60 Chapter 6
Grimace by smiling and/or frowning to create a
leak in the respirator face seal. This exercise will
often result in a failed fit factor, which is why the
OSHA standard allows you to exclude that fit
factor when computing the overall fit factor.
When performing the grimace, you are
intentionally creating a break in the face seal in
order to see if the respirator re-seals itself
afterwards. Successful re-sealing is proven by
achieving a passing fit factor on the next
exercise.
The OSHA protocol includes special provisions
for the grimace exercise. It is allowed to be 15
seconds long and the resulting fit factor may be
discarded (excluded) before calculating the
overall fit factor. This is allowed because the
grimace exercise is done to intentionally break
the face seal in order to make sure the
respirator reseats itself before the next exercise.
Breathe normally while slowly bending over at
the waist as if you were touching your toes and
then moving back to an upright position. Each
cycle from upright to bending over should take
several seconds, pausing momentarily at each
extreme to take a breath.
Remain still and breathe normally.
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