What is FFU?
FFU, the full name in English is Fan Filter Unit, and in Chinese it is fan filter unit-. It is an air purification treatment equipment composed of a fan, a high-efficiency (or ultra-high-efficiency) air filter, a box and a control unit. It has a certain module size and standard specifications, and is installed with a standard keel.
Simply put, FFU is a modular air supply device with its own power and filtering function. The fan sucks the air from the top of the FFU, filters it with a high-efficiency filter, and sends it out at a uniform wind speed over the entire air outlet surface. FFU can be connected and used in a modular manner, and is widely used in clean rooms, clean workbenches, clean production lines, assembled clean rooms and local level 100 applications.
Since different clean rooms have different requirements for cleanliness level, installation space, energy consumption, control methods, etc., FFU has derived many types in practical applications. Understanding these classifications is the first step to correct selection.
The main classification methods of FFU
1. Classification according to structural form
FFU can be divided into three types according to structure: integral type, split type and filter bottom type.
Integral FFU : The fan and filter are integrated in the same box. It has good sealing performance, can effectively prevent leakage, has lower noise and vibration, and is suitable for clean rooms with high sealing and stability requirements.
Split FFU : The fan and filter can be separated, making filter replacement more convenient, installation and maintenance less labor-intensive, and more energy-saving and environmentally friendly.
Filter bottom-mounted FFU : The filter is installed from below, and maintenance personnel can replace the filter from the clean room side without entering the ceiling space, which reduces maintenance difficulty and the risk of clean room contamination.
2. Classification by motor type (drive mode)
The motor is the core component of FFU. According to the type of fan, it can be divided into alternating current (AC) system and direct current (EC) system.
AC FFU : uses AC motor, which can be divided into single-phase and three-phase. The AC single-phase motor is code-named A1, and the AC three-phase motor is code-named A3-. AC motors are relatively low cost and suitable for conventional clean rooms that do not require high energy efficiency.
EC DC FFU : Adopts EC (electronically commutated DC brushless) motor-. Compared with AC motors, EC motors have the advantages of energy saving (usually 30%-50% energy saving), low noise (can be as low as 57dB or less), and long life (up to 100,000 hours of trouble-free operation). EC motors can also achieve stepless speed regulation, making the control more precise and flexible. They are the first choice for large-scale clean rooms and long-term operation projects.
At present, more and more new clean room projects tend to choose EC motor FFU. Although the initial investment is slightly higher, the long-term energy saving benefits are significant.
3. Classification by filter efficiency
The core function of FFU is to filter particulate matter in the air. According to the type of filter it is equipped with, it can be divided into high-efficiency filter (HEPA) and ultra-high-efficiency filter (ULPA).
HEPA FFU : Equipped with a high-efficiency filter (HEPA), the filtration efficiency for 0.3μm particles is ≥99.97%-. It is suitable for scenes with ISO level 5 and above cleanliness levels, such as conventional clean rooms, electronic production lines, pharmaceutical workshops, etc. The code name of the high efficiency filter is H-.
ULPA FFU : Equipped with ultra-high efficiency filter (ULPA), the filtration efficiency for 0.12μm ultra-fine particles is ≥99.9995%-. Suitable for scenarios with ISO 1-3 ultra-high cleanliness requirements, such as semiconductor fabs, nanotechnology research, aerospace, etc. The code name of ultra-high efficiency filter is U-.
FFU with pre-filter : There is a coarse-effect pre-filter at the unit inlet, code-named P-. The pre-filter can intercept large particles and extend the service life of high-efficiency/ultra-high-efficiency filters. It is suitable for environments with poor outdoor air quality or high particle concentration.
There are also different choices of filter paper materials for filters. Common ones include ultra-fine glass fiber and PTFE (polytetrafluoroethylene). PTFE filter paper has lower resistance and longer service life, and is suitable for scenarios with higher requirements on energy consumption and operation and maintenance costs.
4. Classification according to control methods
The control method of FFU determines the flexibility and intelligence level of its operation. According to different control methods, they can be divided into the following categories:
Single working mode unit (code S) : Fixed gear operation, suitable for scenarios where cleanliness requirements are stable and frequent adjustments are not required.
Multi-speed switch control : Provides three-speed or five-speed local control options, and the operator can manually switch gears as needed -
Stepless speed control : Continuously adjustable wind speed control is achieved through voltage regulation or frequency conversion, with higher control accuracy.
Remote control : Supports 0-10V, MODBUS, RS485 and other communication protocols, and can be remotely adjusted through the central control system.
