Qualitative Fit Test
A qualitative fit test (QLFT) is a pass/fail respirator fit test that evaluates whether a tight-fitting respirator seals adequately to a worker's face by relying on the worker's ability to taste, smell, or react to a test agent (e.g., Bitrex, saccharin, isoamyl acetate, irritant smoke), rather than using instruments to measure leakage. It is used for half-mask respirators with an assigned protection factor (APF) of 10 or less.
In a manufacturing or shop floor setting, QLFT is used to verify the fit of half-mask elastomeric respirators or N95s for workers exposed to metal fumes, solvents, dust, or welding fumes where exposures are below 10 times the permissible exposure limit. The process includes pre-screening for medical clearance and facial hair, a sensitivity test without the respirator, donning the respirator with user seal checks, performing standard exercises (e.g., normal breathing, head movements, talking) while exposed to the test agent, and documenting the pass/fail result. Co-worn PPE like safety glasses or hearing protection must be worn during the test to reflect actual work conditions.
What specific standards govern QLFT in BC and in the US?
In British Columbia, QLFT must comply with WorkSafeBC OHS Regulation Part 8, section 8.40, which requires fit testing per CSA Standard Z94.4-18. In the US, QLFT procedures are prescribed in 29 CFR 1910.134 and its Appendix A, with limitations for use only with APF ≤10.
For which respirator types is QLFT acceptable vs. not acceptable?
QLFT is acceptable for filtering facepiece respirators (e.g., N95) and half-mask elastomeric air-purifying respirators with APF 10. It is not acceptable for full-facepiece negative-pressure APRs (APF 50), tight-fitting supplied-air respirators, or tight-fitting PAPRs where higher APF is needed; these require QNFT.
How does QLFT differ from QNFT in sensitivity and outcome?
QLFT is a pass/fail test relying on the worker's sensory perception, validated to a fit factor of 100, suitable for APF ≤10. QNFT uses instruments to measure a numeric fit factor, is more objective, and is required for higher APFs (e.g., full-face, SCBA).