What Is a Cleanroom?
A cleanroom is more than a white room with filters. It is a carefully engineered volume of air, surfaces and procedures that keeps particles within strict limits.
Think of a cleanroom as a “tool” that shapes the air, not just the walls.
Air enters through HEPA or ULPA filters, flows in a predictable pattern and is continuously replaced to sweep particles away from critical work.
Every surface — panels, windows, doors and pass-throughs — is chosen for smoothness, chemical resistance and ease of cleaning, so particles have nowhere to hide.
Classification alone is not enough. Gowning, cleaning and maintenance routines are built into the design so real-world performance stays within the specified ISO class.
ISO 14644-1 Explained
ISO 14644-1 links your required “cleanliness class” to particle concentrations. Use the slider to see how classes tighten as you move towards more critical applications.
Choose a class to preview typical particle limits (0.5 µm) and where it is commonly used.
ISO 7 is a common choice for pharmaceutical support areas and general electronics assembly where full cleanroom procedures are still needed, but the process is less particle-sensitive than wafer fabrication.
- Particle limits are measured per cubic metre of air.
- Sampling plans and locations are defined in ISO 14644-1 and -2.
- Other parts of ISO 14644 cover testing, operation and terminology.
Legacy Standards in Two Lines Each
Before ISO 14644, many projects relied on FS 209E or local standards like BS 5295. You may still see them referenced on older drawings and specifications.
Why they still matter
Understanding legacy standards helps you interpret older documents and map existing facilities to modern ISO classes.
Defined cleanrooms by particles per cubic foot and introduced familiar “Class 100 / 10 000 / 100 000” language.
Provided UK guidance on design and operation, including grades for both physical cleanliness and microbial control.
ISO 14644 replaced FS 209E and many national documents, using particles per cubic metre and a unified class scale (ISO 1–9).
Mapping Classes to Industries
ISO classes are technology-agnostic. This quick map shows how different sectors typically use them. Tap a sector to explore.
Pharmaceutical and biotech facilities combine ISO classes with GMP zoning. Product contact operations often require higher classes than surrounding support areas.
Semiconductor, flat-panel and optics manufacturing push towards tighter classes to protect patterns measured in nanometres.
Hospitals use “cleanroom-like” principles for operating rooms and isolation suites, often aligning with mid-range ISO classes.
Space hardware must survive launch and planetary protection rules, so contamination control extends from assembly to testing.
Food and beverage industries often use ISO concepts alongside hygienic zoning to protect ready-to-eat and high-risk products.
ISO Class Reference Snapshot
Use this pocket table to translate between ISO class, legacy FS 209E notation and approximate 0.5 µm particle limits.
| ISO class | FS 209E approx. | 0.5 µm limit (particles / m³) | Typical uses |
|---|---|---|---|
| ISO 1 | — | 10 | Experimental nanotech, EUV lithography. |
| ISO 2 | — | 100 | High-end semiconductor steps, research tools. |
| ISO 3 | Class 1 | 1 000 | Critical lithography, precision optics assembly. |
| ISO 4 | Class 10 | 10 000 | Photomask manufacturing, some implant tools. |
| ISO 5 | Class 100 | 100 000 | Aseptic filling, laminar flow hoods, clean ORs. |
| ISO 6 | Class 1 000 | 1 000 000 | Support zones for ISO 5, semiconductor sub-fab. |
| ISO 7 | Class 10 000 | 352 000 | Pharma backgrounds, high-hygiene packaging. |
| ISO 8 | Class 100 000 | 3 520 000 | Gown rooms, equipment rooms, general clean areas. |
| ISO 9 | Unclassified | 35 200 000 | Controlled but not fully cleanroom environments. |
How We Help You Choose
Selecting the right class is a balance between regulatory compliance, process needs, and operating costs. Over-specifying wastes energy; under-specifying risks product failure.
The Pak Gusu Engineering Methodology
- Regulatory Mapping: We identify the exact ISO class required by your governing body (e.g., DRAP, WHO, FDA) for your specific dosage form.
- Risk Assessment: We analyze your open phases. Where is the product exposed? That's where you need the highest class (e.g., ISO 5). Surrounding areas can be relaxed (ISO 7 or 8) to save energy.
- Future-Proofing: We design HVAC and pressure cascades that can adapt if your product portfolio expands or regulations tighten.
- Energy Optimization: Fan Filter Units (FFUs) and setbacks used during non-operational hours to reduce power consumption while maintaining minimum background cleanliness.
Plan Your Cleanroom Project Today
Discuss your requirements with our engineering team and get a tailored proposal that matches your specific industry standards.