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CFM Formula:
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CFM (Cubic Feet per Minute) is a measurement of airflow volume. It indicates how many cubic feet of air pass by a stationary point in one minute. CFM is an essential metric in HVAC systems, ventilation, and air quality management.
The calculator uses the CFM formula:
Where:
Explanation: This simple calculation divides the total volume of air by the time it takes for that volume to pass a specific point, giving you the flow rate in cubic feet per minute.
Details: Accurate CFM calculation is crucial for proper HVAC system design, ventilation requirements, industrial processes, and ensuring adequate air exchange rates in buildings for health and safety.
Tips: Enter the total air volume in cubic feet and the time in minutes. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What's the difference between CFM and ACH?
A: CFM measures airflow volume, while ACH (Air Changes per Hour) measures how many times the entire air volume of a space is replaced in one hour.
Q2: What are typical CFM requirements for residential HVAC?
A: Typical requirements range from 350-400 CFM per ton of cooling capacity, but this can vary based on specific system design and building characteristics.
Q3: How does CFM relate to static pressure?
A: CFM and static pressure have an inverse relationship in HVAC systems - as static pressure increases, CFM typically decreases if fan speed remains constant.
Q4: Can I use this calculator for liquid flow rates?
A: While the calculation is mathematically similar, liquid flow is typically measured in GPM (gallons per minute) rather than CFM.
Q5: How accurate are CFM calculations for real-world applications?
A: While the formula is mathematically precise, real-world measurements may vary due to factors like turbulence, temperature variations, and measurement equipment accuracy.