1. What is FPM Calculation?

FPM (Feet Per Minute) calculation determines the velocity of air flow by dividing the volumetric flow rate (CFM) by the cross-sectional area through which the air is moving.

2. How Does the Calculator Work?

The calculator uses the FPM formula:

Where:

• \( FPM \) — Feet Per Minute (velocity)
• \( CFM \) — Cubic Feet Per Minute (volumetric flow rate)
• \( A \) — Cross-sectional Area (square feet)

Explanation: This formula converts volumetric flow rate to linear velocity by dividing the volume flow by the area through which the fluid is passing.

3. Importance of FPM Calculation

Details: FPM calculation is essential in HVAC systems, ventilation design, industrial air flow management, and ductwork sizing to ensure proper air movement and system efficiency.

4. Using the Calculator

Tips: Enter CFM in cubic feet per minute and area in square feet. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical FPM range for HVAC systems?
A: Residential HVAC systems typically operate at 600-900 FPM, while commercial systems may range from 1,000-2,400 FPM depending on application.

Q2: How does FPM relate to air pressure?
A: Higher FPM values generally indicate higher velocity pressure, which can affect system performance and noise levels.

Q3: Can I use this for liquid flow calculations?
A: While the principle is similar, liquid flow typically uses different units (GPM instead of CFM) and may require density corrections.

Q4: What if my area is in square inches?
A: Convert square inches to square feet by dividing by 144 (since 1 ft² = 144 in²) before entering the value.

Q5: Why is FPM important in duct design?
A: Proper FPM ensures adequate air distribution, minimizes energy loss, prevents noise issues, and maintains system efficiency.