Assigned Protection Factors by Country: US, UK, EU, AU (2026)

How do assigned protection factors differ by country?

Published August 4, 2026 · Last updated August 4, 2026

Short answer: assigned protection factors (APFs) answer the same question everywhere — how many times cleaner is the air inside the facepiece than outside? — but the credited numbers differ by jurisdiction. OSHA's Table 1 rates every half-face device at 10 and a full facepiece at 50; the UK runs a five-rung ladder of 4, 10, 20, and 40 (plus 2000) that credits an FFP3 with twice the American half-face number; European selection starts from EN 529's laboratory-derived nominal protection factors with each member state assigning its own workplace APFs; and Australia's AS/NZS 1715 adds the rule that P3-level protection exists only on a full facepiece. Same physics, four rulebooks.

This guide is the cross-border companion to our US-focused Assigned Protection Factors Explained — read that one for the OSHA arithmetic (APF × exposure limit = maximum use concentration), and this one when a spec sheet, tender, or multinational program crosses a border. It is part of the international respirator standards pillar.

Why this matters.
The protection factor is the number that turns a measured exposure into a legal selection decision, and it does not travel. A half mask with 99.95%-class filters is credited 10× protection in Denver, 20× in London, and 30× under German DGUV rules — while the identical filter-and-facepiece combination in Sydney is credited only P2-level protection because AS/NZS 1715 reserves the top class for full facepieces. Copy a maximum use concentration across a border and the calculation is wrong before the worker ever dons the mask.

Part 1 — The APF concept in one paragraph

An APF is the minimum level of protection a properly functioning, correctly fitted respirator class is expected to deliver inside a complete program. APF 10 means the wearer breathes air at least ten times cleaner than ambient; multiply the APF by the occupational exposure limit and you get the maximum concentration in which that class may be used. The inputs on both sides of that multiplication are national: the APF comes from the jurisdiction's table, and the exposure limit from its list — OSHA PELs, UK WELs, or the ACGIH TLVs many programs adopt voluntarily, a distinction unpacked in the TLV-vs-PEL guide.

Part 2 — APF vs NPF: assigned versus nominal

Europe's system introduces a second number that trips up readers of EU spec sheets. The nominal protection factor (NPF) is laboratory arithmetic: 100 divided by the device class's maximum permitted total inward leakage under EN 149 or the facepiece standard. An FFP2's 8% leakage ceiling yields an NPF of 12.5; an FFP3's 2% yields 50. The NPF is a certification artifact, not a workplace promise — EN 529 and national authorities then assign workplace APFs at or below it, reflecting field reality the same way OSHA's 2006 APF table did for the US. The UK's HSG53 ladder (4, 10, 20, 40, 2000) is one national implementation; German DGUV rules credit an FFP3 at 30. When a European datasheet says "protection factor 50" for an FFP3, check which number it is quoting — nominal, almost certainly.

Part 3 — The master table: four systems, one device list

Values below are the workhorse air-purifying classes; atmosphere-supplying equipment extends every ladder upward. UK values follow HSG53; US values OSHA 29 CFR 1910.134 Table 1; Australian treatment follows AS/NZS 1715; European NPFs follow the EN-class leakage arithmetic with national APFs assigned beneath them.

Three rows deserve a second look. The 94–95% disposable row is the world's most harmonized number — effectively 10 everywhere, which is why N95/FFP2/P2 programs translate so cleanly. The 99%-class row is the opposite: 10, 20, 30, or "P2-level" depending on the flag, the single biggest cross-border discrepancy in respiratory protection. And the full-facepiece row shows the US as the outlier on the generous side at 50 against the UK's 40. Device-level context for these rows lives in the N95 vs P100 guide, the PAPR guide, and the EN 149 guide.

Safety note: every ladder in this table stops at the same wall — no APF, in any jurisdiction, authorizes an air-purifying respirator in oxygen-deficient atmospheres or IDLH conditions, which are reserved for supplied-air and SCBA equipment selected by a qualified professional.

Part 4 — The three cross-border traps

Trap 1: same device, different credit

A half mask wearing HEPA-class filters — the classic 3M 6000 series with 2097 P100s build — is credited 10 in the US, and its FFP3/P3-class counterparts 20 in the UK and 30 under German rules. The hardware's capability didn't change; the regulatory philosophy did.

Trap 2: Australia's full-facepiece gate

Under AS/NZS 1715, that same half-mask configuration is credited only P2-level protection — the P3 class opens exclusively with a full facepiece, as our AS/NZS 1716 guide details. Translating "half mask + P100, APF 10" from a US program into "P3 protection" in an Australian tender is the classic error in both directions.

Trap 3: maximum use concentrations don't travel

MUC = APF × exposure limit, and both factors are national. Respirable-silica limits, lead limits, and solvent limits differ across OSHA PELs, UK WELs, and other national lists — so even where the APF matches, the MUC usually doesn't. Recompute per jurisdiction, per the worked method in APF Explained, with the silica case study in the OSHA silica guide.

