1. What is the GPM Flow Rate Formula?

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

Purpose: It helps engineers, plumbers, and fluid system designers calculate water flow rates in piping systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( V \) — Fluid velocity (feet per second, ft/s)
• \( A \) — Cross-sectional area of pipe (square feet, ft²)
• 448.83 — Conversion factor (cubic feet to gallons and seconds to minutes)

Explanation: The velocity multiplied by area gives flow in cubic feet per second, which is then converted to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculations ensure proper pipe sizing, pump selection, and system performance in plumbing, irrigation, and industrial applications.

4. Using the Calculator

Tips: Enter the fluid 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: What's a typical velocity for water in pipes?
A: Residential plumbing: 4-8 ft/s, Irrigation: 5-10 ft/s, Industrial: up to 15 ft/s depending on application.

Q2: How do I calculate area for a circular pipe?
A: Area = π × r² where r is the radius in feet (diameter/2).

Q3: Why is the conversion factor 448.83?
A: It combines 7.48052 (gallons per cubic foot) and 60 (seconds per minute): 7.48052 × 60 = 448.8312.

Q4: Can this be used for other liquids?
A: Yes, but the conversion factor assumes water density. For other liquids, additional adjustments may be needed.

Q5: What's the maximum flow rate this can calculate?
A: There's no theoretical maximum, but practical pipe systems rarely exceed 10,000 GPM.