46 CFR § 153.312 - Ventilation system standards.
A cargo handling space ventilation system must meet the following:
(a) A ventilation system exhaust duct must discharge no less than 10 m (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces.
(b) A ventilation system must not recycle vapors from ventilation discharges.
(c) Except for the space served by the ventilation duct, a ventilation duct must not pass through a machinery room, an accommodation space, or working spaces.
(d) A ventilation system must be operable from outside the space it ventilates.
(e) A ventilation system must be sized to change the air in the ventilated space at least 30 times per hour.
(f) A ventilation system must not allow air to stagnate in any part of a ventilated space.
(g) A ventilation system must be able to exhaust air from both above and below the deck plates of a ventilated space.