1. What is FPM to CFM Conversion?

FPM (feet per minute) to CFM (cubic feet per minute) conversion calculates the volumetric flow rate of air through a duct based on the velocity of the air and the cross-sectional area of the duct.

2. How Does the Calculator Work?

The calculator uses the CFM formula:

Where:

• \( CFM \) — Cubic feet per minute (volumetric flow rate)
• \( FPM \) — Feet per minute (air velocity)
• \( \text{Duct Area} \) — Cross-sectional area of the duct in square feet

Explanation: This formula converts air velocity (FPM) to volumetric flow rate (CFM) by multiplying the velocity by the cross-sectional area through which the air is flowing.

3. Importance of CFM Calculation

Details: Accurate CFM calculation is essential for HVAC system design, ventilation requirements, airflow measurement, and ensuring proper air circulation in various industrial and residential applications.

4. Using the Calculator

Tips: Enter FPM (feet per minute) and Duct Area (square feet). Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between FPM and CFM?
A: FPM measures air velocity (speed), while CFM measures volumetric flow rate (volume of air moving per minute).

Q2: How do I measure duct area?
A: For rectangular ducts: width × height. For circular ducts: π × (radius)². Convert all measurements to feet before calculating.

Q3: What are typical FPM values in HVAC systems?
A: Typical values range from 500-2000 FPM for supply ducts and 300-1000 FPM for return ducts, depending on the application.

Q4: Can this calculator be used for any duct shape?
A: Yes, as long as you provide the correct cross-sectional area in square feet for the specific duct shape.

Q5: Why is CFM important in ventilation systems?
A: CFM determines the actual volume of air being moved, which is crucial for meeting ventilation requirements, maintaining air quality, and ensuring proper system performance.