The pressure remaining in a water distribution system when water is flowing is referred to as what kind of pressure?

The pressure remaining in a water distribution system when water is flowing is referred to as residual pressure. This type of pressure is crucial for ensuring that there is sufficient water supply for firefighting efforts. Residual pressure is measured while water is actively moving through the pipes, which helps identify how much pressure is available for firefighters to effectively utilize at the nozzle during an operation.

Understanding residual pressure is essential for firefighters because it can indicate the efficiency of the water supply system and can significantly influence operational tactics during a fire. High residual pressure generally means that there is a robust supply available for firefighting, while low residual pressure can signal issues with supply or increased demand on the system.

Other types of pressure, such as static pressure, refer to the pressure within the system when no water is flowing, and hydrostatic pressure typically relates to pressure exerted by a fluid at rest. These definitions are important as they highlight the different conditions within the system but do not describe the condition needed during active flow scenarios like firefighting.