42 C.F.R. § 84.203 – Breathing resistance test; minimum requirements.

(a) Resistance to airflow will be measured in the facepiece, mouthpiece, hood, or helmet of a chemical cartridge respirator mounted on a test fixture with air flowing at a continuous rate of 85 liters per minute, both before and after each test conducted in accordance with §§ 84.206 through 84.207.

(b) The maximum allowable resistance requirements for chemical cartridge respirators are as follows:

Maximum Resistance[Millimeter water column height]
Type of chemical-cartridge respirator	Inhalation	Exhalation
Initial	Final 1
Other than single-use vinyl chloride respirators:
For gases, vapors, or gases and vapors	40	45	20
For gases, vapors, or gases and vapors, and particulates	50	70	20
Single-use respirator with valves:
For vinyl chloride	20	25	20
For vinyl chloride and particulates	30	45	2
Single-use respirator without valves:
For vinyl chloride	15	20	(2)
For vinyl chloride and particulates	25	40	(2)
1 Measured at end of service life specified in Table 11 of this subpart.
2 Same as inhalation.