The Cleanroom Design Process: Complete Step-by-Step Guide
Designing a cleanroom is complex. It requires balancing regulatory requirements, operational needs, budget constraints, and timeline goals. This guide walks through the cleanroom design process from initial concept through final certification.
Phase 1: Pre-Design Assessment
Step 1: Define Your Requirements
Product & Manufacturing Details:
- What are you manufacturing? (pharmaceuticals, electronics, medical devices, biologics)
- What processes occur in the cleanroom?
- What contamination risks exist?
- What are regulatory requirements?
Space & Infrastructure:
- Available square footage?
- Existing utility infrastructure (electrical, water, gas)?
- Building structure limitations?
- Future expansion plans?
Personnel & Operations:
- How many people work in the cleanroom?
- What gowning requirements?
- What equipment/materials enter the space?
- Traffic patterns and workflow?
Step 2: Risk Assessment
Document your risks:
- Product contamination risks
- Personnel contamination risks
- Equipment reliability risks
- Regulatory compliance risks
This risk analysis justifies your ISO classification choice to regulators.
Step 3: Determine ISO Classification
Using your risk assessment:
- ISO Class 8 (100,000): General light manufacturing
- ISO Class 7 (10,000): Pharmaceutical, medical device packaging
- ISO Class 6 (1,000): Electronics, semi-conductors
- ISO Class 5 (100): Sterile drug filling, biologics
- ISO Class 4 or better (most critical operations)
Lower number = stricter (and more expensive).
Step 4: Regulatory Requirements Research
For pharmaceutical:
- FDA 21 CFR Part 11 (GMP)
- ICH Q7 (API manufacturing)
- Specific guidance for your product type
For medical devices:
- FDA Quality System Regulation (QSR)
- ISO 13485 (quality management)
For electronics:
- IPC-A-600 standards
- ANSI/AIAA standards
Your cleanroom design must address these from the start.
Phase 2: Conceptual Design
Step 5: Space Planning & Layout
Typical Cleanroom Layout:
Corridor (Non-Classified)
↓
Gowning Room (ISO 8) → Personnel Airlock (ISO 8)
↓
Grade D Support Area (ISO 8)
↓
Grade C Materials Staging (ISO 7)
↓
Grade B Processing Support (ISO 6)
↓
Grade A Processing (ISO 5)Design Considerations:
- Unidirectional airflow in Grade A/B (laminar flow)
- Separate material interlocks
- Pass-through chambers for equipment
- Adequate space for personnel movement
- Emergency exits and accessibility
Step 6: HVAC System Design
Key HVAC Elements:
-
Air Handling Unit (AHU)
- Sized for required air change rates (ACH)
- HEPA or ULPA filtration
- Temp/humidity control
- Pressure maintenance
-
Supply Diffusers
- Even distribution across ceiling
- For unidirectional flow: large low-velocity diffusers
- For non-unidirectional: smaller high-velocity diffusers
-
Return/Exhaust
- Floor-level return grilles in Grade A/B (for laminar flow)
- Adequate sizing to prevent negative pressure
- Secondary HEPA filtration on exhaust (if applicable)
-
Pressure Control
- Pressure differentials: 10-15 Pa per zone
- Continuous monitoring and alarm systems
- Backdraft dampers to prevent air reversal
Typical ACH Requirements:
- Grade A: 20-30 ACH (unidirectional)
- Grade B: 15-20 ACH
- Grade C: 12-15 ACH
- Grade D: 6-10 ACH
Step 7: Material & Surface Selection
Interior Surfaces Must:
- Be seamless and non-shedding
- Withstand repeated disinfection
- Resist damage from chemicals and cleaning
- Be easily cleanable
Common Selections:
- Walls/Ceilings: Epoxy-coated steel panels, PVC-coated GRP
- Flooring: Continuous epoxy resin or static-dissipative flooring
- Doors: Stainless steel or anodized aluminum
- Corners: Coved (never 90-degree) to eliminate dust traps
Step 8: Utility Planning
Critical Utilities:
- Electrical (dedicated circuits for monitoring equipment)
- Water (if needed for manufacturing)
- Gas supplies (if required)
- Compressed air (filtered, controlled)
- Drain systems (sealed to prevent contamination entry)
All penetrations must be:
- Sealed at entry/exit points
- Routed to avoid contaminating airflow
- Accessible from non-classified spaces
Phase 3: Detailed Design
Step 9: Engineering Drawings & Specifications
Deliverables:
- Floor plans with dimensions and equipment locations
- Elevation drawings showing heights, clearances
- HVAC flow diagrams and ductwork routing
- Electrical single-line diagrams
- Material and finish specifications
- Door and window schedules
Step 10: Compliance Planning
Document for Regulators:
- Risk assessment justifying your ISO class choice
- Environmental control strategy
- Monitoring program (particle, microbial, temperature, humidity)
- Cleaning and disinfection procedures
- Personnel training program outline
- Change control procedures
- Deviation and investigation protocols
For FDA submissions:
- Pre-submission meeting (optional but recommended)
- Facility Design Narrative
- Validation protocol outline
Step 11: Cost Estimation & Budgeting
Major Cost Categories:
- Modular structure: 25-35%
- HVAC system: 25-35%
- Installation labor: 15-25%
- Flooring/finishes: 10-15%
- Doors/pass-throughs: 5-10%
- Validation/certification: 5-10%
Note: Modular cleanrooms typically cost 20-30% less than traditional build-in-place construction.
