The outdoor openings size shall be calculated in accordance with the following:
- The ratio of interior spaces shall be the volume of the communicating spaces divided by the required volume.
- The outdoor size reduction factor shall be one minus the ratio of interior spaces.
- The size of outdoor opening(s) shall be not less than the full size of outdoor opening(s) calculated in accordance with Section 701.6, multiplied by the reduction factor. The dimension of air openings shall be not less than 3 inches (76 mm). [NFPA 54:9.3.4(3)]