Masks intended to comply with ASTM F3502 “Standard Specification for Barrier Face Coverings” should undergo the sodium chloride aerosol challenge (NaCl) to evaluate filtration efficiency and airflow-resistance test to evaluate breathability.
The following is a table of performance requirements according to ASTM F3502:
|Performance Property||Level 1 (Lower Performance)||Level 2 (Higher Performance)|
|Sub-micron particulate-filtration efficiency|
|≥ 20%||≥ 50%|
|Air-flow resistance, inhalation||≤ 15mm H2O||≤ 5mm H2O|
Note: Products may comply with either level of each test and should be labelled accordingly. This means there may be products which perform at Level 2 for the sub-micron particulate-efficiency test but only Level 1 for the air flow resistance test. Performance should be indicated according to the results of each test.
Bacterial-filtration efficiency may also be assessed, which may give more information about the performance of a barrier face covering, but results from this test are not required to claim compliance with the standard.
Barrier face coverings should be assessed for biocompatibility to ensure the materials contacting the wearer’s skin are non-irritating and nontoxic. Cytotoxicity, skin sensitization, and irritation should be evaluated using ISO/ANSI/AAMI 10993.
Flammability should be assessed per 16 CFR Part 1610 if the barrier face covering will be used in areas where there may be thermal hazards, such as flame, high heat, or electrical applications.
According to the standard, reusable products should be tested new and after the maximum number of laundering or cleaning cycles according to the care instructions.
A leakage assessment is required, and the manufacturer can report this through product-design analysis self-declaration, or they can conduct a quantitative test according to ASTM F3407 to supplement the product-design declaration.
For filtration efficiency and airflow resistance:
Both the airflow resistance and the sodium chloride aerosol challenge test uses the TSI® CERTITEST® Model 8130 Automated Filter Tester. The samples are preconditioned at 85 ± 5% RH and 38 ± 2.5°C for 25 hours prior to assessing the airflow resistance and filtration efficiency. After preconditioning the samples are tested for filtration efficiency using aerosolized NaCl and airflow resistance on the same samples for 4-15 seconds. The NaCl particles have a count median diameter of 75 ± 20 nm, and the concentration of aerosolized particles is measured before and after impact with the sample. The amount of NaCl that passes through the sample is used to calculate the filtration efficiency of the sample. For both airflow resistance and NaCl testing the flow rate is 85 Liters per minute if the sample is a formed mask and mounted on a plate so that the entire mask is tested. If the sample is a flat material, the sample is secured into the filter-tester holder and the flow rate is adjusted to reach a face velocity of 10 cm/sec.
If the mask is intended to be laundered or cleaned and reused, testing should be performed to evaluate the impact of multiple cycles on sub-micron particulate-filtration efficiency, airflow resistance, and leakage assessment. We have the capability to perform cleaning or laundering and drying according to your specific user instructions.
For Fit Testing:
ASTM F3407 clinical evaluation provides an increased assurance that the mask will effectively fit the general population. The clinical evaluation according to ASTM F3502 can be modified to ten (10) test subjects to evaluate fit capability on a variety of facial shapes and sizes using a modified panel composition described by NIOSH. The exercises and pass/fail criteria of the test are identical to those required by OSHA for respirator users in the professional workplace for protection from hazardous gases and particulates. All clinical testing conducted by BioScience Laboratories is fully compliant with FDA Good Clinical Practices (GCP) to ensure the safety of test subjects.
If you have additional questions about barrier face-covering tests or would like to consult with the experts at Nelson Labs, just send us a request or call us at +1 (801) 290-7500.