1. What is the Water Pump Horsepower Formula?

The water pump horsepower formula calculates the power required to move fluid through a system. It accounts for flow rate, head pressure, fluid density, and pump efficiency.

2. How Does the Calculator Work?

The calculator uses the pump horsepower formula:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total head in feet (ft)
• \( SG \) — Specific gravity of the fluid (1 for water)
• \( \eta \) — Pump efficiency (0-1, typically 0.7-0.9)
• 3960 — Conversion factor for units to horsepower

Explanation: The formula calculates the theoretical power needed to move the fluid, then divides by pump efficiency to get actual required horsepower.

3. Importance of Pump Horsepower Calculation

Details: Proper horsepower calculation ensures you select a pump with adequate power for your application while avoiding oversized, inefficient pumps.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency (typically 0.7-0.9). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is total head in pumping systems?
A: Total head is the sum of static head (vertical distance) and friction head (pressure loss due to pipe friction).

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically have 70-90% efficiency, while positive displacement pumps may reach 90-95%.

Q3: How does specific gravity affect horsepower?
A: Higher specific gravity fluids (denser than water) require more power to pump at the same flow rate and head.

Q4: What if my flow is in L/min instead of GPM?
A: Convert to GPM by dividing L/min by 3.785 before using the calculator.

Q5: Should I add a safety factor to the calculated HP?
A: Yes, it's common practice to add 10-20% to the calculated HP to account for system variations and future needs.