ISO Class - Particles, Size: Understanding Cleanroom Classifications
Particle Size and Concentration: The Foundation of Cleanroom Standards
The basis for cleanroom standards revolves around the measurement of particle sizes, typically measured in micrometers (µm), which indicates the size of the particles to be filtered from the air.
Cleanrooms are classified based on how clean the air is and by the amount and size of particles present per volume of air.
The classification system provides clear thresholds for
acceptable particle concentrations, ensuring that the cleanroom environment meets the necessary cleanliness standards for sensitive manufacturing or processing tasks.
Cleanroom Classification by Particle Size
The ISO 14644-1:2015 standard defines cleanroom classifications based on the maximum allowable particle concentration in the air, by size and number.
Cleanrooms are classified into ISO Classes that correspond to the maximum concentration of airborne particles for specific particle sizes, measured in particles per cubic meter (m³) of air.
Each cleanroom classification corresponds to a specific
particle size and
concentration limit to ensure that contaminants do not affect the quality or safety of the products being manufactured.
Particle Size and Concentration Limits by ISO Class
Below is a table outlining the maximum allowable particle concentrations for each ISO Class according to ISO 14644-1:2015. This table lists the particle size (in micrometers) and the corresponding maximum particle concentration limits.
| ISO Class | ≥ 0.1 µm/ m3 | ≥ 0.2 µm/ m3 | ≥ 0.3 µm/ m3 | ≥ 0.5 µm/ m3 | ≥ 1 µm/ m3 | ≥ 5 µm/ m3 |
|---|---|---|---|---|---|---|
| ISO 1 | 10 | 2 | 0 | 0 | 0 | 0 |
| ISO 2 | 100 | 24 | 10 | 4 | 0 | 0 |
| ISO 3 | 1,000 | 237 | 102 | 35 | 8 | 0 |
| ISO 4 | 10,000 | 2,370 | 1,020 | 352 | 83 | 0 |
| ISO 5 | 100,000 | 23,700 | 10,200 | 3,520 | 832 | 0 |
| ISO 6 | 1,000,000 | 237,700 | 102,000 | 35,200 | 8,320 | 293 |
| ISO 7 | - | - | - | 352,000 | 83,200 | 2,930 |
| ISO 8 | - | - | - | 3,520,000 | 832,000 | 29,300 |
| ISO 9 | - | - | - | 35,200,000 | 8,320,000 | 293,000 |
Particle Sizes and Their Relevance
Particles ≥ 0.1 µm, 0.2 µm, 0.3 µm, and so on, represent the various particle sizes that can affect cleanroom operations. Some classifications do not require certain particle sizes to be tested. Here’s a breakdown of the particle sizes typically tested for cleanroom qualification:
- Particles ≥ 0.1 µm: This size encompasses a large variety of contaminants and is typically the smallest size considered for testing in high-precision cleanrooms (such as those used in electronics manufacturing).
- Particles ≥ 0.2 µm and 0.3 µm: These sizes are particularly significant in industries like pharmaceuticals, where even tiny particles can affect the sterility and quality of drugs or medical devices.
- Particles ≥ 1.0 µm: Larger particles that are visible to the naked eye, often considered when dealing with less stringent environments.
Important Notes on Testing
Some classifications do not require testing for certain particle sizes. For example, in ISO 9 cleanrooms, particles larger than 5 microns may not be tested, as the level of cleanliness is sufficient for less sensitive processes.
The larger the cleanroom class number, the more relaxed the particle concentration limits are.
ISO Class 1 represents the cleanest, most particle-free environment, while
ISO Class 9 has less stringent controls.
Why Particle Control Matters in Cleanrooms
Controlling particle concentration is essential in cleanrooms because airborne particles can negatively impact the manufacturing and processing of sensitive products, such as:
- Pharmaceuticals: Contaminants can affect drug purity or sterility.
- Electronics: Dust particles can damage electronic components or impair functionality.
- Medical Devices: Even small contaminants can compromise device safety and reliability.
- Aerospace: Contaminants can impact the performance of sensitive equipment used in space and defense sectors.
Contact Me for Cleanroom Classification Guidance
Understanding the particle concentration limits and how they apply to your cleanroom’s classification is vital for maintaining a controlled environment that meets industry standards. Whether you’re designing a new cleanroom or ensuring your current facility complies with ISO standards, I’m here to guide you through the classification process and help ensure your cleanroom meets the required specifications.
Contact me today
to learn more about cleanroom classifications, particle size limits, and how they apply to your industry!