NOTE: Each opening shall have a free area of not less than 1 square inch per 1,000 Btu per hour of the total input rating of all appliances in the enclosure and not less than 100 square inches.
FIGURE 702.3 ALL AIR FROM INSIDE THE BUILDING
NOTE: The inlet and and outlet air openings shall each have a free area of not less than 1 square inch per 4,000 Btu per hour of the total input rating of all appliances in the enclosure.
FIGURE 703.1.1ALL AIR FROM OUTDOORS -INLET AIR FROM VENTILATED CRAWL SPACE AND OUTLET AIR TO VENTILATED ATTIC
FIGURE 703.1.2ALL AIR FROM OUTDOORS THROUGH VENTILATED ATTIC
FIGURE 703.1.3ALL AIR FROM OUTDOORS THROUGH HORIZONTAL DUCTS OR DIRECT OPENINGS
Exception: Within dwelling units, unobstructed stud and joist spaces shall not be prohibited from conveying combustion air, provided that not more than one required fireblock is removed.