What is Clean Room Air Flow?

     Clean room air flow refers to the arrangement of a particular air supply, return or exhaust outlet, combined with controlled air movement patterns, to regulate indoor air quality, pollutant dispersion, and removal efficiency.

I.The Importance of Clean room air flow 
Ensuring Indoor Air Quality and Cleanliness
Effectively control pollutant dispersion: Reasonable airflow organization enables indoor air to flow in a predetermined direction, effectively controlling pollutant spread and minimizing its impact on work areas, ensuring air quality meets specified cleanliness standards. For example, unidirectional cleanrooms use HEPA filters to deliver fresh air at uniform velocity, forming a single-directional airflow that rapidly expels contaminants.
Avoid dead corners and vortex areas: Good airflow organization can ensure the uniform distribution of indoor air, avoid the formation of dead corners and vortex areas, prevent pollutants from accumulating in local areas, so as to maintain the cleanliness of the entire clean room.

Guaranteeing Product Quality
Reduce product contamination risks: In industries such as pharmaceuticals, microelectronics, and food processing, products require ultra-clean environments. Cleanroom airflow systems promptly remove dust, microorganisms, and other contaminants generated during production, minimizing pollution risks and improving product pass rates and quality consistency. Stable production environments: Consistent airflow organization helps maintain stable temperature, humidity, and pressure parameters within cleanrooms, providing optimal conditions for production processes and ensuring product quality uniformity.

Protecting Workers' Health
Mitigate health risks: Cleanroom airflow design ensures workers operate in comfortable environments, reducing potential health threats from airborne pollutants. Proper airflow distribution minimizes contaminant inhalation, protecting respiratory and overall health.

Improving Energy Utilization Efficiency
Rational determination of supply air volume: Well-designed airflow organization precisely calculates air supply rates to meet cleanliness requirements while avoiding energy waste related to over ventilation, reducing energy consumption and operational costs.
Optimize equipment operation: Reasonable air flow organization can make clean room air handling equipment (such as filters, fans, etc.) operate more efficiently, extend equipment life, and reduce equipment maintenance and replacement costs.

Meeting Process Production Needs
Adapting to process requirements: Different production processes have different requirements for the air flow organization of clean rooms. Particle-sensitive processes may require unidirectional flow, while less critical applications may use turbulent flow. Rational air distribution design can meet the needs of various process production and improve production efficiency.

II.Types of Airflow in Cleanroom

Turbulent Flow

Unidirectional Flow :Vertical Flow

Unidirectional Flow : Horizontal Flow

III.Why Does Air Exchange Rate Affect Cleanliness?
Dilution and Removal of Pollutants
  Air exchange rate directly impacts contaminant concentration in cleanrooms. Higher ACH rapidly dilutes and removes suspended particles, microorganisms, and other pollutants, maintaining cleanliness.
Principle: Pollutants (such as dust and microorganisms) in the clean room will continue to be produced, and these pollutants can be quickly discharged and their concentration reduced by increasing the air exchange rate.
Application: In high-level clean rooms (such as ISO Class 5 or Class A), air exchange rates are often as high as hundreds of times per hour to ensure that contaminants are quickly removed.

Maintaining Airflow Uniformity
  Air exchange rate is closely related to airflow organization. Higher ACH enhances airflow uniformity and stability, preventing contaminant accumulation in localized areas.
Principle: The higher the air exchange rate, the faster the airflow speed, the more uniform the air flow, which can effectively cover all corners of the clean room and reduce dead corners.
Application: In unidirectional flow clean rooms, high air exchange rates ensure that air flows in a laminar flow form, creating an "air barrier" that prevents pollutants from entering critical areas.

Controlling Temperature and Humidity
  Air exchange rate also influences temperature and humidity control. Higher ACH facilitates faster adjustment of environmental parameters, ensuring stability.
Principle: By increasing the air exchange rate, the treated air (temperature and humidity have been adjusted) can be sent into the clean room faster, reducing the impact of the external environment on the indoor temperature and humidity.
Application: In clean rooms requiring strict control of temperature and humidity (such as pharmaceutical manufacturing workshops), high air exchange rates help maintain a stable production environment.

