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

The term used to describe the pressure in a firefighting system when no water is flowing is "static pressure." Static pressure reflects the potential pressure available in the system and is critical for understanding how much pressure can be expected when the system is activated. In this state, water remains in a confined space without movement, allowing for the measurement of pressure from a hydrant or a standpipe when no flow is occurring. This reading helps firefighters assess the overall capacity and functionality of the water supply system before they engage in firefighting operations.

Understanding static pressure is essential for effective firefighting, as it sets the baseline for evaluating how much pressure will be available when water begins to flow. This is distinct from concepts like operational or flow pressures, which come into play when water is actively being used in the system.