Worldwide Standard Cleanliness
Cleanliness
The cleanroom classification standards FS 209E and ISO 14644-1 require specific particle count measurements and calculations to classify the cleanliness level of a cleanroom or clean area.
ISO 14644-1
Maximum concentration limits (particles/m3 )
Classification Number (N)
0.1μm
0.2μm
0.3μm
0.5μm
1.0μm
5.0μm
ISO Class 1
10
2
–
–
–
–
ISO Class 2
100
24
10
4
–
–
ISO Class 3
1,000
237
102
35.2
8
–
ISO Class 4
10,000
2,370
1,020
352
83
–
ISO Class 5
100,000
23,700
10,200
3,520
832
29
ISO Class 6
1,000,000
237,000
102,000
35,200
83,200
293
ISO Class 7
–
–
–
352,000
832,000
2,930
ISO Class 8
–
–
–
35,200,000
8,320,000
29,300
ISO Class 9
–
–
–
–
–
293,000
Federal Standard 209E Airborne Particulate Cleanliness Classes
Diameter for Airborne Particle
ICR Cleanliness
0.1μm
0.2μm
0.3μm
0.5μm
0.5μm
Volume Units
Volume Units
Volume Units
Volume Units
Volume Units
SI
Class
(m3)
(ft3)
(m3)
(ft3)
(m3)
(ft3)
(m3)
(ft3)
(m3)
(ft3)
M1
350
9.91
75.7
2.14
30.9
0.875
10.0
0.283
–
–
M1.5
1
1240
35.0
265
7.50
106
3.00
35.3
1.00
–
–
M2
3,500
99.1
757
21.4
309
8.75
100
2.83
–
–
M2.5
10
12,400
350
2,650
75.0
1,060
30.0
353
10.0
–
–
M3
35,000
991
7,570
214
3,090
87.5
1,000
28.3
–
–
M3.5
100
–
–
26,500
750
10.600
300
3,530
100
–
–
M4
–
–
75,700
2,140
30,900
875
10,000
283
–
–
M4.5
1000
–
–
–
–
–
–
35,300
1,000
247
7.00
M5
–
–
–
–
–
–
100,000
2,830
618
17.5
M5.5
10,000
–
–
–
–
–
–
353,000
10,000
2,470
70.0
M6
–
–
–
–
–
–
1,000,000
28,300
6,180
175
M6.5
100,000
–
–
–
–
–
–
3,530,000
100,00
24,700
700
M7
–
–
–
–
–
–
10,000,000
283,000
61,800
1,750
JIS B 9920
Class
Maximum concentration limits (particles/m3 )
0.1μm
0.2μm
0.3μm
0.5μm
1μm
05μm
Class1
10
2
—
—
—
—
Class2
100
24
10
4
—
—
Class3
100
237
102
35
8
—
Class4
10,000
2,370
1,020
352
83
—
Class5
100,000
23,700
10,200
3,520
832
29
Class6
—
237,000
102,000
35,200
8,320
293
Class7
—
—
—
352,000
83,200
2,930
Class8
—
—
—
3,520,000
832,000
29,300
Class9
—
—
—
35,200,000
8,320,000
293,000
Britain BS 5295
Classs
Maximum concentration limits (particles/m3 )
0.5μm
1μm
5μm
10μm
25μm
Class 1
3,000
—
0
0
0
Class [...]