What immediate action must be taken for any failure of a fire protection system?

The immediate action that must be taken for any failure of a fire protection system is to notify building management and the Fire Department. This is crucial because fire protection systems are vital for life safety and property protection. Prompt notification ensures that appropriate measures are taken to evaluate the situation, potentially evacuate building occupants if necessary, and initiate any emergency response procedures.

By involving building management, there can be an immediate assessment of the situation, and the Fire Department can be alerted to prepare for any potential fire hazards that may arise due to the system's failure. This action prioritizes safety and minimizes risks associated with fire emergencies in the building.

The other options do not provide the immediate response required in such situations. Simply notifying occupants would not address the systemic issue or ensure that emergency services are prepared. Documenting the failure is important for records but doesn't address the urgent need for safety and intervention. Repairing the system before notifying anyone could lead to dangerous situations if a fire occurs while the system is down, as occupancy could still remain unprotected during that time.