Model selection
About cleanliness class
Cleanliness classes of clean rooms are defined by the conventionally used FED standard and the international standard ISO14644-1
as specified below.
as specified below.
FED-STD-209D
| Class | 1 | 10 | 100 | 1,000 | 10,000 | 100,000 |
| Ventilation frequency | - | - | 250 - 400 | 150 | 75 | 20 |
| Particle concentration (pcs/CFT) | 1 | 10 | 100 | 1,000 | 10,000 | 100,000 |
| Metric equivalent (pcs/CBM) | 35 | 353 | 3,530 | 35,300 | 353,000 | 3,530,000 |
| ISO class equivalent | 3 | 4 | 5 | 6 | 7 | 8 |
| Examples of site | - | - | LCD/IC Precision industry |
Surgery room | Pharmaceutical factory |
PC assembly plant |
- Ventilation frequency : This shows the required number of air changes per hour.
- Number of particles : This shows the maximum allowable number of particles larger than 0.5μm per 1 CFT.
ISO-14644-1
| Class | 0.1µｍ | 0.2µｍ | 0.3µｍ | 0.5µｍ | 1µｍ | 5µｍ |
| ISO1 | 10 | 2 | ||||
| ISO2 | 100 | 24 | 10 | 4 | ||
| ISO3 | 1,000 | 237 | 102 | 35 | 8 | |
| ISO4 | 10,000 | 2,370 | 1,020 | 352 | 83 | |
| ISO5 | 100,000 | 23,700 | 10,200 | 3,520 | 832 | 29 |
| ISO6 | 1,000,000 | 237,000 | 102,000 | 35,200 | 8,320 | 293 |
| ISO7 | 3,520,000 | 83,200 | 2,930 | |||
| ISO8 | 35,200,000 | 832,000 | 29,300 | |||
| ISO9 | 8,320,000 | 293,000 |
Formula for model selection
Example of model selection
When the space dimension is W2xD2xH2m and the cleanliness class 10,000 is desired to be maintained.
- Calculate the cubic volume of the space.
2m×2m×2m ＝ 8CBM - Calculate the required air volume from the ventilation rate.
75 times/h×8CBM = 600CBM/h - Calculate the air volume per minute.
600CBM/h÷60min = 10CBM/min → Required air volume is 10CBM/min
| Model | OFU-102H-AW | OFU-105H-AW | OFU-110H-AW | OFU-117H-AW |
| Max. air volume | 2m3 ／min | 5m3 ／min | 10m3 ／min | 17m3／min |
→ Recommended model is OFU-110H-AW
