Standardizing Barrier Face Covering Testing

[...]there is growing awareness that a clear regulatory difference exists between personal protective equipment (PPE) used in an occupational or healthcare setting - N95 respirators and surgical masks for example - and barrier face coverings that may be used by the general public such as the face co...

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Bibliographic Details
Published in:Textile World 2021-07, Vol.171 (4), p.28-30
Main Authors: Lee, Davis, Kirkpatrick, Erin, Fitzharris, Emily, Levitt, Ariana, Posson, Michael, Siskey, Ryan, Roberts, Mark
Format: Article
Language:English
Subjects:
Aerosols
Charged particles
Coronaviruses
Coverings
COVID-19
Diameters
Disease control
Efficiency
Evaluation
Filtration
Masks
Particle size distribution
Personal protective equipment
Respirators
Supply chains
Textile industry
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Summary:[...]there is growing awareness that a clear regulatory difference exists between personal protective equipment (PPE) used in an occupational or healthcare setting - N95 respirators and surgical masks for example - and barrier face coverings that may be used by the general public such as the face coverings as described by the Centers for Disease Control and Prevention (CDC).1 While established standards and requirements already exist for many types of PPE, this was not the case for the barrier face coverings that have been in wide-use by the general public in response to the COVID-19 pandemic.2 The textile community responded to the need for barrier face coverings in unprecedented fashion. The purpose was to provide a tes: method that evaluates the ability of a face covering to act as a barrier to the transfer of aerosolized particles anc large droplets of saliva and/or mucus, while also being reasonably comfortable to the wearer.4 The evaluation places a focus on the filtration efficiency, breathability, fit and expected usage conditions.5 This article reviews the importance of standardized test methods, and some of the key issues related to face coverings. Even though limitations of the detection method were discussed in the article, many news outlets reported on the implication that in some cases, a neck gaiter may be worse than no mask at all.7'8'9'10 These media conclusions have since been disproven by a number of different studies showing that neck gaiters can be effective at blocking a range of particle sizes, especially when worn as a double layer.11'12 Moreover, the higher number of particles detected in the initial study have led some to speculate that this was the result of fibers shedding from the fabric.13 However, even with these new results, the controversy of "Gaitergate" left the public confused over the efficacy of face covering options during a time when supply chain constraints were making it necessary for the general public to use all available options. The standard also permits supplemental quantitative testing to determine the leakage ratio based on ASTM F3407: Standard Test Method for Respirator Fit Capability for Negative-Pressure Half-Facepiece Particulate Respirators.25 * Charge Neutralizing Aerosol Particles: Charged particles can impact filtration efficiency due to electrostatic interactions with the mask material and other nearby particles.26,27'28 For instance, aerosols that contain moisture can change diameter during testing
ISSN:0040-5213