Reducing Contaminant Residence Time
  Higher ACH reduces contaminant residence time within cleanrooms, minimizing pollution risks.
Principle: The retention time of pollutants in the air is proportional to its concentration and exposure time. High air exchange rates can quickly remove contaminants, reducing their potential impact on products and the environment.
Application: In sterile production areas, high air exchange rates ensure that microorganisms and particles are quickly removed after production, reducing the risk of contamination.

Meeting Cleanliness Standards
 Different cleanliness classes specify air exchange rate requirements. Higher classes demand higher ACH for compliance.ISO 14644-1 standards：
ISO 5（Class A）：300-600 air changes per hour (ACH).
ISO 6（Class B）：60-90 air changes per hour (ACH).
ISO 7（Class C）：30-40 air changes per hour (ACH).
ISO 8（Class D）：20-30 air changes per hour (ACH).
Application: According to the production process and cleanliness level requirements, reasonable design of air exchange rate to ensure that the clean room meets the GMP standard.

Balancing Energy Consumption
While high ACH improves cleanliness, it increases energy consumption and operational costs. 
A balance must be struck between cleanliness requirements and energy efficiency.
 

IV. What type of airflow organization is suitable for different industries?
  How to reduce pollution sources, improve air flow efficiency and avoid dead corners and airflow interference through reasonable air flow design：

1. Pollution Reduction
Through reasonable air flow design, the generation and diffusion of pollution sources can be effectively reduced.
Design Principles:
Local exhaust: Install hood systems at pollution sources (e.g., material inlets, reactors, packaging machines) to capture powders, gases, or VOCs.
Negative pressure: Apply negative pressure in high-pollution zones (e.g., API production areas) to prevent cross-contamination.
Airflow barriers: Use unidirectional (laminar) airflow barriers in critical zones (e.g., filling lines) to block external contaminants.
Implementation:
Install exhaust hoods over powder/gas-emitting equipment.
Use HEPA filters to purify exhausted air.
Place airlocks or air showers at cleanroom entrances to minimize human-borne contamination.

2. Air Circulation Optimization
Efficient airflow design ensures uniform air flow and quick removal of pollutants.
Design Principles:
Unidirectional airflow: Implement unidirectional laminar flow in high-cleanliness zones (e.g., filling areas) for uniform "air piston" effect.
Reasonable airflow velocity: Maintain airflow speed between 0.36–0.54 m/s based on cleanliness requirements.
High-efficiency filtration: Use HEPA/ULPA filters to ensure air purity.
Implementation:
Distribute HEPA filters uniformly across cleanroom ceilings.
Regularly monitor airflow velocity with anemometers.
Replace/maintain filters periodically to sustain efficiency.

3. Dead Zone Elimination
Dead corners are areas in the cleanroom where airflow is not smooth and pollutants are easy to accumulate.
Design Principles：
Balanced air distribution: Position supply and return vents strategically to cover entire cleanroom areas.
Rounded corners: Use rounded walls/ceilings/equipment to reduce airflow resistance.
CFD simulation: Analyze airflow patterns with computational fluid dynamics (CFD) to identify deadzones.
Implementation:
Place return vents in cleanroom corners/edges for uniform circulation.
Avoid large obstacles blocking airflow.
Conduct regular cleanliness testing to identify/remediate dead zones.

4. Avoiding Airflow Interference
Airflow interference can lead to unstable air flow and affect cleanliness.
Design Principles:
Pressure differential control: Direct airflow from high-cleanliness to low-cleanliness zones via strategic pressure differential design to prevent reverse flow.
Airflow zoning: Segment the cleanroom into distinct airflow regions to avoid cross-contamination.
Turbulence reduction: Implement unidirectional flow in critical zones (e.g., filling lines) to minimize turbulence.

Implementation:
Install airlocks between cleanrooms and adjacent areas to stabilize pressure differentials.
Use pressure gauges to continuously monitor and maintain pressure differentials per design specifications.
Optimize equipment/Personnel zones within the cleanroom to reduce airflow disruption.

5.Comprehensive Optimization
Through comprehensive optimization of air flow design, the performance of clean rooms can be further improved.
Design Principles:
Modular design: Adopt flexible modular cleanroom layouts adaptable to changing production needs.
Intelligent control: Utilize smart systems for real-time monitoring and adjustment of airflow speed, pressure, and humidity.
Regular validation: Perform periodic performance verification to meet GMP compliance.
Implementation:
Integrate production processes, equipment layout, and personnel movement into cleanroom design for optimized airflow organization.
Deploy automated controls to adjust supply/return airflow rates dynamically.
Conduct routine validations including airflow velocity, pressure, and cleanliness testing per GMP standards.

