scholarly journals A Sew-Free Origami Mask for Improvised Respiratory Protection

2020 ◽  
Author(s):  
Jonathan Realmuto ◽  
Michael T. Kleinman ◽  
Terence Sanger ◽  
Michael J. Lawler ◽  
James N. Smith
Keyword(s):  
Filtration Efficiency ◽  
Respiratory Protection ◽  
Minimal Cost ◽  
Fabrication Technique ◽  
Optimal Filtration ◽  
Filtration Material

Recently, respiratory aerosols with diameters smaller than 100 μm have been con- firmed as important vectors for the spread of SARS-CoV-2. While cloth masks afford some protection for larger ballistic droplets, they are typically inefficient at filtering these aerosols and require specialized fabrication devices to produce. We describe a fabrication technique that makes use of a folding procedure (origami) to transform a filtration material into a mask. These origami masks can be fabricated by non-experts at minimal cost and effort, provide adequate filtration efficiencies, and are easily scaled to different facial sizes. Using a mannequin fit test simulator, we demonstrate that these masks can provide optimal filtration efficiency and ease of breathing with minimal leak- age. Because this mask provides greater comfort compared to commercial alternatives, it is likely to promote greater mask wearing tolerance and acceptance.

scholarly journals Challenge of N95 Filtering Facepiece Respirators with Viable H1N1 Influenza Aerosols

2013 ◽  
Vol 34 (5) ◽  
pp. 494-499 ◽  
Author(s):  
Delbert A. Harnish ◽  
Brian K. Heimbuch ◽  
Michael Husband ◽  
April E. Lumley ◽  
Kimberly Kinney ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Occupational Safety ◽  
Inhalation Exposure ◽  
H1n1 Influenza ◽  
Filtration Efficiency ◽  
Polystyrene Latex ◽  
Respiratory Protection ◽  
Clinical Environment ◽  
Flow Rates ◽  
Significant Difference

Objective.Specification of appropriate personal protective equipment for respiratory protection against influenza is somewhat controversial. In a clinical environment, N95 filtering facepiece respirators (FFRs) are often recommended for respiratory protection against infectious aerosols. This study evaluates the ability of N95 FFRs to capture viable H1N1 influenza aerosols.Methods.Five N95 FFR models were challenged with aerosolized viable H1N1 influenza and inert polystyrene latex particles at continuous flow rates of 85 and 170 liters per minute. Virus was assayed using Madin-Darby canine kidney cells to determine the median tissue culture infective dose (TCID50). Aerosols were generated using a Collison nebulizer containing H1N1 influenza virus at 1 × 108 TCID50/mL. To determine filtration efficiency, viable sampling was performed upstream and downstream of the FFR.Results.N95 FFRs filtered 0.8-μm particles of both H1N1 influenza and inert origins with more than 95% efficiency. With the exception of 1 model, no statistically significant difference in filtration performance was observed between influenza and inert particles of similar size. Although statistically significant differences were observed for 2 models when comparing the 2 flow rates, the differences have no significance to protection.Conclusions.This study empirically demonstrates that a National Institute for Occupational Safety and Health-approved N95 FFR captures viable H1N1 influenza aerosols as well as or better than its N95 rating, suggesting that a properly fitted FFR reduces inhalation exposure to airborne influenza virus. This study also provides evidence that filtration efficiency is based primarily on particle size rather than the nature of the particle's origin.

scholarly journals Covid-19 respiratory protection: the filtration efficiency assessment of decontaminated FFP2 masks responding to associated shortages

2021 ◽  
Author(s):  
M. Benboubker ◽  
B. Oumokhtar ◽  
F. Hmami ◽  
K. El Mabrouk ◽  
L.EL Alami ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Structural Changes ◽  
Fourier Transforms ◽  
Chemical Characterization ◽  
Small Variation ◽  
Filtration Efficiency ◽  
Respiratory Protection ◽  
Filter Media ◽  
Test Protocol ◽  
Efficiency Measures

