Air Filters

What air filters are used in clean rooms?

Air filter refers to the air filter device, which is generally used in clean workshop,laboratory and clean room, or used for dust prevention of electronic machinery communication equipment. There are primary filter, medium efficiency filter, high efficiency filter and sub high efficiency model. Different models have different standards and performance.In clean rooms, High-Efficiency Particulate Air (HEPA) filters and sometimes Ultra-Low Particulate Air (ULPA) filters are commonly used to maintain the required level of air cleanliness.

1. High-Efficiency Particulate Air (HEPA) Filters: These filters are designed to remove at least 99.97% of particles that are 0.3 micrometers in diameter, which includes most bacteria and viruses. HEPA filters trap contaminants through a combination of mechanisms including interception, impaction, and diffusion. They are essential for controlling airborne particle contamination in clean room environments.

2. Ultra-Low Particulate Air (ULPA) Filters: ULPA filters provide even higher levels of filtration efficiency, capturing at least 99.999% of particles as small as 0.1 micrometers. These filters are often used in applications where extremely low particulate counts are necessary, such as semiconductor manufacturing or certain biotechnology processes.

In addition to these primary filters, other types of filters may be used in the clean room's HVAC system:

• Pre-Filters: These are typically coarse filters that capture larger particles to protect the more expensive and sensitive HEPA/ULPA filters from rapid clogging.

• Activated Carbon Filters: Although not primarily designed for particle removal, they can be included to absorb volatile organic compounds (VOCs) and odors.

• Blower Filter Units (BFUs): In some cases, fan-filter units (FFUs) or laminar flow hoods directly integrate HEPA/ULPA filters into their design to create unidirectional airflow patterns critical for maintaining cleanroom standards.

Clean room air handling systems will have multiple stages of filtration and are designed to ensure that the filtered air is distributed evenly throughout the space to maintain consistent cleanliness levels. The selection of filters depends on the specific requirements of the clean room class, according to ISO 14644 standards or Federal Standard 209E (FS209E), depending on the industry and location.