(a) Resistance to airflow will be measured in the facepiece or mouthpiece of a gas mask mounted on a breathing machine both before and after each test conducted in accordance with §§84.124, 84.125, and 84.126, with air flowing at a continuous rate of 85 liters per minute.

(b) The maximum allowable resistance requirements for gas masks are as follows:

Maximum Resistance

[mm. water-column height]

Open Table
Type of gas mask Inhalation Exhalation
Initial Final1
Front-mounted or back-mounted (without particulate filter) 60 75 20
Front-mounted or back-mounted (with approved particulate filter) 70 85 20
Chin-style (without particulate filter) 40 55 20
Chin-style (with approved particulate filter) 65 80 20
Escape (without particulate filter) 60 75 20
Escape (with approved particulate filter) 70 85 20

1Measured at end of the service life specified in Tables 5, 6, and 7 of this subpart.


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