In a cross-zoned smoke detection system, what must happen after the activation of a detector before the actual alarm will sound?

In a cross-zoned smoke detection system, what must happen after the activation of a detector before the actual alarm will sound?

• A. The second detector must activate
• B. The main panel must reset
• C. The third detector must be involved
• D. The building owner must confirm

Answer: (A)

In a cross-zoned smoke detection system, two detectors in different zones must be triggered before the alarm will sound. This setup provides confirmation that there is actual smoke spreading across areas, reducing the chance of a false alarm from a single detector. When the first detector activates, the system doesn’t immediately sound the alarm; it awaits a second detector in another zone to also sense smoke within a short window. Once that second detector is triggered, the control panel sounds the building alarm. The other options—resetting the main panel, involving a third detector, or requiring owner confirmation—are not part of the automatic alarm sequence in this configuration.

In a cross-zoned smoke detection system, two detectors in different zones must be triggered before the alarm will sound. This setup provides confirmation that there is actual smoke spreading across areas, reducing the chance of a false alarm from a single detector. When the first detector activates, the system doesn’t immediately sound the alarm; it awaits a second detector in another zone to also sense smoke within a short window. Once that second detector is triggered, the control panel sounds the building alarm. The other options—resetting the main panel, involving a third detector, or requiring owner confirmation—are not part of the automatic alarm sequence in this configuration.