The Basics of Fire Flows

Flow switches work only on wet pipe systems. As the name implies, they display a reed or remote that gets in the water's path and moves when it flows. But in dry systems where water quickly replaces or compresses, when sprinklers are activated, this panel can be damaged or broken - thus a restriction on wet pipe systems.

For smaller pipe sizes (usually under two inches), these switches may take the form of a "TAPT". They have a threaded inlet and a protruding paddle that attaches to a threaded fitting. Others have a remote control and select a horseshoe bolt. When opened, this U-bolt holds the sensor in place over a cut hole in the tube.

Flow orientation and positioning

Spade and vane type flow switches must face the flow of water. However, they can cross into a pipe that runs vertically or horizontally. A local standard for these switches varies depending on where water enters the system.

Activation and signaling

Flows are activated when the flow exceeds a predetermined rate. However, they can also use a mechanism to delay these signals, preventing false alarms due to pressure pressures.

They typically feature two electrical switches: a beacon or fire alarm control panel and one that sounds a bell or other audio visual alarm. Because flow switches connected to a control panel must have a non-silent circuit, this means that the panel cannot change the switch alarm signal. Talk with us!