ISO 14644 vs GMP Cleanroom Standards: Key Differences Explained
Cleanrooms are classified to ensure the air quality meets the requirements of the processes conducted within them. Two major classification systems dominate the industry: ISO 14644-1:2015 — the international standard for cleanrooms and associated controlled environments — and EU GMP Annex 1 — the regulatory standard for pharmaceutical sterile manufacturing.
While both systems define cleanroom cleanliness by airborne particle concentration, they serve different purposes and have distinct requirements. Understanding the differences is essential for selecting, designing, and operating the right cleanroom for your application.
What is ISO 14644-1:2015?
ISO 14644-1:2015 is the international standard that specifies the classification of air cleanliness by the concentration of airborne particles in cleanrooms and clean zones.It defines nine ISO classes (ISO Class 1 through ISO Class 9), with ISO Class 1 being the cleanest and ISO Class 9 being the least clean.
The standard provides maximum allowable particle concentrations for each class at various particle sizes — 0.1 µm, 0.2 µm, 0.3 µm, 0.5 µm, 1.0 µm, and 5.0 µm.
ISO 14644-1:2015 Cleanroom Classification Table
ISO Class | ≥0.1 µm | ≥0.2 µm | ≥0.3 µm | ≥0.5 µm | ≥1.0 µm | ≥5.0 µm |
ISO 1 | 10 | d | d | d | d | e |
ISO 2 | 100 | 24 | 10 | d | d | e |
ISO 3 | 1,000 | 237 | 102 | 35 | d | e |
ISO 4 | 10,000 | 2,370 | 1,020 | 352 | 83 | e |
ISO 5 | 100,000 | 23,700 | 10,200 | 3,520 | 832 | d,e,f |
ISO 6 | 1,000,000 | 237,000 | 102,000 | 35,200 | 8,320 | 293 |
ISO 7 | c | c | c | 352,000 | 83,200 | 2,930 |
ISO 8 | c | c | c | 3,520,000 | 832,000 | 29,300 |
ISO 9 | c | c | c | 35,200,000 | 8,320,000 | 293,000 |
Note: All concentrations are cumulative. "c" indicates limits not applicable due to very high particle concentration; "d" indicates classification inappropriate due to sampling limitations; "e" indicates sample collection limitations.
Key changes in ISO 14644-1:2015: The 2015 revision removed the 29 particles ≥5.0 µm per m³ limit for ISO Class 5, addressing counting uncertainty issues. Classification is now based on a table rather than a formula, with intermediate sizes calculated using the formula: Cn = (0.1/D)^2.08 × 10^N.
What is EU GMP Annex 1?
EU GMP Annex 1 is the regulatory guideline for the manufacture of sterile medicinal products. It defines four cleanroom grades — A, B, C, and D — with Grade A representing the highest level of cleanliness required for critical operations like aseptic filling.
Unlike ISO 14644, which focuses solely on non-viable particle counts, GMP Annex 1 also requires monitoring of microbiological contamination — viable particles like bacteria and mold.
EU GMP Annex 1 Grade Classification
Grade | At Rest (≥0.5 µm/m³) | In Operation (≥0.5 µm/m³) | At Rest (≥5.0 µm/m³) | In Operation (≥5.0 µm/m³) |
A | 3,520 | 3,520 | Not specified | Not specified |
B | 3,520 | 352,000 | Not specified | 2,930 |
C | 352,000 | 3,520,000 | 2,930 | 29,300 |
D | 3,520,000 | Not predetermined | 29,300 | Not predetermined |
Critical distinction: Grade A requires the same particle limit (3,520 particles ≥0.5 µm/m³) in both at-rest and in-operation states. Grade B allows more particles during operation (352,000) but maintains the same strict limit at rest.
How ISO Classes Map to GMP Grades
The EU GMP Annex 1 explicitly maps its grades to ISO 14644-1 classes:
A GMP-compliant cleanroom will always have an ISO classification, but an ISO-graded cleanroom may not qualify for a GMP grade — because GMP Annex 1 requires additional conditions beyond ISO 14644-1.
Key Differences Between ISO and GMP
Aspect | ISO 14644-1 | EU GMP Annex 1 |
Scope | All industries | Pharmaceutical sterile manufacturing |
Classification | ISO Classes 1–9 | Grades A, B, C, D |
Particle sizes | 0.1, 0.2, 0.3, 0.5, 1.0, 5.0 µm | 0.5 and 5.0 µm (primarily) |
Operational states | Typically at-rest only for classification | Both at-rest and in-operation |
Microbiological limits | Not included | Viable particle limits (CFU/m³) |
Continuous monitoring | Not required | Required for Grade A during operations |
Regulatory status | International standard | Regulatory requirement |
Microbiological Limits in GMP Annex 1
Grade | Air Sample (CFU/m³) | Settle Plates (CFU/4h) | Contact Plates (CFU/plate) |
A | <1 | <1 | <1 |
B | 10 | 5 | 5 |
C | 100 | 50 | 25 |
D | 200 | 100 | 50 |
Which Standard Should You Use?
ISO 14644-1 is appropriate for semiconductor manufacturing, electronics, optics, automotive, medical device assembly, and any industry requiring particle control without the strict microbiological requirements of pharmaceuticals.
EU GMP Annex 1 is mandatory for pharmaceutical sterile manufacturing, aseptic processing, and any application where product sterility is critical.
FDA-regulated facilities follow similar principles, with FDA guidance stating that sterile drugs should be produced only in ISO 5 or better air quality under dynamic conditions, and terminally sterilized drugs in ISO 8 or better.
Why This Matters for Your Cleanroom Project
Choosing the right classification standard affects every aspect of your cleanroom — from FFU selection and filter grade to airflow design, monitoring systems, and validation protocols.
For ISO-classified cleanrooms, the focus is on non-viable particle counts. For GMP-grade cleanrooms, you must also address microbiological control, requiring additional design considerations like:
HEPA/ULPA filtration with validated integrity
Unidirectional airflow in Grade A zones
Pressure differential cascades (typically 10–15 Pa between grades)
Continuous viable and non-viable monitoring in Grade A
Rigorous cleaning and disinfection protocols
How DSX Can Help
Wujiang Deshengxin Purification Equipment Co., Ltd. (DSX) manufactures FFU, EFU, HEPA filters, ULPA filters, chemical filters, and other clean air solutions — with in-house production of fans, motors, control systems, and filter media.
Whether you are designing an ISO-classified cleanroom for semiconductor manufacturing or a GMP-grade facility for pharmaceutical production, DSX offers vertically integrated solutions that ensure consistent airflow, reliable filtration, and regulatory compliance.
About Wujiang Deshengxin Purification Equipment Co., Ltd.
Based in Suzhou, China, Wujiang Deshengxin Purification Equipment Co., Ltd. (DSX) is a dedicated R&D and manufacturing enterprise with over 20 years of experience in cleanroom technology. The company specializes in fans, filter units, and cleanroom accessories for semiconductor, pharmaceutical, medical device, electronics, and other clean-critical industries. As a vertically integrated manufacturer, DSX produces core components — motors, filters, and control systems — in-house, enabling fast customization, consistent quality, and cost efficiency.
Contact:
Nancy
nancy@shdsx.com
www.ffufan.com
+86-512-63211760
