Designing a cleanroom is not just about creating a sterile space—it’s about precision, control, and compliance. Whether you’re building a Class 100 environment for microelectronics or an ISO 7 suite for pharmaceutical packaging, every detail—from airflow patterns to gowning procedures—matters.
This checklist is a comprehensive guide for engineers, facility managers, and cleanroom planners. It breaks down the essential aspects of cleanroom design, helping you build a facility that meets regulatory standards, operational needs, and long-term performance requirements.
1. Determine Cleanroom Classification & Purpose
Start by identifying the cleanroom’s intended use and corresponding cleanliness level. ISO classifications (ISO 5 to ISO 8) define the maximum allowable particle counts per cubic meter. The classification impacts the entire design, from air change rates to filtration and construction materials.
Typical examples:
ISO 5 (Class 100): semiconductor lithography, aseptic pharmaceutical filling
ISO 7–8: medical device packaging, electronics assembly
2. Plan the Layout & Flow
A well-planned layout ensures logical movement of people, materials, and equipment while minimizing contamination risks. Define:
Entry/exit zones for personnel and materials
Airlocks and gowning rooms
Directional flow from “dirty” to “clean” zones
Placement of mechanical rooms and emergency exits
Use pressure cascades to ensure that cleaner areas maintain higher positive pressure than adjacent lower-classified spaces.
3. Build the Structural Envelope
The cleanroom envelope should support easy cleaning and contamination control:
Walls and ceilings: made from smooth, non-shedding, chemical-resistant materials like coated steel, aluminum, or FRP panels
Windows: flush-mounted and sealed for visibility without compromising pressure
Doors: interlocked where needed, with airtight seals and minimal gaps
4. Choose Proper Flooring & Surface Finishes
Surfaces should be durable, easy to disinfect, and minimize particle accumulation:
Flooring: seamless options like epoxy or heat-welded vinyl are standard
Coved edges: floor-to-wall junctions should be curved to eliminate corners
Finishes: resistant to disinfectants and non-porous to prevent microbial growth
5. Design HVAC & Filtration Systems
Cleanroom HVAC systems are designed not only for comfort but also for airborne particulate control. Key factors include:
Air changes per hour (ACH): varies by classification (e.g., >250 ACH for ISO 5)
HEPA/ULPA filters: installed in terminal or fan filter units to remove 99.97%+ of 0.3 μm particles
Pressure differentials: maintain cascading pressures between cleanroom zones
Temperature and humidity control: stable levels are critical for certain materials and processes
6. Implement Gowning Protocols & Entry Control
Personnel are one of the biggest sources of contamination. Entry design should include:
Gowning areas sized based on peak occupancy
Air showers to blow off loose particles
Clear signage and SOPs to guide the sequence: hand wash → don gown → step into clean zone
7. Plan for Material Transfer
Materials entering or exiting cleanrooms must follow controlled pathways:
Pass-through cabinets for small items
Roll-up doors or cart airlocks for equipment or bulk materials
Interlock systems to prevent both doors from opening at once
This ensures cleanroom integrity and reduces risks of contamination from high-traffic areas.
8. Coordinate Utilities & Equipment Integration
All infrastructure must be compatible with cleanroom operations:
Electrical: recessed, sealed outlets; surge protection; emergency backup
Lighting: uniform, shadow-free, and sealed to avoid dust collection
Equipment: must be low-shedding and positioned for accessibility and cleaning
Utilities should be routed in ceiling plenums or chases, away from airflow-critical areas.
9. Establish Monitoring & Validation Systems
To maintain regulatory compliance, the cleanroom must be validated and continuously monitored:
Particle counters, pressure gauges, and humidity sensors should be installed at key locations
Conduct regular IQ/OQ/PQ validation during setup and periodically thereafter
Develop SOPs for responding to excursions or deviations
Logging and alarm systems are crucial for audit trails and operational safety.
10. Design Cleaning Protocols & Contamination Control
Routine cleaning is essential for maintaining cleanroom classification:
Assign dedicated cleaning tools and materials
Establish schedules for daily, weekly, and monthly cleaning tasks
Use disinfectants appropriate for surface compatibility and microbial control
Train personnel on contamination control techniques, including wiping methods and garment handling
Summary Table
| Checklist Category | Key Considerations |
|---|---|
| Classification & Purpose | ISO standard, industry-specific needs |
| Layout & Flow | People/material zoning, directional airflow |
| Structural Envelope | Sealed walls, ceilings, doors, windows |
| Surface Finishes | Epoxy/vinyl flooring, coved edges, chemical resistance |
| HVAC & Filtration | HEPA filters, ACH, temperature/humidity, pressure control |
| Gowning & Entry Control | Air showers, gowning rooms, donning sequence |
| Material Transfer | Pass-throughs, interlocks, transfer procedures |
| Utilities & Equipment | Cleanroom-compatible, sealed, serviceable |
| Monitoring & Validation | Sensors, IQ/OQ/PQ, real-time logging |
| Cleaning Protocols | SOPs, disinfectant selection, tool segregation |
