Qualification & Compliance in Pharma Facilities
16/01/2026
To meet the established cleanroom standard, we must focus on minimizing contamination risk (cross-contamination from lower-grade areas, airborne contamination, contamination brought in by personnel or equipment).
The facility layout will be affected by the addition of airlocks between areas of differing classification. The room finishes must ensure that they are fully sealed to their adjacent environment, using smooth, non-porous, and easy-to-clean surfaces that are resistant to chemical exposure related to cleaning agents or manufacturing processes.
Airflow is critical to minimizing particulates and preventing airborne contamination.
The airflow solution will be determined first by the required grade of cleanroom. For example, an ISO 5 area, which may be required for aseptic production, would typically require unidirectional airflow, HEPA filtered at the point of supply. ISO 14644-3 recommends an air velocity (measured 150mm to 300mm below the plenum) of between 0.36 m/s and 0.54 m/s, with low-level return air paths incorporated into the room fabric, to ensure that the air remains unidirectional throughout its travel through the space.
Typically, ISO 6,7 and 8 cleanrooms may be designed using non-unidirectional airflow in combination with filtered point of supply and low-level return paths.
Air Change Rates should be calculated to maintain the specified maximum particulate concentration while considering the occupancy and levels of gowning. The traditionally specified air change rates, which prescribe a fixed rate to meet a specified grade, take no account of the specific operation of individual facilities, and generally result in higher than required airflows with resultant energy waste and increased capital expenditure.
Pressure gradients should be designed to provide airflow cascades from higher to lower grades, to prevent airborne contamination ingress, or to provide containment where cross-contamination is deemed a risk.
Global Standards & Classifications
Cleanrooms and critical environments are regulated differently around the world, and part of our role is navigating those frameworks:
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UK / International: ISO 14644 standards define cleanroom classes based on allowable particle counts per cubic metre.
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Americas: The US FDA follows Federal Standard 209E terminology (now historical but still widely referenced), where environments are classified as Class 100, 10,000, etc.
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Europe: EU GMP guidelines use a “Grade A–D” system, where Grade A represents the most stringent environment for sterile product handling.
ISO Standard and Equivalent Classifications For Air Change rates and Maximum Concentration Limits For Particles ≥ 0.5 µm/m³
| Air Changes Per Hour | Airflow Velocity (m/s) | Ceiling Coverage (%) | Maximum particles/m³ | ISO | US FED STD 209E | EU GMP (at rest) | EU GMP (in operation | BS 5295 |
| 360-600 | 0.31-0.51 | 90-100 | 0.35 | 1 | ||||
| 360-600 | 0.31-0.51 | 80-100 | 3.5 | 2 | ||||
| 360-540 | 0.31-0.46 | 60-100 | 35 | 3 | 1 | C | ||
| 300-540 | 0.25-0.46 | 50-90 | 352 | 4 | 10 | D | ||
| 240-480 | 0.20-0.41 | 35-70 | 3,520 | 5 | 100 | A, B | A | E, F |
| 150-240 | 0.13-0.20 | 25-40 | 35,200 | 6 | 1000 | G' H | ||
| 60-90 | 0.05-0.08 | 15-20 | 352,000 | 7 | 10000 | C | B | J |
| 5-48 | 0.005-0.04 | 5-15 | 3,520,000 | 8 | 100000 | D | C | K |
| 0-25 | 0-0.025 | 5-10 | 35,200,000 | 9 |
