of DMF were higher in the workplaces in which LEVs were working abnormally, but there was not statistically significant. In addition, the urine NMF levels were correlated with management of LEV within the workers who did not use the respirators (p<0.048). These results implied that LEV should be installed and maintained properly to protect the workers from the exposure to DMF. Management of PPE should be also necessary to protect the workers from chemical hazards.

• 한국입자에어로졸학회지
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• 제12권3호
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• pp.95-102
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• 2016

본 연구에서는 호흡용 보호구 필터의 나노물질에 대한 여과특성을 측정하기 위해서 소금(NaCl)과 은나노입자(Ag)를 대상으로 입경별 집진효율을 평가하였다. 호흡용 보호구 필터는 특급 방진마스크와 1급 방진마스크의 두 가지 안면부 여과식 방진마스크인 사용하였고, 마스크의 배기밸브 부분을 제외한 필터 여재 부분을 직경 47 mm로 잘라내어 필터홀더에 부착하여 입경별 입자제거효율을 시험하였다. 시험입자는 일반적으로 시험 입자로 사용되는 소금입자는 분무형 입자발생장치를 사용하여 발생하였고 중화기를 통과시켜 입자의 하전특성을 볼츠만 분포로 만들어 공급하였다. 은나노입자의 경우, 기화-응축 방법을 이용한 금속나노입자 생성방법인 ISO10801 방법을 사용하였다. 작업장의 은나노입자의 고농도 노출을 모사하기 위해, 중화기를 통과하지 않은 나노입자를 시험입자로 사용하였다. 은나노입자의 경우 소금입자로 만들기 어려운 20nm 이하의 입자를 안정적으로 효과적으로 만들어 시험에 적용하였고, 나노 크기에서도 매우 안정적인 데이터를 확보할 수 있었다. 1급 마스크 필터와 특급 마스크 필터에 대한 소금입자의 평가에서, 입경별 최소효율이 30~50nm 사이에서 나타나는 특성은 기존 연구와 비슷한 결과를 얻었다. 반면, 은나노입자의 경우 1급 마스크 필터와 특급 마스크 필터 모두에서 비슷한 크기의 소금 입자와 비교할 때 높은 효율을 나타냈다. 이것은 소금 입자의 경우 중화기를 통과시켜 시험입자로 사 용한 반면, 은나노입자의 경우 중화기를 통과시키지 않았기 때문이다. 본 연구에서는 작업장에서 은나노 입자가 고농도로 노출될 경우를 모사하여, 기화-응축에 의한 방법의 은나노입자 발생장치를 사용하였는데, 이 때 상대적으로 높게 대전된 입자들이 많이 만들어진다(Jung et al., 2006). 이로 인해, 정전필터인 마스크 필터의 포집 효과가 상대적으로 크기 때문에, 입경별 효율이 높아진 것으로 생각된다. 본 연구에서 평가한 1급 및 특급 방진마스크 여재의 최소 포집효율은 유럽 EN 149 기준인 95 LPM 유량 기준을 만족하는 것으로 나타났지만, 이것은 여재에 대한 평가 결과로, 실제 마스크에 대해서는 여재의 구조적인 불균일성이나 마스크를 착용하는 과정에서 밀착이 되지 않아 누출될 가능성은 마스크 사용에 고려되어야 한다. 불시에 발생할 수 있는 작업장 내 안전사고의 예방을 위하여 적절한 보호구의 선택과 올바른 착용 및 유지관리가 필요할 것으로 생각된다.

• 한국화재소방학회논문지
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• 제26권4호
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• pp.77-81
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• 2012

본 연구 목적은 화재시에 사용하는 공기호흡기의 성능개선에 필요한 기초자료를 마련하는데 있다 공기호흡기에서 발생하는 문제점을 파악하고 부식의 발생과정을 알아보기 위하여 3가지 실험조건하에서 용기내부의 압력을 배출시킨 경우 주변 온도와의 차이를 확인하고, 용기 내 외부의 수분의 발생여부를 확인하였다. 실험조건으로 설정온도는 $-20{\sim}40^{\circ}C$이고, 용기 압력배출은 1차 감압기와 정압밸브를 사용하여 0.4~0.8MPa의 범위로 실험하였다. 실험결과 용기 외부의 온도와 수분은 변화가 없었으며, 내부에서도 수분은 발생되지 않았다. 다만, 압력게이지의 내측에서 수분이 발생하였지만 "호흡보호장비 안전관리에 관한 기준 고시"에서 제시한 25 $mg/m^3$ 범이를 초과하여 발생하지 않았다. 따라서 공기호흡기에서 가장 치명적인 문제인 용기내부에서의 수분이 발생하는 원인은 제조 및 생산과정에서 발생하기 보다는 일반적으로 사용처에서 관리 및 공기를 교체하는 과정에서 수분이 발생할 가능성이 높은 것으로 판단하였다.

