To supersede the requirements of Sentence 188.8.131.52.(1) and not require a fire separation with a fire resistance rating, if certain conditions are met [i.e. smoke-tight barrier of not less than 12.7 mm gypsum board is installed on both sides of the walls and on the underside of floor-ceiling framing separating the exit from the remainder of the building], on the basis that the construction of rated fire separations may be cost prohibitive and the reduction in protection from spread of fire is offset by more stringent requirements for notification of occupants.
To limit the probability that smoke or fire will spread into an exit, 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 smoke or fire will spread from one floor area to another floor area by means of an exit, which could lead to harm to persons in the other floor area.