Total Dynamic Head (TDH) is the sum of which components?

• A. The sum of friction loss, elevation head, and suction lift that the pump must overcome
• B. The sum of nozzle pressure, friction loss, and velocity head
• C. The difference between static and residual pressure
• D. The static pressure plus the flow velocity

Answer: (B)

Total Dynamic Head is the energy the pump must add to push water to the point of use. It combines three energy components in the discharge path: nozzle pressure (the pressure at the nozzle), friction losses in the piping and fittings, and velocity head (the water’s kinetic energy due to its flow). Adding these three parts gives the total head the pump has to overcome.

Why this fits best: the discharge side of the system requires enough energy to overcome the nozzle’s pressure, the resistance from piping, and the motion energy of the flowing water. Other options either mix in suction-side terms, omit a major component, or describe a simple pressure difference rather than the total energy the pump must supply to the discharge path.