What is FFU? Structure, working principle, application scenarios and selection guide

FFU is a kind of clean air equipment that combines fans, air filters, boxes and control functions . It is mainly used to continuously deliver filtered air to clean rooms, clean sheds, production equipment or local clean areas.

When FFU is running, the fan sucks air into the box and establishes air flow and pressure. After the air passes through the HEPA or ULPA filter, the particles in it are filtered, and then sent to the target clean area from the air outlet surface.

FFU basic workflow: air enters → fan establishes air flow → HEPA/ULPA filtration → clean air is sent out → enters the target clean area

FFU can be used as a single device or as a system composed of dozens, hundreds or even more devices. Different projects need to be configured according to the cleanliness level, installation space, air volume and speed, filtration efficiency and control method.

1. What is the main function of FFU?

The main function of FFU is to continuously provide filtered air to designated areas and cooperate with clean rooms or production equipment to form the required clean environment.

Therefore, FFU is not just a 'fan + filter', but an air handling unit in the clean air system.

2. How does FFU work?

The working principle of FFU is not complicated.

After the equipment is started, the motor drives the fan to run, and air enters the box from the FFU air inlet area. The fan powers the air flow, allowing the air to overcome filter and system resistance.

The air then passes through a HEPA or ULPA filter, which filters out particulate matter in the air.

The filtered air is sent from the FFU outlet surface to the clean area.

The whole process can be summarized as:

The motor drives the fan → the fan establishes air volume and pressure → the air passes through the filter → particles are filtered → clean air is sent out

When a large number of FFUs are installed on the top of the clean room, they can jointly provide filtered air to the clean area through reasonable system configuration.

3. What are the main parts of FFU?

Common FFU mainly include cabinets, motors, fans, filters, control systems and air inlet and outlet structures.

There is a direct relationship between these components.

The filter generates resistance → the fan overcomes the resistance and provides air volume → the motor drives the fan → the control system adjusts the operating status → the box forms an internal air channel

Therefore, FFU selection should be considered from the perspective of the entire machine, rather than just looking at one of its components.

4. What is the relationship between FFU and HEPA?

FFU and HEPA are not the same product.

FFU is an air filtration device with a power system, and HEPA is an air filter used for particle filtration.

It can be simply understood as:

FFU = fan system + cabinet + control system + HEPA/ULPA filter

Among them, the fan is responsible for the continuous flow of air, the filter is responsible for filtering particulate matter, and the control system is responsible for equipment operation management.

Therefore, whether the FFU can achieve the designed air volume cannot only depend on the fan, nor can it only depend on the filter.

The fan air volume, air pressure and filter resistance need to be reasonably matched.

5. Should FFU be equipped with HEPA or ULPA?

FFU can configure different levels of filters according to clean environment and process requirements.

Which one to choose requires comprehensive consideration:

Cleanliness level → Process requirements → Particle control requirements → Filter resistance → Target air volume → FFU fan capacity

It should be noted that higher filtration efficiency is not suitable for all projects.

After the filtration level and filter structure change, parameters such as resistance may also change, so the matching between the fan and filter needs to be reconsidered.

6. What is the relationship between FFU air volume and wind speed?

In FFU selection, air volume and wind speed are two parameters that often appear.

Air volume represents the volume of air passing through the equipment per unit time.

Wind speed represents the speed of air passing through a specified section.

Under simplified conditions:

Air volume = effective air outlet area × average wind speed

Therefore, for FFU with the same air outlet area, when the average wind speed changes, the corresponding air volume will also change.

Actual projects also need to consider filter resistance, box structure, system resistance and measurement methods.

Therefore, when purchasing FFU, it is not recommended to just ask 'What is the wind speed?', you should also confirm:

7. What are the common driving methods for FFU?

According to different motor and drive solutions, FFU commonly has AC, DC, EC and other forms.

Different solutions have differences in speed regulation methods, control methods, input power, operating characteristics, and project costs.

For projects that require long-term operation or air volume adjustment according to production status, you can focus on fan efficiency and control methods.

For example, some DC or EC solutions can adjust the speed according to actual working conditions:

Normal production → Working speed | Reduced demand → Reduce operating speed | Maintenance status → Shut down or designated equipment operation

When the fan speed changes, the air volume, wind pressure and input power will also change with the operating point.

The actual energy-saving effect is related to fan characteristics, system resistance, operating time and control strategy, and should be calculated or tested based on specific projects.

8. Can FFU be controlled centrally?

Can.

A small number of FFU can be controlled in a relatively simple way.

When dozens, hundreds or even more FFUs are installed in a clean room, centralized control can be adopted depending on the project scale.

The group control system can be implemented according to configuration:

Partition management → Start and stop control → Fan speed setting → Working mode → Duty mode → Single machine status management

Aili Industrial can configure corresponding control solutions based on the number of FFU and project scale.

Small projects can use corresponding controllers; larger projects can be configured with computer group control according to the system design to facilitate the unified operation and management of a large number of FFUs.

9. What is the difference between FFU and EFU?

Both FFU and EFU can be used for clean air filtration, but the product structure and application direction are different.

