1. What is CFM Calculation?

CFM (Cubic Feet per Minute) calculation from PSI measures the flow rate of air based on pressure change in a known volume over time. This is commonly used in compressed air systems to determine air compressor performance.

2. How Does the Calculator Work?

The calculator uses the CFM formula:

Where:

• \( V \) — Volume of the tank (ft³)
• \( \Delta P \) — Pressure change (psi)
• \( t \) — Time for pressure change (minutes)
• 14.7 — Atmospheric pressure at sea level (psi)
• 60 — Conversion factor from minutes to seconds

Explanation: The equation calculates how much air (in cubic feet) flows per minute based on the pressure change observed in a tank of known volume over a measured time period.

3. Importance of CFM Calculation

Details: Accurate CFM measurement is crucial for sizing air compressors, designing pneumatic systems, and troubleshooting air flow problems in industrial applications.

4. Using the Calculator

Tips: Enter tank volume in cubic feet, pressure change in psi, and time in minutes. All values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is 14.7 used in the formula?
A: 14.7 psi represents standard atmospheric pressure at sea level, which is the reference pressure for most CFM calculations.

Q2: How accurate is this method?
A: This method provides a good estimate for most applications, but actual CFM may vary due to temperature changes, tank geometry, and measurement errors.

Q3: Can I use this for any gas?
A: The formula works best for air. For other gases, you would need to account for different gas properties and compressibility factors.

Q4: What's a typical CFM range for compressors?
A: Small shop compressors might be 5-30 CFM, while industrial compressors can range from 50 to several thousand CFM.

Q5: How does altitude affect the calculation?
A: At higher altitudes, you should use the local atmospheric pressure instead of 14.7 psi for more accurate results.