Figure 3. Fit test using the quantitative respiratory fit testing system.

Physicians insert the test tube into the N95 respirator for keeping them closely attached to the skin (A), which counted the particles in the N95 respirator with relaxed respiration for 30 seconds. Another tube outside of the N95 respirator detected the particles in atmospheric air (A). The leak rate (in this case) was 3.52% (B). The acceptable leak rate for passing the test was 5%.