1. Air Cleanliness Control
Through a three-stage filtration system — pre-filters, medium filters, and HEPA/ULPA high-efficiency filters — airborne particle concentrations at target sizes (≥0.1μm, ≥0.3μm, ≥0.5μm) are rigorously maintained below the limits defined by ISO 14644-1 for each cleanliness class, spanning the full range from ISO Class 1 (≤10 particles/m³ @0.1μm) to ISO Class 9.
2. Airflow Pattern & Distribution
Based on process requirements, airflow is designed as turbulent (non-unidirectional), laminar (unidirectional), or mixed-flow configurations to ensure uniform air distribution with no dead zones or eddies. Contaminants generated at source points are swiftly carried away, maintaining the self-cleaning capacity and protective airflow barrier of the work zone.
3. Temperature & Humidity Precision Control
Utilizing HVAC air handling units (AHU) with chilled water, hot water, or steam piping systems, indoor temperature is controlled within ±0.5°C to ±2°C and relative humidity within ±3% to ±5% RH, meeting the exacting environmental requirements of processes such as lithography, coating, and aseptic filling.
4. Pressure Cascade & Contamination Isolation
Positive or negative pressure differentials of 5–15 Pa are established and maintained between adjacent zones of different cleanliness grades: positive pressure prevents external contamination ingress, while negative pressure contains hazardous substances. Dynamic pressure control is achieved through differential pressure sensors interlocked with variable air volume (VAV) valves, with real-time monitoring.
5. Envelope Structure & Sealing
Full enclosure is constructed using color-coated steel panels, stainless steel panels, or antibacterial clean wall panels with matching clean ceilings, airtight doors, and windows. All joints are sealed with specialized sealants, and internal corners are rounded to eliminate dust-accumulating dead zones, forming a complete physical isolation barrier.
6. Electrostatic Discharge (ESD) Control
Anti-static epoxy self-leveling flooring or anti-static PVC/raised access flooring is installed and integrated with the grounding system, maintaining surface resistance within the 10⁴–10⁹ Ω range. This effectively dissipates static charges from personnel, equipment, and materials, protecting ESD-sensitive devices from damage.
7. Personnel & Material Purification
Gowning rooms, changing areas, air showers, buffer rooms, and pass boxes are configured to standardize personnel gowning procedures and material transfer routes. High-velocity clean air jets for personnel blow-off and UV/pass-through sanitization for items minimize the contamination load introduced by people and materials.
8. Intelligent Environmental Monitoring
Online particle counters, viable airborne samplers, differential pressure sensors, temperature/humidity probes, and airflow velocity sensors are deployed to collect real-time environmental parameters, uploaded to a central BMS/EMS. The system supports data logging, trend analysis, limit alarm notifications, and audit trails, ensuring compliance with GMP data integrity requirements.
9. Energy Efficiency & Operational Optimization
Energy-saving measures — including variable-frequency drive (VFD) fans, heat recovery wheels, and reduced-frequency setback modes during night/idle periods — are combined with zoned independent control and dynamic adjustment via the automation system. This significantly reduces HVAC energy consumption while maintaining cleanliness compliance, enabling low-carbon operation.
10. Validation & Compliance Management
In accordance with ISO 14644 and GMP standards, installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ) are conducted, covering HEPA filter leak testing, airflow visualization smoke studies, recovery (self-cleaning) time testing, temperature/humidity uniformity mapping, and more — ensuring the cleanroom remains fully compliant from handover through long-term operation.
