On a post indicator valve (PIV), what is used to show the position of the valve?

The telltale is a crucial component of a post indicator valve (PIV) as it provides a visual indication of the valve's position. Typically, when the valve is closed, the telltale often displays a specific color or design, which provides a clear, immediate cue to users about its status. This functionality is vital for effective operation, especially in firefighting situations where knowing whether the water supply is available is critical.

The design of the telltale also ensures that it is easily visible from a distance, enabling firefighters and maintenance personnel to quickly assess the valve's position without the need for direct observation of the valve itself. In contrast, while indicator lights, gauges, and signal flags can provide various forms of information regarding systems, they do not specifically convey the operational status of a PIV in the standardized manner that a telltale does. Understanding the role of the telltale helps in appreciating the importance of valve visibility and operational readiness in fire protection systems.