Pharmaceutical Industry Airflow Distribution Design Summary

I. Relationship Between GMP Standards and Cleanroom Airflow Distribution
  GMP (Good Manufacturing Practice) regulations aim to ensure production environments for pharmaceuticals and medical devices meet high standards, preventing contamination and cross-contamination.    Cleanroom airflow organization plays a critical role in maintaining aseptic conditions and avoiding cross-contamination.

GMP Requirements for Cleanrooms
1. Air Cleanliness: Cleanrooms must achieve specific air cleanliness classes defined by ISO 14644-1. Different cleanliness levels impose strict limits on airborne particle concentrations.
2. Temperature and Humidity Control: Cleanrooms must maintain stable temperature and humidity to ensure process stability and product quality.
3. Pressure Control: Appropriate pressure differentials between cleanrooms and adjacent areas must be maintained to prevent prevent contaminants from entering high-cleanliness areas from low-cleanliness areas.
4. Airflow Organization: Rational airflow design is essential to effectively remove contaminants and sustain cleanliness.

Role of Airflow Organization​
1.Unidirectional Flow (Laminar Flow):
In a high cleanliness level cleanroom, (e.g., filling areas). Air flows uniformly at a consistent speed and direction, creating an "air piston" effect to rapidly expel contaminants. This minimizes particle accumulation and ensures dust-free environments in critical zones.
2.Non-Unidirectional Flow (Turbulent Flow):
Applied in lower-cleanliness cleanrooms. HEPA-filtered air enters through ceilings and exits via floors/sides, forming a recirculation pattern. While less effective than laminar flow for particle control, it balances cost and performance for non-critical areas.
3.Pressure Control:
Critical for maintaining directional airflow. Positive-pressure cleanrooms prevent external contaminants from entering, while negative-pressure cleanrooms prevent internal contamination leakage. Stable pressure differentials ensure cross-contamination prevention.
4.Air Filtration:
Relies on HEPA or ULPA filters to remove particles/microorganisms. Filter placement and maintenance directly impact airflow efficiency and contaminant removal effectiveness.

  GMP regulations strictly govern cleanroom design. Effective airflow organization—through laminar/turbulent flow systems, pressure control, and filtration—ensures cleanliness requirements are met, safeguarding product quality and production safety.

  A comparison of airflow requirements for raw materials, finished products, packaging, and other zones, aligned with regulatory standards and cleanliness class differences, is summarized below:

Supplementary Notes:
  Dynamic Testing Requirements: Smoke tests should be carried out in all areas during simulated production interventions (e.g. environmental monitoring, equipment operation) to document airflow dead spots and turbulence risks;
  Priority of airflow direction: Critical exposed areas (such as grade A filling points) must ensure that the "First Air" is not contaminated; Special material handling: Radioactive, live virus and other materials need to be independent air flow design, may use negative pressure isolation technology.
  Full regulatory details can be found in EU GMP Appendix 1 (Version 2022) and the ISO 14644-3 Clean Room testing standard.

II. Airflow Requirements for Different Pharmaceutical Manufacturing Processes
  Different pharmaceutical production processes have distinct airflow requirements in cleanrooms, primarily depending on the nature of the drug products (such as sterile drugs, non-sterile drugs, biologics, etc.), the characteristics of the manufacturing processes (e.g., dust generation, microbial control requirements), and GMP-specific cleanliness standards.

The following is an analysis of airflow requirements for typical pharmaceutical production processes:
1. Sterile Drugs (e.g., Injectable Solutions, Ophthalmic Preparations)
Sterile drugs require the strictest airflow controls in cleanrooms, as any microbial or particulate contamination could pose severe risks to patients.
Airflow Requirements:
-Unidirectional airflow (laminar flow): Implemented in critical operation areas (e.g., filling lines, lyophilizer entrances) to ensure air flows uniformly at a consistent speed and direction, forming an "air barrier."
-High air exchange rates: Typically 300–600 air changes per hour (ISO 5 or Class A) to rapidly remove contaminants.
-Positive pressure design: Prevents external contaminants from entering sterile zones.
-High-efficiency filtration: HEPA or ULPA filters are used to minimize airborne particulates and microorganisms.
Application Scenarios:
Filling areas, lyophilization zones, aseptic connection areas, and other critical operations.

