During non-flow conditions, static pressure is usually higher than residual pressure.

During non-flow conditions, static pressure is usually higher than residual pressure.

• A. Higher
• B. Lower
• C. Equal
• D. Variable

Answer: (A)

Static pressure is the pressure in the piping when no water is moving. Residual pressure is the pressure you measure while water is flowing and losses from friction, turbulence, and fittings have occurred. When water flows, those losses reduce the pressure along the line, so the pressure during flow (the residual) is lower than the pressure with no flow. That’s why, under non-flow conditions, the static pressure is higher. For example, a system charged to a high static pressure will read lower once a hose is opened and water starts moving, due to friction losses and other head losses.

Static pressure is the pressure in the piping when no water is moving. Residual pressure is the pressure you measure while water is flowing and losses from friction, turbulence, and fittings have occurred. When water flows, those losses reduce the pressure along the line, so the pressure during flow (the residual) is lower than the pressure with no flow. That’s why, under non-flow conditions, the static pressure is higher. For example, a system charged to a high static pressure will read lower once a hose is opened and water starts moving, due to friction losses and other head losses.