AbstractDuring the Covid-19 pandemic, healthcare workers were extremely vulnerable to infection with the virus and needed continuous protection. One of the most effective and widely used means of protection was the FFP2 respirator. Unfortunately, this crisis created a shortage of these masks, prompting hospitals to explore opportunities to reuse them after decontamination.An approach for assessing the filtration efficiency of decontaminated FFP2 masks has been proposed and applied to evaluate the possibilities of their safe reuse. The decontamination processes adopted are those based on moist heat or hydrogen peroxide. The approach introduces efficiency measures that define the filtration and protection capacity of the masks, which characterize both chemical and structural changes, and encompasses many techniques including scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The test protocol was applied to mask samples that had endured different decontamination cycles and the results of their efficiency measures were compared to brand-new masks’ performances.The main result was that chemical and structural characterization of the decontaminated masks have shown no substantial change or deformation of their filter media structures. Indeed, the respiratory resistance test has shown that the results of both the FFP2 masks that have undergone a hydrogen peroxide disinfection cycle or a steam autoclave cycle remained constant with a small variation of 10 Pa from the EN149 standard. The chemical characterization, on the other hand, has shown that the filter media of the decontaminated masks remains unchanged, with no detectable chemical derivatives in its constituents.

scholarly journals Design of Polypropylene Electret Melt Blown Nonwovens with Superior Filtration Efficiency Stability through Thermally Stimulated Charging

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2341
Author(s):  
Haifeng Zhang ◽  
Nuo Liu ◽  
Qianru Zeng ◽  
Jinxin Liu ◽  
Xing Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Particulate Matter ◽  
Filtration Efficiency ◽  
Personal Protection ◽  
Air Filtration ◽  
Air Resistance ◽  
Filtration Material ◽  
Charge Stability ◽  
Novel Strategy ◽  
Production Probability

Electret filters are widely used in particulate matter filtration due to their filtration efficiency that can be greatly improved by electrostatic forces without sacrificing the air resistance. However, the attenuation of the filtration efficiency remains a challenge. In this study, we report a novel strategy for producing an electret melt blown filter with superior filtration efficiency stability through a thermally stimulated charging method. The proposed approach optimizes the crystal structure and therefore results in the increased production probability of the charge traps. In addition, the re-trapping phenomenon caused by the thermal stimulation during the charging process can greatly increase the proportion of deep charge to shallow charge and improve the charge stability. A superior electret melt blown filtration material with a high filtration efficiency of 99.65%, low pressure drop of 120 Pa, and satisfactory filtration efficiency stability was produced after three cyclic charging times. The excellent filtration performance indicated that the developed material is a good air filtration candidate component for personal protection applications.

The Filtration Efficiency of Single-Layer Textiles for Respiratory protection

2021 ◽  
Vol 3 (2) ◽  
pp. 1-12
Author(s):  
Behnam Pourdeyhimi ◽  
Simon Schick ◽  
Robert Groten
Keyword(s):  
Particle Size ◽  
Single Layer ◽  
Face Mask ◽  
Filtration Efficiency ◽  
Respiratory Protection ◽  
Test Protocol ◽  
Astm Standard ◽  
The Face

Due to the increasing number of corona cases and the face mask industry's associated bottleneck, this work focuses on the various single-layer textiles used as cloth masks. The purpose of this work is to test ten different single-layer textiles for their suitability as face masks. All tests in this work were carried out based on the ASTM F2299 and the new ASTM Standard for barrier masks (3502-21). The new standard offers a more precisely defined test protocol and is consistent with how respirators are tested. The results show that only one of the ten textiles tested meets the ASTM requirements for a barrier mask. We also include data for ASTM F2299 and report the results for unneutralized challenge particles at various face velocities for the same single-layer textiles. These results are different from those of the ASTM 3502 because the particle size and the procedure used are different.  Under ASTM 3502, the resistance values ​​are significantly higher, and the efficiency values ​​are significantly lower than those reported by using the ASTM F2299.

