For individuals wearing respirators that just cover their nose and mouth, or half-mask respirators, qualitative fit testing is normally used. Filtering face piece respirators, or N95s, and elastomeric respirators are considered half-mask respirators.
To detect leakage into the respirator face piece, qualitative fit tests use your sense of taste or smell, or your reaction to an irritant. This is a pass/fail method that relies on whether or not you detect leakage of the test substance into your face piece. OSHA accepts four qualitative fit test methods:
* Isoamyl acetate, which smells like bananas;
* Saccharin, which leaves a sweet taste in your mouth;
* Bitrex, which leaves a bitter taste in your mouth; and
* Irritant smoke, which can cause coughing.