Traditional FFU is widely used in clean room ceilings and larger clean areas.

EFU is designed more based on the local cleaning requirements of the equipment.

Therefore it can be simply understood as:

The overall cleanliness of the clean room → Focus on FFU | Partial cleanliness on the equipment side → EFU can be further considered

The final decision still needs to be made based on the installation space, target air volume, filtration level and equipment structure.

10. In which industries is FFU mainly used?

FFU has been used in a variety of production and experimental environments that require air cleanliness.

Different industries may have different requirements for the cleanliness level, air volume, wind speed, filtration efficiency, size, material and control method of FFU.

Therefore, FFU should be configured according to the specific application, rather than using the exact same product parameters for all industries.

11. How to choose FFU?

It is recommended to confirm at least the following 10 parameters when selecting FFU.

If it is a semiconductor equipment or automation equipment application, you also need to confirm:

Equipment internal space → Allowable installation height → Inlet and outlet air direction → Equipment structure → Target clean area → Actual operating conditions

Then decide whether to use regular FFU or device-side EFU.

12. Why can’t we just compare prices for FFUs of the same size?

Two FFUs with the same external dimensions do not mean that the internal configuration and overall machine parameters are exactly the same.

Therefore, when purchasing FFU, a more reasonable comparison method is:

Size + air volume + wind speed + filtration level + residual pressure + power + control method + material + installation method

By comparing different solutions under the same project requirements and technical conditions, it is easier to judge whether FFU is truly suitable for the project.

13. Aili Industrial FFU manufacturing and supporting capabilities

Aili Industry focuses on R&D and manufacturing of FFU, EFU and clean air equipment.

In the FFU product system, it covers:

Motor→Fan→Control system→HEPA/ULPA filter→Sheet metal→Complete machine assembly and testing

This product system is conducive to collaborative matching of different components according to the operation requirements of the FFU machine.

For standard and non-standard projects, product configuration can be carried out based on the installation size, target air volume, wind speed, filtration level, control method and actual use environment.

14. FFU Frequently Asked Questions FAQ

What is FFU?

FFU is a kind of clean air equipment that combines a fan, air filter, box and control functions. The fan drives the air through the HEPA or ULPA filter, and then sends the filtered air into the target clean area.

What is the main function of FFU?

FFU is mainly used to continuously provide filtered air to clean rooms, clean sheds, production equipment and local clean areas.

Is there HEPA in FFU?

Common FFU can be configured with HEPA according to project requirements, and some high-cleaning applications can also be configured with ULPA. The specific filtration level needs to be determined based on cleanliness requirements and process conditions.

What is the difference between FFU and HEPA?

FFU is an air filtration device with fan power, while HEPA is an air filter and can be used as a filter component in FFU.

What is the difference between FFU and EFU?

FFU is widely used in clean rooms and clean areas. EFU is more structurally designed based on the local cleanliness requirements of the equipment end. The final decision needs to be based on the installation space, air volume and equipment structure.

Can FFU adjust the wind speed?

Some FFUs can achieve speed adjustment through corresponding fans and control systems. The specific speed adjustment method needs to be determined according to the product configuration.

Can FFU be controlled centrally?

Can. Multiple FFUs can use centralized control or computer group control according to the project scale to achieve partition, start-stop, speed and operating status management.

How often should FFU filters be replaced?

There is no fixed period that applies to all projects. The service life of the filter is related to factors such as ambient particle concentration, operating time, air volume, resistance changes, and maintenance management, and should be judged based on the actual operating status.

Does FFU mean that the higher the wind speed, the better?

no. The wind speed needs to be determined comprehensively based on the cleanliness level, production process, equipment requirements, noise, energy consumption and system design.

Can FFU customize the size?

Non-standard size matching can be carried out according to the project installation space, air volume, filter and structural requirements. The specific plan needs to be determined based on the actual project parameters.

15. Summary of FFU selection

If you need to quickly determine how to choose FFU, you can follow the following sequence:

Application scenario → Cleanliness requirements → Installation dimensions → Air volume and wind speed → HEPA/ULPA filtration level → System resistance → Fan matching → Drive mode → Control mode → Material and installation structure → Confirmation of complete machine parameters

For clean rooms, semiconductor equipment, electronic manufacturing, lithium batteries, photovoltaics, and other clean air projects, FFU needs to be configured based on actual working conditions, rather than determining products based only on one size or wind speed parameter.

Aili Industrial can focus on FFU, EFU, HEPA/ULPA filters and control systems, and match products according to the installation space, air volume, wind speed, filtration level, system resistance, control method and usage environment of the project.

Related products

FFU fan filter unit ｜ EFU equipment side fan filter unit ｜ HEPA/ULPA high efficiency filter ｜ FFU group control system

Related reading

What are the main components of FFU? Detailed explanation of fans, filters and control systems | How to choose FFU? What parameters are recommended to confirm before purchasing | What is the relationship between FFU air volume and wind speed | Should FFU choose AC, DC or EC | What is the difference between FFU and EFU