Qualitative Fit Testing

Qualitative Fit Testing (QLFT) is a pass/fail method used to assess the fit of half-face respirators by relying on the wearer’s sense of taste or smell to detect any air leakage. This type of testing is appropriate for respirators that require a fit factor of 100 or less.

During the test, a harmless, aerosolized agent—typically Bitrex (which has a bitter taste) or Saccharin (which has a sweet taste)—is released into a hood worn over the respirator. If the wearer detects the test substance, it means the respirator is not sealing properly, and the test is considered a fail.

Key Points:

Purpose: To confirm whether the respirator creates a proper seal to protect the wearer.

Test Method: Uses taste-based detection to identify air leaks.

Pass/Fail Criteria: Detection of the test substance results in a failed test.

Test Agents:

Bitrex: A bitter-tasting chemical used to detect leakage.

Saccharin: A sweet-tasting alternative for those who cannot detect bitterness.

Important Requirement:
If the applicant does not have a current medical clearance certificate, they must complete an OSHA Respirator Medical Evaluation Questionnaire prior to testing, as required by OSHA regulations. This ensures the individual is medically fit to wear a respirator.