Which device provides an audible or visible alarm when water begins to move through the system?

• A. A backflow preventer.
• B. A waterflow alarm.
• C. A tamper switch.
• D. A pressure gauge.

Answer: (B)

When water starts moving through the piping, you want an indicator that actively alerts occupants or the fire alarm system. A waterflow alarm is designed for this exact purpose: its sensor detects actual flow in the pipes and triggers an audible horn or a visible indicator (or sends a signal to the fire alarm panel). This immediate alert is crucial because it confirms that water is discharging from the system, typically due to sprinkler activation or a significant leak.

A backflow preventer primarily stops contaminated water from flowing back into the clean water supply; it may require maintenance or have leakage indicators, but it does not inherently provide an alarm for when the system starts moving water.

A tamper switch watches for unauthorized access or changes to equipment, not the movement of water itself, so it won’t alert you when water begins to flow.

A pressure gauge shows system pressure, which can imply activity but does not automatically produce an audible or visual alarm on water movement; it’s a passive indicator rather than an active alarm device.

So, the device that provides an audible or visible alarm specifically when water begins to move through the system is the waterflow alarm.