42 C.F.R. § 84.122
(b) The maximum allowable resistance requirements for gas masks are as follows:
| 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. |