QualiBFE™ Test Principle & Aerosol Generation
Our Face Mask Bacterial Filtration Efficiency (BFE) Tester - QualiBFE™ measures exactly how much of those wet, germy clouds get trapped by your protective fabric layers. The testing process blasts the material with a super-focused, highly consistent mist of Staphylococcus aureus—the standard, widely accepted biological choice for checking medical surgical masks against strict guidelines like ASTM F2101 and EN 14683.
Using its highly specialized, liquid-spraying aerosol generator, the machine creates wet little droplets that sit right around 3.0 ± 0.3 microns. Because this specific method focuses entirely on the wet spray from human coughs or sneezes rather than tiny dry dust specks, the main goal is stopping these micro-droplets right at the physical barrier. The highly adjustable liquid spray flow makes sure the misty cloud remains incredibly even from the first second to the last.
Dual-Path Six-Stage Andersen Sampler Setup
Right inside the heavily secured negative pressure cabinet of our Face Mask Bacterial Filtration Efficiency (BFE) Tester sit two tall stacks of metal collection plates, known as the dual six-stage Andersen samplers. Using a completely synchronized, two-way sampling method that compares the A and B air pathways side-by-side, the internal peristaltic pump pulls the misty air down through the mask at a steady, unchanging 28.3 liters every single minute.
As the air rushes down, these six physical layers sort the wet droplets by size to perfectly mimic how a deep, drawn-out breath travels into the human respiratory tract. When those bacteria land on the sticky agar collection plates, they stay put to grow into visible spots for counting.
BFE Test Parameters & Requirements
To ensure your final numbers stand up to the absolute strictest regulatory auditors, the test theory requires following these precise, non-negotiable rules:
- The Swatch: You need a cleanly cut square of fabric to test a fair, truly representative chunk of material.
- Pre-Test Conditioning: The fabric sits quietly in a controlled space at 21 degrees Celsius and a highly humid 85% for at least four hours to reach a relaxed, perfectly evened-out state.
- Which Side Up: Always spray the side that normally touches the wearer's face to see how the mask stops outward transmission.
- The Blank Runs: You run the machine twice without any mask inside to verify that exactly 2200 ± 500 little germ spots actually grow on the control plates.
- Replication: You run the test at least five completely separate times to secure a statistically valid, highly accurate final value.
Filtration Efficiency Calculation & Data Output
Calculating the final filtration percentage relies on a straightforward, scientifically proven formula:
BFE = [ (C - T) / C ] × 100
You subtract the germ spots that snuck through the mask (T) from your blank run count (C), divide by the blank runs, and multiply by one hundred. To account for those tricky instances where multiple germs land on the exact same spot during the Face Mask Bacterial Filtration Efficiency (BFE) Tester operation, the methodology fully supports standard positive-hole correction tables to keep your final percentage incredibly clean and ready for the toughest audit. Operation is completely dictated through the massive 10.4-inch color touchscreen, and once finished, you simply pull your pristine data via the built-in USB port.
