Phoenix Journal · LEV & Air Quality
Respiratory protective equipment is the mask, the respirator, the powered hood: the last thing standing between a worker's lungs and the dust, fume or mist in the air. It is also the control most often got wrong, because it is the cheapest to buy and the hardest to make work. A box of disposable masks is not a respiratory protection programme.
RPE sits at the very bottom of the hierarchy of control, below elimination, substitution, enclosure and local exhaust ventilation. It is the residual control for the exposure that genuinely cannot be removed at source, and for short-duration or emergency work where engineering controls are not practical. Reaching for masks before controlling the hazard at source is both poor practice and, where better controls were reasonably practicable, a breach of the duty under COSHH to prevent or adequately control exposure. The mask should be catching what is left after the real work has been done, not standing in for it.
When RPE is the right answer, two things have to be true at once. It must be adequate, meaning it reduces exposure enough for the specific hazard and concentration, and it must be suitable, meaning it fits the wearer, matches the task and works in the actual environment. A respirator that is perfect on paper but wrong for the job, or that no one can wear for a full shift, protects nobody. Getting either half wrong quietly leaves the worker exposed while everyone assumes they are safe.
Broadly there are two families. Tight-fitting facepieces, from disposable FFP masks through reusable half masks to full-face respirators, rely on a seal against the skin so that air is drawn through the filter rather than around the edges. Loose-fitting types, such as powered hoods and visors, supply filtered air into a headpiece and do not depend on a facial seal. The difference matters enormously the moment facial hair enters the picture.
Adequate and suitable
Every tight-fitting respirator carries an assigned protection factor, or APF, which is shorthand for how much it divides down the exposure. A disposable FFP2 has an APF of 10, meaning the wearer breathes roughly a tenth of the airborne concentration outside the mask; an FFP3 or a half mask with P3 filters has an APF of 20, and a powered hood can reach an APF of 40. To choose correctly you therefore need two numbers: how much of the contaminant is in the air, and the exposure limit you must get below. Only then can you tell whether an APF of 20 is enough or whether the job needs more.
Suitability is where good intentions come unstuck. Tight-fitting RPE only seals on skin, so a wearer must be clean-shaven where the mask meets the face, ideally shaving within a few hours of the shift, because even a day's stubble breaks the seal and lets contaminated air leak straight in. Where someone cannot be clean-shaven, for religious or other reasons, the answer is loose-fitting powered RPE that does not rely on a seal, not a tight mask worn in hope.
And no one facepiece fits everyone. Faces differ in shape and size, with real variation between individuals of different sex and ethnicity, so a model that seals beautifully on one worker may fail on the next. That is why selection is a per-person exercise, not a bulk purchase, and why it has to be proven rather than assumed.
Prove the seal
A tight-fitting respirator only delivers its protection factor if it actually seals to the individual wearing it, and the only way to know that is to test it. This is why face-fit testing is not optional under the COSHH approved code of practice: it checks that the specific make, model and size seals on that person's face. Testing is done once at selection, but it does not end there. Every wearer should also do a quick fit check, a pre-use seal check, each time they put the mask on, because a facepiece that passed a test last year still has to be donned correctly today.
Match it to the hazard
The right filter and protection factor depend entirely on what is in the air, which is why selection has to start from the hazard rather than from whatever masks are in the cupboard. Understanding dust, fume and mist and knowing what you are dealing with is the first step, because a filter suited to coarse dust may do little against fine fume or a gas. Around the right choice sits the rest of the programme: training in correct use, storage that keeps masks clean and undamaged, inspection and maintenance of reusable RPE, and supervision to make sure it is actually worn. Miss any of those and the protection factor on the box becomes a number that never reaches the worker.
Questions
A simple nuisance dust mask is not adequate RPE for hazardous substances. Proper RPE is rated to a standard with an assigned protection factor, such as FFP3 or a half mask with P3 filters, selected for the specific hazard and fit tested to the wearer. A comfort mask offers no reliable protection against fume or fine dust.
Tight-fitting respirators rely on a seal between the mask and bare skin. Stubble or a beard along the seal line creates gaps that let unfiltered air leak in, so the protection factor no longer applies. Workers who cannot be clean-shaven should use loose-fitting powered RPE, such as a hood, which does not need a facial seal.
Adequate means the RPE reduces exposure enough for the specific substance and concentration, judged against its protection factor. Suitable means it fits the wearer, matches the task and works in the actual environment. RPE has to be both, and a respirator that is adequate on paper but cannot be worn properly for the task is not suitable.
Phoenix Duct Clean · by the numbers
RPE is the backstop for exposure your extraction has not captured. Phoenix tests and services LEV to COSHH Regulation 9 so the mask is the last line, not the only one. UK-wide.