Stored potential energy for forcing water thru pipe, fittings, fire hose and adaptors is known as ______.

• A. Static pressure
• B. Head pressure
• C. Residual pressure
• D. Flow pressure

Answer: (A)

Static pressure is the stored potential energy of water in a charged pipe system. When the piping, hose, and fittings are filled and sealed, the water is under pressure but not necessarily moving, so the energy available to push water laterally or through a nozzle is stored as pressure. This static pressure represents the energy per unit volume that can be converted into motion or work when the flow is released. As water begins to move, part of that potential energy becomes kinetic energy (velocity head) and is consumed by friction losses along the line, but the fundamental stored energy in the system is static pressure. Other terms describe different situations: residual pressure refers to the pressure remaining after flow has occurred, and flow pressure is the pressure during active flow; head pressure is a less standard way of expressing pressure as an equivalent water column, whereas static pressure is the standard term for the stored energy in a non-flowing system.