1. What is Total Dynamic Head?

Total Dynamic Head (TDH) is the total equivalent height that a fluid is to be pumped, taking into account both the static head (vertical distance) and friction losses in the system. It's a crucial parameter for selecting and sizing water pumps.

2. Understanding the Calculation

The TDH formula is simple but fundamental:

Where:

• Static Head — The vertical distance between the water source and the discharge point (in feet)
• Friction Loss — The head loss due to friction in pipes, fittings, and valves (in feet)

Explanation: While static head is straightforward to measure, friction loss requires calculations based on pipe size, length, material, flow rate, and number of fittings.

3. Importance of TDH Calculation

Details: Accurate TDH calculation is essential for:

• Selecting the right pump size and type
• Ensuring adequate water pressure and flow rate
• Preventing pump overload or underperformance
• Optimizing energy efficiency

4. Using the Calculator

Tips:

• Measure static head as the vertical distance from water source to discharge
• Calculate friction loss using pipe specifications or manufacturer charts
• For complex systems, consider using specialized hydraulic software
• Always add a safety factor (typically 10-20%) to your calculated TDH

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between static head and pressure?
A: Static head is vertical height (feet), while pressure is force per area (PSI). They're related by: 1 PSI = 2.31 feet of water head.

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

Q3: Does pipe material affect friction loss?
A: Yes, smoother materials (like PVC) have less friction than rough materials (like corroded steel).

Q4: Should I include velocity head in TDH?
A: For most water systems, velocity head is negligible and can be ignored unless dealing with very high velocities.

Q5: What if my system has multiple discharge points?
A: Calculate TDH for the worst-case scenario (highest head/longest run) or consider using a looped system design.