1. What is the Pipe Diameter Flow Rate Formula?

Definition: This calculator determines the required pipe diameter based on the flow rate and desired flow velocity.

Purpose: It helps engineers and plumbers size pipes correctly for fluid transport systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( D \) — Pipe diameter (feet)
• \( Q \) — Flow rate (gallons per minute, GPM)
• \( V \) — Flow velocity (feet per second, ft/s)
• \( \pi \) — Pi (approximately 3.1416)
• 7.481 — Conversion factor (gallons per cubic foot)

Explanation: The formula calculates the minimum pipe diameter needed to maintain the desired flow velocity for a given flow rate.

3. Importance of Proper Pipe Sizing

Details: Correct pipe sizing ensures efficient flow, prevents excessive pressure drops, and avoids erosion from high velocities.

4. Using the Calculator

Tips: Enter the flow rate in GPM and desired velocity in ft/s (default 5 ft/s for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical flow velocity for water pipes?
A: For water, 3-8 ft/s is common (5 ft/s is often used as a default).

Q2: How does pipe material affect the calculation?
A: The formula is independent of material, but material affects pressure loss and maximum allowable velocity.

Q3: Can I use this for gases or other fluids?
A: Yes, but adjust velocity limits based on fluid properties and application.

Q4: What if I get an unusually large/small diameter?
A: Check your inputs - extremely high velocities or low flow rates may give impractical results.

Q5: How do I convert the result to inches?
A: Multiply the result by 12 (1 foot = 12 inches).