2.Non-Sterile Drugs (e.g., Oral Solid Dosages, Topical Formulations)
Non-sterile drugs require moderate cleanliness controls to manage dust and microbial contamination.
Airflow Requirements:
-Non-unidirectional airflow (turbulent flow): HEPA-filtered air enters through ceilings and exits via floors or sidewalls.
-Moderate air exchange rates: Typically 20–60 air changes per hour (ISO 7 or ISO 8) to control dust and microorganisms.
-Positive pressure design: Prevents external污染物from entering production areas.
-Local exhaust systems: Installed at dust-generating points (e.g., tablet presses, capsule fillers).
Application Scenarios:
Compression areas, capsule filling zones, packaging areas, etc.

3. Biologics (e.g., Vaccines, Monoclonal Antibodies)
The production of biologics involves live cells or microorganisms, requiring specialized cleanliness and airflow organization.
Airflow Requirements:
-Unidirectional airflow (laminar flow): Implemented in critical areas (e.g., cell culture rooms, purification zones) to maintain aseptic environments.
-High air exchange rates: Typically 150–300 air changes per hour (ISO 5 or ISO 6) for rapid contaminant removal.
-Positive or negative pressure design: Cell culture areas are typically positive pressure, while areas involving live microorganisms may use negative pressure.
-High-efficiency filtration: HEPA or ULPA filters ensure minimal particulate and microbial levels.
Application Scenarios:
Cell culture rooms, fermentation areas, purification zones, filling areas, etc.

4. Active Pharmaceutical Ingredient (API) Production
API production often involves chemical reactions, fermentation, crystallization, and may generate dust, gases, or volatile organic compounds (VOCs).
Airflow Requirements:
-Non-unidirectional airflow (turbulent flow): Air filtered through a high efficiency filter (HEPA) enters through the ceiling and exits through the floor or side walls.
-Negative pressure design: Prevents dust or harmful gases from spreading to other clean areas.
-Local exhaust systems: Installed at dust/gas generation points (e.g., material feeding ports, reactors).
-Moderate air exchange rates: Typically 20–40 air changes per hour (ISO 7 or ISO 8) to control contaminants.
Application Scenarios:
Reaction zones, crystallization areas, drying areas, grinding areas, etc.

5. Traditional Chinese Medicine (TCM) Formulations
TCM formulation production may involve significant dust and volatile components, requiring specialized airflow organization.
Airflow Requirements:
-Non-unidirectional airflow (turbulent flow): Air filtered through a high efficiency filter (HEPA) enters through the ceiling and exits through the floor or side walls.
-Negative pressure design: Prevents dust or volatile components from spreading to other clean areas.
-Local exhaust systems: Installed at dust/volatile generation points (e.g., grinders, extraction tanks).
-Moderate air exchange rates: Typically 20–40 air changes per hour (ISO 7 or ISO 8) to control contaminants.
Application Scenarios:
Grinding areas, extraction areas, drying areas, packaging areas, etc.

6. Hormonal Drugs and Highly Potent Active Pharmaceuticals (HPAPI)
Hormonal drugs and HPAPI require strict personnel protection and cross-contamination prevention.
Airflow Requirements:
-Unidirectional airflow (laminar flow): Implemented in critical areas to prevent pollutant dispersion.
-Negative pressure design: Prevents drug dust or aerosols from spreading to other areas.
-High-efficiency filtration: HEPA or ULPA filters ensure minimal particulate and active ingredient concentrations.
-High air exchange rates: Typically 150–300 air changes per hour (ISO 5 or ISO 6) for rapid contaminant removal.
Application Scenarios:
Weighing areas, mixing areas, filling areas, etc.
 

Conclusion:

III. Air Change Rate and Cleanliness Control（Specifically refer to the content of IV chapter）
  Introduces the importance of air exchange rate (ACH) in pharmaceutical production. The higher exchange rate facilitates rapid dilution and removal of pollutants from the air. 
Discusses the effect of air exchange rate on temperature and humidity control and how to balance cleanliness and environmental comfort, especially in pharmaceutical environments where temperature and moisture control are strictly required.

