1. What is a Pipe Flow Rate Calculator?

Definition: This calculator estimates the volumetric flow rate of liquid through a pipe in gallons per minute (gpm) based on pipe diameter and flow velocity.

Purpose: It helps engineers, plumbers, and technicians determine the flow capacity of pipes in various systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q_{gpm} \) — Flow rate (gallons per minute)
• \( d \) — Pipe diameter (inches)
• \( V_{fps} \) — Flow velocity (feet per second)

Explanation: The formula calculates flow rate by multiplying the pipe's cross-sectional area (converted to gallons per foot) by the velocity.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate system performance, prevents pipe overpressure, and helps in pump selection.

4. Using the Calculator

Tips: Enter the pipe diameter in inches and flow velocity in feet per second. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical flow velocity in pipes?
A: For water systems, 4-8 ft/s is common for supply lines, while 2-5 ft/s is typical for drain lines.

Q2: Does this work for any liquid?
A: Yes, but the formula assumes water-like viscosity. For viscous fluids, additional factors are needed.

Q3: What's the 2.45 constant represent?
A: It combines unit conversions (square inches to square feet) and volume conversions (cubic feet to gallons).

Q4: How accurate is this calculation?
A: It provides theoretical maximum flow. Actual flow may be lower due to friction, fittings, and elevation changes.

Q5: Can I use this for pipe sizing?
A: Yes - work backward from desired flow rate to find required diameter at a given velocity.