Breathing resistance test; minimum requirements.

(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] Type of gas mask Inhalation Exhalation Initial Final 1 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 1 Measured at end of the service life specified in Tables 5, 6, and 7 of this subpart.