What kind of air filtration systems are used in hardwall clean rooms?

What Kind of Air Filtration Systems Are Used in hardwall Clean rooms?

• HEPA Filters

High-Efficiency Particulate Air (HEPA) filters are the cornerstone of air filtration in hardwall clean rooms. These filters are capable of capturing 99.97% of particles as small as 0.3 microns. HEPA filters help maintain ISO5 or better environments, which are required for many pharmaceutical and Semiconductor applications.

• ULPA Filters

Ultra-Low Penetration Air (ULPA) filters offer even higher filtration efficiency than HEPA filters, capturing 99.999% of particles down to 0.1 microns. This level of filtration is essential for clean rooms requiring ISO4 or lower. ULPA filters are often used in applications such as biotechnology and microElectronics, where contamination control is critical.

• Pre-Filters

Pre-filters are used in conjunction with HEPA or ULPA filters to extend the lifespan of the more expensive final filters. These filters typically capture larger particles, such as dust and lint, which can otherwise clog the HEPA and ULPA filters. By removing up to 85% of particles larger than 10 microns, pre-filters help maintain optimal airflow and filtration efficiency.

• Fan Filter Units (FFUs)

Fan Filter Units (FFUs) integrate fans and filters into a single unit, providing a compact solution for air filtration in modular clean rooms. These units can be ceiling-mounted or placed in the walls, allowing for flexible designs. FFUs are capable of delivering high volumes of filtered air, often exceeding 400 cubic feet per minute (CFM), making them suitable for maintaining ISO5 environments.

- ISO 14644-1: This standard provides the classification of air cleanliness by particle concentration.

- iso 14644-2: This outlines the monitoring and control of clean room environments.

- ISO 14644-3: This details the test methods for measuring the cleanliness of clean rooms and controlled environments.

- FED-STD-209E: Although it has been superseded by ISO standards, this federal standard provided guidelines for Clean Room Classifications and is referenced in many older protocols.

- GMP (Good Manufacturing Practice): These guidelines ensure that products are consistently produced and controlled according to quality standards, including clean room specifications.

What are the Air Requirements for a Clean Room?

1. Temperature Control

Maintaining a consistent temperature is crucial in clean rooms. Ideal temperatures typically range from 20°C to 22°C (68°F to 72°F), depending on the specific application and materials involved.

2. Humidity Levels

Humidity control is vital for preventing static electricity and product degradation. Clean rooms usually require relative humidity levels between 30% to 60%, ensuring optimal conditions for sensitive processes.

3. Air Changes Per Hour

Clean rooms must have a specific air change rate to maintain air quality. Typically, 20 to 60 air changes per hour are necessary, depending on the cleanliness class and operational requirements.

What are the Different Types of Air Flow in a Clean Room?

• Laminar Flow

Laminar flow provides uniform airflow in a straight line, minimizing turbulence and contamination. This type of airflow is essential for applications requiring the highest cleanliness levels, such as semiconductor manufacturing.

• Turbulent Flow

Turbulent flow mixes air in a less predictable manner, which can be beneficial in certain clean room environments. While it may not achieve the same cleanliness as laminar flow, it can provide adequate air change rates.

• Unidirectional Flow

Unidirectional flow systems direct air in a single direction, typically from the ceiling to the floor. This design helps maintain a consistent clean environment by reducing the risk of particle accumulation.

• Non-Unidirectional Flow

Non-unidirectional flow systems allow for more flexible airflow patterns. While they may be less efficient in maintaining cleanliness, they can be suitable for applications with lower contamination sensitivity.

What is the Ventilation Rate for a Clean Room?

Definition of Ventilation Rate

The ventilation rate refers to the amount of outside air supplied to a modular cleanroom. This is critical for diluting contaminants and maintaining desired air quality levels as per cleanliness standards.

Typical Ventilation Rates

Clean rooms typically require ventilation rates ranging from 20 to 60 air changes per hour. This ensures that airborne contaminants are effectively removed and replaced with filtered air.

Factors Affecting Ventilation Rates

Several factors affect ventilation rates, including the clean room's size, the number of occupants, and the types of processes being conducted. These should be carefully evaluated during design.

How to Ventilate a Clean Room?

1. Air Filtration Systems: Effective ventilation begins with high-efficiency particulate air (HEPA) or ultra-low penetration air (ULPA) filters. These systems capture particles and ensure that the air supplied to the clean room meets required cleanliness standards.

2. Design for Airflow: Proper airflow design is essential for effective ventilation. Clean rooms are often designed with unidirectional airflow patterns that help maintain clean air distribution and minimize contamination risks.

3. Monitoring Systems: Continuous monitoring of airflow, temperature, and humidity is vital for maintaining clean room conditions. Advanced sensors and control systems can alert operators to any deviations from established parameters.

4. Maintenance Protocols: Regular maintenance of ventilation systems is crucial to ensure optimal performance. This includes routine filter changes, system checks, and cleaning to prevent contamination buildup and ensure air quality.

What Is a Clean Room in HVAC?

1. HVAC Role in Clean Rooms

HVAC systems play a critical role in maintaining the controlled environment of a clean room. They manage air filtration, temperature, humidity, and airflow to meet stringent cleanliness standards.

2. Importance of Air Filtration

Air filtration is a key component of clean room HVAC systems. High-efficiency filters help remove contaminants and prevent them from entering the clean room, ensuring compliance with cleanliness classifications.

3. Design Considerations

When designing HVAC systems for clean rooms, factors like airflow patterns, pressure differentials, and energy efficiency must be considered. Proper design helps maintain the desired environment while optimizing energy use.