How PFE Is Measured on a Medical Face Mask: ASTM F2299
Two numbers appear on almost every medical face mask report, and buyers often treat them as interchangeable. They are not. One comes from a bacterial aerosol and the other from a fine particle challenge, and ASTM F2299 is the method behind the second.
Understanding the distinction makes a mask specification conversation much shorter.
What does ASTM F2299 measure?
The method determines the initial efficiency of a mask material against particulate penetration. A sample is challenged with a defined aerosol of particles, and the share that the material stops is reported as a percentage. The result describes a material property at the start of use, not a performance figure that changes with wear time.
Because the particles are not biological, this test can use a narrower particle size than the bacterial method, which is exactly why the two results answer different questions.
How does PFE relate to BFE?
| Test | Challenge | Particle size focus | Question it answers |
|---|---|---|---|
| BFE (ASTM F2101) | Bacterial aerosol | Larger droplets | How much droplet-borne challenge the material blocks |
| PFE (ASTM F2299) | Inert particle aerosol | Smaller particles | How the material performs against fine particles |
| Fluid resistance (ASTM F1862) | Synthetic blood under pressure | Not a filtration test | Whether the material resists a splash |
| Mask specification (ASTM F2100) | Combines the tests above | Sets minimums by level | Which level a mask qualifies for |
A mask standard sets minimums for the filtration tests and groups them into levels. A level is a statement about which minimums the product met, not a ranking of quality beyond those thresholds.
Why does the initial efficiency wording matter?
Because the test is run on new material. A mask that is stored in a damp cupboard, compressed in a pocket or worn for a full shift has been used beyond what the test describes. The result is a design input, not a promise about the fifth hour of wear.
The same logic explains why a high particle filtration figure on a mask that sits loose on the face still leaves gaps at the cheeks. Material performance and facial fit are separate problems, and only one of them can be measured in a laboratory dish.
Which masks carry these test results?
Routine clinical stock is where the numbers matter most. Level 1 procedure masks cover routine contact, boxed bulk clinic packs keep treatment rooms stocked, and level 3 masks are held back for procedures with a splash risk. Each level carries its own set of test minimums, which is why two masks can look identical on a shelf and sit at different levels.
What should a buyer do with this?
Ask three questions when a level claim is made: which standards were used, what the reported results were for each test, and whether the report covers the exact product code you are ordering. Then file the answer. A supplier who can produce the report is easier to keep in a vendor file, and the document is what makes the level claim verifiable rather than promotional.
If you are standardising masks across rooms or sites, the wholesale account is a simple way to compare levels in your own setting, and wholesale ordering is available once volumes justify case purchases.
References
- ASTM F2299 - Standard test method for determining the initial efficiency of materials used in medical face masks to penetration by particulates (checked 19 September 2026)
- ASTM F2100 - Standard specification for performance of materials used in medical face masks (checked 19 September 2026)
- Public Health Ontario - infection prevention and control guidance for clinical settings (checked 19 September 2026)
Related Reading
- Face masks for Canadian clinics and care homes
- Learning Hub - clinical and procurement guides
- Wholesale and multi-site ordering
- ASTM F1862 explained: blood penetration resistance for face masks
- BFE testing for face masks: what ASTM F2101 measures
- Mask fit testing for clinic staff in Canada: CSA Z94.4 steps
- free Ontario sterilization compliance log
Frequently Asked Questions
What does PFE measure on a face mask?
Particle filtration efficiency. A mask material sample is challenged with an aerosol of particles of a defined size, and the share of those particles the material blocks is reported as a percentage. The test measures the material, not the fit of the mask on a face.
Why does a mask report list both BFE and PFE?
They use different challenge aerosols at different particle sizes. The bacterial method reflects the droplet-borne challenge a mask meets in clinical work, while the particle method reflects performance against finer particles. A report lists both because a mask has to perform against both.
Does a high PFE mean the mask protects the wearer?
It means the material filtered that share of the challenge aerosol in a laboratory test. Protection in use depends on the fit, the seal around the nose and cheeks, and how long the mask is worn, which no material test can measure.
Where can I find the test report for masks I buy?
Ask the supplier for the report behind the level claim. It should name the standards used, the challenge aerosol and the result for each test, so you can file it with your infection control records instead of relying on a claim printed on the box.
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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