
According to the standards issued by the U.S. government, cleanrooms can be classified into six levels. They are Class 1, Class 10, Class 100, Class 1000, Class 10000, and Class 100000. Class 1: This level of cleanroom is mainly used in the microelectronics industry for manufacturing integrated circuits. Class 10: This level of cleanroom is primarily used in the semiconductor industry for processes with bandwidths less than 2 micrometers. Class 100: Class 100 cleanrooms can be used for sterile manufacturing processes in the pharmaceutical industry, among others. Class 1000: This level of cleanroom is mainly used for the production of high-quality optical products. Class 10000: Class 10000 cleanrooms are used for the assembly of hydraulic or pneumatic equipment. Class 100000: Class 100000 cleanrooms are used in many industrial sectors.

















I know the five levels of cleanrooms are primarily classified based on the ISO 14644-1 standard, with the common ones being ISO 5, ISO 6, ISO 7, ISO 8, and ISO 9. ISO 5 represents the highest cleanliness level with the fewest particles, such as only a few thousand particles per cubic meter. This is commonly found in semiconductor factories or operating rooms because it requires nearly dust-free air to avoid affecting precision components or surgical safety. ISO 6 is slightly more lenient, suitable for medical device assembly, where the particle count is higher but still relatively clean. ISO 7, like some pharmaceutical cleanrooms, offers moderate environmental control with less dust but easier daily operations. ISO 8 is even more lenient and can be used in food packaging environments, where the air is relatively clean but strict sterilization isn’t necessary. ISO 9 is the lowest level, with a higher particle count, used in basic industries like automotive parts cleaning, where dust has minimal impact. The key to these classifications is controlling contamination sources through high-efficiency filters and airflow design, so the choice must balance product requirements and cost—too high or too low would waste resources.

When studying industrial , I learned about the five cleanliness levels of cleanrooms, simply categorized by the amount of airborne particles, ranging from ISO 5 to ISO 9. ISO 5 is the cleanest, comparable to a hospital operating room with ultra-clean air; ISO 6 is slightly less stringent, suitable for testing areas in electronics factories; ISO 7 is a mid-level, like a pharmaceutical production area with moderately clean air; ISO 8 is more lenient, used for packaging lines in food factories where dust is higher but still controllable; ISO 9 is the lowest grade, with significantly higher particle counts, such as in warehouses or mechanical assembly areas. Learning this is quite intuitive because each level corresponds to the practical needs of different industries—for example, high-tech products require ISO 5 to protect sensitive components, while ordinary items can use ISO 9 to save maintenance effort. Understanding these levels helps avoid contamination incidents, reduce product rework, and improve overall efficiency.

In the workshop, I've encountered these five cleanliness levels: ISO 5 is the strictest, requiring full protective gear to enter; ISO 6 is slightly less stringent but still requires wearing cleanroom suits; ISO 7 is moderate, needing regular sweeping for daily cleaning; ISO 8 is more lenient, with frequent dust handling; ISO 9 is the most relaxed, requiring only basic cleaning. Each level affects work comfort—higher levels mean fresher air but slower movement, while lower levels allow faster work but are prone to dust accumulation. Control relies on equipment like particle counters, with regular testing to maintain the standards.

During a recent visit to a pharmaceutical factory, they emphasized that the workshop has five cleanliness grades: ISO 5 for the core area, where the air is ultra-clean; ISO 6 is suitable for semi-critical areas; ISO 7 is commonly found in preparation rooms; ISO 8 is used for storage; and ISO 9 is for peripheral general areas. The grading system made me feel that space is better, reducing the risk of cross-contamination and making operations efficient and comfortable. The classification is based on particle count control to protect product quality and safety.

As an industry consultant, I often mention that cleanrooms are classified into five levels from ISO 5 to 9. ISO 5 has the fewest particles, approximately 3,520 particles per cubic meter, and is used in microelectronics. ISO 6 has slightly more particles. ISO 7, with tens of thousands of particles, is common in pharmaceuticals. ISO 8 has more relaxed particle limits and is used in light industry. ISO 9 has the lowest cleanliness. These classifications originate from international standards to ensure control over contaminants like dust and humidity. When selecting a level, companies must balance cost and effectiveness: higher levels require stronger filtration systems to improve product yield, while lower levels save operational costs but limit application scope. Regular reviews of standard updates are also crucial.


