If mechanical actuation of the clean agent suppression system is possible, which device is required?

• A. Discharge pressure switch
• B. Flow sensor
• C. Temperature sensor
• D. Alarm bell

Answer: (A)

Mechanical actuation of a clean agent system still needs a way to verify that the agent actually discharged. The discharge pressure switch serves this purpose: it monitors the pressure in the discharge piping and, when the actuator releases the agent and pressure builds, it closes a circuit to confirm discharge and trigger the appropriate alarms/interlocks. Without this pressure-based confirmation, there’s no reliable signal that the agent flowed.

A flow sensor would detect movement of the agent but isn’t the standard requirement for confirming actuation. A temperature sensor isn’t related to confirming discharge, and an alarm bell by itself only provides an audible alert without the essential verification signal.