Of all personal protective equipment sizing challenges, accurate sizing for respirators is the most critical. Confusion sometimes occurs because respirator sizes are given descriptors (small, medium and large), but these do not relate to any measurable value.
Respirators are made with the assumption that most peoples faces and heads have about the same width and length. This means that a medium size will fit approximately 70 percent of the adult population. Small (7 percent) and large (23 percent) sizes are made for a minority of the population.
People who need these sizes generally know from their experience buying hats or prescription eyewear that their face and head size falls outside the norm. The only way to accurately select the correct respirator size is by doing respirator fit testing.
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