Standard explainer · EN 149
Disposable dust masks carry the most misunderstood rating in PPE. The FFP number matters — but the seal against your face matters more, and a top-grade mask worn over stubble can protect worse than a lower grade fitted properly.
How it works
EN 149 covers filtering facepieces — masks where the whole facepiece is the filter. The grades measure two things together: how much the filter material stops, and how much leaks in around the edges. That's why the standard's real-world lesson is about fit: air takes the path of least resistance, and a gap at the nose or a bearded jawline turns any grade into decoration.
UK workplaces requiring tight-fitting RPE need face-fit testing for each wearer — and a clean-shaven seal line where the mask meets the face. That's HSE's position, not a manufacturer upsell.
The grades
| Grade | Filters (approx.) | Right for | Wrong for |
|---|---|---|---|
| FFP1 | ~80% — nuisance dusts | Hand sanding softwood, general dusty tidying | Silica, hardwood dust, anything toxic |
| FFP2 | ~94% | Plaster, softwood machine dust, general construction dust | Silica-heavy cutting, welding fume at volume |
| FFP3 | ~99% | Silica (concrete/stone cutting), hardwood dust, welding fume | Nothing above it in disposables — beyond this is powered/supplied air |
The letters
NR (non-reusable) means single shift — bin it after use; most site disposables are NR. R marks reusable facepieces that tolerate cleaning per the maker's instructions. D means the mask passed the dolomite clogging test — it breathes acceptably even as dust loads up, which matters for full-shift wear in heavy dust.
Valves ease exhalation on long wear but filter nothing on the way out — a consideration anywhere protecting others matters (food production lines, clinical settings). And frequency changes the format decision: someone in FFP3 conditions daily is usually better served by a reusable half-mask with replaceable filters — cheaper per week and easier to fit-test — which is the reusable side of the disposable vs reusable question.
Questions
Filter efficiency and permitted leakage: FFP2 stops roughly 94% of test aerosol, FFP3 roughly 99% with a tighter leakage allowance. FFP3 is the disposable grade for silica dust, hardwood dust and welding fume; FFP2 covers general construction dusts like plaster.
Tight-fitting disposables don't seal over stubble or beards — leakage around the edge bypasses the filter entirely. Bearded workers needing respiratory protection should use loose-fitting powered hoods or shave the seal line; a fit test will fail otherwise.
Non-reusable: the mask is certified for a single shift, then binned. R-marked facepieces tolerate reuse with cleaning per the manufacturer. The D mark separately shows the mask passed a clogging test and stays breathable through a dusty shift.
Where tight-fitting RPE is used to control workplace exposure in the UK, yes — HSE expects each wearer to be face-fit tested on the specific mask model they use, and refitted if the model changes or their face changes significantly.
Helmets, masks, eye protection, gloves and the rest of the PPE wall, certified and in stock.