What types of fan filter units are there?

Fan filter units (such as FFU, BFU, etc.) can be classified into various types based on different classification criteria. The following is a detailed introduction to their main types and features from dimensions such as application scenarios, filtration efficiency, power methods, and structural characteristics:
1. Classification by application scenarios and cleanliness levels
Industrial-grade fan filter unit
Features: It is suitable for scenarios with strict requirements for dust particles, such as electronic manufacturing, semiconductors, and photovoltaics. The cleanliness level usually reaches ISO 5 (10,000 grade) to ISO 1 (10 grade).
Typical applications: Semiconductor wafer production workshops and LCD panel clean rooms, where particles smaller than 0.1μm need to be filtered. High-efficiency filters (HEPA) or ultra-high-efficiency filters (ULPA) are often used in combination.
2. Medical-grade fan filter unit
Features: Emphasizing microbial control, it may be equipped with antibacterial coatings or disinfection modules (such as ultraviolet lamps) to meet the sterility requirements of GMP workshops, operating rooms, and other scenarios.
Typical applications: Sterile filling lines in pharmaceutical factories and laminar flow operating rooms in hospitals, where both bacteria (≥0.5μm) and viruses (≥0.3μm) need to be filtered simultaneously.
3. Laboratory-grade fan filter unit
Features: Designed for the special needs of scientific research experiments, it may have explosion-proof, anti-corrosion, or negative pressure functions (such as biosafety cabinets).
Typical applications: P3/P4 biological laboratories and chemical analysis rooms, where harmful aerosols or volatile organic compounds (VOCs) need to be filtered.
Ii. Classification by filtration efficiency and filter type
HEPA fan filter unit
Filtration efficiency: The filtration efficiency for 0.3μm particles is ≥99.97% (EN 1822 standard), suitable for cleanrooms ranging from Class 10,000 to Class 1,000.
Application scenarios: Electronic assembly workshops, food aseptic workshops.
2. ULPA fan filter unit
Filtration efficiency: The filtration efficiency for 0.12μm particles is ≥99.999%, suitable for clean rooms ranging from Class 100 to Class 10 (such as semiconductor lithography processes).
Features: It needs to be paired with a fan of higher static pressure, and its energy consumption is slightly higher than that of the HEPA type.
3. Composite filtration fan unit
Structure: Integrated pre-filter (G3-G4) + HEPA/ULPA + chemical filter (such as activated carbon).
Function: Besides particles, it can also adsorb gaseous pollutants such as formaldehyde and ozone, and is suitable for semiconductor etching processes and laboratory ventilation.
Iii. Classification by power and control mode
Single-phase/three-phase motor-driven type
Single-phase motor: Suitable for small FFUs (air volume ≤1000m³/h), with low power consumption (about 100-300W), commonly found in laboratories or local purification equipment.
Three-phase motor: Suitable for large BFU (air volume ≥2000m³/h), high static pressure (≥500Pa), and suitable for large clean rooms (such as semiconductor factories).
2. Variable frequency speed regulation type
Features: It achieves step-less speed regulation through a frequency converter (such as 0-100% air volume adjustment), and can automatically adjust according to the load of the clean room, with significant energy-saving effects (saving more than 30% electricity compared to the fixed-speed type).
Control mode: Supports centralized control by PLC or local adjustment through touch screen, and is often used in scenarios where dynamic pressure difference balance is required.
Iv. Classification by Structure and Installation Method
Ceiling-mounted type (standard type)
Installation position: Embedded in the ceiling keel of the clean room (T-Grid), with a downward air supply, is the most common installation method.
Size: The standard size is 1175mm×575mm (corresponding to the internationally recognized keel spacing), and non-standard specifications can also be customized.
2. Floor-standing/mobile
Features: Equipped with a built-in stand or roller, it can be flexibly arranged in a clean area for local purification (such as around equipment, and temporary clean workstations).
Application scenarios: Manual soldering stations for electronic components, and temporary isolation wards in hospitals.
3. Laminar flow hood type
Structure: The top integrates a fan filter unit, and curtains or fences are set up around it to form a local 100-level laminar flow area.
Typical applications: semiconductor chip testing benches, and sterile batching areas in pharmaceutical factories.
V. Special Function Type Fan Filter Unit
Explosion-proof FFU
Design standard: Comply with ATEX or UL 913 explosion-proof certification. The motor and electrical components adopt explosion-proof packaging, suitable for flammable and explosive environments (such as lithium battery workshops).
2. Negative pressure type FFU
Function: A negative pressure zone is formed by reverse air supply to prevent the spread of pollutants. It is often used in biosafety laboratories (BSL-3) or harmful gas treatment rooms.
3. High-temperature resistant FFU
Material: Heat-resistant plastic or metal frames (with a temperature resistance of ≥120℃) are adopted, suitable for baking processes (such as PCB board curing workshops).
Vi. Types of Integration with Other Devices
The FFU is integrated with the air shower.
Application: The air shower area at the entrance of the clean room ensures air purification when personnel enter. The fan filter unit is used for the air supply filter of the air shower nozzles.
2. FFU is integrated with the weighing hood
Scene: Raw material weighing room in a pharmaceutical factory. The fan filter unit provides vertical laminar flow to prevent the spread of drug dust.
Different types of comparison and selection suggestions
Classification dimensions, typical types, core advantages, applicable scenarios
ULPA-type ultra-high efficiency filtration (≥99.999%) for semiconductor photolithography and chip packaging
Power-controlled variable frequency speed regulation type energy-saving, flexible air volume adjustment, large-area clean room, dynamic pressure difference control
The structure is equipped with laminar flow hood type local 100-level purification, flexible deployment of precision instrument operation tables, and temporary clean areas
Special function explosion-proof type to prevent flammable and explosive gases from igniting lithium battery production and chemical workshops
Summary
There are various types of fan filter units, and the core differences lie in filtration accuracy, power performance, structural design, and functional expandability. When making a choice, comprehensive consideration should be given to the cleanroom grade, type of contaminants, installation space, and energy consumption requirements. For instance, in the semiconductor industry, ULPA + high static pressure BFU is preferred, while in medical scenarios, more emphasis is placed on antibacterial and microbial control functions.