46 CFR §108.181

1. (a)Each enclosed space must be vented or ventilated.
2. (b)There must be a means to close each vent or ventilating system.
3. (c)Each fan in a ventilating system must have remote controls installed in accordance with part 111, subpart 111.103, of this chapter.
4. (d)There must be a means to close each doorway, ventilator, and annular space around each funnel or other opening to machinery, stowage, or working spaces. The means must be located outside the space.
5. (e)Each intake in a ventilating system must be located so as to prevent, as far as practicable, the intake of noxious fumes.