1. What is the Pump Size Calculation?

The pump size calculation determines the required horsepower (HP) for a pump based on the flow rate, head pressure, and pump efficiency. Proper sizing ensures the pump can handle the required workload without being oversized.

2. How Does the Calculator Work?

The calculator uses the pump power formula:

Where:

• Flow Rate — Gallons per minute (GPM) of fluid being pumped
• Head — Total dynamic head in feet (ft)
• Efficiency — Pump efficiency as a decimal (typically 0.7-0.9)
• 3960 — Conversion factor to horsepower

Explanation: The formula calculates the theoretical power required to move fluid at a specific rate against a specific head pressure, adjusted for pump efficiency.

3. Importance of Pump Sizing

Details: Proper pump sizing is critical for energy efficiency, system performance, and equipment longevity. Oversized pumps waste energy, while undersized pumps can't meet system demands.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, and pump efficiency as a decimal between 0 and 1 (typically 0.7-0.9 for centrifugal pumps). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical pump efficiency value?
A: Centrifugal pumps typically have efficiencies between 70-90% (0.7-0.9). Positive displacement pumps can be higher.

Q2: How do I determine total dynamic head?
A: TDH includes static head, friction losses, and pressure differences. It's calculated from your system characteristics.

Q3: Should I add a safety factor to the calculated HP?
A: Yes, it's common to add 10-20% safety factor to account for system variations and future needs.

Q4: Can this be used for all pump types?
A: This formula works best for centrifugal pumps. Positive displacement pumps may require different calculations.

Q5: What if my flow rate is in m³/h instead of GPM?
A: Convert m³/h to GPM by multiplying by 4.40287 before using the calculator.