1. What is Fire Pump Flow Rate Calculation?

Definition: This calculator estimates the flow rate of a fire pump based on pump horsepower, efficiency, and total head.

Purpose: It helps fire protection engineers and designers determine the water flow capacity of fire pumps for system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( HP \) — Pump horsepower
• \( \eta \) — Pump efficiency (dimensionless, 0-1)
• \( H \) — Total head (feet)

Explanation: The formula converts mechanical power to hydraulic power, accounting for pump efficiency and water properties.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation ensures proper fire protection system design, meeting NFPA requirements and building safety standards.

4. Using the Calculator

Tips: Enter pump horsepower, efficiency (default 0.85), and total head in feet. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical pump efficiency value?
A: Most fire pumps have efficiencies between 0.75-0.90 (75-90%).

Q2: How do I determine total head?
A: Total head includes static head, friction losses, and pressure requirements at the most remote sprinkler.

Q3: What does the 3960 constant represent?
A: This is a conversion factor that relates horsepower to foot-pounds per minute (1 HP = 3960 ft-lb/min).

Q4: Why is 8.34 in the denominator?
A: This represents the weight of one gallon of water in pounds (8.34 lb/gal).

Q5: Does this account for system curves?
A: No, this is the theoretical maximum flow. Actual flow depends on the system curve intersection with the pump curve.