To limit the probability that a fire involving certain rooms will spread to the exit, which could lead to delays or ineffectiveness in fire emergency response operations, which could lead to the spread of fire, which could lead to damage to the building.
To limit the probability that venting of equipment in washrooms, toilet rooms and laundry rooms will lead to a negative pressure in the exit and draw in products of combustion from other spaces, which could lead to delays or ineffectiveness in fire emergency response operations, which could lead to the spread of fire, which could lead to damage to the building.