9.0 Qualitative Fit Test Requirements
Qualitative fit testing is limited to protection factors of 10 (i.e. ten times the PEL). Although full face respirators and PAPRs may be able to provide greater protection, protection factors can only be verified to a maximum of 10 when using qualitative fit testing.
Qualitative fit testing must be repeated at least annually. In addition, qualitative fit testing shall be repeated immediately if the test subject has:
A weight change of 20 lbs. or more.
Significant facial scarring in the area of the face piece seal.
Significant dental changes, i.e., multiple extractions without prosthesis, or dentures.
Reconstructive or cosmetic surgery.
Or any other condition that may interfere with face piece seal.
The test subject shall be shown how to put on a respirator, proper positioning on the face, and how to set strap tension. Respirator straps should not be over tightened for testing and should be adjusted by the wearer to give a reasonably comfortable fit typical of normal use.
The test subject shall conduct negative and positive pressure user seal checks until an acceptable fit is obtained with the selected respirator.
Prior to performing a qualitative fit test, the test subject shall be given complete instructions regarding the test procedures and shall wear the face piece for at least five minutes.
9.1 BitrexTM (Denatonium Benzoate) Solution Aerosol Qualitative Fit Test Protocol
9.1.a Taste Threshold Screening
The Bitrex taste threshold screening, performed without wearing a respirator, is intended to determine whether the individual being tested can detect the taste of Bitrex.
During threshold screening as well as during fit testing, subjects shall wear an enclosure about the head and shoulders that is approximately 12 inches (30.5 cm) in diameter by 14 inches (35.6 cm) tall. The front portion of the enclosure shall be clear from the respirator and allow free movement of the head when a respirator is worn. An enclosure substantially similar to the 3M hood assembly, parts # FT 14 and # FT 15 combined, is adequate.
The test enclosure shall have a \3/4\ inch (1.9 cm) hole in front of the test subject's nose and mouth area to accommodate the nebulizer nozzle.
The test subject shall don the test enclosure. Throughout the threshold screening test, the test subject shall breathe through his or her slightly open mouth with tongue extended. The subject is instructed to report when he/she detects a bitter taste
Using a DeVilbiss Model 40 Inhalation Medication Nebulizer or equivalent, the test conductor shall spray the Threshold Check Solution into the enclosure. This Nebulizer shall be clearly marked to distinguish it from the fit test solution nebulizer.
The Threshold Check Solution is prepared by adding 13.5 milligrams of Bitrex to 100 ml of 5% salt (NaCl) solution in distilled water.
To produce the aerosol, the nebulizer bulb is firmly squeezed so that the bulb collapses completely, and is then released and allowed to fully expand.
An initial ten squeezes are repeated rapidly and then the test subject is asked whether the Bitrex can be tasted. If the test subject reports tasting the bitter taste during the ten squeezes, the screening test is completed. The taste threshold is noted as ten regardless of the number of squeezes actually completed.
If the first response is negative, ten more squeezes are repeated rapidly and the test subject is again asked whether the Bitrex is tasted. If the test subject reports tasting the bitter taste during the second ten squeezes, the screening test is completed. The taste threshold is noted as twenty regardless of the number of squeezes actually completed.
If the second response is negative, ten more squeezes are repeated rapidly and the test subject is again asked whether the Bitrex is tasted. If the test subject reports tasting the bitter taste during the third set of ten squeezes, the screening test is completed. The taste threshold is noted as thirty regardless of the number of squeezes actually completed.
The test conductor will take note of the number of squeezes required to solicit a taste response.
If the Bitrex is not tasted after 30 squeezes (step 10), the test subject is unable to taste Bitrex and may not perform the Bitrex fit test.
If a taste response is elicited, the test subject shall be asked to take note of the taste for reference in the fit test.
Correct use of the nebulizer means that approximately 1 ml of liquid is used at a time in the nebulizer body.
The nebulizer shall be thoroughly rinsed in water, shaken to dry, and refilled at least each morning and afternoon or at least every four hours.
9.1.b Bitrex Solution Aerosol Fit Test Procedure
The test subject may not eat, drink (except plain water), smoke, or chew gum for 15 minutes before the test.
The fit test uses the same enclosure as that described in 4. (a) above.
The test subject shall don the enclosure while wearing the respirator selected according to section I. A. of this appendix. The respirator shall be properly adjusted and equipped with any type particulate filter(s).
A second DeVilbiss Model 40 Inhalation Medication Nebulizer or equivalent is used to spray the fit test solution into the enclosure. This nebulizer shall be clearly marked to distinguish it from the screening test solution nebulizer.
The fit test solution is prepared by adding 337.5 mg of Bitrex to 200 ml of a 5% salt (NaCl) solution in warm water.
As before, the test subject shall breathe through his or her slightly open mouth with tongue extended, and be instructed to report if he/she tastes the bitter taste of Bitrex.
The nebulizer is inserted into the hole in the front of the enclosure and an initial concentration of the fit test solution is sprayed into the enclosure using the same number of squeezes (either 10, 20 or 30 squeezes) based on the number of squeezes required to elicit a taste response as noted during the screening test.
After generating the aerosol, the test subject shall be instructed to perform the exercises in section I. A. 14. of this appendix.
Every 30 seconds the aerosol concentration shall be replenished using one half the number of squeezes used initially (e.g., 5, 10 or 15).
The test subject shall indicate to the test conductor if at any time during the fit test the taste of Bitrex is detected. If the test subject does not report tasting the Bitrex, the test is passed.
If the taste of Bitrex is detected, the fit is deemed unsatisfactory and the test is failed. A different respirator shall be tried and the entire test procedure is repeated (taste threshold screening and fit testing).