Open to the Atmosphere : A space or compartment that has at least 15 in. 2 of net open area directly exposed to the atmosphere for each cubic foot of net compartment volume (0. 34 m2/m3)
NFPA 302 Fire Protection Standard for Pleasure and Commercial Motor Craft, 1998 ed. https://www.nfpa.org/assets/files/AboutTheCodes/30 2/302-A2003-rop.PDF, (Std: Fr Prac for Pleasure and Comm Motor Craft - Amer) {292 NFC}