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The cost of building a cleanroom:ISO 5,ISO 6,ISO 6,ISO 8
The Cost of Building a CleanroomISO 5, ISO 6, ISO 7, ISO 8 ClassificationsBuildi
iso 5 cleanrooms have very strict requirements for air cleanliness and are controlled by the HVAC system. For particle control, and for maintaining a suitable pressure differential, the HVAC system must also control for temperature and humidity.
A poorly designed HVAC system for an ISO 5 cleanroom will incur excessive operating costs, increase the complexity of maintenance, and will likely fail certification. A good design, on the other hand, will function reliably and meet all the relevant regulations.
Core principle: ISO 5 cleanroom HVAC is not about "more air" — it is about delivering the most stable, controllable, and efficient clean air distribution.
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Executive Summary
- ISO 5 cleanrooms are highly filtered and require constant airflow. The airflow needs to be controlled in such a way that the particles are locked onto a specific path and there is as little turbulence as possible.
- A clean room's HVAC system can be designed with the following elements in mind: uniform supply of air, maintenance of pressure difference, T/H (temperature/humidity) control, filtration in stages, and system redundancy.
- Deiiang™ offers custom AHU solutions, precision controls, energy optimization and on-site commissioning to optimize cleanliness and operating costs.
- Deiiang™ supports projects with custom AHU solutions, with control systems for precise control, energy optimization and on-site commissioning to achieve the required cleanliness while also considering operating costs.
What Is ISO 5 Cleanroom and Why HVAC Matters
ISO 5 (Class 100) limits to 3,520 particles ≥0.5 µm/m³ and 220 particles ≥0.3 µm/m³. ISO 5 cleanrooms are required for the production of sterile pharmaceuticals, for semiconductor photolithography, for precision optics, and for highly advanced medical devices.
A proper designed ventilation system for an ISO 5 cleanroom is the core of contamination control. Even the best architecture for a cleanroom does not help if the ventilation system is not properly designed.
📌 2022 EU GMP Annex 1 update: For Grade A (ISO 5) areas, continuous particle monitoring (CPM) is now mandatory during operations. Bioburden limits are tightened, and HVAC systems must demonstrate robust recovery performance. This raises the bar for AHU design and control responsiveness.
Real-world applications:
- Semiconductor fabrication (wafer processing)
- Sterile injectable drug manufacturing
- Medical implant production
- Precision optical assembly
Biological research laboratories
ISO 5 cleanrooms serve:
ISO 5 cleanroom applications in pharma, semiconductor, and medical devices.
For pharmaceutical clients, ISO 5 aligns with GMP Grade A. For manufacturing, the focus is on maintainability, stability, and energy control. Deiiang™ integrates these perspectives into every design.
Core HVAC Design Goals for ISO 5 Cleanrooms
An effective iso 5 cleanroom hvac design must achieve multiple interdependent objectives. These goals form the foundation of a robust system.
- Particle concentration: ISO 5 levels must be maintained at all times when the enclosure is in operation.
- Pressure differential: Positive stable pressure differential (typically 10–15 Pa) to prevent cross-contamination.
- Temperature control: Maintain ±0.5 °C or tighter for process stability.
- Humidity control: Achieve ±2% RH or better to prevent condensation and ensure prevention of static electricity.
- Airflow uniformity: Unidirectional flow to minimize turbulence and ensure no 'dead' areas in the work area.
- Operational reliability: Support 24/7/365 continuous operation with redundancy.
- Cost efficiency: lowest energy consumption per unit of clean air produced.
Design relationship: Cleanliness → Airflow/Filtering → Pressure Differential → Stability → Energy Consumption. Each element affects the others.
Cleanroom Ventilation System Design
Airflow Organization
Unidirectional (laminar) airflow is typically used in ISO 5 cleanrooms. Air flows down from the ceiling HEPA/ULPA filters through the work area and then is extracted from low-level returns. This airflow pattern helps to sweep particles away from critical areas.
- Unidirectional flow: Essential for ISO 5; air velocity of 0.45 m/s ±20% is common.
- Return placement: Low-level returns on opposite walls prevent recirculation.
- Dead zone elimination: Use computational fluid dynamics (CFD) to identify and correct stagnant areas.
- High-pollution zones: Isolate with additional local exhaust or dedicated returns.
