ASTM F3502-24 PDF

SCOPE 1.1 This specification is intended to help ensure barrier face coverings meeting the stated requirements provide (1) a means of source control for individual wearers by reducing expelled aerosols from the wearer’s nose and mouth into the air; and (2) a degree of particulate filtration that potentially reduces the amount of aerosols inhaled by the wearer. Note 1: The source control/protection provided by barrier face coverings depends on several factors not considered in this specification, such as material degradation from wearer challenges including perspiration, talking, sneezing, and the length of time the barrier face covering is worn. Further research is needed to expand the evidence base for the protective effect of face coverings and, in particular, to identify the combinations of materials that maximize both their blocking and filtering effectiveness, as well as fit, comfort, durability, and consumer appeal. (https://www.cdc.gov/coronavirus/2019-ncov/more/masking-science-sars-cov2.html.) Note 2: There are currently no established methods for measuring outward leakage from a barrier face covering, medical mask, or respirator. Nothing in this specification addresses or implies a quantitative assessment of outward leakage and no claims can be made about the degree to which a barrier face covering reduces expired human-generated aerosols. 1.2 This specification establishes minimum design, performance (testing), labeling, user instruction, reporting and classification, and conformity assessment requirements for barrier face coverings. 1.2.1 Design criteria include setting minimum areas of face coverage over the wearer’s nose and mouth, prohibiting open vents or valves, requiring a means for retaining the barrier face covering on the wearer’s head, and providing a representation of product sizing. Manufacturers are further required to perform a design analysis for assessing leakage of exhaled air from the barrier face covering where the general approach is described in the product report. Manufacturers are permitted to conduct quantitative testing as specified in this specification to supplement the design analysis. Accessories, such as braces or other devices that allow the barrier face covering to better conform to the wearer’s face, are addressed as part of this specification if used for the purpose of reducing leakage. 1.2.2 Performance and testing criteria define minimum barrier face covering filtration efficiency and airflow resistance performance properties. Sub-micron particulate filtration efficiency represents the ability to capture and reduce respirable aerosols that potentially contain viruses and bacteria. Airflow resistance represents the wearer’s ease of breathing or breathability while wearing the barrier face covering. The impact of repeated cleaning or laundering on continued performance is applied for measuring performance properties for those barrier face coverings that are intended for reuse. Manufacturers are permitted to also provide test results for bacterial filtration efficiency (BFE) as supplemental information to the mandatory performance measurement of sub-micron particulate filtration efficiency. Note 3: The principal performance criteria for barrier face covering determined by testing are sub-micron particle filtration efficiency and airflow resistance. Quantitative leakage assessment testing is optional for information purposes and is not required. This testing is not likely to be representative of outward leakage from the barrier face covering and should not be claimed to represent the amount of source control offered by the face covering. Bacterial filtration efficiency testing is also optional and not required. It is significantly different than sub-micron filtration efficiency, and the results of BFE testing cannot be interchanged or directly compared. 1.2.3 Labeling requirements specify the minimum content for labels that appear on the barrier face cover...