Class 100 Cleanroom
The Class 100 cleanroom represents one of the highest levels of cleanliness. Its core definition is that the number of airborne particles equal to or greater than 0.5 micrometers per cubic meter of air shall not exceed 3,520. This grade corresponds to ISO Class 5 according to international standards and is typically referred to as a Grade A high-risk operational zone under China's GMP regulations. The key to achieving this level lies in the mandatory use of unidirectional airflow (formerly known as "laminar flow"). Air is supplied at a uniform cross-sectional velocity (typically 0.36-0.54 meters per second) through ceiling-mounted HEPA filters, flowing vertically or horizontally in a single direction like an "air piston." This method instantly forces contaminants away from the core process area. Its primary purpose is to protect critical points where the product is directly exposed, such as during the filling of sterile pharmaceuticals, in the surgical incision area, or during the photolithography stage in high-precision semiconductor manufacturing.
Class 1,000 Cleanroom
The cleanliness of a Class 1,000 cleanroom is defined as: the number of airborne particles equal to or greater than 0.5 micrometers per cubic meter of air shall not exceed 35,200. It corresponds to ISO Class 6, serving as a background or buffer zone of very high cleanliness. This grade typically employs a non-unidirectional (turbulent) airflow pattern, relying on a very high air change rate (usually 70-160 times per hour) to rapidly dilute and remove contaminants generated within the room. In the pharmaceutical industry, the Class 1,000 cleanroom often serves as the implementation standard for a Grade B area. It provides a high-quality environmental background for localized Class 100 (Grade A) zones and is also used for processes with stringent cleanliness requirements, such as the preparation and sterile filtration of solutions for sterile products, as well as core areas in high-level biosafety laboratories.
Class 10,000 Cleanroom
The Class 10,000 cleanroom is the most widely used mainstream cleanroom grade. Its definition is: the number of airborne particles equal to or greater than 0.5 micrometers per cubic meter of air shall not exceed 352,000. It corresponds to ISO Class 7 and to Grade C in China's pharmaceutical GMP. This level is maintained through non-unidirectional airflow and a moderate air change rate (typically 30-70 times per hour), achieving an excellent balance between environmental control effectiveness and construction/operational costs. The Class 10,000 cleanroom forms the foundational "area-wide" environment for clean production. It is used for important but non-critical process steps, such as component preparation and solution preparation (prior to sterile filtration) in sterile pharmaceutical manufacturing, as well as final assembly and packaging areas for non-sterile products, high-end food items, and medical devices.