The iso 5 cleanroom ventilation system must be designed with airflow patterns that minimize turbulence and prevent particle entrapment.
air changes and Supply Logic — with Formulas
ISO 5 cleanrooms are defined by unidirectional flow, not by air changes per hour (ACH). The critical parameter is face velocity (typically 0.36–0.54 m/s) across the entire ceiling area.
$$ Q = A \times v \times 3600 $$
Where:
- Q = supply airflow (m³/h)
- A = cleanroom cross-sectional area (m²)
- v = average face velocity (m/s)
For a 10 m² ISO 5 zone at 0.45 m/s: Q = 10 × 0.45 × 3600 = 16,200 m³/h. ACH would be ~1,620 h⁻¹ — but the velocity is the real design driver.
Why ACH is misleading: ACH is a derived number. For unidirectional flow, the key is uniform velocity. Oversizing based on ACH leads to turbulence and energy waste.
HEPA ceiling coverage typically ranges from 60% to 100% of the ceiling area. Higher coverage improves velocity uniformity and reduces dead zones.
Cleanroom Recovery & Dynamic Control
iso 14644-3 mandates the recovery test (100:1 decay time) — the time needed for particle concentration to drop from 100× to 1× the ISO 5 limit. Typically, this must be < 15–20 minutes.
Recovery time calculation (simplified): \( t = \frac{2.3}{n} \times \log_{10}(C_1/C_2) \)
Where \( n \) = air change rate (h⁻¹), \( C_1 \) = initial concentration, \( C_2 \) = target concentration.
For ISO 5, a well-designed system achieves recovery in ≤15 min. Deiiang™ projects consistently verify recovery < 12 min during FAT.
Where \( n \) = air change rate (h⁻¹), \( C_1 \) = initial concentration, \( C_2 \) = target concentration.
For ISO 5, a well-designed system achieves recovery in ≤15 min. Deiiang™ projects consistently verify recovery < 12 min during FAT.
Dynamic control includes fast-acting VAV dampers and pressure-independent valves to maintain stability during filter loading and door operations.
The AHU is the core component of any iso 5 cleanroom air handling unit system and after being conditioned it is distributed in the cleanroom with the utmost precision and reliability.
Deiiang™ provides state-of-the-art custom AHU solutions. They have vast experience in cleanrooms and design each AHU unit to meet project specific requirements.
Pressure Differential Control & Airlock Strategy
A positive pressure of 10-15 Pa above adjacent lower grade areas will prevent contamination of clean areas by external contamination. The pressure in each area will decrease in a cascading manner from the cleanest area to the least clean area.
- Use pressure-independent control valves or VAV terminals.
- Monitor differential pressure at every critical door and pass-through.
- Compensate for door openings with fast-acting control loops.
Airlock types for ISO 5:
| Airlock Type | Pressure Pattern | Application |
|---|---|---|
| Bubble | High → Low → High (internal positive) | Protecting ISO 5 from adjacent lower-grade areas |
| Sink | Low ← High ← Low (internal negative) | Containment of hazardous materials |
| Cascade | Stepped gradient (e.g., ISO 7 → ISO 5) | Standard pharma/semicon cleanroom suites |
| Type | Pattern | Use |
|---|---|---|
| Bubble | High→Low→High | Protect ISO 5 |
| Sink | Low←High←Low | Hazard containment |
| Cascade | Stepped gradient | Standard suites |
Airlock pressure strategies for ISO 5 cleanroom entry.
Temperature and Humidity Control
While not part of the ISO 5 definition, temperature (typically 20–22 °C) and humidity (45–55% RH) are vital for process stability, worker comfort, and static control.
- Precision cooling coils with dehumidification capacity.
- Reheat systems for tight humidity control in humid climates.
- Humidification with clean steam or ultrasonic systems.
- Fan heat gain: In recirculation systems the heat from the fan motor can add up to 2-4° C to the supply air. This must be included in the cooling load calculations to avoid under-sizing the cooling.
Air Handling Unit Selection for ISO 5
The AHU is the core component of any iso 5 cleanroom air handling unit system and after being conditioned it is distributed in the cleanroom with the utmost precision and reliability.
Deiiang™ provides state-of-the-art custom AHU solutions. They have vast experience in cleanrooms and design each AHU unit to meet project specific requirements.
Key AHU Components
- Fan section: Plug-fan or belt-driven centrifugal, with VFD for speed control.
- Pre-filter (G4/F5): Removes coarse particles to protect downstream filters.
- Cooling coil: DX or chilled water, sized for peak sensible and latent loads.
- Heating coil: Hot water or electric for winter heating and reheat.
- Humidification: Clean steam or ultrasonic, with 0.5 °C control precision.
