What is ASTM F3502?

ASTM F3502-compliant barrier face coverings are Designed to fit snugly to the face, covering both the mouth and nose, and reducing gaps Primarily intended for use as source control and are not considered medical masks. Since February of 2020, we’ve been asking for standards for masks/face coverings used by our communities. Finally, the American Society for Testing and Materials (ASTM) has established a national standard (ASTM F3502) for “Barrier Face Coverings” that are neither medical masks according to ASTM F2100 standards nor respirators according to NIOSH standards. This new standard establishes minimum requirements for design, performance, and testing that will allow users to compare mask options, and provides mask makers standards to strive for. These standards are not mandatory, but can help distinguish well-tested masks in the marketplace. For home sewists and small manufacturers, the ASTM guidance can help clarify what types of testing to look for in our reading, and clarify testing goals for those headed to the lab.

 

For covers plans that are not centered on making a tight seal/fit to the face (e.g., creased clinical covers), air can spill around the edges of the veil, conveying unfiltered particles in and out. ASTM F3502 requires covers be intended to fit cozily to the face, covering both the mouth and nose, and decreasing holes. Covers should have a method of being held to the face, and estimating data ought to be given. Plans should be investigated to show that the item lessens spillage around the edge of the veil or different territories. Vents or valves are precluded. Click here for more astm f3502-21 information !

 

F3502 Filtration

In general, masks that provide more filtration offer the user more protection than those that provide less filtration. However, when it comes to filtration testing, results depend strongly on the size of the particles used and specific testing methods. Studies should always be compared apples to apples” with the same particle sizes, materials, flow rates, and humidity levels.

ASTM F3502 follows the NIOSH methodology for NaCl Aerosols Testing utilizing 0.3um particles .Importantly, 0.3um is the most profoundly penetrant size for most materials, making this a most pessimistic scenario filtration test. Filtration execution against bigger particles, for example, respiratory beads somewhere in the range of 1um and 10um, is by and large a lot higher. Buy now click here supplier of f3502 masks

 

Relevance for Sewists and Makers

 

Face coverings that are compliant with these new standards are most likely to be produced by medium-to-large scale manufacturers that have the resources and access to accredited testing labs required to be in compliance with all the ASTM F3502 standards described above (see the Appendix for additional details on testing costs etc). However, this does not mean that sexists should stop making masks, nor does it mean that there is nothing useful in these standards for sexists and small-scale mask makers. Here is more information reusable f3502 masks

Testing Performance:

 

To qualify as ASTM F3502-compliant, the minimum criteria (Level 1) for both sub-micron particulate filtration efficiency of 20% and air flow resistance 15 mm H2O must be met. In addition, a higher performance criteria (Level 2) for filtration is available for masks with 50% filtration efficiency. For breathability, Level 2 performance classification is available for masks with an air flow resistance of 6 mm H2O. It is important to note that filtration and breathability are evaluated separately, so it is possible to have Level 1 filtration and Level 2 breathability and vice versa. Classifications are based on the poorest results of all tested samples.