1. What is CFM Calculation Formula?

The CFM (Cubic Feet per Minute) calculation formula estimates fan airflow capacity based on fan blade area, rotational speed (RPM), and air velocity factor. It provides an accurate assessment of fan performance and ventilation capacity.

2. How Does the Calculator Work?

The calculator uses the CFM formula:

Where:

• \( Fan\ Blade\ Area \) — Area of fan blades in square feet (ft²)
• \( RPM \) — Rotational speed in revolutions per minute (rev/min)
• \( Air\ Velocity\ Factor \) — Air velocity factor in feet per minute (ft/min)

Explanation: The equation calculates the volume of air moved by the fan per minute, considering the physical dimensions and operating speed of the fan.

3. Importance of CFM Calculation

Details: Accurate CFM calculation is crucial for HVAC system design, industrial ventilation, fan selection, and ensuring adequate air circulation in various applications.

4. Using the Calculator

Tips: Enter fan blade area in ft², RPM in rev/min, and air velocity factor in ft/min. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is CFM used for?
A: CFM is used to measure airflow capacity in ventilation systems, HVAC equipment, industrial fans, and cooling applications.

Q2: How do I measure fan blade area?
A: Fan blade area is typically calculated as the total surface area of all blades that move air, usually provided by manufacturer specifications.

Q3: What affects air velocity factor?
A: Air velocity factor depends on blade design, pitch angle, duct configuration, and system pressure losses.

Q4: Are there limitations to this formula?
A: This formula provides theoretical values; actual performance may vary due to system resistance, blade efficiency, and air density variations.

Q5: What is a good CFM range for residential fans?
A: For residential applications, bathroom fans typically range 50-110 CFM, kitchen hoods 100-400 CFM, and whole-house fans 1000-7000 CFM.