• 한국산업보건학회지
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• 제33권2호
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• pp.247-264
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• 2023

Objectives: The study was to examine the features of three-dimensional(3D) face dimensions and to develop fit test panels for the labor population using respirators in South Korea. Methods: This study was part of the first-year work of a two-year-project conducted at Occupational Safety and Health Research Institute in 2021. After 3D head dimensions data were collected from Size Korea Center managing Sixth Size Korea databases, 3D face dimensions DB for the South Korean labor population was established for 21 items of face dimensions in line with the ISO/TS 16976-2 and KS A ISO 15535. With the South Korean labor population 3D face dimensions DB, in accordance with the ISO/TS 16976-2, the descriptive statistics of 3D face dimensions were calculated and two fit test panels were developed. Results: A total of 2,752 subjects were finally determined and they were 52.9% for male, 41.2% for the highest age-group of 15-29, and residents in the capital area. Mean and standard deviation were obtained for each of the 21 3D face dimensions items for the South Korean labor population. Among the items, male and female face widths were 137.6±5.7 mm, 133.2±5.0 mm, respectively. Male and female face lengths were 116.6±7.0 mm, 107.8±6.8 mm, respectively. Two new South Korean fit test panels, a bivariate test panel and a principal component analysis test panel, were developed using the 3D face dimensions DB as well. Conclusions: Using the 3D face dimensions DB, the mean and standard deviation were featured for each of the 21 items and also the two fit test panels were newly developed in the study. It is suggested that the study outputs should be utilized practically and effectively in selection, use, and management of respirators at work, expecting that respiratory protection can be furthermore improved for respirator users including labor population across the country.

• 한국산업보건학회지
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• 제18권3호
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• pp.204-215
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• 2008

Many researches for service-life of chemical cartridges of respirators have been performed in many countries. On the result of these researches a few softwares programs were eventually developed to be used. In spite of that, it is difficult to apply these researches and softwares practically in the work spot because of too many factors that influence on service-life of chemical cartridges. This study was the first of two conducted for the purpose of developing program for estimating exchange period or service-life of chemical cartridges available feasibly in the workplaces. Collecting plan of cartridges discarded after use is in principle that three cartridges from three workers at a time, three steps of 1/2 exchange time due to smelling, just routine exchange time and 1.2 to 1.3 expanded time of routine exchange, total nine cartridges are collected in the same job site. 33 cartridges for organic vapor were collected in paint spray process of ship yard and paint factory, and 6 cartridges for acid were collected in plating process. These cartridges were analysed the remaining breakthrough time in 3M Innovation Center. Challenge vapor and breakthrough concentration were complied with Korean regulation for chemical cartridge respirators. Estimated breakthrough time was determined from previously used time plus breakthrough time for the remaining. Exchange period of cartridge would be the shortest time among three estimated breakthrough times. On the result breakthrough time for organic vapor was found to be relatively easily estimated, but that for acid aerosol or vapor was difficult to be confident. Even though this method was difficult to be precisely predicted exchange period of cartridge, it could be an alternative program practically available in the job site.

• 한국산업보건학회지
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• 제25권3호
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• pp.328-337
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• 2015

Objectives: The purpose of this study is to investigate differences in concentration according to the position at the left or right shoulder within a 30 cm of radius of workers' respirators and provide basic data for the establishment of an industrial health policy. Methods: Personal samples were collected from a total of 65 workers from 27 manufacturing firms in South Gyeongsang-do Province from November 5, 2011 to December 30, 2012 after classifying the laborers into left- and right-side groups. The organic compound samples were collected and analyzed in accordance with the NIOSH Manual of Analytical Methods (NMAM) 1501. Results: In terms of the concentration of organic compounds collected from both left and right shoulders at the position of workers' respirators, isobutyl acetate was the highest with 145 ppm at the left shoulder, followed by ethyl acetate (133.5 ppm) and toluene (38.13 ppm). At the right shoulder, on the contrary, ethyl acetate (149.3 ppm) was the highest, followed by toluene (46.26 ppm), xylene (29.63ppm) and isopropyl alcohol (28.06 ppm). Overall, the right shoulder was higher than the left shoulder in terms of concentrations. Conclusions: For the measurement of the working environment, workers' personal samples should be collected at the place closest to the respirator. In terms of the reduction of error, the attachment of two sample media is expected to reduce errors in exposure assessment.

