Which device causes a fire detection system to indicate an alarm?

In a fire detection system, the device responsible for triggering an alarm is the alarm initiation device. This device plays a crucial role in identifying the presence of smoke, heat, or flames, and it directly initiates the alarm signal that alerts occupants and/or the monitoring station.

Alarm initiation devices include smoke detectors, heat detectors, manual pull stations, and other sensors designed to detect signs of a fire. When these devices sense a potential fire hazard, they send a signal to the fire control panel, which then processes the information and activates the alarm notification devices to alert individuals in the building.

While smoke detectors fall under the category of alarm initiation devices, the broader classification as an initiation device emphasizes the fundamental function of detecting a hazardous condition and prompting an alarm. This conveys the essential mechanism of how fire detection systems react to potential threats. The fire control panel acts as the central hub that interprets inputs from initiation devices but does not directly cause the alarm to be indicated without the input from these devices.

Hence, the correct answer highlights the primary role these initiation devices play in ensuring safety during a fire event.