46 CFR § 153.352
B/3 and 4 m venting system outlets
April 15, 2021
A B/3 or 4 m venting system outlet must:
(a) Discharge vertically upwards; and
(b) Prevent precipitation from entering the vent system.
A B/3 or 4 m venting system outlet must:
(a) Discharge vertically upwards; and
(b) Prevent precipitation from entering the vent system.