1. What is the Flow Rate Equation GPM?

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

Purpose: It helps engineers, plumbers, and fluid system designers calculate flow rates for pipes, channels, and other conduits.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( V \) — Velocity (feet per second)
• \( A \) — Cross-sectional area (square feet)
• 448.83 — Conversion factor (cubic feet to gallons and seconds to minutes)

Explanation: The formula converts the basic volumetric flow rate (V × A) from cubic feet per second to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculations are essential for proper system design, pump selection, and ensuring adequate fluid delivery.

4. Using the Calculator

Tips: Enter the fluid velocity in ft/s and the cross-sectional area in ft². Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the conversion factor 448.83?
A: It combines 7.48052 (gallons per cubic foot) and 60 (seconds per minute): 7.48052 × 60 ≈ 448.83.

Q2: How do I find the cross-sectional area?
A: For circular pipes: A = π × (diameter/2)². For rectangular channels: A = width × height.

Q3: What's a typical velocity for water in pipes?
A: Residential plumbing: 4-8 ft/s. Industrial systems: up to 10 ft/s depending on application.

Q4: Can this be used for gases?
A: Yes, but gas flow rates are often measured in different units (CFM, SCFM).

Q5: How does pipe diameter affect flow rate?
A: Flow rate increases with the square of the diameter (for the same velocity).