1. Positive pressure test: Close off exhalation valve and exhale gently—no leak detected in 10 seconds.

2. Negative pressure test: Close off inlet opening or openings and inhale gently—no leak detected in 10 seconds.

3. Irritant smoke test: Air purifying respirators equipped with HEPA filter cartridges are work by personnel who are then placed inside a challenge chamber. Eyes are closed in the case of half-face respirators, and while moving head in vertical, horizontal, and circular directions, irritant smoke is injected into the chamber. Test subjects are checked for face piece leaks as noted by coughing symptoms.

4. Employees are cautioned to wear respirators as originally designed, i.e., all arts in place, straps secure, no part modified, nothing between respirator and fact (facelets void the approval of the respirator).

5. Facial hair (beards, sideburns, mustaches, and certain hair styles) is incompatible with the use of respirators. It is imperative that clean, smooth skin be in contact with the respirator seal. Even a mild growth of whiskers can interfere with a good facial seal. Fit testing cannot be performed for these employees.