The pressure in a system when no water is flowing is called?

The pressure in a system when no water is flowing is referred to as static pressure. This type of pressure is crucial in understanding how a fire protection system, such as a sprinkler system or standpipe, operates, especially when assessing how much pressure is available to facilitate the delivery of water when needed. Static pressure reflects the potential energy available in the system without any influence from moving water. It is typically measured at a point in the system with no active flow, giving firefighters and engineers a benchmark for evaluating the effectiveness of the water supply during emergency operations.

Elevation pressure is related to the height of water in a system and its gravitational effects, while flow pressure pertains to the pressure that exists when water is actively flowing in a system. Residual pressure measures the pressure remaining in a system while water is flowing, which is vital for understanding how much water can still be delivered under operational conditions. Each of these pressures offers essential insights into different aspects of hydraulic systems, but static pressure specifically captures the state of the system with no flow occurring.