Cleanroom ISO Class Standards

1. Introduction to ISO Cleanroom Classification

The ISO 14644-1:2015 standard serves as the cornerstone for classifying cleanrooms. It categorizes cleanrooms into 9 distinct classes (ISO 1 to ISO 9) based on the number and size of particles present in each cubic meter of air. This classification system ensures consistency across industries, helping businesses select the right controlled environment for their specific needs. ISO 1 represents the highest level of cleanliness, with the fewest particles, while ISO 9 stands as the least stringent, allowing the most particles.

2. Key Classification Criteria

At the heart of the ISO cleanroom classification lies the measurement of particle counts. The standard defines maximum allowable particle concentrations for various sizes, including 0.1μm, 0.2μm, 0.3μm, 0.5μm, 1μm, and 5μm. Each class has strict limits for these particle sizes, with lower ISO numbers permitting far fewer particles. This focus on particle size and quantity ensures that cleanrooms meet the precise requirements of sensitive processes.

3. Detailed Breakdown of ISO Classes

3.1 ISO 1

• Particle Limits (per cubic meter): ≥0.1μm ≤10; ≥0.2μm ≤2
• Characteristics: Boasts the highest cleanliness level, with extremely tight controls on the smallest particles. It finds application in ultra-precision manufacturing and advanced research.

3.2 ISO 2

• Particle Limits (per cubic meter): ≥0.1μm ≤100; ≥0.2μm ≤24; ≥0.3μm ≤10; ≥0.5μm ≤4
• Features: Maintains a very high level of cleanliness, suitable for processes where even minute particles can cause significant issues, such as in certain microelectronics manufacturing steps.

3.3 ISO 3

• Particle Limits (per cubic meter): ≥0.1μm ≤1,000; ≥0.2μm ≤237; ≥0.3μm ≤102; ≥0.5μm ≤35; ≥1μm ≤8
• Note: Does not allow particles larger than 1μm. It is used in high-precision industries requiring strict contamination control, like semiconductor production.

3.4 ISO 4

• Particle Limits (per cubic meter): ≥0.1μm ≤10,000; ≥0.2μm ≤2,370; ≥0.3μm ≤1,020; ≥0.5μm ≤352; ≥1μm ≤83
• Trait: Similar to ISO 3, it prohibits particles over 1μm. It serves applications that demand high cleanliness but with slightly more tolerance than ISO 3, such as in some medical device manufacturing.

3.5 ISO 5

• Particle Limits (per cubic meter): ≥0.1μm ≤100,000; ≥0.2μm ≤23,700; ≥0.3μm ≤10,200; ≥0.5μm ≤3,520; ≥1μm ≤832; ≥5μm ≤29
• Application: Widely used in Grade A production, particularly for aseptic preparation and filling of pharmaceutical products, where sterility is critical.

3.6 ISO 6

• Particle Limits (per cubic meter): ≥0.1μm ≤1,000,000; ≥0.2μm ≤237,000; ≥0.3μm ≤102,000; ≥0.5μm ≤35,200; ≥1μm ≤83,200; ≥5μm ≤2,930
• Usage: Covers a range of particle sizes and is employed in various industries, including electronics and pharmaceuticals, for processes that require moderate to high cleanliness.

3.7 ISO 7

• Particle Limits (per cubic meter): ≥0.5μm ≤352,000; ≥1μm ≤832,000; ≥5μm ≤2,930
• Details: Classified as Grade C. During operation, it can allow up to 3,500,000 particles of ≤0.5μm. It is commonly used in the pharmaceutical industry for various production stages.

3.8 ISO 8

• Particle Limits (per cubic meter): ≥0.5μm ≤3,520,000; ≥1μm ≤832,000; ≥5μm ≤29,300
• Role: Known as Grade D, it has a cleanliness level slightly higher than ordinary indoor air. It is utilized in non-critical stages of sterile product manufacturing.

3.9 ISO 9

• Particle Limits (per cubic meter): ≥0.5μm ≤35,200,000; ≥1μm ≤8,320,000; ≥5μm ≤293,000
• Status: The least clean class, allowing the highest number of particles. It finds use in industries where basic contamination control is sufficient, such as some general manufacturing areas.