StacksVerified U.S. regulatory reference

42 CFR §84.154

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Airflow resistance shall be determined when the respirator is completely assembled with the respiratory-inlet covering and the hose in the maximum length to be considered for approval, coiled in loops 1.5 to 2.1 m. (5 to 7 feet) in diameter.
  2. (b)Airflow resistance shall not exceed 38 mm. (1.5 inches) of water-column height to air drawn at the flow rate of 85 liters (3 cubic feet) per minute.
  3. (c)The exhalation resistance shall not exceed 25 mm. (1 inch) of water-column height at this flow rate.