The Virginia Mechanical Code discusses natural ventilation options in Section 402. And has an image to accompany it (shown below).
@simonxi you mentioned today another requirement for residential specifically that would allow natural ventilation as an option for when there is a specific exhaust configuration? Can you confirm what code section that is in relation to? Also, for residential projects, we would use the Residential code, correct? Could you refer me to the natural ventilation requirements in that code section?