• 한국환경보건학회지
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• 제37권1호
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• pp.50-56
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• 2011

The adsorption capacity of charcoal is a function of the airborne concentration of the target chemical. To evaluate the adsorption capacity of charcoal packed in the cartridges of air purifying respirators, breakthrough tests were conducted with carbon tetrachloride for three commercial cartridges (3M models #7251, #6000 and AX) at 25, 50, 100, 250 and 500 ppm. Adsorption capacities were calculated using a mass transfer balance equation derived from the curve fitting to the breakthrough curves obtained experimentally. Carbon micropore volumes were estimated by iteration to fit the Dubinin/Radushkevich (D/R) adsorption isotherm. They were 0.6566, 0.5727 and 0.3087 g/cc for #7251, #6000 and the AX cartridge, respectively. Above 100 ppm (at high challenge concentrations), #7251 and #6000 showed higher adsorption capacities. However, as the challenge concentration decreased, the adsorption capacities of #7251 and #6000 sharply dropped. On the other hand, the adsorption capacity of the AX cartridge showed little change with the decrease of the challenge concentration. Thus, the AX showed a higher adsorption capacity than #7251 and #6000 at the 5-50 ppm level. It is concluded that service-life tests of cartridges and adsorption capacity tests of charcoal should be conducted at challenge concentration levels reflecting actual working environmental conditions. Alternatively, it is recommended to use the D/R adsorption isotherm to extrapolate adsorption capacity at low concentration levels from the high concentration levels at which breakthrough tests are conducted, at a minimum of two different concentration levels.

• Safety and Health at Work
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• 제11권1호
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• pp.61-70
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• 2020

Background: This study aims to assess whether the TSI PortaCount (Model 8020) is a measuring instrument comparable with the flame photometer. This would provide an indication for the suitability of the PortaCount for determining the workplace protection factor for particulate filtering facepiece respirators. Methods: The PortaCount (with and without the N95-Companion^TM) was compared with a stationary flame photometer from Moores (Wallisdown) Ltd (Type 1100), which is a measuring instrument used in the procedure for determining the total inward leakage of the particulate filtering facepiece respirator in the European Standard. Penetration levels of sodium chloride aerosol through sample respirators of two brands (A and B) were determined by the two measuring systems under laboratory conditions. For each brand, thirty-six measurements were conducted. The samples were split into groups according to their protection level, conditioning before testing, and aerosol concentration. The relationship between the gauged data from two measuring systems was determined. In addition, the particle size distribution inside the respirator and outside the respirator was documented. Linear regression analysis was used to calculate the association between the PortaCount (with and without the N95-Companion^TM) and the flame photometer. Results: A linear relationship was found between the raw data scaled with the PortaCount (without N95-Companion^TM) and the data detected by the flame photometer (R² = 0.9704) under all test conditions. The distribution of particle size was found to be the same inside and outside the respirator in almost all cases. Conclusion: Based on the obtained data, the PortaCount may be applicable for the determination of workplace protection factor.

• Safety and Health at Work
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• 제15권1호
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• pp.42-52
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• 2024

Background: The lack of headforms that accurately reflect the head characteristics of Koreans and the demographic composition of the Korean population can lead to inadequate FFR testing and reduced effectiveness of FFRs. Method: Direct measurements of 5,110 individuals and 3D measurements of 2,044 individuals, aged between 9 and 69 years, were sampled from the data pool of Size Korea surveys based on the age and gender ratios of the Korean resident demographics. Seven head dimensions were selected based on the ISO 16976-2, availability of Size Korea measurements, and their relevance to the fit performance of FFRs. A principal component analysis (PCA) was performed using the direct measurements to extract the main factors explaining the head characteristics and then the main factors were standardized and remapped to 3D measurements, creating five size categories representing Korean head shapes. Lastly, representative 3D headforms were constructed by averaging five head shapes for each size category. Results: The study identified two main factors explaining Korean head characteristics by the PCA procedure specified in ISO 16976-2 and developed five representative headforms reflecting the anthropometric features of Korean heads: medium, small, large, short & wide, and long & narrow. Conclusion: This study developed representative headforms tailored to the Korean population for conducting total inward leakage (TIL) tests on filtering facepiece respirators (FFRs). The representative headforms can be used for TIL testing by employing robotic headforms to enhance the performance of FFRs for the Korean target population.