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ROI CalculatorCleanroom zone classification involves the global standardization of categorizing controlled environments based on the maximum concentrations of airborne particles allowed per cubic meter of air. This classification is defined by ISO 14644-1.
Widely used in pharmaceuticals, biotech facilities, aerospace manufacturing, semiconductor manufacturing, and medical device manufacturing, cleanroom classification is important to prevent contamination of products produced within them. Its main goal is to achieve a proper balance between the classification of zones and the critical processes within them.
ISO 14644-1 is regarded as the international standard in classification of cleanrooms that range from ISO Class 1 (cleanest) to ISO Class 9 (least clean, similar to room air). On the other hand, in pharmaceutical manufacturing, classifications are referred to using the EU Good Manufacturing Practice classification, where grades range from Grade A (critical, aseptic processing) down to Grade D (less critical support process).
ISO Class 5 / Grade A: Critical zones for aseptic processing and high-purity filling operations.
ISO Class 7 / Grade B & C: Cleanroom support environments and preparation zones.
ISO Class 8 / Grade D: Lower-criticality background zones for less sensitive processes.
Maintaining cleanroom classification requires more than physical isolation. It involves coordinated engineering measures, continuous environmental monitoring, and strict adherence to protocols:
High Efficiency Particulate Air (HEPA) Filters: Any air coming into the classified area needs to go through HEPA or ULPA (Ultra-Low Particulate Air) filtering systems. Air flow rate and direction of flow need to be monitored; the laminar (unidirectional) flow system is used for high-purity areas such as Grade A/ISO 5, while a turbulent (non-unidirectional) air flow system is applied to lower-grade areas.
Pressure Differentiation: To avoid air with contamination reaching the cleaner areas, differential air pressures are applied. The higher positive pressure needs to be maintained inside the area of higher purity compared to the lower adjacent areas. As a result, whenever a door opens, air pushes out, thus not allowing outside contaminants to enter.
Strict Gowning and Personal Hygiene: Humans represent a major source of particle and microbial shedding in cleanroom environments. Staff are required to wear special clothes that do not shed; for example, in some areas, they should wear a hood, mask, gloves, and boots.
Facilities should perform sampling from the air and surfaces inside the classified area on a continuous basis for both microbial and non-microbial particles. However, permanently installed sensors and data transmission systems that collect environmental data in real-time, along with automated counting equipment and agar plates, are continuously deployed to verify that the area falls within its specified classification limits.
Consequences of not maintaining the required class of the zone may be severe, including rejection of an entire batch, product recalls, penalties, and, in the worst cases, enforcement actions such as FDA warning letters.
Engineers designing the facilities should consider material and personnel flows to ensure that items and people move from lower to higher zones through airlocks and change rooms. This helps prevent contamination of sensitive areas and keeps patients safe, as well as regulated industries secure.
