無塵室等級如何定義
無塵室的等級說明
使用者在開無塵室的等級給供貨商時，有以下幾個小技巧。
首先是等級定義的模式如下：
Class X (at Y μm )
其中X是無塵室的等級，例如100或10000等等，Y是粒徑如0.2μm , 0.5μm等，可復選。意思就是使用者規(guī)定，該無塵室微粒含量，在這些粒徑必須滿足該等級的限度。這樣可以減少紛爭，以下是幾個例子：
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….)，一般看一個粒徑即可。在Classes Less than 100 (M3.5)? (Class 10，1…. )，一般要看多幾個粒徑。
第二個技巧是規(guī)定無塵室的狀態(tài)，例如：
Class X (at Y μm )，At-rest
供貨商就很清楚知道無塵室要在At-rest狀態(tài)下驗收。
第三個技巧是自訂微粒濃度上限，一般在As-built時無塵室都很干凈，微?？刂颇芰y試不易，這時可以干脆把驗收上限壓低，例如：
Class 10000 (0.3 μm <= 10000)，As-built
Class 10000 (0.5 μm <= 1000)，As-built
這樣做的目的是確保無塵室在Operational狀態(tài)時，依然有足夠的微?？刂颇芰?。
以下兩個表是Fed-Std-209E的等級定義，和ISO-14644的等級定義。
|
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.
Equation (1): Cn = 10NX (0.1/D)2.08其中Cn是微粒濃度，N是潔凈度，D是粒徑 |
||||||
比較以上兩表我們可看出
