(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 | 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 |