1. What is the Pump Horsepower Formula?

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

2. How Does the Calculator Work?

The calculator uses the pump horsepower equation:

Where:

• \( HP \) — Horsepower (output)
• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total head in feet (ft)
• \( SG \) — Specific gravity of fluid (1 for water)
• \( \eta \) — Pump efficiency (decimal, 0-1)
• 3960 — Conversion factor (foot-pounds per minute per horsepower)

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

3. Importance of Pump Horsepower Calculation

Details: Accurate horsepower calculation ensures proper pump selection, prevents under/over sizing, and helps estimate energy requirements and operating costs.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency as decimal (0.85 for 85%). All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is specific gravity?
A: The ratio of fluid density to water density at standard conditions. Water = 1, most oils = 0.8-0.9.

Q2: How do I estimate pump efficiency?
A: Typical centrifugal pumps are 50-85% efficient. Check manufacturer specs or use 0.75-0.85 as default.

Q3: What is total head?
A: The total pressure the pump must overcome, including static head, friction loss, and pressure differences.

Q4: How does viscosity affect horsepower?
A: Higher viscosity increases power requirements beyond what specific gravity accounts for.

Q5: Should I add a safety factor?
A: Yes, typically 10-20% additional horsepower to account for system variations and future needs.