1. What is Gas Velocity in Pipe?

Gas velocity in pipe refers to the speed at which gas flows through a pipe or duct. It's a critical parameter in HVAC systems, industrial processes, and ventilation design, affecting pressure drop, noise levels, and system efficiency.

2. How Does the Calculator Work?

The calculator uses the gas velocity equation:

Where:

• \( V \) — Gas velocity (feet per second)
• \( Q \) — Flow rate (cubic feet per minute)
• \( A \) — Cross-sectional area (square feet)

Explanation: The formula converts volumetric flow rate (CFM) to linear velocity by dividing by the cross-sectional area and converting minutes to seconds.

3. Importance of Gas Velocity Calculation

Details: Proper gas velocity ensures efficient system operation, prevents excessive pressure drops, reduces noise, and maintains proper air/gas distribution. Too high velocity causes turbulence and noise; too low velocity may lead to sedimentation.

4. Using the Calculator

Tips: Enter flow rate in cubic feet per minute (CFM) and cross-sectional area in square feet. Both values must be positive numbers. For circular pipes, area = π × (diameter/2)².

5. Frequently Asked Questions (FAQ)

Q1: What is the typical gas velocity range in HVAC systems?
A: Typically 800-2,000 feet per minute for main ducts, 600-900 FPM for branch ducts, and 300-700 FPM for residential systems.

Q2: How do I calculate area for different pipe shapes?
A: Circular: π × r², Rectangular: width × height, Square: side². Ensure consistent units throughout.

Q3: Why is velocity important in pipe design?
A: Velocity affects pressure drop (higher velocity = higher drop), noise levels, erosion potential, and energy consumption.

Q4: What happens if velocity is too high?
A: Excessive noise, vibration, erosion of pipe walls, increased energy consumption, and potential system damage.

Q5: How does temperature affect gas velocity?
A: Higher temperatures increase gas volume (thermal expansion), which may increase velocity if flow rate remains constant.