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Qualitative Fit Test (QLFT)

Last updated: June 21, 2022

What Does Qualitative Fit Test (QLFT) Mean?

A qualitative fit test (QLFT) is a type of respirator fitting test that relies on the user’s sense to determine whether there is any leak in the seal of the respirator to his/her face. The test procedures include testing at a sensitivity level that establishes whether the user would be able to sense the presence of the test agent by taste, smell or cough while wearing the respirator.

Safeopedia Explains Qualitative Fit Test (QLFT)

A qualitative fit test (QLFT) is a pass/fail test for a respirator. It is fitted to a person to assess the adequacy of respirator fit. It relies entirely on the individual’s sensory detection of the test agent.

Advantages of a QLFT are that it is an inexpensive and simple procedure, it determines the brand and respirator size of the user. However, a QLFT cannot determine the limit of protection-factor or numerical results and there are chances of user deception.

During the test, a challenge agent is administered outside the respirator and the presence of the agent is detected by the user. Test agents include the following:

  • Saccharin - A sweet tasting solid aerosol
  • Isoamyl acetate - A liquid that produces a banana-like flavor
  • Bitrex - A bitter tasting aerosol
  • Irritant smoke - A stannic oxychloride aerosol that produces hydrochloric acid in the presence of water vapor. It produces an involuntary coughing reaction. This is not recommended by National Institute for Occupational Safety and Health (NIOSH) due to health risk factors.


respiratory fit test, respirator fit test, respirator fitting, respirators usage, respirator selection criteria, PPE

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