IV. Application of Positive and Negative Pressure Control in Airflow
1.Overview of Positive/Negative Pressure Control:
  In cleanroom design, positive and negative pressure control are essential for directing airflow, preventing cross-contamination, and protecting critical zones. Below are specific applications and principles:
Positive Pressure Control
Positive pressure ensures indoor air pressure exceeds that of adjacent areas, preventing external contaminants from entering the cleanroom.

Application Scenarios：
1. Aseptic Production Areas:
-Examples include injection filling areas, lyophilization zones.
-Positive pressure prevents external particles/microbes from infiltrating sterile environments.
2. High-Cleanliness Zones:
-ISO 5 (Class A) or ISO 7 (Class B) cleanrooms.
-Maintains cleanliness by blocking air from lower-cleanliness areas.
3. Packaging Areas:
-Pharmaceutical or medical device packaging zones.
-Prevents external dust/pollutants from compromising product quality.
4.Quality Control Laboratories:
-Microbial testing labs, analytical labs.
-Ensures stable environments for accurate test results by resisting external contamination.
Implementation Methods:
-Maintaining higher supply airflow than exhaust airflow to sustain positive pressure.
-Using differential pressure sensors to monitor and stabilize pressure differentials.
-Installing airlocks or air showers at cleanroom entrances for additional contamination protection.

Negative Pressure Control
Negative pressure means that the air pressure in the clean room is lower than the air pressure in the adjacent area, and the air flows into the clean room from the outside to prevent the diffusion of internal pollutants to the outside.
Application Scenarios:
1.API Production Areas:
-Examples include reaction zones, grinding areas, and drying areas.
-Negative pressure prevents dust or harmful gases from diffusing to other regions.
2.Biosafety Laboratories:
-Such as laboratories handling pathogenic microorganisms.
-Negative pressure ensures microorganisms do not leak into the external environment.
3.Isolation Areas:
-Such as isolation wards or dedicated production zones.
-Negative pressure prevents pathogens or hazardous substances from escaping.
4.Hormonal Drugs or HPAPI Production Areas:
-Such as weighing areas and mixing areas.
-Negative pressure prevents drug dust or aerosols from dispersing, protecting operator safety.

Implementation Methods:
-Maintaining exhaust airflow exceeding supply airflow to sustain negative pressure.
-Using high-efficiency filters (HEPA) to treat exhausted air and prevent pollutant leakage.
-Installing buffer rooms at cleanroom exits to further prevent the spread of pollutants.

Combined Application of Positive and Negative Pressure Control
  In complex cleanroom designs, positive and negative pressure control may be integrated to meet the requirements of different zones.
Application Scenarios:
(1) Multi-Level Cleanrooms:
-Aseptic drug production workshops where filling areas are under positive pressure, while raw material weighing areas are under negative pressure.
-Gradient pressure differential design ensures air flows from high-cleanliness zones to low-cleanliness zones.
(2)Biologics Production Facilities:
-Cell culture areas operate under positive pressure to protect the aseptic environment.
-Positive pressure protects the cell culture environment. Fermentation areas use negative pressure to prevent microbial dispersion during fermentation processes.

(3)Hospital Cleanrooms:
-Positive pressure in the operating room and negative pressure in the isolation ward.
-Positive pressure ensures the operating room is sterile, and negative pressure prevents the spread of pathogens.

Implementation Methods:
-Rational design of supply and exhaust airflow to control differential pressure between zones.
-Use of differential pressure sensors and automated control systems for real-time pressure regulation.
-Installation of airlocks or buffer rooms between zones to stabilize pressure differentials.

Airflow Path Design
1.Principles of Airflow Path Design
(1) Unidirectional (Laminar) Flow Design
Applicable Areas: Critical zones such as aseptic drug filling areas and lyophilization zones.
Design Essentials:
Air flows at a uniform speed and direction (typically 0.36–0.54 m/s).
Airflow direction is parallel to critical operation areas to form an "air barrier."
Supply air inlets (ceilings) and return air outlets (floors or sidewalls) are symmetrically arranged to ensure full coverage of the area.