Step 12: Timeline Planning
Typical Project Timeline:
| Phase | Duration |
|---|---|
| Design & Engineering | 4-8 weeks |
| Procurement | 4-6 weeks |
| Installation | 6-12 weeks |
| Pre-operational validation (IQ/OQ) | 2-4 weeks |
| Performance qualification (PQ) | 4-8 weeks |
| Certification & handoff | 1-2 weeks |
| Total | 5-9 months |
Timeline Drivers:
- Complexity of HVAC system
- Utility infrastructure availability
- Equipment lead times
- Regulatory submission requirements
- Validation scope
Phase 4: Implementation
Step 13: Procurement & Contracting
Key Decisions:
- Buy modular system or build in-place?
- Who provides HVAC? (often separate vendor)
- General contractor or turnkey service?
- Warranty and support terms?
Step 14: Installation & Construction
Quality Control During Installation:
- Weekly inspections
- Verify materials match specifications
- Document deviations promptly
- Test connections and systems as completed
- Photo documentation of progress
Step 15: Pre-Operational Testing
Before moving to validation:
- HVAC system startup and balancing
- Air handler operation verification
- Temperature/humidity control confirmation
- Pressure differential testing
- Filter integrity testing
- Visual inspection of all surfaces
Phase 5: Validation & Certification
Step 16: IQ (Installation Qualification)
Verify:
- All equipment installed per specifications
- Serial numbers and calibration records
- Documentation completeness
- As-built drawings updated
Step 17: OQ (Operational Qualification)
Test:
- HVAC system performance (airflow velocity)
- Filter integrity (DOP test)
- Temperature/humidity control
- Pressure maintenance
- System responsiveness to changes
Step 18: PQ (Performance Qualification)
Demonstrate:
- Room maintains ISO classification (at rest)
- Room maintains classification during operations
- Microbial monitoring protocols work
- All monitoring systems function reliably
- Data supports regulatory submission
Minimum Testing:
- At least 3 successful certification runs
- At rest and in operation
- Multiple time points
- Documented acceptance criteria
Step 19: Regulatory Certification
FDA (if applicable):
- Submit validation package pre-approval (optional)
- Include IQ/OQ/PQ results
- Risk assessments and SOPs
- Receive FDA inspection and approval
Continuing Compliance:
- Annual recertification (minimum)
- Monitoring trending
- Change control procedures
- Deviation investigation and reporting
Design Best Practices
1. Start with End in Mind
- Understand regulatory requirements upfront
- Design for validation from the start
- Plan monitoring infrastructure into design
2. Right-Size Your Space
- Don’t over-specify entire facility for small critical area
- Use zones of different classifications efficiently
- Consider modular for future flexibility
3. Plan for Change
- Utility infrastructure for future additions
- Flexible HVAC capacity
- Documented change control procedures
4. Invest in Expertise Early
- Design consultation prevents costly mistakes
- Early regulatory feedback prevents redesigns
- Validation expertise saves time during implementation
5. Communication & Documentation
- Clear specifications prevent construction errors
- Regular meetings with all stakeholders
- Documented decisions create regulatory trail
Common Design Mistakes to Avoid
- Inadequate HVAC capacity - Can’t maintain required air changes
- Poor material selection - Shedding or incompatible surfaces
- Insufficient interlocks - Creates contamination pathways
- No redundancy for critical systems - Downtime = production loss
- Undersizing the space - Congestion increases contamination risk
- Forgetting utility requirements - Retrofitting is expensive
- Inadequate monitoring infrastructure - Can’t verify compliance
Your Cleanroom Design Partner
AAK CLEANROOMS provides:
- Complete design-to-certification services
- Regulatory expertise (FDA GMP, ICH, ISO 14644)
- Fast, modular construction (20-30% cost savings)
- Full validation and certification support
- Ongoing compliance consulting
From concept to certification, we handle it all.
Ready to Design Your Cleanroom?
Contact AAK CLEANROOMS for a design consultation.
Call (646) 406-0623 or email for a free scope assessment.