46 CFR §154.330

1. (a)Entrances, forced or natural ventilation intakes and exhausts, and other openings to accommodation, service, or control spaces, except as allowed in paragraph (c) of this section, must be:
   1. (1)At least L/25 or 3.05m (10 ft) from the athwartship bulkhead facing the cargo area, whichever is farther, except that the distance need not exceed 5m (16.4 ft); and
   2. (2)On a house athwartship bulkhead not facing the cargo area or on the outboard side of the house.
2. (b)Each port light, located on the athwartship bulkhead of a house facing the cargo area or the house sides within the distance specified in paragraph (a)(1) of this section, must be a fixed type.
3. (c)Wheelhouse doors and windows that are not fixed may be within the distance specified in paragraph (a)(1) of this section from the athwartship bulkhead of a house facing the cargo area, if they have gaskets and pass a tightness test with a fire hose at not less than 207 kPa gauge (30 psig).
4. (d)Port lights in the hull plating below the uppermost continuous deck and in the first tier of the superstructure must be a fixed type.
5. (e)Air intakes and openings into accommodation, service, and control spaces must have metal closures that pass a tightness test with a fire hose at not less than 207 kPa gauge (30 psig).
6. (f)On liquefied toxic gas vessels, the closures required in paragraph (e) of this section must be capable of being closed from inside the space.