1. What is a Zero Pressure Air Flow Meter?

Definition: This calculator measures air flow rate (in GPM equivalent) at atmospheric pressure using velocity and cross-sectional area.

Purpose: It helps engineers and technicians estimate air flow rates in ventilation systems, pneumatic systems, and HVAC applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Air flow rate (gallons per minute, GPM equivalent)
• \( V \) — Air velocity (feet per second, ft/s)
• \( A \) — Cross-sectional area (square feet, ft²)
• 448.83 — Conversion factor (ft³/s to GPM)

Explanation: The formula converts volumetric air flow to an equivalent liquid flow rate for easier comparison with hydraulic systems.

3. Importance of Air Flow Measurement

Details: Accurate air flow measurement is crucial for system efficiency, proper ventilation, and equipment performance in industrial and building systems.

4. Using the Calculator

Tips: Enter the air velocity in ft/s and cross-sectional area in ft². All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why use GPM for air flow measurement?
A: GPM provides a familiar unit for comparison with liquid systems, though CFM (cubic feet per minute) is more common for air systems.

Q2: How do I measure air velocity?
A: Use an anemometer or pitot tube to measure air velocity at the point of interest.

Q3: What's a typical air velocity in ducts?
A: HVAC systems typically maintain 500-1200 ft/min (8.3-20 ft/s) in main ducts.

Q4: Does this account for pressure differences?
A: No, this calculates flow at zero pressure differential (atmospheric pressure).

Q5: Can I use this for compressed air systems?
A: This is for atmospheric pressure only. For compressed air, use appropriate compressible flow equations.