| 1(888)341-2393 | (301) 608-0370


ASTM F2101: Evaluating the Bacterial Filtration Efficiency (BFE) of Medical Face Mask Materials, Using a Biological Aerosol of Staphylococcus aureus

Purpose and Goals

  • Evaluate and compare the bacterial filtration efficiency (BFE) of filter samples (such as HVAC filters, face masks, and other filtration media) in laboratory-controlled aerosol filtration testing. 


  • This testing will be performed according to ASTM F2101-22, ISO 14683:2017, or BS EN 14683:2019.
  • A liquid suspension of bacteria (Staphylococcus aureus ATCC 6538) will be aerosolized via a nebulizer and used to fill a glass chamber with microscopic droplets.
    • This test can also be modified for viruses based on ASTM F1671.
  • One filter sample will be clamped over the end of the glass chamber.
  • The aerosolized bacteria will be pulled via vacuum through the filter sample and sorted by size into the different stages of an Andersen 6-stage sieve stack cascade impactor sampler and propelled onto agar-filled Petri dishes.
    • A control set of Petri dishes will also be used to directly collect aerosolized bacteria without a filter over the end of the glass chamber.
  • The Petri dishes will be incubated for 24-48 hours to grow the bacteria into visible colonies. The numbers and distribution of bacterial colonies on each stage are used to calculate the average size and the total number of aerosol droplets that passed through the system.
  • The filtered results are compared with the unfiltered results. This ratio (BFE percentage) expresses how well the test filter material captures aerosolized bacteria.
  • Optional: Follow-up Post-BFE Testing to determine how well an antimicrobial agent in the filter material reduces bacterial burden over time is available by request.

Data Analysis

  • Data will be analyzed to determine the consistency between replicate filter samples.

Turn Around Time

  • 2-4 weeks