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FPM Formula:
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The CFM to FPM conversion calculates air velocity (feet per minute) from volumetric flow rate (cubic feet per minute) and cross-sectional area. This is essential for HVAC system design, ventilation calculations, and airflow analysis.
The calculator uses the FPM formula:
Where:
Explanation: The formula converts volumetric flow rate to linear velocity by dividing the flow rate by the cross-sectional area through which the air is moving.
Details: Accurate FPM calculation is crucial for proper ventilation system design, ensuring adequate air movement, preventing stagnation, and maintaining proper air distribution in residential, commercial, and industrial settings.
Tips: Enter CFM value in cubic feet per minute and area in square feet. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is the difference between CFM and FPM?
A: CFM measures volumetric flow rate (volume of air moving per minute), while FPM measures linear velocity (speed of air movement in feet per minute).
Q2: What are typical FPM values for HVAC systems?
A: Typical duct velocities range from 600-900 FPM for low-pressure systems, 1,200-2,200 FPM for medium-pressure systems, and up to 3,000 FPM for high-pressure systems.
Q3: Why is area important in this calculation?
A: Area determines how the volumetric flow is distributed. Smaller areas result in higher velocities for the same CFM, while larger areas result in lower velocities.
Q4: Can this formula be used for liquids?
A: While the principle is similar, liquid flow calculations often use different units and considerations. This formula is primarily for air flow applications.
Q5: How does FPM affect ventilation efficiency?
A: Proper FPM ensures adequate air movement without excessive noise or pressure drop. Too low FPM can cause poor air distribution, while too high FPM increases energy consumption and noise.