- Final filter section: HEPA/ULPA with airtight frame.
- Control system: PLC-based with Modbus/BACnet integration.
AHU Selection Criteria
- Airflow range: 3,000–60,000 m³/h or higher, matched to cleanroom volume and velocity.
- Static pressure: 800–1,500 Pa typical, with margin for filter loading.
- Temperature control: ±0.3–0.5 °C precision.
- Humidity control: ±1–2% RH precision.
- Filter staging: G4 + F7/F9 + H13/H14.
- Redundancy: N+1 fan/filter configuration for critical applications.
- Energy efficiency: EC fans and inverter compressors reduce part-load energy by 20–35%.
Deiiang™ specification example: Custom AHU with 18,000 m³/h airflow, 1,200 Pa static pressure, ±0.3 °C temperature control, and integrated H13 HEPA filtration — designed by Jason.peng for a semiconductor cleanroom project.
Performance Comparison: AHU Types
| Feature | Standard AHU | Deiiang™ Custom AHU |
|---|---|---|
| Airflow range (m³/h) | 5,000–40,000 | 3,000–60,000+ |
| Static pressure (Pa) | 600–1,200 | 800–1,500+ |
| Temp. precision (°C) | ±0.5 | ±0.3 |
| Humidity precision (% RH) | ±2 | ±1 |
| Filter staging | G4+F7+H13 | G4+F7+F9+H13/H14 |
| Energy saving (vs. fixed-speed) | 15–20% | 25–35% |
| Redundancy | Optional | N+1 standard |
| Feature | Std AHU | Deiiang™ |
|---|---|---|
| Airflow (m³/h) | 5k–40k | 3k–60k+ |
| Static pressure (Pa) | 600–1200 | 800–1500+ |
| Temp. precision (°C) | ±0.5 | ±0.3 |
| Humidity precision (%RH) | ±2 | ±1 |
| Filter staging | G4+F7+H13 | G4+F7+F9+H13/H14 |
| Energy saving | 15–20% | 25–35% |
| Redundancy | Optional | N+1 |
Comparison of standard AHU vs. Deiiang™ custom AHU for ISO 5 cleanrooms.
Filtration Strategy: HEPA vs ULPA
Filtration is the most critical element of any iso 5 cleanroom air handling unit system. The final filter stage determines the actual cleanliness level achieved.
HEPA Filters (H13/H14)
- H13: ≥99.95% efficiency at MPPS (≥99.97% at 0.3 µm).
- H14: ≥99.995% efficiency at MPPS.
- Sufficient for most ISO 5 pharmaceutical and medical applications.
- Lower pressure drop than ULPA, reducing fan energy.
ULPA Filters (U15–U17)
- U15: ≥99.9995% at 0.12 µm.
- U16: ≥99.99995% at 0.12 µm.
- U17: ≥99.999995% at 0.12 µm.
- Required for semiconductor sub-10nm processes and advanced research.
- Higher pressure drop; must be balanced with system static capability.
Selection rule: Filter grade must be balanced against airflow, pressure drop, system energy, and process requirements. Higher grade is not always better — it must be the right grade for the application.
Filter Selection Matrix
| Filter Grade | Efficiency (0.3µm) | Typical Application | Pressure Drop (Pa) | Cost Index |
|---|---|---|---|---|
| H13 | ≥99.97% | Pharma, medical devices, general ISO 5 | 180–220 | 1.0 |
| H14 | ≥99.995% | Sterile filling, advanced pharma | 200–250 | 1.3 |
| U15 | ≥99.9995% | Semiconductor (sub-10nm), research | 240–300 | 1.8 |
| U16 | ≥99.99995% | Semiconductor (sub-7nm), nanotech | 280–350 | 2.5 |
| U17 | ≥99.999995% | Atom-scale research, extreme clean | 320–400 | 3.5 |
| Grade | Efficiency | Application | ΔP (Pa) |
|---|---|---|---|
| H13 | 99.97% | Pharma, general ISO 5 | 180–220 |
| H14 | 99.995% | Sterile filling | 200–250 |
| U15 | 99.9995% | Semiconductor | 240–300 |
| U16 | 99.99995% | Sub-7nm fab | 280–350 |
| U17 | 99.999995% | Atom-scale research | 320–400 |
HEPA vs ULPA filter grades for ISO 5 cleanroom applications.
Deiiang™ offers both HEPA and ULPA filter housings with airtight frames, certified to EN1822 and IEST-RP-CC034. The Jason.peng design team can recommend the optimal filter grade based on your process requirements and energy budget.
