To limit the probability that smoke will spread through door openings from one zone to another zone of the floor area, which could lead to harm to persons in the other zone.
To limit the probability that smoke will spread through door openings from one zone to another zone of the floor area, which could lead to fire emergency response operations involving the other zone being delayed or ineffective, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.