Federal standard 209e and its replacement ISO standard 1446 are the federal guidelines for cleanroom construction. United Maintenance uses these standards in every environment we construct. These standards set the bar for cleanliness classes and for the monitoring and testing of cleanroom environments. The standards were put in place as a guideline to assure the environment meets or exceeds its requirements. United Maintenance has been building environments to these standards for over twenty years and guarantees every project we design or construct to meet or exceed the particulate counts and procedures set forth in these guidelines.
ISO Standards
The ISO (International Organization for Standardization) has recently established a guide for controlled environments.
| Class | Maximum Particles / m³ | U.S. Federal Standard 209E Equivalent |
|||||
| ≥0.1 µm | ≥0.2 µm | ≥0.3 µm | ≥0.5 µm | ≥1 µm | ≥5 µm | ||
| ISO 1 | 10 | 2 | |||||
| ISO 2 | 100 | 24 | 10 | 4 | |||
| ISO 3 | 1,000 | 237 | 102 | 35 | 8 | Class 1 | |
| ISO 4 | 10,000 | 2,370 | 1,020 | 352 | 83 | Class 10 | |
| ISO 5 | 100,000 | 23,700 | 10,200 | 3,520 | 832 | 29 | Class 100 |
| ISO 6 | 1,000,000 | 237,000 | 102,000 | 35,200 | 8,320 | 293 | Class 1000 |
| ISO 7 | 352,000 | 83,200 | 2,930 | Class 10,000 | |||
| ISO 8 | 3,520,000 | 832,000 | 29,300 | Class 100,000 | |||
Federal Standard 209 Chart
Many people find the older Federal Standard 209 chart easier to understand and apply.
| Classes | Particles 0.5 microns or larger / cubic foot | ||
| Class 1 | 1 | ||
| Class 10 | 10 | ||
| Class 100 | 100 | ||
| Class 1,000 | 1,000 | ||
| Class 10,000 | 10,000 | ||
| Class 100,000 | 100,000 | ||
There are additional standards applied to the air changes per hour: (filter face velocity = 90 feet per minute)
| Class | >Air Changes Per Hour m^3 / m^2 x H | Velocity m/s | Type of Airflow | |
| ISO Class 2 | 0.3 -0.5 m/s | Unidirectional | ||
| ISO Class 3 | 0.3 -0.5 m/s | Unidirectional | ||
| ISO Class 4 | 0.3 -0.5 m/s | Unidirectional | ||
| ISO Class 5 | 0.2 -0.5 m/s | >Unidirectional | ||
| ISO Class 6 | 70-160 | Non-Unidirectional or Mixed | ||
| ISO Class 7 | <30-70 | Non-Unidirectional or Mixed | ||
| ISO Class 8 | 10-20 | Non-Unidirectional or Mixed | ||
| ISO Class 9 | 0-10 | Non-Unidirectional or Mixed | ||