When a pumper is discharging water, what does the intake gauge display?

When a pumper is discharging water, the intake gauge displays residual pressure, which reflects the pressure available in the system that remains after considering the effects of flow. Residual pressure is critical for understanding how much pressure is available for effective firefighting when water is being drawn from a supply source, such as a hydrant or a water tank.

In terms of context, residual pressure is important because it gives the firefighter an indication of whether the source can meet the demands of the operation. If too many lines are flowing and the residual pressure drops significantly, it may indicate that the supply is insufficient, which could affect the flow and pressure at the nozzle.

Dynamic pressure, which might be confused with residual pressure, refers to the pressure under flowing conditions, but it does not specifically relate to the pressure available at the intake when the pumping action is taking place. Static pressure, on the other hand, measures pressure when no water is being discharged, and flow pressure is associated with the pressure measured at the nozzle while water is flowing. Therefore, understanding residual pressure is key to effective firefighting and ensuring that adequate water supply and pressure are maintained during operations.