1. What is Water Flow Rate Measurement?

Definition: This calculator determines the volumetric flow rate of water in gallons per minute (GPM) based on water velocity and pipe cross-sectional area.

Purpose: It helps engineers, plumbers, and irrigation specialists design and analyze water systems by calculating flow rates.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( V \) — Water velocity (feet per second)
• \( A \) — Cross-sectional area (square feet)
• 448.83 — Conversion factor (ft³/s to GPM)

Explanation: The velocity and area are multiplied to get cubic feet per second, then converted to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate measurement ensures proper system design, adequate water supply, and efficient operation of pumps and piping systems.

4. Using the Calculator

Tips: Enter the water velocity in ft/s and the pipe's cross-sectional area in ft². For circular pipes, area = π × (diameter/2)².

5. Frequently Asked Questions (FAQ)

Q1: How do I measure water velocity?
A: Use flow meters, pitot tubes, or calculate from pressure differentials using Bernoulli's equation.

Q2: What's a typical water velocity in pipes?
A: Domestic water systems typically range 4-8 ft/s, while irrigation systems may be 2-5 ft/s.

Q3: Why 448.83 as the conversion factor?
A: It converts cubic feet per second to gallons per minute (1 ft³/s = 448.83 GPM).

Q4: Can I use this for other liquids?
A: Yes, but the conversion factor changes based on liquid density (use 448.83 × specific gravity).

Q5: How does pipe diameter affect flow rate?
A: Flow rate increases with the square of pipe diameter (double diameter = 4× flow at same velocity).