What are the clean room class limits according Federal Standard 209?
Note! Federal Standard 209E is canceled and superseded by International Organization for Standardization (ISO) Standards - International Standards for Cleanrooms and associated controlled environments, ISO 14644.
Clean room maintained virtually free of contaminants, such as dust or bacteria, are used in laboratory work and in the production of precision parts for electronic or aerospace equipment.
The air quality of a clean rooms are described in Federal Standard 209 "Airborne Particulate Cleanliness Classes in Cleanrooms and Clean Zones" (A through D) where the classes are named after the maximum number of particles of 0.5 micrometers or more in diameter which is acceptable in air.
|
Maximum Number of Particles in Air
(particles per cubic foot air) |
|||||
|
Class
|
|||||
|
0.1 µm
|
0.2 µm
|
0.3 µm
|
0.5 µm
|
5.0 µm
|
|
|
1
|
35
|
7.5
|
3
|
1
|
 |
|
10
|
350
|
75
|
30
|
10
|
|
|
100
|
|
750
|
300
|
100
|
|
|
1,000
|
|
|
|
1,000
|
7
|
|
10,000
|
|
|
|
10,000
|
70
|
|
100,000
|
|
|
|
100,000
|
700
|
In a clean room rated as "Class 10,000" there may not exists more than 10,000 particles larger than 0.5 microns in a cubic foot of air.
Classes and their Typical Uses
- Class 1 & 10 - production laboratories for electronic integrated circuits ..
- Class 100 - production areas for photo labs, medical implants ..
- Class 10,000 - production locales for TV tubes, hospital operating theaters ...
- Class 100,000 - production of ball bearings
Federal Standard 209 E uses metric units and the classes are defined as:
|
Maximum Number of Particles in Air
(particles per volume unit) |
|||||||||||
|
Class
|
|||||||||||
|
0.1 µm
|
0.2 µm
|
0.3 µm
|
0.5 µm
|
5 µm
|
|||||||
|
SI
|
English
|
m³
|
ft³
|
m³
|
ft³
|
m³
|
ft³
|
m³
|
ft³
|
m³
|
ft³
|
|
M 1
|
|
350
|
9.91
|
75.7
|
2.14
|
30.9
|
0.875
|
10.0
|
0.283
|
|
|
|
M 1.5
|
1
|
1,240
|
35.0
|
265
|
7.50
|
106
|
3.00
|
35.3
|
1.00
|
|
|
|
M 2
|
|
3,500
|
99.1
|
757
|
21.4
|
309
|
8.75
|
100
|
2.83
|
|
|
|
M 2.5
|
10
|
12,400
|
350
|
2,650
|
75.0
|
1,060
|
30.0
|
353
|
10.0
|
|
|
|
M 3
|
|
35,000
|
991
|
7,570
|
214
|
3,090
|
87.5
|
1,000
|
28.3
|
|
|
|
M 3.5
|
100
|
|
|
26,500
|
750
|
10,600
|
300
|
3,530
|
100
|
|
|
|
M 4
|
|
|
|
75,700
|
2,140
|
30,900
|
875
|
10,000
|
283
|
|
|
|
M 4.5
|
1,000
|
|
|
|
|
|
|
35,300
|
1,000
|
247
|
7.00
|
|
M 5
|
|
|
|
|
|
|
|
100,000
|
2,830
|
618
|
17.5
|
|
M 5.5
|
10,000
|
|
|
|
|
|
|
353,000
|
10,000
|
2,470
|
70.0
|
|
M 6
|
|
|
|
|
|
|
|
1,000,000
|
28,300
|
6,180
|
175
|
|
M 6.5
|
100,000
|
|
|
|
|
|
|
3,350,000
|
100,000
|
24,700
|
700
|
|
M 7
|
|
|
|
|
|
|
|
10,000,000
|
283,000
|
61,800
|
1,750
|