sterile cleanroom

Understanding Cleanroom Classifications

Cleanrooms are specially designed facilities that minimize the presence of airborne particles and contaminants. They play a critical role in industries such as pharmaceuticals, biotechnology, electronics, and semiconductor manufacturing, where even the slightest presence of contaminants can have detrimental effects on product quality and performance.

Cleanrooms are classified based on their ability to control particle count within specific size ranges. The classification system, typically defined by international standards, ensures a standardized approach to cleanroom design, operation, and maintenance. The most commonly referenced standard is the ISO 14644-1:2015, which categorizes cleanrooms into different classes based on the allowable particle concentration per cubic meter of air.

Cleanroom Classification Standards

  • ISO 14644-1:2015
    ISO 14644-1:2015 provides a globally recognized framework for cleanroom classification. It defines classes ranging from ISO Class 1 (the cleanest) to ISO Class 9 (the least clean). Each class has a corresponding maximum allowable particle count for particles of specific sizes. These classifications ensure that cleanroom users can maintain a consistent environment across different facilities and industries.
  • Federal Standard 209E (Obsolete)
    Previously, the Federal Standard 209E was the go-to standard for cleanroom classifications in the United States. However, this standard was replaced by ISO 14644-1:2015, which introduced a more stringent and globally harmonized approach to cleanroom classifications. It is important to note that some industries may still reference the Federal Standard 209E due to historical reasons, but ISO standards are widely recognized and adopted today.

Cleanroom Classes and Particle Size Limits

Let’s explore the various cleanroom classes and their associated particle size limits, as defined by ISO 14644-1:2015.

ISO Class 1

Particle Size Limits:
≤ 0.1 µm: 10 particles/m³
≤ 0.2 µm: 2 particles/m³
≤ 0.3 µm: 1 particle/m³
≤ 0.5 µm: 0 particles/m³
≤ 1.0 µm: 0 particles/m³
≤ 5.0 µm: 0 particles/m³

The ISO Class 1 cleanroom represents the highest level of cleanliness. It is designed for extremely sensitive manufacturing processes, such as the production of advanced microelectronics or aerospace components.

ISO Class 2

Particle Size Limits:
≤ 0.1 µm: 100 particles/m³
≤ 0.2 µm: 24 particles/m³
≤ 0.3 µm: 10 particles/m³
≤ 0.5 µm: 2 particles/m³
≤ 1.0 µm: 0 particles/m³
≤ 5.0 µm: 0 particles/m³

ISO Class 2 cleanrooms are suitable for industries that demand high precision and have stringent cleanliness requirements, such as optical manufacturing or medical device assembly.

ISO Class 3 (Class 1)

Particle Size Limits: ≤ 0.1 µm: 1,000 particles/m³
≤ 0.2 µm: 237 particles/m³
≤ 0.3 µm: 102 particles/m³
≤ 0.5 µm: 35 particles/m³
≤ 1.0 µm: 8 particles/m³
≤ 5.0 µm: 0 particles/m³

ISO Class 3 cleanrooms find applications in the pharmaceutical, biotechnology, and nanotechnology industries. These controlled environments are crucial for processes that require a low level of airborne contaminants.

ISO Class 4 (Class 10)

Particle Size Limits: ≤ 0.1 µm: 10,000 particles/m³
≤ 0.2 µm: 2,370 particles/m³
≤ 0.3 µm: 1,020 particles/m³
≤ 0.5 µm: 352 particles/m³
≤ 1.0 µm: 83 particles/m³
≤ 5.0 µm: 0 particles/m³

ISO Class 4 cleanrooms are commonly found in semiconductor manufacturing, research laboratories, and precision optics industries. They provide a controlled environment for processes that require a moderate level of cleanliness.

ISO Class 5 (Class 100)

Particle Size Limits: ≤ 0.1 µm: 100,000 particles/m³
≤ 0.2 µm: 23,700 particles/m³
≤ 0.3 µm: 10,200 particles/m³
≤ 0.5 µm: 3,520 particles/m³
≤ 1.0 µm: 832 particles/m³
≤ 5.0 µm: 29 particles/m³

ISO Class 5 cleanrooms are commonly used in industries such as pharmaceutical compounding, medical device manufacturing, and biotechnology research. They provide a controlled environment for critical processes while maintaining a higher particle threshold compared to ISO Classes 1-4.

ISO Class 6 (Class 1,000)

Particle Size Limits: ≤ 0.1 µm: 1,000,000 particles/m³
≤ 0.2 µm: 237,000 particles/m³
≤ 0.3 µm: 102,000 particles/m³
≤ 0.5 µm: 35,200 particles/m³
≤ 1.0 µm: 8,320 particles/m³
≤ 5.0 µm: 293 particles/m³

ISO Class 6 cleanrooms are less common and find applications in industries that require controlled environments but can tolerate a slightly higher particle count. Examples include food packaging, general assembly, and some types of metal fabrication.

  • ISO Classes 7 and 8 (Class 10,000 and 100,000)
    ISO Classes 7 and 8 are considered less critical in terms of particle control but are still important for specific industries. They have higher particle thresholds, making them suitable for industries such as automotive manufacturing, certain types of printing, and non-critical cleanroom applications.
  • Maintaining Cleanroom Integrity
    Achieving and maintaining the desired level of cleanliness in a cleanroom requires meticulous planning, design, and ongoing monitoring. Here are a few key aspects to consider:
  • Proper HVAC Systems
    Cleanroom HVAC systems play a crucial role in maintaining the required air quality. They ensure adequate air filtration, temperature control, humidity control, and air circulation to minimize particle contamination. High-efficiency particulate air (HEPA) filters are commonly used to remove airborne particles effectively.
  • Cleanroom Design and Construction
    Cleanrooms must be constructed with materials that minimize particle generation and facilitate easy cleaning. Walls, ceilings, and floors should have smooth, non-shedding surfaces. Sealed joints, rounded corners, and seamless flooring help eliminate potential areas where contaminants could accumulate.
  • Regular Testing and Monitoring
    Periodic testing and monitoring of the cleanroom environment are essential to ensure compliance with the designated cleanroom classification. This includes particle count measurements, air velocity testing, air change rate calculations, and microbial monitoring. Continuous monitoring systems provide real-time data, enabling prompt corrective actions if deviations occur.
  • Proper Personnel Training and Gowning
    Cleanroom personnel must undergo thorough training on cleanroom protocols, including proper gowning procedures and behavior within the controlled environment. Strict adherence to gowning practices and minimizing human activity within the cleanroom are vital to prevent particle generation.

Cleanroom classifications are an integral part of maintaining optimal air quality in advanced manufacturing processes. By adhering to the ISO 14644-1:2015 standards, industries can ensure consistent and controlled environments that minimize the presence of contaminants. Proper design, construction, HVAC systems, and ongoing monitoring are essential to achieving and maintaining the desired cleanliness level in cleanrooms.

Finding a Solution that Works for You:

With over 30 years of experience designing, constructing, and maintaining cleanroom and laboratory facilities, Pacific Environmental Technologies is an industry leader widely recognized for quality, service, and technical expertise. We offer solutions from simple modular enclosures to large-scale manufacturing facilities to mobile, trailerable, and containerized solutions for field-deployment at the required point-of-use.

Let’s work together to find a solution that meets for your unique needs!

by Pacific Environmental Technologies October 2, 2023