Cleanroom Airflow Principles

Cleanroom airflow is a core functional component in achieving a cleanroom controlled environment. Proper airflow management helps minimize the presence of airborne contaminants, ensuring the integrity and quality of sensitive products and processes.Below are three common modes of operation for cleanroom airflow:

Airflow Pattern

Laminar Flow: Vertical Flow from Top to Bottom
Turbulent Flow: Mixed Flow

Air Change Rate (ACH)

The higher the cleanroom class, the higher the air change rate.
For example, an ISO Class 5 cleanroom may require an ACH of 240 or higher.

Filtration

HEPA Filter
ULPA Filter

Environment

Temperature and Humidity Control: Varies, but typical:
Temperature: 18-24°C (64-75°F), Relative
Humidity: 30-60%.

External air introduction:
The fresh air system introduces a large amount of fresh air from the outside.
Air filtration:
The air is deeply filtered through HEPA or ULPA filters to ensure that the cleanliness meets the required ISO level.
Air distribution:
Laminar flow (such as unidirectional flow) or mixed flow is usually used to maintain the uniformity and fluidity of indoor air.
Airflow exhaust:
In the fresh air system, most of the air will be exhausted, and the air is reintroduced.

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Air supply from air conditioner:
The air treated by the air conditioner is sent to the return air layer
Air filtration:
The air is deeply filtered through HEPA or ULPA filters to ensure that the cleanliness meets the required ISO level.
Air distribution:
Laminar flow (such as unidirectional flow) or mixed flow is usually used to maintain the uniformity and fluidity of indoor air.
Air return:
The clean room air passes through the return air layer, and 15% of the return air returns to the air conditioner for further treatment

FFU fan:
External air is driven by the FFU fan to be sent in
Air filtration:
The air is deeply filtered through HEPA or ULPA filters to ensure that the cleanliness meets the required ISO level.
Air distribution:
Laminar flow (such as unidirectional flow) or mixed flow is usually used to maintain the uniformity and fluidity of indoor air.
Air exhaust:
Clean room air is discharged through a pressure relief valve or a floor elevated layer

FAQ

Q:What is the air flow in a clean room?
A:Airflow in a cleanroom refers to the controlled movement of air that helps maintain a specified level of cleanliness by minimizing contamination from airborne particles, microorganisms, and other pollutants. The design and management of airflow are critical components of cleanroom operation,

Q:How do you calculate cleanroom airflow?
A:Calculating cleanroom airflow involves determining the necessary airflow rates to achieve specific cleanliness levels and maintain optimal environmental conditions. Several factors need to be considered in this calculation, including the cleanroom volume, the required air change rate (ACH), and the design of the ventilation system.

Q:What is the flow rate of a clean room?
A:The flow rate of a cleanroom refers to the volume of air that is supplied to or removed from the cleanroom per unit of time, typically measured in cubic feet per minute (CFM) or cubic meters per hour (m³/h). The specific flow rate required for a cleanroom depends on several factors, including the cleanroom's size, desired cleanliness level, air change rate (ACH), and the specific design of the ventilation system.

Q:What is the first air rule means the air in a cleanroom?
A:The term "first air" in cleanroom environments refers to the clean, filtered air that is first introduced into the cleanroom space, typically coming directly from HEPA (High-Efficiency Particulate Air) or ULPA (Ultra-Low Penetration Air) filters.

Cleanroom Airflow Principles

FAQ

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