1. What is a Fire Pump Flow Rate Calculator?

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

Purpose: It helps fire protection engineers and technicians determine the expected flow rate of fire pumps for system design and verification.

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 the energy required to move water against head pressure.

3. Importance of Fire Pump Flow Rate Calculation

Details: Accurate flow rate calculation ensures fire pumps meet system demands, comply with NFPA standards, and provide adequate fire protection.

4. Using the Calculator

Tips: Enter the pump horsepower, efficiency (default 0.85), and total head in feet. All values must be > 0, with efficiency between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is the constant 3960 in the formula?
A: This is the conversion factor to relate horsepower to foot-pounds per minute (1 HP = 3960 ft-lb/min).

Q2: What's a typical pump efficiency value?
A: Most fire pumps operate at 70-85% efficiency (0.7-0.85), but check manufacturer specifications for exact values.

Q3: How is total head (H) determined?
A: Total head includes static head, friction losses, and pressure requirements at the most remote sprinkler.

Q4: Does this account for system demand?
A: No, this calculates pump capacity. Compare results with your hydraulic calculations to verify adequacy.

Q5: How does flow rate affect fire protection?
A: Flow rate determines how much water the pump can deliver to sprinklers or standpipes during a fire.