How to test gas masks before use?

      How do we conduct a sealing test before using gas masks? The manufacturer of activated carbon gas masks provides you with the following methods:

Method 1: Cover the exhalation valve with the palm of your hand and exhale slowly. If you feel a certain amount of pressure on your face but do not feel any air leakage between your face and the mask, it indicates good fit when wearing it; If there is a leak between the face and the mask, it is necessary to readjust the headband and mask to eliminate the leakage.

Method 2: Cover the connection port of the gas filter box with your palm and inhale slowly. If you feel difficulty breathing, it indicates that the sealing of the gas mask is good. If you feel like you can inhale air, you need to readjust the position of the mask and adjust the tightness of the headband to eliminate air leakage.

Repeat method one and method two above to conduct a sealing test until the sealing performance is good.