1. What is Total Dynamic Head (TDH)?

Total Dynamic Head (TDH) is the total equivalent height that a fluid is to be pumped, taking into account friction losses in the pipe. It represents the actual workload on the pump and is crucial for proper pump selection and system design.

2. How Does the Calculator Work?

The calculator uses the TDH equation:

Where:

• Static Head — Vertical distance from water surface to discharge point (ft)
• Friction Loss — Head loss due to friction in pipes and fittings (ft)
• Pressure Head — Additional pressure required at discharge (converted to ft of head)

Explanation: TDH accounts for all resistance the pump must overcome, including elevation changes, pipe friction, and any back pressure at the discharge.

3. Importance of TDH Calculation

Details: Accurate TDH calculation is essential for selecting a properly sized pump that can deliver the required flow rate against the system's total resistance. Underestimating TDH can lead to inadequate pump performance.

4. Using the Calculator

Tips:

• Measure static head as the vertical distance from source to discharge
• Calculate friction loss using pipe size, length, flow rate, and material
• Include pressure head if the system requires pressure at discharge (e.g., for sprinklers)
• All values must be in feet of head

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between static head and TDH?
A: Static head is just the vertical elevation difference, while TDH includes all resistances the pump must overcome.

Q2: How do I calculate friction loss?
A: Use the Hazen-Williams equation or consult friction loss charts based on pipe diameter, length, material, and flow rate.

Q3: When is pressure head needed?
A: When the discharge requires pressure (e.g., irrigation systems, pressure tanks). Convert psi to feet (1 psi = 2.31 ft).

Q4: What's a typical TDH range?
A: Residential systems often range 30-100 ft, while industrial systems can be much higher depending on application.

Q5: How does TDH affect pump selection?
A: Pumps are selected based on their performance curves showing flow rate at various TDH values. The operating point should be near the pump's best efficiency point.