Qualitative Fit Testing
This can best be defined as a pass/fail test measuring a subject’s ability to detect any leakage of gas into the respirator based on taste, smell or reaction to an irritant by the user. Using OHSA’s approved methods of testing, the user should be able to do the following without reaction; breathing normally, breathing deeply, turning head from side to side, moving head up and down as well as talking. This testing applies to half-mask respirators such as N95 face masks.Due to the fact that qualitative fit tests cannot be considered equivalent to quantitative methods, and because full-face respirators require a true minimum fit factor of 500, the qualitative methods cannot be used for full-face respirators.
Types of Qualitative Testing Methods Set By OSHA:
Isoamyl Acetate Screening
Odor threshold screening, performed without wearing a respirator, is intended to determine if the individual tested can detect the odor of isoamyl acetate at low levels (banana smell).
Saccharin Solution Aerosol Screening
Taste threshold screening, performed without wearing a respirator, is intended to determine whether the individual being tested can detect the taste of saccharin (sweet tasting).
Bitrex (Denatonium benzoate) Screening
Taste threshold screening, performed without wearing a respirator, is intended to determine whether the individual being tested can detect the taste of Bitrex (bitter taste).
Irritant Smoke (Stannic Chloride)
Test uses a person’s response to the irritating chemicals release in the “smoke” produced by a stannic chloride ventilation smoke tube to detect leakage into the respirator of the irritant smoke.