SCFM Calculator
Convert between ACFM and SCFM — Standard Cubic Feet per Minute flow rate calculations
Calculate SCFM (Standard Cubic Feet per Minute)
Actual flow rate at operating conditions
Temperature at which gas flow is measured
Gauge pressure (0 psig = atmospheric pressure)
Compression Ratio
Mass Flow Rate
Density Ratio
Application
Standard Conditions vs Operating Conditions
Conversion Formula
ACFM to SCFM: SCFM = ACFM × (294.26 / (T + 273.15)) × ((14.7 + P) / 14.7)
Where: T = temperature (°C), P = gauge pressure (psig)
Calculation: 98.70 = 100 × (294.26 / (25.0 + 273.15)) × ((14.7 + 0.0) / 14.7)
Example Calculation
Pneumatic System Analysis
Given: ACFM = 100 ft³/min, Temperature = 50°C, Pressure = 20 psig
Standard Conditions: 70°F (21.11°C), 14.7 psia (0 psig)
Find: SCFM (Standard Cubic Feet per Minute)
Step-by-Step Solution
1. Apply SCFM formula: SCFM = ACFM × (294.26 / (T + 273.15)) × ((14.7 + P) / 14.7)
2. Temperature correction: 294.26 / (50 + 273.15) = 294.26 / 323.15 = 0.910
3. Pressure correction: (14.7 + 20) / 14.7 = 34.7 / 14.7 = 2.361
4. SCFM = 100 × 0.910 × 2.361 = 214.9 ft³/min
Result: The system produces 214.9 SCFM under standard conditions
Flow Rate Applications
1-10 SCFM
Small tools, spray guns
10-100 SCFM
Impact tools, sanders
100-500 SCFM
Industrial machinery
>500 SCFM
Large industrial systems
Standard Conditions
Temperature
70°F (21.11°C) - Standard reference temperature
Pressure
14.7 psia (0 psig) - Sea level atmospheric pressure
Humidity
Dry air (0% relative humidity)
Purpose
Enables consistent comparison across systems
ACFM vs SCFM
ACFM: Actual conditions measurement
SCFM: Standardized for comparison
Usage: Equipment sizing and selection
Critical: Compressor specifications
Understanding SCFM and ACFM
What is SCFM?
SCFM (Standard Cubic Feet per Minute) is a flow rate measurement corrected to standard conditions of 70°F (21.11°C) and 14.7 psia (0 psig). This standardization allows for accurate comparison of gas flow rates regardless of operating conditions.
Why Standardize?
- •Equipment Sizing: Consistent basis for compressor selection
- •System Design: Accurate pipeline and component sizing
- •Performance: Compare systems across different conditions
- •Specifications: Universal language for engineers
What is ACFM?
ACFM (Actual Cubic Feet per Minute) represents the actual volume of gas flowing at the specific temperature and pressure conditions where measurement occurs. This reflects real-world operating conditions.
Key Applications
- •Pneumatic Tools: Air consumption specifications
- •HVAC Systems: Ventilation and air handling design
- •Process Control: Industrial gas flow monitoring
- •Compressor Systems: Capacity and efficiency analysis
Conversion Formula and Physics
SCFM = ACFM × (294.26 / (T + 273.15)) × ((14.7 + P) / 14.7)
Temperature and pressure correction formula
Density ∝ P/T
Ideal gas law relationship
Mass Flow = Volume × Density
Mass conservation principle
294.26 = 21.11 + 273.15
Standard temperature in Kelvin
• Higher temperature → Lower density
• SCFM < ACFM when T > 70°F
• SCFM > ACFM when T < 70°F
• Higher pressure → Higher density
• SCFM > ACFM when P > 0 psig
• SCFM < ACFM when P < 0 psig
• Compressor sizing accuracy
• Energy consumption estimation
• System pressure drop calculations