1. What is Fire Pump Electrical Load Calculation?

Definition: This calculator determines the electrical power required to operate a fire pump based on hydraulic parameters.

Purpose: Helps engineers and designers properly size electrical systems for fire protection pumps.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_e \) — Electrical load (kW)
• \( Q \) — Flow rate (gallons per minute)
• \( H \) — Head pressure (feet)
• \( \rho \) — Fluid density (pounds per gallon)
• \( \eta \) — Pump efficiency (0-1)

Explanation: The formula converts hydraulic power to electrical power, accounting for pump efficiency and unit conversions.

3. Importance of Electrical Load Calculation

Details: Proper calculation ensures the electrical system can handle the pump's demands during fire emergencies, preventing circuit overloads.

4. Using the Calculator

Tips: Enter the pump's rated flow (GPM), total head (ft), fluid density (default 8.34 lb/gal for water), and pump efficiency (typically 0.7-0.9).

5. Frequently Asked Questions (FAQ)

Q1: Why is the 0.746 factor included?
A: This converts horsepower to kilowatts (1 HP = 0.746 kW).

Q2: What's the 3960 constant?
A: This is the unit conversion factor that relates GPM, feet of head, and horsepower.

Q3: When would I change the density value?
A: For fluids other than water (like antifreeze solutions) or at different temperatures.

Q4: How do I determine pump efficiency?
A: Check pump manufacturer specifications or use 0.85 as a typical value.

Q5: Should I add a safety factor?
A: NFPA 20 requires fire pumps to be sized for 125% of full load current.