From an interconnected suppression system control unit to the main fire alarm control unit, the duct detector actuation is permitted to cause which of the following signals?

• A. Alarm signal only
• B. Supervisory signal only
• C. Both an alarm signal and a supervisory signal
• D. No signal

Answer: (C)

When a duct detector in an interconnected suppression system acts, its signal to the main fire alarm control unit is designed to do two things at once: alert occupants and convey system status to monitoring staff. The alarm signal ensures the building’s audible and visual alerts go off so people can evacuate, while the supervisory signal informs the control unit (and responders) that the duct detector has actuated and that the suppression-related event is in progress or requires attention. This dual signaling helps coordinate immediate evacuation with proper monitoring and control of the suppression system.

So, the duct detector actuation is permitted to cause both an alarm signal and a supervisory signal.