How To Control The Cleanliness in A Clean Room Through Airflow Organisation?

In Cleanrooms, Operating Rooms, Laboratories and other environments with high requirements for air cleanliness, CFD airflow organisation is one of the key factors in controlling cleanliness. Through reasonable airflow organisation design, airborne particles, microorganisms and other pollutants can be effectively controlled to ensure that the environment meets the required cleanliness standards.

1. Choose the right type of airflow organisation

Unidirectional flow (laminar flow): Air flows in a single direction at a uniform velocity, usually vertically from the ceiling to the floor. This type of airflow organisation can effectively prevent the spread of pollutants, and is suitable for areas with high cleanliness requirements (e.g. ISO 5 Cleanrooms or higher ), such as Operating Theatres and semiconductor production lines.

Non-unidirectional flow (turbulence): The arrangement of turbulent airflow channels air through high-efficiency filters to the room before sending it out from the return air outlet. The selected airflow organization works best when the establishment demands minimum levels of cleanliness such as electronic plants alongside general laboratories.

2. Reasonable design of airflow path

Optimise the layout of air supply and return vents: According to the cleanliness requirements, reasonably arrange the position, number and size of air supply and return vents to ensure even distribution of airflow and avoid dead ends and eddies.

Control wind speed and direction: Maintain appropriate wind speed in critical areas to control the diffusion of particles and pollutants. Adjust the wind speed and direction of the air supply outlets to make the air flow according to the predetermined path.

3.Maintaining differential pressure control

Positive pressure control: To maintain the clean room internal air pressure is higher than the external environment, to prevent the entry of external pollutants, applicable to most clean.

Negative pressure control: To make a specific area air pressure lower than the surrounding area, to prevent the leakage of internal pollutants, commonly used in the production of harmful substances in the region.

4. Airflow organisation optimisation strategy

Reduce the dead space of airflow: The dead space of airflow must be minimized by organizing air supply and return air outlets correctly so pollutants can move rapidly away from the area.

Controlling pollutant sources: The placement of return air outlets relative to pollutant sources and equipment (personnel) helps to decrease their pollutant dispersal range.

Use of high-efficiency filters: To achieve clean air delivery the facility should use HEPA Boxes together with ultra-high-efficiency filters (ULPA) for air supply and return systems to trap tiny particles in the air circulation system.

5. Real-time monitoring and dynamic adjustment

Installation of monitoring system: Real-time monitoring of indoor cleanliness, wind speed, differential pressure and other parameters, timely detection and treatment of abnormalities.

Dynamic simulation and optimisation: Using computer software to simulate the airflow distribution, find out the problems in advance and make optimisation adjustment.

6. Application cases

Operating theatre: The surgical area maintains protection through vertical unidirectional flow systems which preserve clean air to decrease surgical infection risks.

Electronic Manufacturing Workshop: Production equipment and work zones in Electronic Manufacturing Workshop benefit from horizontal unidirectional flow design which protects against particulate contamination.

Summary

The air cleanliness in a Clean Room can be effectively controlled through reasonable airflow organisation design. The key lies in choosing the appropriate airflow organisation (unidirectional or non-unidirectional flow), optimising the location of air supply and return outlets, controlling the airflow rate and the number of air changes, and verifying the effectiveness of the airflow organisation through testing. Together, these measures ensure that the Cleanroom meets the required cleanliness standards and satisfies the requirements of production and experimentation.