Computer group control : Connect a large number of FFUs to a unified group control system to achieve centralized monitoring and intelligent management. Aili Industrial's intelligent group control system software and hardware are all independently developed, supporting centralized management and control of up to 100,000 FFUs, and can dynamically adjust operating parameters according to cleanliness requirements to achieve energy-saving operation and maintenance.
5. Classification by box thickness
Installation space is an important constraint for FFU selection. According to the thickness of the box, it can be divided into standard type and ultra-thin type.
Standard FFU : The thickness is usually between 250-350mm, suitable for clean rooms with sufficient ceiling space.
Ultra-thin FFU : The thickness can be as thin as 200mm or even 70mm-. Ultra-thin FFU is specially designed for scenarios with limited installation space, such as the top mezzanine of semiconductor equipment (often only 80-150mm space). The 70mm ultra-thin FFU launched by Aili Industrial uses a self-developed 28mm flat motor and an ultra-thin flow channel optimized by CFD simulation to achieve excellent air supply performance in an extremely thin space.
6. Classification according to unit static pressure
According to the different static pressure of the unit, FFU is divided into standard static pressure type and high static pressure type.
Standard static pressure type (code S) : suitable for conventional clean rooms, the air pressure meets the standard air duct resistance and filter resistance requirements -.
High static pressure type (code H) : suitable for high resistance filtration systems or scenarios requiring long-distance air supply ducts. Under high static pressure conditions, FFU requires stronger fan capacity to overcome system resistance and maintain rated air volume.
7. Classification by box material
The box material of FFU affects its durability, anti-corrosion ability and applicable environment. Common materials include:
Galvalume plate : standard configuration, economical and durable, suitable for most conventional clean rooms.
Stainless steel (SUS304/316) : corrosion-resistant, easy to clean, suitable for GMP clean workshops in pharmaceuticals, food, medical and other industries that have strict requirements on hygiene and anti-corrosion.
Steel plate sprayed with plastic : The surface is sprayed with plastic, which has a certain anti-corrosion ability and beautiful appearance.
Aluminum alloy : lightweight design, suitable for installation scenarios with special weight requirements.
8. Classification by module size
FFU uses standard module sizes to facilitate modular installation -. Common module sizes include -:
600×600mm (2×2 feet): suitable for small area scenes such as local clean areas, laboratories, clean workbenches, etc.
1200×600mm (4×2 feet): mainstream size in the market, suitable for ISO 5-7 clean rooms such as semiconductors, panel displays, pharmaceuticals, etc.-
1200×900mm (4×3 feet): suitable for large-area clean room ceiling installation
1200×1200mm (4×4 feet): suitable for high cleanliness and large area clean rooms
In addition, many FFU manufacturers also provide non-standard customized size services to meet the installation needs of special equipment or special-shaped spaces.
How to choose the appropriate FFU type?
Faced with so many classification dimensions, it is recommended to gradually filter in the following order when selecting:
First look at the installation space : Is the ceiling height sufficient? If space is tight (such as the top mezzanine of semiconductor equipment), give priority to ultra-thin FFU。
Let’s look at the cleanliness level : If you need ISO level 5 or above, choose HEPA FFU ; if you need ISO level 1-3, choose ULPA FFU.。
Then look at the budget and operating costs : For large-scale clean rooms that operate for a long time, is preferred EC motor FFU . The energy-saving benefits will cover the initial price difference within a few years.
Next, look at the control requirements : choose single machine control for small scale, choose intelligent group control system for large scale。
Finally, look at the environmental requirements : choose for pharmaceuticals/food stainless steel boxes , and galvanized sheets for normal environments.
FFU seems simple, but in fact it has a wealth of choices in multiple dimensions such as structure, motor, filtration, control, size, and material. The correct selection can not only ensure the stable operation of the clean room, but also save considerable energy consumption and maintenance costs in long-term operation.
Aili Industry—Full industry chain FFU manufacturer
Aili Industrial has been deeply involved in the field of clean room equipment for nearly two decades. From fan winding, box processing to control system development, the entire industry chain independently manufactures FFU fan filter units. The products cover a full range of standard, ultra-thin, energy-saving (EC motor), group control, and stainless steel types, supporting full-dimensional customization in size, material, motor, control method, filtration level, etc., and adapting to the different cleaning needs of 13 major industries including semiconductors, panel displays, pharmaceuticals, food, and data centers.
If you need FFU selection suggestions or customized solutions, please contact the professional technical team of Aili Industry.