The deposition of nanofibers onto a traditional filtration medium and their effects on filtration efficiency

2021 ◽  
pp. 004051752110441
Author(s):  
Adéla Kotzianová ◽  
Zuzana Hrubá ◽  
Štěpán Vondrovic ◽  
Ondřej Židek ◽  
Marek Pokorný ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Critical Size ◽  
Filtration Efficiency ◽  
Excessive Pressure ◽  
Low Area ◽  
Filtration Membranes ◽  
Filtration Material ◽  
Micrometer Scale ◽  
Filtration Medium ◽  
Scanning Electron

Traditional filtration media composed of fibers with sizes on the micrometer scale have difficulty filtering particles a little smaller than 300 nm. Even though nanofibrous materials are able to capture these particles and can have excellent filtration efficiency, their widespread use continues to be inhibited by several obstacles, particularly an excessive pressure drop and the inability to form self-supporting filtration membranes. We have prepared two types of composite materials, namely an ultra-thin nanofibrous layer made of polyurethane or nylon with various fiber diameters and pore areas. Scanning electron microscopy was used for their characterization. The nanofibrous layer was deposited directly onto a traditional melt-blown polypropylene filtration fabric with a very low area weight of 30 g/m2, which facilitates handling and bypasses the need for the layer to be self-supporting. Moreover, a fine polyethylene mesh was added as a separate layer to prevent humidity from passing through the filtration material as well as to cover fabrics. The filtration efficiency and the pressure drop of the prepared materials were determined. The results showed that the incorporation of a nylon nanofibrous layer with smaller fiber diameters and pore areas leads to a significant increase in the filtration efficiency (92%) against the most penetrating particles, the critical size of which decreased to 50 nm, while the pressure drop was comparable to the pressure drop of a commercially available FFP2 respirator. The prepared filtration material could be used to manufacture respirators.

Study on Filtration Performance of Cylinder Metal Rubber Filtering Material

2009 ◽  
Vol 79-82 ◽  
pp. 75-78
Author(s):  
Ya Dong Guo ◽  
Hui Yan ◽  
Yu Hong Xia ◽  
Hong Yuan Jiang
Keyword(s):  
Pressure Drop ◽  
Small Diameter ◽  
Initial Pressure ◽  
Filtration Efficiency ◽  
Material Research ◽  
Filtration Performance ◽  
Metal Rubber ◽  
Filtration Material ◽  
Liquid Condition ◽  
Drop Flow

As a novel porous functional material, metal rubber (MR) had many advantages of high loading capacity, high anti-blocked capacity and adjustable porosity with outside pressure made the MR more suitable as filtration material. However, there was no related study and successful application nowadays except in Russia. This study detailed investigated the filtration performance of MR including the influence of wire line diameter, porosity and molding thickness on initial pressure drop under clean liquid condition and their effects on pressure drop-flow rate property and filtration efficiency under contaminated liquid condition. The results indicate that the initial pressure drop increased with the decrease of porosity and wire line diameter, however decreased with the decrease of molding thickness when the flow was constant. Filtration drop increased significantly with the decrease of porosity. MR material made of small diameter wires showed a high filtration efficiency and large pressure drop because of its’ fine micro-pore. Filtration drop rose with the increase of molding thickness however, the filtration efficiency was little affected. These results provide a suitable guideline for further MR filter appliance and MR material research.

scholarly journals Effectiveness of Different Cellulose-Based Filtration Materials against Inhalation of SARS-CoV-2-Like Particles

2021 ◽  
Vol 1 (2) ◽  
pp. 57-66
Author(s):  
Alyne R. de Araújo ◽  
Lívio C. C. Nunes ◽  
Karla C. B. F. Oliveira ◽  
Maria G. F. M. Carvalho ◽  
Juliana C. Cardoso ◽  
...  
Keyword(s):  
Low Cost ◽  
Filter Material ◽  
Face Mask ◽  
Filtration Efficiency ◽  
Testing Time ◽  
Respiratory Protection ◽  
Health Crisis ◽  
The Public ◽  
Public Health Crisis ◽  
Retention Testing

