Which of the following is NOT a common initiating device used in fire alarm systems?

• A. All of the above.
• B. Smoke detectors
• C. Heat detectors
• D. Manual pull stations

Answer: (A)

Initiating devices are the parts of a fire alarm system that start the alarm signal when they sense something or are activated by a person. In most systems, the common initiating devices are automatic smoke detectors, automatic heat detectors, and manual pull stations. Smoke detectors respond to smoke particles, signaling that there’s a fire; heat detectors respond to a rise in temperature or a high fixed temperature; manual pull stations require a person to trigger the alarm by pulling a handle.

The option All of the above isn’t a device at all; it’s a test-choice label. It doesn’t represent a real initiating device, unlike the other three options, which are actual initiating devices used to start a fire alarm. That’s why it’s the one that fits the idea of NOT being a common initiating device.