Understanding ISO Cleanroom Classifications

If you’re in manufacturing, you might assume it’s clear what type of cleanroom your operation requires. But, in reality that’s rarely the case. Many professionals often don’t know what they don’t know—especially when it comes to the complexities of ISO cleanroom classifications. 

These standards define strict particulate limits, and choosing the wrong classification can result in noncompliance, wasted resources, or even product failure. Cleanroom design isn’t a one-size-fits-all process; it requires expert insight into airflow, filtration, pressure differentials, and how your specific application aligns with ISO requirements. Understanding the nuances of ISO cleanroom classifications is essential to getting it right the first time.

Applications for ISO Cleanroom Classifications 

ISO standards define the allowable levels of airborne particulate within a controlled environment. But here’s the twist: the lower the ISO number, the stricter the cleanliness standard.

Cleanrooms are generally ranked from ISO Class 1 (the cleanest) to ISO Class 9 (the least clean). At Technical Air Products, our solutions are most often used in ISO Class 4 through ISO Class 8 cleanrooms — a critical range for industries like pharmaceuticals, biotech, electronics, aerospace, and more.

Both softwall and rigidwall cleanrooms offer flexible, cost-effective solutions for achieving ISO 4 through ISO 8 classifications, depending on how they are configured. Softwall cleanrooms with their modular vinyl curtain walls are more ideal for ISO 6–9 environments, where lower particulate control is required and ease of assembly or reconfiguration is a priority. Rigidwall cleanrooms, on the other hand, provide enhanced environmental control and the ability to control air pressure differentials, making them well-suited for stricter classifications like ISO 4-6. When configured correctly, both cleanroom types can meet a wide range of cleanliness standards across all industries.

ISO Class 8 Cleanrooms

Max particles ≥0.5 microns: ~3,520,000 per cubic meter

Used for:

• Packaging and labeling of pharmaceuticals
• Clean zones in general manufacturing
• Pre-assembly of parts before higher-class transfer
• Food and beverage quality testing
  

ISO Class 7 Cleanrooms

Max particles ≥0.5 microns: ~352,000 per cubic meter

Used for:

• Pharmaceutical preparation areas
• Compounding pharmacies (non-hazardous)
• Aerospace systems testing
• Diagnostic and lab testing equipment assembly
  

ISO Class 6 Cleanrooms

Max particles ≥0.5 microns: ~35,200 per cubic meter

Used for:

• Medical device manufacturing
• Implantable device packaging
• Optics and precision laser work
• Microelectronics production
  

ISO Class 5 Cleanrooms

Max particles ≥0.5 microns: ~3,520 per cubic meter

Used for:

• Semiconductor fabrication (wafer processing)
• Sterile filling and aseptic processing in pharmaceutical manufacturing
• Nanotechnology research
• Advanced aerospace component assembly
  

Where Technical Air Products Fits In

At Technical Air Products, we provide modular cleanrooms and components for every classification from ISO 4 to ISO 8.  We offer pre-engineered and custom-configured systems to meet your compliance and performance goals.

Choosing the Right ISO Class Cleanroom Solution

Understanding ISO classifications is step one in choosing the right cleanroom system to meet the standards needed for your application. Contact Technical Air Products today to get expert help selecting the right components. Whether you’re building an ISO 4 cleanroom from scratch or upgrading your ISO 8 facility for better efficiency, we can help. 

FAQ: Softwall and Rigidwall Cleanrooms for ISO 4–8 Applications

Q: Can both softwall and rigidwall cleanrooms meet ISO cleanroom classifications?

Yes. Both softwall and rigidwall cleanrooms can be configured to meet ISO classifications from ISO 4 to ISO 8, depending on the cleanroom design, airflow, and filtration setup. The key is selecting the right type of enclosure for your application and ensuring it is paired with the proper number and type of fan filter units (FFUs).

Q: What is the difference between softwall and rigidwall cleanrooms?

Softwall cleanrooms use flexible curtain panels (usually vinyl) and are ideal for applications that require higher ISO classifications (ISO 6–9), mobility, or modular expansion. Rigidwall cleanrooms are built with solid panels (often acrylic, polycarbonate, or tempered glass) allowing for better cleanability and control of air pressure, making them better suited for cleaner environments like ISO 4 and ISO 5.

Q: Which cleanroom type is more affordable—softwall or rigidwall?

Softwall cleanrooms are generally more cost-effective due to their lighter materials and simpler construction. They are an excellent option for facilities that need temporary or flexible clean environments. Rigidwall cleanrooms involve a higher upfront cost but offer superior particle and pressure control.

Q: Can a softwall cleanroom achieve ISO 4 compliance?

Yes, with 100% laminar airflow, using ULPA filtration, a softwall cleanroom can achieve an ISO 4 certification.  However, softwall cleanrooms are typically used for ISO 6–8 environments, as most applications that require ISO 4 or ISO 5 certification, also require more stringent cleaning regiments and the need for more control of air pressure differentials. Rigidwall cleanrooms are generally recommended for ISO 4 and ISO 5 environments, due to their ability to offer more environmental control. 

Q: What industries use ISO 4–8 cleanrooms?

• ISO 4–6: Semiconductor manufacturing, pharmaceutical aseptic processing, nanotechnology, gene therapy, medical device manufacturing
• ISO 7–8: Medical device assembly, electronics manufacturing, aerospace systems, compounding pharmacies, packaging areas, general lab prep zones, non-critical manufacturing environments

Q: How do I know which ISO classification my cleanroom needs to meet?

Your ISO classification should be based on regulatory requirements (e.g. GMP, USP, etc.), product sensitivity, and specific industry best practices.