(2) Non-Unidirectional (Turbulent) Flow Design​
Applicable Areas: Lower-cleanliness zones (e.g., packaging areas, API production areas).
Design Essentials:
Air enters through supply inlets (ceilings) and exits via return outlets (floors or sidewalls).
Airflow velocity is lower (typically 0.25–0.35 m/s) but must still cover the entire area.
(3)Pressure Differential Control
Design Essentials:
Maintain an appropriate pressure differential (typically 10–30 Pa) between cleanroom and adjacent areas.
Air flows from high-cleanliness zones to low-cleanliness zones to prevent reverse contamination.

(4)Avoiding Dead Zones
Design Essentials:
Rational placement of supply and return air inlets to ensure full airflow coverage.
Avoid large obstacles within cleanroom to maintain unobstructed airflow.

(5)Preventing Airflow Short-Circuiting
Design Essentials:
Ensure reasonable distance between supply and return air inlets to avoid direct airflow bypass.
Install airflow barriers in critical operation areas to prevent short-circuiting.

2.Implementation Methods
(1) Layout of Supply and Return Air Outlets
Supply air outlets:
High-efficiency filters (HEPA or ULPA) are uniformly arranged in the ceiling of the cleanroom.
The area of supply air outlets shall cover the entire cleanroom to ensure uniform air distribution.
Return air outlets:
Return air outlets are arranged on the floor or side walls of the cleanroom.

(2)Airflow Velocity Control
According to the cleanliness class requirements, select appropriate airflow velocities:
Unidirectional flow area: 0.36-0.54 m/s.
Non-unidirectional flow area: 0.25-0.35m /s.
Use an anemometer to regularly test airflow velocities and ensure compliance with design specifications. 
Return air outlets should be far away from the supply air outlet to avoid airflow short-circuiting.
(3) Pressure Differential Control
Install pressure differential sensors between the cleanroom and adjacent areas for real-time monitoring.
Adjust supply and return airflow rates to maintain stable pressure differentials.

(4) Airflow Simulation and Verification
Use computational fluid dynamics (CFD) to simulate airflow distribution, identify potential dead zones, and eliminate airflow short-circuits.
Regularly perform cleanroom performance verification, including testing of airflow velocity, pressure differential, and cleanliness levels, to ensure design compliance.

(5) Impact of Equipment and Personnel Activity
Rationally arrange equipment and personnel activity areas to avoid disturbing airflow.
Install local exhaust devices around equipment to promptly remove generated contaminants.

V. Airflow design of different cleanliness levels
  Airflow differences between ISO 5 cleanliness zones and other zones
The airflow differences between the ISO 5 cleanliness area and other areas are mainly reflected in the airflow type, air exchange rate, pressure difference control, filtration requirements, airflow speed and cleanliness level. Here's a comparison:
表格

Airflow Transition Between Cleanroom and Peripheral Areas:
1. Principles of Airflow Transition Design
(1) Pressure Differential Control
Positive pressure transition: The cleanroom's pressure should be higher than that of adjacent non-clean areas to ensure airflow from the cleanroom to non-clean areas, preventing pollutant intrusion.
Gradient pressure differential: A pressure gradient of 10–15 Pa is typically set between different cleanliness levels.

(2) Airflow Direction
Unidirectional flow: Ensure airflow moves from high-cleanliness areas to low-cleanliness areas to avoid reverse airflow.
Avoid airflow short-circuiting: Properly arrange supply and return air outlets to prevent direct airflow from supply outlets to return outlets.

(3) Buffer Zones
Air lock (Air Lock): Installed between cleanroom and non-clean areas as a buffer zone to further control airflow direction.
Air shower (Air Shower): Used before personnel enter the cleanroom to remove particles from clothing and surfaces.

2.Methods of Airflow Transition Design
(1) Air Lock Design
Function:
Acts as a buffer room between cleanroom and non-clean areas to prevent direct pollutant entry.
The differential pressure control ensures that the air flows from the clean room to the air lock room and then to the unclean area.
Design Essentials:
Doors of the air lock must be interlocked to prevent simultaneous opening from both sides.
Supply and return air outlets are installed inside the air lock to maintain appropriate pressure differential.
The cleanliness class of the air lock should be between that of the cleanroom and non-clean area.

