1. What is CFM and FPM?

CFM (Cubic Feet per Minute) and FPM (Feet per Minute) are measurements used in HVAC and ventilation systems. CFM measures airflow volume, while FPM measures airflow velocity.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( FPM \) — Air velocity in feet per minute
• \( Area \) — Cross-sectional area in square feet
• \( CFM \) — Airflow in cubic feet per minute

Explanation: The formula converts velocity (FPM) to volumetric flow rate (CFM) by multiplying by the cross-sectional area of the duct or opening.

3. Importance of CFM Calculation

Details: Calculating CFM is essential for proper HVAC system design, ensuring adequate ventilation, and maintaining indoor air quality standards.

4. Using the Calculator

Tips: Enter FPM (velocity) and Area (cross-section) values. Both must be positive numbers. The calculator will compute the CFM (volumetric flow rate).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between CFM and FPM?
A: CFM measures the volume of air moving, while FPM measures how fast the air is moving. CFM = FPM × Area.

Q2: How do I measure FPM in practice?
A: Use an anemometer to measure air velocity at various points in the duct and calculate the average FPM.

Q3: What's a typical CFM for residential HVAC?
A: Typical residential systems range from 800-2000 CFM, depending on home size and system capacity.

Q4: Does duct shape affect the calculation?
A: The formula works for any shape as long as you use the correct cross-sectional area (round, rectangular, etc.).

Q5: How does CFM relate to air changes per hour?
A: Air changes = (CFM × 60) / room volume. This helps determine ventilation effectiveness.