To limit the probability of contact or collision with items at or near ceiling level, which could lead to harm to persons.
To limit the probability that exits will have insufficient clear heights to permit efficient egress in an emergency situation, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.
To limit the probability that exits will have insufficient clear heights, which could lead to emergency responders being delayed or ineffective in carrying out their emergency response operations, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.