What are visual indicators that a facepiece seal is effective during a seal check?

What are visual indicators that a facepiece seal is effective during a seal check?

• A. No audible or felt air leakage at the seal, and the facepiece remains snug and immobile during inhalation.
• B. A audible hiss from the seal and the mask loose on inhalation.
• C. A slight fogging under the lenses only.
• D. The facepiece squeaks when touched.

Answer: (A)

The key idea is that an effective facepiece seal shows no escape of air around the seal when you press the mask to your face and breathe in. In practice, you should not hear or feel air leaking at the seal, and the facepiece should stay snug and immobile against your face as you inhale. This indicates the seal remains in contact despite the negative pressure of inhalation. If you hear a hiss or feel air leaking, or if the mask shifts away from your face when you inhale, the seal isn’t adequate and needs adjustment. Slight fogging of the lenses isn’t a reliable indicator of a good seal and can point to leakage paths, so it’s not the best sign of an effective seal. A squeak when touched doesn’t relate to seal integrity.

The key idea is that an effective facepiece seal shows no escape of air around the seal when you press the mask to your face and breathe in. In practice, you should not hear or feel air leaking at the seal, and the facepiece should stay snug and immobile against your face as you inhale. This indicates the seal remains in contact despite the negative pressure of inhalation. If you hear a hiss or feel air leaking, or if the mask shifts away from your face when you inhale, the seal isn’t adequate and needs adjustment. Slight fogging of the lenses isn’t a reliable indicator of a good seal and can point to leakage paths, so it’s not the best sign of an effective seal. A squeak when touched doesn’t relate to seal integrity.