Which term refers to the portion of total available pressure not used to overcome friction or gravity?

• A. Static Pressure
• B. Residual Pressure
• C. Gauge Pressure
• D. Dynamic Pressure

Answer: (B)

In a flowing hose line, the pump supplies total pressure, but part of that pressure is used to overcome friction along the hose and to lift water against gravity. The pressure that remains after accounting for those losses is the residual pressure. It represents the portion still available to push water toward the discharge and nozzle.

Static pressure is the pressure when water isn’t moving, gauge pressure is the reading on a gauge relative to atmospheric pressure, and dynamic pressure relates to the velocity of the flowing water. Residual pressure uniquely describes what’s left after friction and elevation losses.