On October 2, 2020, the testing procedure for the viral particle filtration efficiency (VFE) of medical masks manufactured by 4MASS S.A. was completed.

The test procedure was carried out by the Department of Chemical, Dust and Biological Hazards at the Central Institute for Occupational Protection PIB using the guidelines contained in Annex B (filtration efficiency testing of bacteriophage strains Staphylococcus aureus ATCC 6538) of the European Standard EN 14683:2019+AC. In the VFE test, the generated biological aerosol contained viral particles of bacteriophage strain Phi X174 (AtCC 13796-B1) with a spherical shape with spears of ~ 32 nm in diameter.

Ocena skuteczności filtracji cząsteczek wirusowych VFE wyniosła 98% < 98,8%