Which indicators show proper mask seal during a fit test?

• A. Positive pressure seal check
• B. Absence of air leaks
• C. Positive pressure seal check, absence of air leaks, no fogging of eyewear, and user seal test success
• D. User seal test success only

Answer: (C)

A proper respirator seal during a fit test is shown by multiple confirming signs that together prove the seal is intact. First, a positive pressure seal check is successful, meaning you exhale with the mask in place and air does not leak out around the edges; the facepiece should show a slight outward bulge rather than letting air escape. Second, there should be an absence of air leaks—no audible or perceptible whistling or feelable gaps around the seal. Third, eyewear should not fog up during the check, which indicates breath isn’t escaping upward toward the lenses and the seal around the nose is effective. Finally, you should have a user seal test success, meaning you completed the designated seal test correctly and it passed, confirming the overall fit.

If any of these indicators aren’t met, the seal isn’t reliable and the respirator won’t protect as designed, so you’d re-seat, adjust the headbands, or try a different size/model.