Medical Face Mask Type Check (EN 14683 Type I, II, IIR)

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 5 inputs are read from the form on every keystroke: Positive Control Mean, Count Through the Specimen, Differential Pressure (Breathability), Splash Resistance Passed At and Microbial Cleanliness (Bioburden).
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Highest Type Met (2025 limits) together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Bacterial Filtration Efficiency, Most the Specimen May Pass for 98%, BFE Margin over 98%, Breathability Headroom to 200 Pa (Type I, II), Breathability Headroom to 300 Pa (Type IIR), Breathability in 2019 Units and Type Under the 2019 Limits — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

Substituting

At 198 Pa the same mask is still Type II under 2025, but 198 / 4.9 = 40.4 Pa/cm² would have failed the 2019 limit of 40.

How to use it

1. Work through the input groups in order — Filtration (BFE) and Other Tests. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Highest Type Met (2025 limits) in the dark results panel — that is the headline figure, expressed in type.
4. Check the supporting rows underneath (Bacterial Filtration Efficiency, Most the Specimen May Pass for 98%, BFE Margin over 98%, Breathability Headroom to 200 Pa (Type I, II), Breathability Headroom to 300 Pa (Type IIR), Breathability in 2019 Units and Type Under the 2019 Limits) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Highest Type Met (2025 limits) before a trial is booked, so machine time and material in Medical, Hygiene & Barrier Textiles are committed against a calculated figure rather than an estimate.
• Costing and quotation — Highest Type Met (2025 limits) is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Positive Control Mean) shows how much of the gap in Highest Type Met (2025 limits) each variable explains.
• Teaching and study — the accepted ranges bracket normal Medical, Hygiene & Barrier Textiles practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• Limits per EN 14683:2025 as tabled by Nelson Labs and 4ward Testing: bacterial filtration efficiency at least 95% (Type I) or 98% (Types II and IIR); differential pressure at most 200 Pa (Types I and II) or 300 Pa (Type IIR); splash resistance at least 16.0 kPa for Type IIR only; microbial cleanliness at most 30 cfu/g for every type. The 2019 edition set breathability below 40 Pa/cm² (Types I and II) and below 60 Pa/cm² (Type IIR), measured over 4.9 cm² at 8 L/min; the 2019 figure here is the pressure divided by that area, so treat it as a comparison, not a re-test. BFE = (C - T) / C x 100, where C is the positive control mean and T the count through the specimen. Per 4ward Testing, the 2025 edition sets the bacterial challenge at 1.2 to 3.5 x 10³ CFU per test, counts bioburden over 300 ml of extraction fluid (a whole mask) and drops the AQL 4% batch option, so a mask that passed under 2019 may need re-testing. The Type here is from these four results only: biocompatibility (ISO 10993) and the rest of the conformity route still apply. **This is a reading aid for test reports, not a certification.**
• Every input is bounded to the range normal practice occupies (Positive Control Mean 100 to 10000 CFU, Count Through the Specimen 0 to 10000 CFU and Differential Pressure (Breathability) 0 to 1000 Pa, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Standards and further reading

• EN 14683:2025, Medical face masks: requirements and test methods. Type I, II and IIR; bacterial filtration efficiency, differential pressure in Pa, splash resistance for IIR and microbial cleanliness.
• EN 14683:2019+AC:2019, the previous edition, with differential pressure in Pa/cm².
• ISO 22609, splash resistance with synthetic blood, used for Type IIR.
• EN ISO 11737-1, microbial cleanliness (bioburden).
• ISO 10993, biological evaluation, which every medical mask also needs.

Questions people ask