BFE Testing for Face Masks: What ASTM F2101 Measures
A clinic does not buy a mask because of its filtration number alone, but the number is what tells a buyer whether the product in front of them is a procedure mask, a high-barrier mask or something nobody tested. One of the two figures on every ASTM F2100 report comes from a bacterial aerosol.
The test behind that figure is ASTM F2101. It is a laboratory method rather than a field performance claim, and knowing what it covers keeps a supply conversation honest.
What does BFE measure on a face mask?
BFE is bacterial filtration efficiency. A mask material sample is challenged with an aerosol of a standard bacterium at a controlled flow rate, and the percentage of the challenge that does not pass through the material is reported as BFE. A result of 98 percent means the material blocked 98 percent of that aerosol under the test conditions.
The method is a material test. It says nothing about how the mask fits a face, how long it stays effective, or how it is stored on a shelf.
How is BFE different from PFE?
PFE is particle filtration efficiency and uses a smaller, non-biological challenge aerosol. Both appear on a mask report because a mask has to hold up against droplets and against finer particles.
| Test | Challenge aerosol | What the result tells a buyer |
|---|---|---|
| BFE (ASTM F2101) | Bacterial aerosol at a defined flow rate | How much of a droplet-borne challenge the material blocks |
| PFE (ASTM F2299) | Latex spheres at a smaller particle size | How the material performs against finer particles |
| Fluid resistance (ASTM F1862) | Synthetic blood at pressure | Whether the material resists a splash at a stated pressure |
| Differential pressure | Air flow through the material | How hard the mask is to breathe through |
How do the ASTM F2100 levels use these tests?
The mask standard sets minimums for each test and groups them into levels. Level 1 masks meet the lowest threshold of each test, Level 2 sits above it and Level 3 asks for splash resistance at a higher pressure. A level is not a quality score; it is a statement about which minimums the product met.
What should a clinic check before ordering?
Three things. First, the report behind the level claim, filed with your infection control records. Second, the format you actually use chairside: boxed bulk clinic packs for a treatment room, and ASTM level 1 procedure masks for routine contact, with level 3 masks reserved for procedures with a splash risk. Third, the storage plan, because a carton that sits open in a utility room will not be protected by any test result.
If you need to match mask levels to the way your rooms work, request a quote on a mixed mask order and we will build it around your procedure mix. Facilities that already ask suppliers for test reports can apply the same evidence-first habit to their own autoclave with the 5-pack indicator trial.
References
- ASTM F2101 - Standard test method for evaluating the bacterial filtration efficiency of medical face mask materials (checked 18 September 2026)
- Public Health Ontario - infection prevention and control guidance for clinical settings (checked 18 September 2026)
Ordering for a clinic, lab or care home? Wholesale and multi-site ordering covers case pricing and account setup, and the B2B wholesale collection lists the lines stocked for institutional buyers.
Related Reading
- Face masks for Canadian clinics and care homes
- Learning Hub - clinical and procurement guides
- Surgical mask filtration explained: BFE, PFE and ASTM F2100 testing
- Face mask BFE and PFE testing: what the numbers actually mean
- ASTM F2100 levels 1, 2 and 3 compared: choosing masks for your clinic
- free Ontario sterilization compliance log
Frequently Asked Questions
What does BFE mean on a face mask?
BFE stands for bacterial filtration efficiency. It is the share of a standardised bacterial aerosol that a mask material keeps from passing through during a laboratory test, reported as a percentage. A mask labelled BFE 95 percent filtered at least that share of the challenge aerosol in the test.
How is BFE different from PFE?
BFE uses a bacterial aerosol and reports how much of it the material blocks. PFE uses a latex sphere aerosol at a smaller particle size and reports filtration at that size. The two numbers answer different questions, which is why the mask standard lists both.
Does ASTM F2101 apply to cloth masks?
No. ASTM F2101 is written for medical face mask materials made for single use in health care. A cloth face covering is not tested under it, so it has no BFE or PFE figure you can compare with a procedure mask.
Where do I find BFE results for the masks I order?
Ask the supplier for the test report behind the level claim. A report shows the standard used, the challenge organism, the flow rate and the result, so you can file it with your infection control records instead of relying on a claim printed on the carton.
Last updated: September 2026. CliniEco Medical holds MDEL #35334 issued by Health Canada, and supplies clinics, long-term care homes and home-care programs across Canada.
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