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Navigating CleanRoom Classifications is the first critical step in facility design, but it is not just about picking a number; it is about matching your contamination risk to your operational reality. The ISO 14644-1 standard provides the global framework, but the practical difference between these levels dictates your construction budget, gowning protocols, and daily energy consumption.
Most industrial and pharmaceutical projects fall within the iso5, ISO6, ISO7, and iso8 range. Moving up this ladder significantly increases complexity. For example, an iso8 environment is a standard starting point for general hygiene and transitional zones, often requiring 10-20 air changes per hour. However, stepping up to ISO7 or ISO6 typically triples that airflow demand to manage stricter particle counts.
Field Note: At the peak of this spectrum, ISO5 (equivalent to the old Class 100) relies on unidirectional airflow to protect the most critical processes, such as sterile filling or semiconductor wafer exposure. Selecting the right classification ensures you meet regulatory standards without over-engineering your facility and inflating running costs.
What is A CleanRoom?
A cleanroom is a controlled environment where pollutants like dust, airborne microbes, and aerosol particles are filtered out to provide the cleanest area possible. These specialized rooms are indispensable in modern industries where even microscopic contamination can compromise product quality.
Significance of CleanRoom Classification
Cleanroom classification provides a standardized method to measure and quantify air cleanliness levels. This standardization is crucial for industries where product quality directly correlates with environmental control. For example, in pharmaceutical manufacturing, a single particle can contaminate an entire batch of medication, potentially costing millions and endangering patient safety.
ISO 14644-1 Standard Overview
iso 14644-1 is the international standard for classifying air cleanliness in cleanrooms and controlled environments. This globally recognized standard has replaced many regional classifications, creating a unified system for cleanroom specification.
Core Concept: Particle size and count per cubic meter. The standard defines specific limits for airborne particulate contamination, with classifications ranging from ISO Class 1 (cleanest) to ISO Class 9 (least clean).
ISO 14644-1 Cleanroom Classification System Explained
Understanding Core Parameters of ISO Classification
Particle Sizes
- 0.1 µm (ultrafine particles)
- 0.3 µm (common testing size)
- 0.5 µm (standard reference size)
- 1.0 µm (visible with microscope)
- 5.0 µm (human hair is 50-70µm)
Particle Count per Cubic Meter
This is the fundamental basis for classification. The standard specifies maximum allowable concentrations for particles equal to and larger than the specified sizes.
ISO Classification Levels Reference Table
Table: Maximum allowable particle counts per cubic meter by particle size and ISO class
Particle Count Analysis Chart
This visualization demonstrates how particle count limits decrease exponentially as ISO classification becomes stricter. For example, iso class 5 allows 3,520 particles ≥0.5µm per m³, while iso class 8 allows 3,520,000 - a 1,000x difference.
Key ISO cleanroom classes (ISO 5, ISO 6, ISO 7, iso 8) In-Depth Analysis
Critical Factors in Cleanroom design and Operation
A. Cleanroom Airflow Patterns
Unidirectional (Laminar) Flow
Used primarily in ISO 5 and higher classifications. Air moves in parallel streams with uniform velocity, typically at 0.45 m/s ±20%. This effectively sweeps particles away from critical processes.
Non-unidirectional (Turbulent) Flow
Used in ISO 7, 8 and lower classifications. Air movement is less controlled but sufficient for less critical applications. Relies on dilution principle with adequate air changes.
B. Filtration Systems
HEPA Filters
High Efficiency Particulate Air Filters remove 99.97% of particles ≥0.3µm. Essential for ISO 5-8 classifications. The utilizes specialized HEPA filtration to maintain food-grade purity standards in edible salt production.
ULPA Filters
Ultra Low Penetration air filters remove 99.999% of particles ≥0.12µm. Used in the most stringent applications beyond ISO 5 requirements.
Multi-Stage Filtration System
Most cleanrooms employ a multi-stage approach:
- Pre-filters (MERV 8-13): Capture larger particles, extending HEPA lifespan
- Intermediate filters (MERV 14-16): Additional protection for HEPA filters
- Final filters (HEPA/ULPA): Provide the final cleanliness level
C. Pressure Differential Control
Positive Pressure
Maintains higher pressure inside cleanroom than surrounding areas. Prevents infiltration of contaminants. Typical differential: 10-15 Pascals.
Negative Pressure
Maintains lower pressure inside containment areas. Prevents escape of hazardous materials. Used in pharmaceutical compounding or biohazard labs.