4 Common Pitfalls in ISO 5 Cleanroom HVAC Design
Avoid these costly mistakes with real‑world insight from Deiiang™ field engineers.
Pitfall #1
Picking the ULPA for every ISO 5 project blind. For non-sub-10nm semiconductor and for pharma, using U15/U16 filters increases the initial pressure by 40% and therefore also doubles the fan energy required. For most of the pharmaceutical ISO 5 applications, H14 + high-efficiency pre-filtration is the cost-effective sweet spot.
Pitfall #2
Instead of gasket-sealed HEPA frames use fluid/gel-seal frames. Gasket seals deteriorate with vibration and cause micro-leaks which can lead to high particle counts. ISO 5 cleanrooms need liquid-gel seal (fluid seal) ceiling grids for long-term clean-room integrity.
Pitfall #3
Omitting the fan heat gain. For recirculation systems the heat generated by the fan motors for the supply air can add up to 2-4°C. Omitting this sensible heat load will result in undersized cooling coils and in humidity drift. The fan heat must be included in the cooling load calculation.
Pitfall #4
Skipping on‑site DOP/PAO leak testing. Many systems pass factory tests but fail on‑site due to installation damage. Deiiang™ enforces 100% on‑site PAO testing with a first‑pass rate of 100% in our recent projects.
Energy Efficiency Optimization
One of the key issues in the design of HVAC for iso 5 cleanrooms is the need to balance cleanliness with energy consumption. A 20% reduction in energy usage can translate into hundreds of thousands of dollars in annual savings for a large facility.
Energy-Saving Strategies
- Variable Frequency Drives (VFDs): VFDs control variable speed of fan to reduce energy usage up to 40% while running partial load.
- Zone-based airflow control: Allows for specific airflow rates in individual areas and reduces excess airflow.
- High-efficiency filters: Low-pressure-drop filters reduce fan energy.
- Heat recovery: From exhaust air by preheating of supply fresh air by means of an enthalpy wheel.
- Intelligent controls: PID loops, demand-based ventilation, and real-time monitoring.
- DC inverter compressors: By constantly changing the compressor's capacity in a DX system, savings of up to 35% can be achieved compared to a fixed-speed compressor.
Energy performance benchmark (Deiiang™ custom AHU vs. baseline)
Cooling IPLV ≥4.55 (vs. national Grade 1 standard 4.0) — 26% total energy saving potential.
A 10,000 m² semiconductor cleanroom was optimized for the Iso 5 ventilation system, utilizing VFDs and heat recovery. Estimated annual energy savings and payback would be approximately 22–28% and less than 24 months respectively.
EC Plug Fans Used in Retrofit with Modbus Group Control to Save $48,000/Year in a 10,000m² Semiconductor Cleanroom — 31.4% Savings over AC Fixed-Speed Fan Used Previously.
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ISO 5 Cleanroom Airflow, HEPA & Energy Estimator
Enter room dimensions, face velocity, and system parameters to estimate airflow, HEPA quantity, fan power, cooling load, and total AHU input power.
Deiiang™ Case Study: Semiconductor ISO 5 Cleanroom
Project: Advanced semiconductor photolithography cleanroom
Location: Southeast Asia (high ambient temperature and humidity)
Cleanroom grade: ISO 5 (Class 100), 800 m² production area
Process: 300 mm wafer handling with sub-10nm line widths
Deiiang™ AHU installation
Deiiang™ AHU installation for semiconductor ISO 5 cleanroom.
Project Challenges
- Stringent particle control: ≤3,520 particles ≥0.5 µm/m³ continuous.
- Temperature stability: ±0.3 °C required for photolithography tools.
- Humidity control: 45±1% RH to prevent static discharge and resist drift.
- Limited mechanical room space; AHU footprint constrained.
- High ambient dew point (28°C) necessitating deep dehumidification.
- 24/7 operation with zero downtime tolerance.
Deiiang™ Solution
- Custom AHU with 42,000 m³/h airflow, 1,450 Pa static pressure and ±0.3 °C / ±1% RH control.
- Filter staging for the new AHU: G4 pre-filter / F7 bag filter / F9 bag filter / H14 HEPA terminal filter.
- DX cooling coil with inverter scroll compressor.
- The EC plug fans run with VFD to minimize energy consumption by 32% compared with the fixed speed solution.
- This can be integrated using a PLC with Modbus output to the BMS to log a 14 day trend.
- N+1 fan redundancy, and dual cooling circuits for fail-safe operation.
