8.0 Quantitative Fit Testing Procedures
Quantitative fit testing is the preferred testing method. The ambient aerosol condensation nuclei counting (CNC) method, using a Portacount® Plus instrument, has been selected as the quantitative fit test protocol of choice for UNR. This instrument counts the number of particles inside and outside the mask and calculates a fit factor, consisting of the ratio of the inside air concentration to the outside air concentration, for each exercise. Once the test exercise series is complete, the instrument calculates an overall fit factor. A respirator with a half mask facepiece must achieve an overall fit factor of 100 and a respirator with a full-face mask must achieve an overall fit factor of 500 to be deemed acceptable for use.
Quantitative fit testing must be repeated at least annually. In addition, quantitative fit testing shall be repeated immediately if the test subject has:
8.0.1.
A weight change of 20 lbs. or more;
8.0.2.
Significant facial scarring in the area of the face piece seal;
8.0.3.
Significant dental changes, i.e., multiple extractions without prosthesis, or dentures;
8.0.4.
Reconstructive or cosmetic surgery; or
8.0.5.
Any other condition that may interfere with face piece sealing.
8.1 Negative Pressure User Seal Check
This test must be performed before each use and should be performed periodically during use.
This test is performed by closing off the inlets of the canister, cartridges or filters by covering with the palms of the hands, by placing seals over the canister or cartridge inlets, or by squeezing breathing tubes so that air cannot pass. Inhale gently so the face piece collapses slightly and hold breath for ten seconds. If the face piece remains slightly collapsed and inward leakage is not detected, the respirator is assumed tight and the exhalation valve and face piece are not leaking.
8.2 Positive Pressure User Seal Check
This test must be performed before each use and should be performed periodically during use.
This test is performed by closing off the exhalation valve and exhaling gently into the face piece. The fit is considered satisfactory if a slight positive pressure can be built up inside the face piece without any evidence of outward leakage. For some respirators, the exhalation valve cover must be removed. Carefully replace it after the test.
8.3 Quantitative Fitting Procedures
8.3.1.
The selected respirator must be equipped with the appropriate probed adaptor and a HEPA/P100 filter prior to commencing the fit test.
8.3.2.
The test subject shall be shown how to put on a respirator, the proper position 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.
8.3.3.
The test subject shall conduct negative and positive pressure user seal checks until an acceptable fit is obtained with the selected respirator.
8.3.4.
Prior to performing a quantitative 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.
8.3.5.
The Portacount® instrument's air sampling tubes will be connected to the facepiece and the test subject's personal data will be entered into the data base.
8.3.6.
The test subject shall perform the exercises as posted on the monitor screen, in the given order. Following each individual test exercise, the Portacount® will calculate and display a fit factor for that exercise. Failure to achieve the appropriate fit factor for any single exercise will invalidate the entire fit test. In such a case, the test subject will be required to choose another respirator or adjust the fit of the already selected respirator, repeat the user seal checks, and repeat the fit test process.
8.3.6.a. Normal breathing
Without talking, the subject shall breathe normally for at least one minute.
8.3.6.b. Deep breathing
The subject shall do slow deep breathing for at least one minute, pausing so as not to hyperventilate.
8.3.6.c. Turning head side to side
The subject shall slowly turn his/her head from side to side between the extreme positions to each side for at least one minute. The head shall be held at each extreme position for at least five seconds. Perform for at least three complete cycles.
8.3.6.d. Moving head up and down
The subject shall slowly move his head up and down between the extreme position straight up and the extreme position straight down (take care not to dislodge the respirator against the chest) for at least one minute. The head shall be held at each extreme position for at least five seconds. Perform for at least three complete cycles.
8.3.6.e. Reading
The subject shall read the Rainbow Passage (Appendix G) out loud so as to be heard clearly by the test monitor.
8.3.6.f. Grimace
The subject shall alternate between smiling and frowning.
8.3.6.g. Exercise
The subject shall either jog in place or bend at the waist for at least one minute to simulate work activity.
8.3.6.h. Normal breathing
Without talking, the subject shall breathe normally for at least one minute.
8.3.7.
Upon successful completion of the final test exercise, the Portacount® will calculate an overall fit factor and display a pass message.
8.3.8.
A copy of the fit test record will be printed and signed by both the test subject and the qualified individual conducting the fit test. The individual should take this form to their supervisor as documentation of completing the fit testing.