FFP2 vs FFP3 vs half-mask: what UK trades actually need to wear

So you walked onto a site, the dust storm from the mason was head-high, and you thought about the mask screwed up in your toolbox. The honest question is not which brand to buy, but which protection class you need for the work you do most. The gap between FFP2 and FFP3 is bigger than the price difference suggests, and the gap between a disposable and a half-mask is bigger still.

Here is how the three options compare in the real jobs that UK trades do, and what fit test and inspection you need to make the kit do what the box says it will.

The protection numbers explained

Three figures matter. Filtration efficiency on the mask itself, assigned protection factor as used on site, and the workplace exposure limit of the substance you are breathing. FFP2 filters 94 percent of airborne particles under the EN 149 standard. FFP3 filters 99 percent. P3 cartridges on a half-mask filter 99.95 percent.

HSE guidance translates those figures into assigned protection factors. FFP2 is APF 10. FFP3 is APF 20. A half-mask with P3 cartridges is APF 20 as well, but the extra material and the mechanical seal mean the real world performance tends to sit closer to the lab figure than a paper mask does.

The APF is what you compare against the exposure. If a workplace is at 2 mg/m³ of airborne dust, an APF 10 mask drops that to 0.2 mg/m³ at the lung. For most routine construction dust at that concentration, an FFP2 is enough. If the WEL is 0.1 mg/m³, you need to drop the exposure further, and FFP3 or a half-mask with P3 is the step up.

Silica: FFP3 is the floor

Respirable crystalline silica has a UK workplace exposure limit of 0.1 mg/m³ averaged over 8 hours. Any dry cut, dry grind or dry drill of concrete, mortar, brick, kerb, stone or paving releases silica dust at concentrations that can go well into the single digits of mg/m³ at the operator's face. HSE's Construction Dust guidance is clear that water suppression is the first control, extraction is the second, and RPE is the backup. The RPE part says FFP3 or better.

For a bricklayer cutting a day's worth of blocks on a bench saw, water suppression on the saw plus an FFP3 is the standard combination. For a groundworker breaking out concrete with a 10 kg demolition breaker, a half-mask with P3 cartridges is more comfortable than an FFP3 for a two hour run, and it is what most sensible site managers now specify.

Wood dust: softwood is FFP2, hardwood and MDF are FFP3

Softwood dust has a 5 mg/m³ WEL. For most routine joinery work, an FFP2 on top of LEV extraction is proportionate. Hardwood dust has a 3 mg/m³ WEL and is a Category 1 carcinogen in UK labelling. For planing, routing or sanding oak, ash, beech or any dense hardwood, FFP3 is where you start.

MDF sits in a strange place. The WEL for it is the softwood 5 mg/m³, because the base fibre is pine. The fines are much smaller and go deeper into the lung than natural softwood dust, and the formaldehyde in the resin is a separate respiratory irritant. In practice, most workshops that sand MDF for more than an hour at a time put workers in FFP3, and nobody writes to HSE to complain.

Isocyanate paints: this is cartridge territory

Two pack polyurethane finishes used on commercial vehicle refinishing release isocyanate vapours during spray. A particulate FFP2 or FFP3 does not stop vapour. The right RPE for isocyanates is an air-fed respirator with a positive pressure hood, not a disposable mask. If you are a vehicle refinisher and someone has handed you an FFP3 and told you to crack on, they have handed you the wrong kit.

Solvent based paints, 2K lacquers, body filler sanding, panel bonder vapours — all need the same category of thought. The pragmatic rule is that if the datasheet mentions a half-mask with ABEK or similar cartridges, a disposable paper mask is not the right tool, whatever its FFP rating.

Welding: a different kind of problem

Welding fume is a mix of metal particulates, nitrogen oxides and other combustion products. HSE moved welding fume into its own enforcement category after reclassifying mild steel welding fume as a Group 1 human carcinogen in 2019. On any welding work indoors or in a confined space you want local exhaust ventilation at the arc. For RPE, a powered air-purifying respirator with a welding helmet shell is now the standard choice for anything beyond a short tack weld. These are £450 to £900 for the 3M Speedglas or Jackson equivalent kits, which is a step up from an FFP3 but a sensible investment if you weld daily.

Why fit matters more than filter class

A great filter on a mask that does not seal to your face is a useless filter. The air takes the easy route, which is around the edge of the mask, past your cheek bones and into your nose. Face-fit testing is a check of whether the exact mask on your face, with your facial hair, glasses, helmet and shift pattern, actually seals.

Qualitative fit tests are a hood over the head and a bitter or sweet aerosol sprayed in. If you can taste it, the mask leaks. Quantitative fit tests use a Portacount machine to count particles inside and outside the mask and give a numerical fit factor. The qualitative test is £30 to £40 a worker and covers you for disposable FFP masks. The quantitative test is £80 to £120 and is the one you want for half-masks and powered respirators.

Fit tests expire. Change your mask make or model, grow a beard, lose two stone or add dentures and you need a fresh test. For most trades a two-year repeat cycle is the practical maximum, and a yearly repeat is sensible if you work in a safety-critical environment.

Half-masks: when they stop being optional

If you wear an FFP3 for more than two hours a day on a regular basis, a half-mask with P3 cartridges will cost you less over a year. A good half-mask like the Moldex 7000 or 3M 6500QL is £35 to £60, cartridges are £5 to £10 a pair, and the mask lasts years with the body wiped down and the valves replaced annually. The maths beats throwing away two FFP3 masks a day.

The comfort is the real win. A half-mask has an exhalation valve that pushes out moist warm air, so the inside stays dry. An FFP3 with your breath condensing against the inside is uncomfortable after an hour and most people start to pull it off. A half-mask you can wear for a four hour shift.

Beards, glasses and helmet straps

Any beard that touches the sealing surface of a tight-fitting mask breaks the seal. Not a trimmed beard that stops short of the sealing edge. Not a day's stubble that is still growing out at the end of the week. A clean shave on the sealing area is required. For workers who do not want to shave on religious grounds, a loose-fitting powered respirator is the alternative, and HSE accepts that as an equivalent control.

Safety glasses with thick arms can lift the mask off the bridge of the nose. Check the fit with the glasses you actually wear. Helmet straps run over the top of the mask, not under the sealing edge. If your helmet is pushing the mask off the cheek line, swap the strap position or move to a different helmet.

How to buy for the way you work

If you are a general builder doing a mix of brick cutting, timber work and plasterboarding, an FFP3 is the right default. Buy a box of 10 to 20 of a brand you have been fit tested on, keep them in a sealed bag in the van, and treat each one as single-shift wear. A box of valved FFP3 from 3M or JSP costs £30 to £50, so £3 to £5 a mask.

If you do more than two hours a day of hard dust work, buy a half-mask kit. Get fit tested on it. Keep a labelled spare pair of cartridges in your toolbox and change them when breathing resistance goes up or every month, whichever comes first. Clean the mask body with mild soap at the end of each week, and store it in a sealed bag so dust does not settle on the sealing edge.

If you weld, spray paint or work with isocyanates, upgrade to a powered respirator for those tasks. Keep the disposable masks for passing exposures and the half-mask for routine. The right RPE is the one you will actually wear through the hour it matters, and that comes down to comfort as much as filtration.