FAD reflects real-world performance under standard conditions, while displacement is theoretical.
Selecting the right air compressor goes beyond horsepower or brand reputation. Airflow—measured in CFM, L/min, or m³/min—is the real performance indicator. Misunderstanding these units can lead to undersized systems, poor tool performance, and wasted investment.
Understanding Airflow Units
What Is Airflow and Why It Matters
Airflow determines whether your pneumatic tools operate efficiently. Pressure provides force, but without sufficient airflow, tools stall or underperform.
CFM, L/min, and m³/min Explained
- CFM: Cubic Feet per Minute (US standard)
- L/min: Liters per Minute (metric)
- m³/min: Cubic Meters per Minute (industrial scale)
Conversions:
- 1 CFM ≈ 28.3 L/min
- 1 m³/min ≈ 35.3 CFM
Flow Ratings and Why They Matter
Displacement vs FAD
- Displacement: Theoretical output.
- FAD (Free Air Delivery): Real usable air at ISO 1217 conditions. Always use FAD for sizing.
Sizing Your Compressor
Matching Tools to Capacity
Continuous-use tools need higher FAD and larger receivers; intermittent-use tools can rely on stored air. Add 20–30% margin for future needs.
Worked Examples
Paint booth: Spray gun needs 10 CFM → choose compressor with 15 CFM FAD.
Frequently Asked Questions
Multiply CFM by 28.3. For example, 10 CFM ≈ 283 L/min.
Tools underperform, causing poor results and increased wear.
