Fire and burglar alarms should be monitored on a regular schedule and should be connected to a fire or police department or a remote guard or security post manned 24 hours a day. Burglar alarms should be set when the library or rare book department closes and should include both door and motion alarms. Fire alarms should be designed to alert the occupants of the building while at the same time notifying the appropriate emergency services. The most effective fire alarms for libraries are ionization detectors, since they react to combustion gases rather than heat, flame, or visible smoke.

In areas that may be vulnerable to flooding (from rain, tank water from the roof, or rising water from an outside source), water alarms are important. Water alarms are electronic disks or cables laid onto the floor that are activated when a circuit is completed by moisture. Like the other alarm systems, water alarms should produce both an audible warning and a remote alarm to a manned post.