304.5.3.2 Combining spaces in different stories.
FGC § 304.5.3.2
The volumes of spaces in different stories shall be considered as communicating spaces where such spaces are connected by one or more openings in doors or floors having a total minimum free area of 2 square inches per 1,000 Btu/h (4402 mm 2 /kW) of total input rating of all appliances.