D. air changes per hour (ACH)
ACH measures how many times the total air volume in a room is replaced per hour. Calculated as:
ACH = (Total Airflow in m³/h) ÷ (Room Volume in m³)
Recommended ACH Ranges by ISO Class:
- ISO 5: 240-600 ACH (typically 360 ACH for pharmaceutical applications)
- ISO 6: 90-180 ACH
- ISO 7: 30-60 ACH
- iso 8: 10-25 ACH
Example Calculation:
For an ISO 7 Cleanroom measuring 10m × 8m × 3m (240m³) with recommended 45 ACH:
Required airflow = 240m³ × 45 ACH = 10,800 m³/h
This translates to approximately 4,500 CFM (cubic feet per minute) for HVAC system design.
iso 14644-1 vs. Federal Standard 209E Comparison
Historical Context
Federal Standard 209E was the predominant cleanroom classification standard in the United States until its official cancellation in 2001. The international ISO 14644-1 standard has since become the global benchmark, creating a unified classification system worldwide.
Key Differences
Measurement Units
FS 209E: Based on particles per cubic foot
ISO 14644-1: Based on particles per cubic meter
Classification Method
FS 209E: Used "Class" designation (Class 100, class 1000, etc.)
ISO 14644-1: Uses "ISO Class" designation (ISO 5, ISO 6, etc.)
Comparison of ISO 14644-1 and Federal Standard 209E Cleanroom Classifications
ISO 3
Highest level of cleanlinessISO 4
ISO 5
ISO 6
ISO 7
ISO 8
Note: The "Class" numbers in the Federal Standard 209E refer to the maximum number of particles ≥0.5µm per cubic foot of air, while the ISO 14644-1 standard uses the number of particles per cubic meter of air.
How to Select the Appropriate ISO Cleanroom Class?
Industry Regulations and Standards
GMP
Pharmaceutical Manufacturing
FDA
Medical Devices
EU GMP Annex 1
Sterile Products
SEMI
Semiconductor Industry
Product and Process Considerations
Product Sensitivity
Evaluate how susceptible your product is to particulate or microbial contamination:
- High sensitivity: Microchips, injectable drugs (ISO 5-6)
- Medium sensitivity: Medical devices, topical products (ISO 7)
- Low sensitivity: Packaging, assembly (ISO 8)
Process Requirements
Consider exposure time and contamination risk during manufacturing:
- Open vs. closed processes
- Manual vs. automated operations
- Product exposure duration
Risk Assessment
Conduct a formal risk analysis based on product and process characteristics. According to Deiiang™ Product Designer Jason.peng, "A thorough risk assessment should consider both particulate and microbial risks, process criticality, and the potential impact of contamination on final product quality."
Call to Action
Unsure which cleanroom classification your project requires? Click here to contact Jason Peng for a free cleanroom design consultation.
Project Completion Gallery
Wuhan University Cellular Laboratory Project
The completed 1000 square meter cell culture laboratory at Wuhan University, showcasing Deiiang™'s commitment to excellence in laboratory design and construction.
© 2024 Deiiang™ Laboratory Solutions | Wuhan University Cell Culture Laboratory Project
Frequently Asked Questions
Q: What is the main difference between an ISO 7 and an iso 8 cleanroom?
Answer: The primary differences are the particle count limits and the Air Change Rate (ACH).
- Particle Count: ISO 7 is cleaner, allowing a maximum of 352,000 particles (≥0.5µm) per cubic meter, whereas ISO 8 allows 3,520,000 particles—ten times more.
- Airflow: To maintain this cleanliness, ISO 7 typically requires 30–60 air changes per hour (ACH), while ISO 8 only requires 10–25 ACH.
- Application: ISO 8 is often used for transitional areas or general packaging, while ISO 7 is standard for medical device assembly, pharmacy compounding, and electronics manufacturing.
Q: How do I decide which ISO Class my project needs?
Answer:Your classification requirements are usually dictated by industry regulations and product sensitivity.
- Regulations: Pharmaceutical manufacturing must follow GMP guidelines, and medical devices often require FDA compliance. For example, sterile filling almost always requires ISO 5.
- Risk: If a microscopic dust particle could ruin your product (like a semiconductor wafer), you need ISO 5 or 6. If you just need to prevent general contamination during packaging, ISO 8 is likely sufficient.
- Tip: Always conduct a risk assessment or consult with a cleanroom engineer before finalizing your design to avoid over-engineering (wasting money) or under-compliance.
Q: What are the gowning requirements for an iso 5 cleanroom?
Answer: Since ISO 5 (formerly Class 100) is a critical environment, humans are the biggest source of contamination, so gowning protocols are extremely strict.
- Required Gear: Personnel must typically wear a full cleanroom bunny suit (coverall), hood, knee-high boots, face mask, goggles, and sterile double gloves.
- Zero Skin Exposure: In an ISO 5 zone, essentially no skin should be exposed to the air. All garments must be made of non-shedding, synthetic materials (like Tyvek/polyester) specifically designed for sterile environments.
