无尘室的等级说明
使用者在开无尘室的等级给供货商时,有以下几个小技巧。
首先是等级定义的模式如下:
Class X (at Y μm )
其中X是无尘室的等级,例如100或10000等等,Y是粒径如0.2μm , 0.5μm等,可复选。意思就是使用者规定,该无尘室微粒含量,在这些粒径必须满足该等级的限度。这样可以减少纷争,以下是几个例子:
Class1 (0.1μm, 0.2μm , 0.5μm)
Class 100(0.2μm , 0.5μm )
Class 100(0.1μm, 0.2μm , 0.5μm )
在Classes 100 (M3.5) and Greater (Class 100,1000,10000....),一般看一个粒径即可。在Classes Less than 100 (M3.5) (Class 10,1.... ),一般要看多几个粒径。
第二个技巧是规定的状态,例如:
Class X (at Y μm ),At-rest
供货商就很清楚知道无尘室要在At-rest状态下验收。
第三个技巧是自订微粒浓度上限,一般在As-built时无尘室都很干净,微粒控制能力测试不易,这时可以干脆把验收上限压低,例如:
Class 10000 (0.3 μm <= 10000),As-built
Class 10000 (0.5 μm <= 1000),As-built
这样做的目的是确保无尘室在Operational状态时,依然有足够的微粒控制能力。
以下两个表是Fed-Std-209E的等级定义,和ISO-14644的等级定义。
Class Name
|
Class Limits |
||||||||||
0.1μm |
0.2μm |
0.3μm |
0.5μm |
5μm |
|||||||
Volume Units |
Volume Units |
Volume Units |
Volume Units |
Volume Units |
|||||||
SI |
U.S. |
(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 |
2140 |
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 |
- |
- |
- |
- |
- |
- |
3,530,000 |
100,000 |
24,700 |
700 |
M 7 |
|
- |
- |
- |
- |
- |
- |
10,000,000 |
283,000 |
61,800 |
1,750 |
ISO classification number(N) |
Maximum concentration limits (particles/m3of air) for particles equal to and larger than the considered sizes shown below (concentration limits are calculated in accordance with equation (1). |
|||||
0.1mm |
0.2mm |
0.3mm |
0.5mm |
1mm |
5mm |
|
ISO Class 1 |
10 |
2 |
|
|
|
|
ISO Class 2 |
100 |
24 |
10 |
4 |
|
|
ISO Class 3 |
1 000 |
237 |
102 |
35 |
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 |
8 320 |
293 |
ISO Class 7 |
|
|
|
352 000 |
83 200 |
2 930 |
ISO Class 8 |
|
|
|
3 520 000 |
832 000 |
29 300 |
ISO Class 9 |
|
|
|
35 200 000 |
8 320 000 |
293 000 |
NOTE Uncertainties related to the measurement process requires that concentration data with no more then three significant figures be used in determining the classification level. |
比较以上两表我们可看出