The respiratory protection equipment (RPE) used by health professionals consists of an essential device to prevent infectious diseases, especially those caused by biological agents such as the coronavirus (SARS-CoV-2). The current epidemiological panorama is worrying, and the context of creation and production of the mask has emerged as an alternative to RPE to face the public health crisis worldwide. The aim of this work is to present a low-cost alternative as an FFP2-like filter for a reusable respirator face mask. This study presents the comparison of different cellulose-based filtering materials performed by retention testing, time saturation testing, aerosol penetration testing, nanoparticle (~140 nm) filtration testing, bacterial filtration efficiency (BFE), analysis of material morphology and usability. The reusable respirator face mask used in this study is an open-source innovation, using 3D printing. Cotton disc proved to be the best filter material for the reusable mask, with satisfactory results and a performance similar to that shown by the N95-type mask. The cotton disc ensured effectiveness over 6 h of use, and after that, the reusable respirator face mask (here, Delfi-TRON®) needed to be sanitized and replenished with a new cotton disc. Upon preliminary analyses of filtration efficiency, the selected filter was shown to be a low-cost biodegradable and biocompatible alternative.

scholarly journals Properties analysis of filtration materials with nanofibers addition

2019 ◽  
Vol 68 (1) ◽  
pp. 111-129
Author(s):  
Tadeusz Dziubak ◽  
Yurii Yendzheiovskyi
Keyword(s):  
Flow Resistance ◽  
Aerodynamic Characteristics ◽  
Filtration Efficiency ◽  
Mass Loading ◽  
Air Filtration ◽  
Air Filter ◽  
Dust Mass ◽  
Filtration Material ◽  
Accuracy Increase ◽  
Positive Effect

Nanofiber properties, methods of their production, and areas of their application have been presented. Parameters describing filtration materials with nanofibers addition were presented, and analyzed. Methodology for testing aerodynamic characteristics as well as characteristics of: efficiency, accuracy, and filter cartridges resistance with nanofibers addition, depending on the dust mass loading km were developed. Characteristic filtration parameters of the materials with nanofibers addition are presented. Five filtration inserts, differing in the filtration material with nanofibers addition, and without this layer were made. Test conditions were developed as well as a test stand was prepared. Aerodynamic characteristics tests of filter cartridges as well as filtration efficiency, accuracy, and flow resistance of standard (cellulose) cartridge, and the ones with nanofibers addition were performed. The positive effect of nanofiber layer on efficiency, and accuracy increase in the inlet engine air filtration was confirmed. Granulometric composition of air dust was assessed on a standard filter cartridge, and on a cartridge with nanofibers addition. Keywords: engine, air filter, nanofibers, filtration efficiency and accuracy, flow resistance, dust mass loading, grain size.

scholarly journals Efficiency of Electret Polycarbonate Nonwovens in Respiratory Protection Against Nanoparticles

2017 ◽  
Vol 17 (2) ◽  
pp. 188-198 ◽  
Author(s):  
Agnieszka Brochocka
Keyword(s):  
Sodium Chloride ◽  
Human Health ◽  
Standard Method ◽  
Negative Charge ◽  
Positive Charge ◽  
Filtration Efficiency ◽  
Protective Equipment ◽  
Respiratory Protection ◽  
Paraffin Oil ◽  
Toxicological Research

Abstract Toxicological research on the influence of noxious nanoparticles on human health indicates the need to develop efficient protective devices. In particular, this concerns respiratory protective equipment employing filtration nonwovens. This paper presents a methodology for the improvement of the filtration efficiency of electret nonwovens against nanoparticles by enriching amorphous polycarbonate (PC) with additives of different electrostatic potentials. We introduced perlite granules (positive charge) and amber granules (negative charge) to the polymer stream in melt-blown technology. Filtration efficiency was assessed by a standard method using paraffin oil and sodium chloride aerosol, as well as by a non-standard method using NaCl nanoparticles. The experiments showed that strengthening the effects of electrostatic forces by the introduction of modifiers is a promising approach to improving the efficiency of electret nonwovens against nanoparticles.

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