Air Velocity and Number of Air Changes per Hour in Clean Rooms (39)
| Class of Clean room | Airflow Type | Average Velocity (Ft./Min.) | Air Changes/hr. |
|---|---|---|---|
| ISO 8 (Class 100,000) | N/M | 1–8 | 5–48 |
| ISO 7 (class 10,000) | N/M | 10–15 | 60–90 |
| ISO 6 (Class 1,000) | N/M | 25–40 | 150–240 |
| ISO 5 (Class 100) | U/N/M | 40–80 | 240–480 |
N is Non-unidirectional; M is Mixed Airflow; U is Unidirectional. Note: 10 ft/min equals 3.048 m/min.