Understanding ISO Cleanroom Classifications: What Do ISO Levels Mean?

Cleanroom classifications play a critical role in contamination control across various industries, including pharmaceuticals, biotechnology, and electronics manufacturing. These classifications define the maximum allowable particle count in the air, ensuring that sensitive manufacturing processes remain free from contamination. Understanding ISO classifications is essential for selecting the right cleanroom to meet industry standards and compliance requirements.
Cleanroom Classification Systems:
What Is ISO 14644?
Cleanrooms are classified based on air cleanliness, which is determined by the number and size of particles per cubic meter of air. The ISO 14644-1 standard is the most widely used classification system, ensuring controlled environments meet specific contamination control requirements.
ISO cleanroom classifications range from ISO 1 to ISO 9, with ISO 1 being the cleanest and ISO 9 being the least clean (though still significantly cleaner than a standard indoor environment). These classifications help manufacturers select the appropriate cleanroom to protect sensitive manufacturing processes, ensure product quality, and comply with regulatory standards.
What Are GMP Guidelines?
While ISO 14644 classifications apply broadly across industries, the Good Manufacturing Practice (GMP) guidelines are specific to pharmaceutical and biopharmaceutical environments. These guidelines set strict requirements for contamination control to ensure products are manufactured under conditions that maintain sterility and minimize the risk of contamination.
Pharmaceutical cleanrooms are classified into Grades A through D, with each grade defining sterility requirements based on the level of contamination control needed for different manufacturing stages. GMP classifications are critical for ensuring product safety, particularly in producing sterile drugs, vaccines, and biopharmaceutical products.
ISO Cleanroom Classifications and Particle Count Requirements
ISO cleanrooms are classified based on the maximum allowable number of airborne particles per cubic meter.
ISO Class Level | Maximum Particles per Cubic Meter (≥0.5 µm) | Typical Applications |
ISO 1 |
10 |
Advanced nanotechnology |
ISO 2 |
100 |
Semiconductor fabs |
ISO 3 |
1,000 |
Microelectronics, aerospace |
ISO 4 |
10,000 |
High-end optics |
ISO 5 |
100,000 |
Pharmaceutical filling (GMP Grade A) |
ISO 6 |
1,000,000 |
Aseptic processing (GMP Grade B) |
ISO 7 |
352,000,000 |
Medical device manufacturing |
ISO 8 |
3,520,000,000 |
ISO Class 8 cleanroom standards for general pharmaceutical environments |
ISO 9 |
35,200,000,000 |
Clean industrial spaces |
ISO Class 7 and ISO Class 8 cleanroom standards are among the most commonly used classifications in industries requiring contamination control:
- ISO 7 Cleanrooms (Class 10,000) are frequently used in pharmaceutical, biotechnology, and semiconductor industries. They require stringent airflow control and filtration to maintain contamination levels suitable for sensitive manufacturing processes.
- ISO 8 Cleanrooms (Class 100,000) are often found in pharmaceutical packaging, general medical device manufacturing, and clean industrial applications where lower contamination control is still necessary.
These classifications ensure businesses operate within defined contamination control limits, maintaining compliance with ISO 14644 standards and industry-specific regulations such as GMP guidelines for pharmaceutical cleanrooms.
How Businesses Determine the Right ISO Level?
Selecting the appropriate cleanroom classification depends on the sensitivity of the manufacturing process and the level of contamination control required for compliance within each industry. Businesses must consider several factors when determining which cleanroom classification best suits their operations:
1. Industry Requirements
Different industries have specific cleanroom standards based on their manufacturing needs. For example:
- Pharmaceutical & Biopharmaceutical Manufacturing: Must comply with GMP guidelines (Grades A-D) to ensure sterility in drug production.
- Semiconductor & Electronics Manufacturing: Requires ISO 3-5 cleanrooms to prevent microscopic defects caused by airborne particles.
- Medical Device Manufacturing: Typically uses ISO 7 or ISO 8 cleanrooms, ensuring product integrity and regulatory compliance.
- Industrial & Aerospace Applications: Often rely on ISO 7-9 cleanrooms for contamination-sensitive assembly processes.
2. Product Sensitivity & Contamination Risk
The cleanliness level of a cleanroom is determined by the acceptable particle count for the product being manufactured.
- Highly sensitive products like sterile pharmaceuticals and microelectronics require ISO 5 or cleaner environments.
- Less sensitive manufacturing, such as medical device packaging or industrial components, can operate in ISO 7 or ISO 8 cleanrooms while still maintaining quality control.
3. Regulatory Considerations
Businesses in regulated industries must adhere to ISO 14644 standards, GMP guidelines, and USP 797/800 regulations to ensure compliance with government and industry-specific standards.
- Pharmaceutical cleanroom classifications must be validated to meet GMP sterility requirements.
- Medical and industrial cleanrooms must be designed to meet ISO particle count limits for their classification.
4. Cleanroom Design & Operational Needs
The required classification influences cleanroom design, air filtration, and operational processes:
- Higher-class cleanrooms (ISO 1-5): Require more stringent airflow control, higher air change rates, and HEPA or ULPA filtration.
- ISO 7 and ISO 8 cleanrooms: Require precise HVAC control, proper gowning procedures, and routine validation to maintain compliance.
5. Compliance Factors: Airflow, Filtration, and Validation
Once a cleanroom classification is determined, it must be maintained through proper contamination control measures:
- Airflow control and air change rates: Cleanrooms regulate airborne contamination by using controlled airflow patterns (unidirectional or non-unidirectional).
- High-efficiency filtration: HEPA and ULPA filters remove particles from incoming air to maintain classification standards.
- Monitoring & validation: Routine testing ensures cleanrooms meet ISO 14644 standards and GMP requirements for sterility and contamination control.
Businesses can select a cleanroom classification that meets their contamination control needs, industry standards, and operational efficiency requirements by evaluating these factors.
Encompass Cleanrooms specializes in designing and constructing stick-built, modular, softwall, hardwall, and rigidwall cleanrooms to meet ISO and GMP compliance standards across multiple industries.
Contact Encompass Cleanrooms for Expert Guidance
Whether you're in pharmaceuticals, biotechnology, electronics, or any other industry requiring stringent contamination control, Encompass Cleanrooms provides tailored solutions to meet your specific needs.
Contact Encompass Cleanrooms today for expert guidance on designing, constructing, and certifying a cleanroom that supports your operations, minimizes contamination risks, and maintains regulatory compliance for years to come.