Part 5 — Worked example: one exposure, four selections

A grinding task measures respirable dust at 12 times the applicable exposure limit. Selecting per jurisdiction:

1. United States: APF 10 (N95 or half mask) fails at 12×; step up to a full facepiece (APF 50) — the route our full-face roundup and the full-face collection serve.
2. United Kingdom: APF 10 fails; an FFP3 or half mask with P3 (APF 20) clears 12× — the UK reaches compliance one rung earlier, per the ladder in our UK RPE guide.
3. Germany (EU): FFP3 at APF 30 clears it with margin; verify the member state's assigned table rather than the EN 529 nominal figure.
4. Australia: half-mask configurations cap at 10 regardless of filter, so 12× forces a full facepiece with P3 or a powered system under the 1715 tables.

Four compliant answers, three different hardware tiers — from one measurement. That's the whole reason this page exists.

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Frequently asked questions

What are assigned protection factors by country — the one-line version?

US: 10 for anything half-face, 50 for full facepieces. UK: 4/10/20/40 with 2000 at the top. EU: nominal factors from the EN classes with national APFs assigned beneath. Australia/NZ: 10 for half-face, with P3-level protection gated to full facepieces.

What is the difference between an APF and an NPF?

An NPF is lab arithmetic — 100 divided by the class's permitted total inward leakage. An APF is the workplace number a regulator actually credits, always at or below the NPF. European datasheets often quote the flattering NPF; selection uses the APF.

What APF does an N95 have?

10 under OSHA — the same as every tight-fitting half-face device in the US system, and effectively the same figure the UK, EU, and Australia credit their 94%-class equivalents.

Why does an FFP3 get APF 20 in the UK but a P100 half mask only 10 in the US?

Different regulatory philosophy: OSHA caps all half-face devices at 10 on fit-limitation grounds, while HSG53 credits the 99%-class media one rung higher. Neither is a measurement of your specific mask — both are policy numbers.

What protection factor does Germany give an FFP3?

German DGUV rules credit FFP3 devices at 30 — between the UK's 20 and the EN 529 nominal figure of 50, and the clearest example of member states setting their own APFs.

Why doesn't Australia credit P3 on a half mask?

AS/NZS 1715 treats the half-mask seal as the limiting factor, so the P3 class is only assigned with a full facepiece; the same filter on a half mask earns P2-level credit.

What is a maximum use concentration (MUC)?

APF multiplied by the occupational exposure limit — the ceiling concentration for that respirator class in that jurisdiction. Both inputs are national, so MUCs must be recomputed when programs cross borders.

Do assigned protection factors assume fit testing?

Yes — every system's APF presumes a complete program: fit testing for tight-fitting facepieces, training, and maintenance. An unfit facepiece delivers an unknown fraction of its APF, which is why fit testing anchors all four systems.

Which country has the highest APF for a full facepiece?

Among the four compared here, the US at 50; the UK assigns 40. European nominal figures run far higher but national assigned values govern selection.

What APF do PAPR hoods get?

US: 25 for loose-fitting hoods/helmets, or 1000 where the manufacturer demonstrates it. UK: 20 or 40 by TH class. The class systems differ enough that PAPR selection should always be run against the local table.

Is there an APF for FFP1 or P1 masks?

The UK assigns 4; the US has no 80%-class occupational device; Australia treats P1 as nuisance-dust protection outside the credited-selection tiers.

Can I use the EN 529 nominal protection factor for selection?

No — select on the assigned factor your jurisdiction publishes. The NPF is the certification-derived ceiling, not the workplace credit.

Where do exposure limits come from in each system?

OSHA PELs in the US (with ACGIH TLVs widely adopted as better practice), workplace exposure limits (WELs) in the UK, national lists across the EU, and workplace exposure standards in Australia — the other half of every MUC calculation.

Does a higher APF mean a safer respirator?

It means a higher credited ceiling, not more comfort or better fit for your face. Below the ceiling, selection quality is about seal, comfort, and maintenance — the themes of our half-mask and fit-testing guides.

Which page should I use for US-only APF math?

Our dedicated Assigned Protection Factors Explained guide — Table 1 values, MUC worked examples, and selection logic entirely inside the OSHA system.

Further reading on this site

• Assigned Protection Factors (APF) Explained — the US arithmetic this page internationalizes.
• International respirator standards: the complete guide — the pillar with all six certification systems.
• UK RPE and face fit testing — the 4/10/20/40/2000 ladder in its enforcement context.
• AS/NZS 1716 explained — the P3 full-facepiece gate in full.
• EN 149 and EN 143 explained — the classes behind the European NPF math.
• ACGIH TLVs vs OSHA PELs — choosing the exposure-limit input.
• Full face mask respirators — the hardware tier the higher rungs demand.