What is the term for the pressure measured at the residual hydrant during flow readings?

The term for the pressure measured at the residual hydrant during flow readings is residual pressure. This measurement indicates the pressure available in the water distribution system when water is flowing, particularly when a fire flow test is being conducted.

Residual pressure is critical because it helps to determine the effectiveness of the water supply for firefighting purposes. It reflects the pressure that remains in the system after a designated flow rate is established, ensuring that there is adequate pressure to support other hydrants or fire protection systems operating simultaneously.

Understanding residual pressure is essential for fire service planning and for ensuring that the system can deliver the necessary water flow and pressure to extinguish a fire safely.