- On-site commissioning performed by Jason.peng and the Deiiang engineering team to verify performance.
- Pre-installation cleaning: Before installation of the ductwork and the AHU units all surfaces have been cleaned to Class 0 standards in order to prevent contamination with debris from the construction site.
Results
- Particle counts consistently below ISO 5 limits (measured via 0.3 µm and 0.5 µm channels).
- Temperature maintained within ±0.25 °C of setpoint over 12 months.
- Humidity stable at 45±0.8% RH across all seasons.
- Total energy consumption reduced by 26% compared with the original fixed-speed system.
- Filter life extended by 18% due to optimized pre-filtration and low-pressure-drop final filters.
- System passed ISO 14644-1 certification on first attempt.
- On‑site PAO leak test: 100% first‑pass rate.
AHU installation
HEPA filter bank
On‑site commissioning
Particle verification
ISO 5 Air Handling Process Flow
Detailed Technical Specifications (Toggle)
- Airflow: 3,000 – 60,000+ m³/h
- Static pressure: up to 1,800 Pa
- Temp. control: ±0.3°C
- Humidity control: ±1% RH
- Filter staging: G4+F7+F9+H13/H14
- Fan types: EC plug fans with VFD
- Refrigerant: R410A inverter scroll
- Certifications: Eurovent, AHRI, CE
- H13, H14, U15, U16, U17
- Frame: anodized aluminum, stainless steel
- Seal: gel/fluid seal or gasket
- Test: DOP/PAO scanning, MPPS efficiency
- Standards: EN1822, IEST-RP-CC034
Frequently Asked Questions
What HVAC system is best for ISO 5 cleanrooms?
A custom AHU, featuring HEPA/ULPA filtration, unidirectional airflow and temperature and humidity control, is the industry standard. Deiiang™ can offer custom solutions that incorporate VFDs, inverter compressors and other intelligent controls in order to optimize performance.
Is HEPA enough for ISO 5 cleanroom design?
Typically for ISO 5 applications such as pharmaceutical and medical products H13 or H14 HEPA filters can be used. Down to sub-10nm process such as for Semiconductors require ULPA filtration (U15–U17). This depends on the processes in question and respective regulations.
How do you maintain pressure differential in a cleanroom?
For ISO 5 applications in the fields of pharmaceuticals/healthcare, H13 or H14 HEPA filters are generally adequate. Processes in the semiconductor industry with structures below 10nm require ULPA (U15–U17) filters.
What is the role of an air handling unit in ISO 5?
The iso 5 cleanroom air handling unit conditions (cool, heat, humidify, dehumidify) and delivers filtered air to the cleanroom. It is the primary equipment for maintaining cleanliness, temperature, humidity, and pressure.
How can ISO 5 cleanrooms improve energy efficiency?
Through VFDs, EC fans, inverter compressors, heat recovery, zone-based airflow control, and high-efficiency filters. Deiiang™ designs achieve 25–35% energy savings vs. conventional fixed-speed systems.
What is recovery time and why does it matter?
This measure characterizes the return time of a cleanroom to an ISO 5 classification after having been contaminated. Recovery time (100:1 decay) typically has to be less than 20 min according to ISO 14644-3. The Deiiang™ systems, however, return within less than 12 min. Thus, they can be recovered quickly from any kind of disturbance.
Conclusion: Integrated Design for ISO 5 Success
Exceptional iso 5 cleanroom HVAC design is not a sum of individual technologies. Air handling, filtration, airflow distribution, pressure and energy are integrated to form a working, reliable whole.
We can help with projects requiring the highest standards of cleanliness, stability and long-term cost effectiveness by working with experienced partners who have real engineering capability.
Ready to design your ISO 5 cleanroom HVAC system?
Get customized AHU solutions, filter selection, and energy optimization from Deiiang™.
Contact Deiiang™ for a consultation | Request AHU selection guidance | Project inquiryReferences
- ISO 14644-1:2015 — Cleanrooms and associated controlled environments, Part 1: Classification of air cleanliness
- ASHRAE Handbook — HVAC Applications, Chapter 18: Clean Spaces
- IEST-RP-CC034 — HEPA and ULPA Filter Leak Test Standards
- EU GMP Annex 1 (2022) — Manufacture of Sterile Medicinal Products
- US DOE — Energy Design Guides for Cleanrooms
Article prepared by the Deiiang™ technical team. Lead engineer: Jason.peng. All performance data based on validated project outcomes and industry standards.
