StacksVerified U.S. regulatory reference

42 CFR §84.173

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Dry exhalation valves and valve seats will be subjected to a suction of 25 mm water-column height while in a normal operating position.
  2. (b)Leakage between the valve and valve seat must not exceed 30 mL per minute.