To limit the probability that an exposing building face will have insufficient fire resistance, which could lead to the spread of fire from the subject building to an adjacent building during the time required for emergency responders to perform their duties, which could lead to damage to the adjacent building.
To limit the probability that an exposing building face will be ignited and contribute to, or be involved in, a fire, which could lead to the spread of fire from the subject building to an adjacent building, which could lead to damage to the adjacent building.