I know that when you hear a periodic chirping noise from smoke detectors, it means the battery needs to be replaced. I had been hearing such a chirping noise in my apartment building for a few hours, and just realized that the sound is not coming from the smoke detector(s), but from the hard-wired horn/strobe device in the hallway.
What could be causing this? To be clear, the alarm is not going off - it is making the exact same sound as a dying smoke detector, but from a hardwired SpectrAlert Classic horn/strobe device. We did just have an intense lightning storm in which the neighboring building lost power. Could the panel have been hit by a surge?