To limit the probability that, during a failure of the normal power supply in a fire emergency situation, emergency generator power supplies to electrical power systems supplying water for firefighting will not be capable of performing their intended functions for a length of time sufficient for emergency responders to carry out their duties, which could lead to firefighting operations being ineffective, which could lead to the fire not being controlled or suppressed, which could lead to the spread of fire to an adjacent building, which could lead to damage to adjacent buildings.