ISO Class 5 cleanrooms play a very important role in modern industrial manufacturing and scientific research, they represent one of the highest standards in air cleanliness technology.
According to the authoritative definition of the International Organization for Standardization ISO 14644-1, the ISO 5 cleanroom classification requires that the number of suspended particles ≥0.5μm per cubic meter of air does not exceed 3,520, which corresponds to no more than 100 particles per cubic foot.
This is precisely the modern standard equivalent of the traditionally classified Class 100 Cleanroom, which is defined by withdrawn U.S. Federal Standard 209E. It is noteworthy that the control standard for smaller 0.1μm particles is even more stringent, with the limit set at 100,000 particles per cubic meter. For every cubic meter of space, the maximum allowed counts are:
≥ 0.1 µm: 100,000 particles
≥ 0.2 µm: 23,700 particles
≥ 0.3 µm: 10,200 particles
≥ 0.5 µm: 3,520 particles
≥ 1.0 µm: 832 particles
≥ 5.0 µm: 29 particles
An ISO Class 5 cleanroom is about 10 to 1000 times cleaner than the more common ISO Classes 6-8 cleanrooms. This requires a carefully designed airflow system to keep the environment stable to achieve this level of cleanliness.
Key Parameters for Building an ISO Class 5 Cleanroom
Achieving and maintaining ISO 5 requires a more rigorous and integrated approach than lower classes.
HEPA/ULPA Filtration: ISO 5 cleanrooms primarily use HEPA filters (99.97% efficient on 0.3µm particles) or ULPA filters (99.999% efficient on 0.12µm particles) to achieve their stringent air cleanliness. If HEPA filters are used only, 100% ceiling coverage should be needed for meeting the standard.
Air Changes Per Hour (ACH): Requires a significantly higher air exchange rate, typically between 240 and 480 air changes per hour. The exact figure is calculated based on a detailed analysis of internal particle generation from equipment, process, and personnel.
| ISO Class | ACH(Air Changes Per Hour) |
|---|---|
| ISO 3 | 360-540 |
| ISO 4 | 300-540 |
| ISO 5(class 100) | 240-480 |
| ISO 6(class 1000) | 50-60 |
| ISO 7(class 10000) | 30-40 |
| ISO 8(class 100000) | 15-25 |
Airflow Pattern: Unidirectional (laminar) air flow is acceptable only with velocity of the air within 0.45±0.1m/s, the vertical airflow from the ceiling works like piston to push contamination outside through raised floor or air return grilles in the walls.
Temperature & Humidity: For most industries, the temperature should be between 20–25°C (68–77°F) and the relative humidity between 40–60%. However, the requirements for semiconductor manufacturing are far stricter. To ensure high product yield, the environment must be held within a temperature variation of no more than ±0.5°C, and relative humidity must be tightly controlled in a narrow range of 45%±5%.
Typical Applications for an ISO Class 5 Cleanroom
1. Semiconductor Manufacturing
In the semiconductor chip manufacturing industry, an ISO Class 5 cleanroom is the standard requirement for critical processes like lithography and etching. For example, in the 28-nanometer manufacturing process, if more than five 0.1μm particles are present on a 300mm diameter silicon wafer, it can lead to short circuits or broken circuits in the chip. Production data shows that in an ISO Class 5 environment, the defect density on a 12-inch wafer can be kept below 0.05 defects per square centimeter. In contrast, in an ordinary environment, this number can be as high as 5 defects per square centimeter or more. This difference of multiple orders of magnitude directly determines the yield and performance of the chips produced.
2. Biopharmaceutical Production
The application of ISO Class 5 standards is equally strict in the biopharmaceutical industry. Sterile filling production lines must ensure that the microbial concentration in the air remains below 1 CFU (Colony Forming Unit) per cubic meter. Achieving this requires not only meeting the ISO Class 5 standard for airborne particles but also implementing additional biological purification measures such as UV sterilization and hydrogen peroxide vaporization. Comparative data shows that under the same sterilization conditions, microbial survival rates in an ISO Class 5 cleanroom are two orders of magnitude lower than in an ISO Class 7 cleanroom. This is crucial for ensuring the sterility and safety of injectable drug products.
3. Precision Optics Manufacturing
Precision optics manufacturing is another key application area. During the production of high-resolution optical lenses, a single 0.3μm dust particle can cause imaging flaws or spots. Test data from a leading optics company indicates that the defect rate for lenses produced in an ISO Class 5 environment is 0.02%, while in an ISO Class 6 environment, the defect rate rises to 0.15%. For a company producing millions of lenses, this difference represents a significant impact on quality control costs and brand reputation.
Looking to Build or Upgrade an ISO 5 (Class 100) cleanroom?
It’s a critical project that demands precision and proven expertise. At KINROM, we simplify the complexity. We help you navigate from initial design to full compliance, ensuring your cleanroom is reliable, efficient, and built to the highest standards.
Talk to our experts today for a clear consultation and a custom solution tailored to your needs.
