Understanding Air Flow Ratings – What Does “L/min (ANR)” Mean?
What is Air Flow (L/min ANR)?
“L/min (ANR)” stands for litres per minute at Atmospheric Normal Reference conditions. It’s a standardised way to measure how much compressed air a pneumatic component can pass in one minute under controlled reference conditions.
Typical ANR test parameters (ISO 6358):
Temperature: 20 °C
Pressure: 1 bar (abs)
Relative humidity: 65 %
When you see Flow = 9000 L/min (ANR), it means the device can flow roughly 9000 litres of air per minute, equivalent to ≈ 318 SCFM (Standard Cubic Feet per Minute).
Why ANR Matters
Using ANR (or SCFM) ensures all manufacturers quote performance on the same basis. This allows direct comparison between valves, regulators, filters, and actuators.
Without ANR, readings can differ dramatically depending on line pressure and temperature.
Conversion Table – L/min (ANR) ↔ SCFM
| Flow (L/min ANR) | Flow (SCFM) |
|---|---|
| 500 | 17.7 |
| 1000 | 35.3 |
| 2000 | 70.6 |
| 3000 | 106 |
| 4000 | 141 |
| 5000 | 176 |
| 6000 | 212 |
| 7000 | 247 |
| 8000 | 283 |
| 9000 | 318 |
| 9400 | 332 |
| 10000 | 353 |
| 12000 | 424 |
| 15000 | 530 |
| 20000 | 706 |
(1 SCFM ≈ 28.3 L/min ANR)
Shako flow test for 1" 316 Stainless steel air regulator USR08
Practical Tip
When sizing pneumatic valves, FRL units, or fittings:
- Match component flow rating (ANR or SCFM) to the actuator’s demand.
- Aim for 20–30 % headroom to avoid restriction.
- Ensure quoted values are measured at ANR — not at operating line pressure — for consistent results.