1. What is a Pipe Size Velocity Calculator?

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

Purpose: It helps engineers and plumbers select appropriate pipe sizes to maintain optimal flow velocities in piping systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of Pipe Sizing

Details: Proper pipe sizing ensures efficient flow, prevents excessive pressure drops, and avoids problems like water hammer or erosion.

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 velocity for water in pipes?
A: For water, 3-5 ft/s is common for supply lines, 5-8 ft/s for drain lines, and 1-3 ft/s for gravity systems.

Q2: Why is velocity important in pipe sizing?
A: Too high velocity causes erosion and noise; too low velocity allows sediment buildup and may not maintain self-cleansing flow.

Q3: How does this apply to different fluids?
A: The formula works for any liquid, but optimal velocities vary based on fluid properties (viscosity, corrosiveness, etc.).

Q4: What about pipe material and friction losses?
A: This calculator gives theoretical diameter. Actual sizing should consider material roughness and system head loss calculations.

Q5: How do I convert between feet and inches?
A: 1 foot = 12 inches. The calculator provides results in both units for convenience.