What is BFU? BFU Maintenance Process

A cleanroom is a constructed and controlled environment designed to minimize the ingress and retention of particles in the air, while also controlling other relevant parameters in the room such as temperature, humidity, and pressure when necessary. BFU – Blower Filter Unit is one of the crucial, indispensable devices in cleanrooms. So, what exactly is BFU? How is the structure and operation principle of BFU in cleanrooms? Let’s explore with INTECH Service in the following article!

What is BFU?

BFU stands for Blower Filter Unit, a vital component in the cleanroom system. BFU functions as a forced air filter, providing a clean air stream and removing dust, bacteria, and other small particles from the air in the cleanroom.

BFU typically consists of a fan and a filter (HEPA or ULPA) combined to form a modular end-unit device with self-contained power supply and filtration.

BFU can operate independently at each door, reducing installation handling, and can achieve cleanliness levels from class 100 to 10,000 as a fan filter unit, ensuring high cleanliness, especially effective in generating clean air for high-level cleanrooms.

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Structure of BFU

A cleanroom BFU consists of three main components: fan, air filter, and air diffuser box.


Provides energy to blow air through the filter.

Speed control system allows adjusting air volume and pressure, optimizing efficiency and energy savings.

The fan operates at high speed, ensuring a strong and efficient air flow, while minimizing noise and creating a comfortable working environment.

Air Filter:

HEPA/ULPA filters can remove fine dust particles and microorganisms with high efficiency.

HEPA removes at least 99.97% of particles sized 0.3 micrometers (µm), while ULPA has higher efficiency, removing up to 99.999% of particles sized up to 0.12 µm.

Various filter materials such as glass fiber, PTFE, PP, each suitable for different needs and usage environments.

bo loc hepa bfu

Air Diffuser Box:

Electrostatically painted steel frame creates a sturdy, aesthetic design, supporting and protecting components inside the BFU.

Protective casing made of electrostatically painted steel or corrosion-resistant material ensures durability and easy cleaning.

Efficient air diffuser design helps to evenly distribute air flow in the cleanroom, reducing noise from the fan.

Additionally, BFU may include control units, sensors, and indicator lights for monitoring and displaying operational status.

Operation Principle of BFU

A cleanroom BFU operates as a selective air exchange process inside and outside a large area, applying the latest cleanroom safety theory. Air containing dust and contaminants is expelled outside, while air from the environment is introduced into the room.

Through the HEPA filter, air containing coarse dust or contaminants from 0.3 microns is expelled to maintain the quality of air in the cleanroom. Therefore, Blower Filter Unit (BFU) should be placed in large-space rooms to ensure clean air and cost-effectiveness.

nguyen ly hoat dong bfu

Applications of BFU in Cleanroom

BFU has the lowest noise and cost compared to other air filtration devices on the market. Therefore, it is commonly used in large cleanrooms ranging from class 100 to 30,000, such as semiconductor manufacturing plants, electronics, or locations with high air quality control requirements.

Advantages and Disadvantages of BFU


BFU utilizes HEPA filters capable of removing 99.97% of dust particles sized 0.3 microns or larger.

High working efficiency, low power consumption, leading to cost savings.

Integrated duct redirection system reduces noise and pressure loss, enhancing fan efficiency.

Optimized airflow diffusion due to aerodynamics.

Flexible with various HEPA and ULPA filter types.

The centrifugal fan used in fan filter units can provide a large air volume and high static pressure conditions, with a lifespan of up to 50,000 hours.

Suitable for use in cleanrooms classified as Class 1-1000 according to ISO 14644-1 standards.

Especially suitable for assembly into ultra-clean production lines, can be arranged according to process requirements for single-use or multiple-use assembly lines.

Easy airflow speed control using various control methods.

Minimal noise during operation.

Easy installation and construction.


Initial investment costs may be higher as BFU has a higher price compared to conventional air filters.

BFU generates noise during operation, which may affect the surrounding environment. Consider using low-noise BFU for areas requiring high quietness.

The filtration efficiency of BFU may be affected by installation location, so it is necessary to arrange BFU reasonably to ensure optimal filtration efficiency.

BFU Maintenance Process

Establishing and implementing maintenance, repair, and equipment inspection procedures can save a significant amount of time. BFU is one of the crucial devices in HVAC and cleanroom systems, so it is essential to develop equipment maintenance and repair procedures to improve BFU operational efficiency, minimize costs, and ensure smooth and safe production operations. Typically, the BFU maintenance and servicing process will include the following steps:

Step 1: Maintenance Planning

Usually conducted by the technical department, this step includes creating a checklist system regarding the maintenance time for each device according to the manufacturer’s specifications.

Step 2: Maintenance Recommendation, Repair Proposal (if necessary)

Step 3: Approval and Implementation

Step 4: Maintenance/Repair Execution

This task will be carried out by skilled and competent technical teams, ensuring compliance with the plan and schedule.

Step 5: Measurement and Acceptance

After completing the inspection, maintenance, and repairs, document the entire process thoroughly. Information needs to be carefully stored, noting the next maintenance milestones, to avoid missing crucial maintenance points.

If you are struggling to find a reliable, competent, and experienced unit in the maintenance/repair/inspection of BFU, contact us – INTECH Service for consultation and support. INTECH Service is proud to be one of the leading units today in providing BFU maintenance, servicing, as well as cleanroom equipment and solutions for businesses.