(2)Air Shower Room Design
Function:
Before personnel enter the cleanroom, high-speed airflow is used to remove particles from clothing and surfaces.
Design Essentials:
Airflow speed in the air shower is typically 20–30 m/s, and the blowing time is usually 15-30 seconds.
Doors of the air shower must be interlocked to prevent simultaneous opening from both sides.
Install high-efficiency filters (HEPA) in the air shower to ensure the cleanliness of the blown air.

(3) Pass Through Design
Function:
Used for transferring materials between cleanroom and non-clean areas, avoiding direct personnel entry.
Design Essentials:
Doors of the pass through must be interlocked to prevent simultaneous opening from both sides.
Install ultraviolet lamps or high-efficiency filters (HEPA) inside the transfer window to ensure material cleanliness.

(4) Pressure Differential Control
Design Essentials:
Install pressure differential sensors between cleanroom and non-clean areas for real-time monitoring.
Adjust supply and return airflow rates to maintain stable pressure differentials.
Set up an alarm system to trigger when pressure differentials exceed the predefined range.

(5) Airflow Simulation and Verification
Design Essentials:
Use computational fluid dynamics (CFD) to simulate airflow distribution, identify potential airflow short-circuits or dead zones, and eliminate them.
Perform regular cleanroom performance verification, including testing for pressure differential, airflow velocity, and cleanliness class, to ensure compliance with design requirements.

â…¥. Airflow Monitoring and Maintenance
Airflow Monitoring and Quality Control​
1.Equipment Selection and Functional Matching
High-precision sensor selection:
Airflow velocity monitoring: Use ultrasonic flow meters or Doppler radar flow meters (principle as mentioned in search results) to capture velocity changes in the range of 0.1–30 m/s with an error rate ≤ ±2%.
Cleanliness parameter monitoring: Integrate PM2.5/PM10 laser scattering sensors, VOC gas sensors (e.g., electrochemical or photoionization principles), and temperature-humidity compensation modules (referencing search results on compensation algorithms) to ensure data accuracy.
Industrial-grade equipment requirements:
Sensors must feature EMC interference resistance design and IP65 or higher protection ratings to adapt to high-dust, high-humidity environments.

2.Monitoring Point Layout and Network Architecture
Grid-based deployment strategy:
Deploy monitoring nodes at 20–50-meter intervals across production zones (e.g., clean workshops, raw material storage areas, exhaust ports) to form a full coverage network, following grid-based layout principles from search results.
Key Areas (Such as Aseptic Production Lines) Require Increased Sampling Points to Achieve Sub-Meter Spatial Resolution Monitoring.
Data Transmission Scheme Data is uploaded in real-time to the cloud platform via 4G/5G or industrial Wi-Fi, supporting integration with government regulatory systems using the HJ212 protocol (e.g., protocol compatibility design as per search results).

3.Core Monitoring Parameters and Threshold Settings

4. Data Integration and Dynamic Control
Intelligent Analysis Platform Construction:
Utilize machine learning algorithms to analyze historical data, predict pollutant dispersion paths (as mentioned in search results on big data technology applications), and automatically generate airflow optimization plans.
Closed-loop Control System:HVAC System Integration: Adjust frequency converter outputs based on real-time flow rate data to maintain laminar flow stability (±10% of set values).
Emergency Response: Automatically activate high-efficiency filters (HEPA) and increase air exchange frequency when PM2.5 levels exceed standards (referencing search results on early-warning linkage mechanisms).

5. Visualization and Collaborative Management
3D Spatial Mapping:
Display airflow vector distribution and pollutant concentration heat maps using BIM modeling to assist decision-making during manual interventions.
Multi-terminal Collaboration:
Support LED screen notifications in factory areas and mobile app alerts (as per search results on remote monitoring features), enabling cross-departmental coordination among production, safety, and equipment teams.
6. Calibration, Maintenance, and Continuous Optimization
Automated Calibration:
Configure zero-point calibration modules and periodically introduce Nâ‚‚ calibration gas to prevent sensor drift (referencing search results on field calibration techniques).
Energy Efficiency Optimization:
Calculate Fan Filter Unit (FFU) operational efficiency using monitoring data, and intelligently adjust energy consumption based on production schedules to achieve energy savings of 15–30%.