To limit the probability that a fire will negatively affect the sprinkler piping, which could lead to the failure of the piping, which could lead to the fire not being suppressed or controlled, which could lead to the spread of fire to other parts of the building, which could lead to damage to the building.
To limit the probability that the water supply to the dry sprinkler piping will be delayed in a fire situation, which could lead to the failure of the piping, which could lead to the fire not being suppressed or controlled, which could lead to the spread of fire to other parts of the building, which could lead to damage to the building.