A cleanroom is a controlled environment designed to minimize airborne particles, microorganisms, and other contaminants. These spaces are fundamental to many industries where microscopic impurities can compromise product quality or processes. Cleanrooms are categorized based on the concentration of particulate matter in their air to standardize cleanliness. This classification system allows industries to specify and maintain the precise environmental conditions required for their operations.
Understanding ISO Cleanroom Classes
Cleanrooms are classified based on the quantity and size of particles per cubic meter of air. The International Organization for Standardization (ISO) established the ISO 14644-1 standard for this classification. This standard defines nine cleanroom classes, from ISO 1 to ISO 9. A lower ISO class number indicates a cleaner environment with a lower concentration of airborne particles. Conversely, a higher ISO class number signifies less stringent cleanliness, with ISO 9 comparable to typical room air.
The Clearest Definition of Cleanliness
Cleanliness within the ISO framework is defined by the maximum allowable concentration of airborne particles per cubic meter of air. The cleanest environment permits the lowest number of these particles, especially at very small sizes. ISO Class 1 is the pinnacle of cleanroom classifications, maintaining the highest standard of cleanliness. For an ISO Class 1 cleanroom, the air can contain a maximum of 10 particles per cubic meter that are 0.1 micrometers (µm) or larger, and 2 particles per cubic meter that are 0.2 µm or larger. This stringent control over airborne particles designates ISO Class 1 as the cleanest cleanroom environment.
Why Different Levels of Cleanliness Matter
Different industries require specific levels of cleanroom cleanliness due to varying product and process sensitivities to contamination. For instance, semiconductor manufacturing, nanotechnology, and biotechnology research demand ultra-clean environments (ISO Class 1, 2, or 3) because tiny particles can cause defects in microscopic components. In these fields, precision and purity are paramount for product functionality and yield.
Pharmaceutical manufacturing, medical device production, and electronics assembly operate within ISO Class 5, 6, or 7 cleanrooms. These environments provide sufficient control for processes like sterile filling or sensitive electronic component assembly, balancing stringent particle control and operational practicality. Less stringent environments like ISO Class 8 are used in some manufacturing processes and general production facilities where contamination risks are lower. The selection of an ISO class directly impacts product quality, safety, and regulatory compliance.
How Clean Environments Are Achieved and Maintained
Achieving and maintaining a cleanroom involves specialized design, equipment, and rigorous protocols. A primary method for air cleanliness involves passing air through High-Efficiency Particulate Air (HEPA) filters, and sometimes Ultra-Low Particulate Air (ULPA) filters, which capture microscopic particles. The more frequently air cycles through these filters, the cleaner the environment becomes.
Cleanrooms operate under positive air pressure, meaning the air pressure inside is greater than outside. This pressure differential ensures that if there are any leaks, air flows outward, preventing unfiltered or contaminated air from entering the clean space. Specialized building materials that do not shed particles, strict operational protocols such as gowning procedures, and continuous environmental monitoring uphold the required cleanliness levels. These measures sustain the controlled conditions necessary for sensitive operations.