Open to the atmosphere
Open to the atmosphere means a compartment that has at least 0.342 square meters of open area directly exposed to the atmosphere for each cubic meter (15 square inches for each cubic foot) of net compartment volume.
46 CFR § 114.400
Terms used in this subchapter are defined in paragraph (b) of this section. The number in parenthesis after certain terms describing areas on a vessel refers to the applicable column and row number where that area is listed in Tables 116.415 (b) and (c) of part 116 of this subchapter.