2-stage systems aren’t something that the codes in the US provide for. It would require approval for a variance from the local Authority Having Jurisdiction.
These systems are mainly used in airports where false evacuations would cause a “ripple effect” of disruptions, not to mention the need for all guests to re-enter through security.
Where approved, here is how these systems generally work.
- Any activation results in a standby message such as these:
EST: x.com
Notifier: https://www.youtube.com/watch?v=bEH_bQh9wXM
Siemens: (the system in the video is a floor-by-floor setup but it’s the only one I could find with this message) https://www.youtube.com/watch?v=d98DGUTBSIo
Simplex: https://www.facebook.com/frelima.sample/videos/10211672547153766/ - If the alarm is not silenced in X minutes, the evacuation message begins.
- The evacuation message will begin immediately if a second initiating device gets activated.
Just curious: what was the usual cause of the false alarms in that particular dorm?