Face fit testing

The test showing that a specific tight-fitting respirator (disposable or half mask) seals to a specific person's face, required before it is relied on as a control and repeated when the face or the mask changes.

A tight-fitting respirator only protects if it seals, and whether it seals depends on the shape of the face wearing it. COSHH requires that RPE be adequate and suitable, and the HSE's guidance makes face fit testing the way to show suitability for tight-fitting masks. The test is done by a competent person (Fit2Fit accreditation is the recognised standard) using either a qualitative method (a hood and a bitter or sweet aerosol, for disposables and half masks) or a quantitative method (a particle counter, for any mask including full-face). It tests one make, model and size of mask on one person; change the mask and the test is void. Facial hair where the seal sits breaks it, which is why sites require clean-shaven faces or powered hoods.

Records of the test (person, mask, method, date, result) are kept and the test is repeated when the person's face changes (weight, dental work, scarring) or the mask changes, and many employers repeat it every two years. A site where everyone wears FFP3 masks and nobody has been fit tested has RPE as a comfort, not a control; for silica and asbestos-adjacent work, that gap is exactly what enforcement looks for.

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