What is the term for the forward pressure measured at a discharge opening while water is flowing?

The term that describes the forward pressure measured at a discharge opening while water is flowing is flow pressure. This pressure is an important metric for understanding how much pressure is available to deliver water through hoses and onto the fire scene while the pump is in operation. Flow pressure indicates the actual pressure in the system while water is moving, reflecting the impacts of both friction loss in the hoses and the characteristics of the discharge equipment being used.

Static pressure, on the other hand, refers to the pressure in a water system when no water is flowing, and it does not account for any losses due to friction or other factors when the water starts to move. Dynamic pressure, while sometimes used interchangeably, typically refers to the pressure measured when the water is moving, but it is often synonymous with flow pressure in practical contexts. Residual pressure is the pressure remaining in the system when water is flowing, and it specifically addresses the available pressure left after accounting for losses, which can differ from flow pressure if there are significant losses in the system. Understanding these distinctions is crucial for effective water supply management in firefighting operations.