How to choose FFU? What parameters need to be confirmed before purchasing?

When purchasing FFU, we often encounter a problem:

Why are FFUs of the same size different in air volume, wind speed, filtration level, control method and even price?

The reason is,The FFU fan filter unit does not determine a box size, and then installs a HEPA filter.

A set of FFU usually involves fans, motors, HEPA/ULPA filters, cabinets, control systems and electrical components . These components need to be matched around actual operating conditions.

Especially in applications such as semiconductor equipment, electronic manufacturing, lithium batteries, and biomedicine, there may also be requirements for ultra-thin EFU, high-wind speed FFU, ULPA filters, and group control of multiple FFUs .

Therefore, a relatively complete set of FFU selection logic should be:

Application scenario → Installation space → Air volume and speed → HEPA/ULPA filtration level → System resistance → Fan and motor → Control method → ​​Box structure → Confirmation of complete machine parameters

The following is a step-by-step description based on the actual project selection process.

1. First determine where FFU is used

The first step in FFU selection is not to ask 'how much does one cost?' but to determine:

Where will FFU be installed?

Because different applications have different requirements for FFU.

For conventional FFU installed on the top of a clean room, the focus is usually on confirming the ceiling module, air volume, filtration level and group control method.

In addition to cleanliness requirements, equipment-side applications such as semiconductor equipment, EFEM, and SMT equipment are also subject to internal installation space limitations of the equipment.

If the structure or height of conventional FFU cannot meet the requirements, further consideration is neededEFU equipment side fan filter unit。

so:

Determine the application scenario first, and then determine the FFU or EFU structure.

2. How to choose FFU size?

The FFU size first needs to match the actual installation structure.

For clean room projects, you can follow:

Ceiling module → Opening size → FFU overall dimensions → Installation method → ​​Maintenance space

Confirm item by item.

For device-side projects, further confirmation is required:

Length | Width | Maximum allowable height | Air inlet space | Air outlet area | Electrical interface | Maintenance space

What is particularly easy to overlook here is the height。

Semiconductor equipment, EFEM, SMT equipment and some automation equipment have mechanical structures, electrical systems, pipelines and process modules internally arranged, and the space left for the air filtration unit may be very limited.

In this case, even if the length and width of the FFU can be installed, it cannot be used if the overall height exceeds the allowable range of the equipment.

For such space-constrained applications, ultra-thin FFU or ultra-thin EFU can be further considered。

The overall height of some of Aili Industrial's ultra-thin EFU solutions can reach about 70 mm, which still needs to be matched according to the target air volume, filter, fan and equipment structure.

therefore:

FFU is the right size ≠ just look at the length and width.

3. How to determine FFU air volume?

Air volume is one of the core parameters in FFU selection.

Simply put, the air volume represents the amount of air delivered by the FFU per unit time.

How much air volume is required for an actual project is usually related to the following factors:

Clean area area | Target wind speed | Number of FFU | Cleanliness requirements | Air flow organization | Production process

Under simplified conditions, it can be understood as:

Air volume = effective air outlet area × average wind speed

For example, if two FFUs of the same size have different required average wind speeds, the corresponding target air volumes will also be different.

Therefore, if you only provide:

'I want 1175×575 mm FFU.'

The information is not complete enough.

It is also recommended to provide:

Installation size + target air volume + target wind speed

Only in this way can the fan, filter and complete machine configuration be further determined.

4. Is the higher the FFU wind speed, the better?

no.

FFU wind speed should be determined based on the clean environment and actual production process.

If the project requires increased wind speed, it will also need to consider:

Increase in wind speed → Change in air volume → Change in fan operating point → Change in wind pressure requirements → Change in input power → Change in noise and airflow organization

Therefore, high wind speed FFU does not simply increase the motor speed.

For example, in some lithium battery production lines, special production equipment or equipment-side clean applications, if higher wind speed is really required, need to be rematched.the fan, motor, filter and internal air flow structure of the box 。

Aili Industrial FFU can match different air volume and wind speed solutions according to actual applications, and the specific parameters should be determined according to the project conditions.

5. Should FFU choose HEPA or ULPA?

Filters are an important part of FFU's ability to control particulate matter.

FFU is commonly configured and can be configuredHEPA/ULPA high efficiency and ultra high efficiency filters。

For conventional high-efficiency particle filtration needs, HEPA filtration grades such as H13 and H14 can be selected according to project requirements; for applications with higher particle control requirements, ULPA filtration grades such as U15, U16 and U17 can be further considered.

Need to pay attention to:

The higher the filtration level, the more suitable it is.

Because in addition to filtration efficiency, you also need to consider:

Rated air volume｜Initial resistance｜Filter material｜Structure｜Sealing method｜Using environment

If your project requires a higher level of particle filtration, learn moreULPA ultra-high efficiency filter is configured based on the target air volume, filter resistance and actual cleanliness requirements.

A more reasonable selection sequence is:

Cleanliness requirements → HEPA/ULPA level → Filter parameters → Resistance → Fan matching → FFU complete machine parameters

6. Why does filter change affect FFU air volume?

Because air will create resistance when passing through a HEPA or ULPA filter.

The fans inside the FFU need to overcome these resistances to maintain the target air flow.

therefore:

Filter changes → Resistance may change → Fan operating point changes → FFU actual air volume may change

This is why we cannot simply think:

'I used to use H13, now I can just switch to ULPA.'

Even if the external dimensions of the filters are the same, filters with different efficiency levels, filter materials, and structures may have different resistance characteristics.

Therefore, when the filter specifications change, the actual operating parameters should be re-confirmed in conjunction with FFU.

7. Why does FFU also look at wind pressure and system resistance?

When purchasing FFU, many people will ask:

'What is the air volume?'

But we should continue to ask:

'Under what resistance conditions is this air volume achieved?'

Because the fan does not operate in an environment without resistance.

During the operation of FFU, you need to overcome:

Filter resistance + FFU internal resistance + project additional resistance

If the FFU needs to overcome special air inlet structures, equipment internal air channels or other external system resistance after installation, further confirmation of the external residual pressure is required.

Therefore, the truly meaningful FFU fan selection should be:

Target air volume + system resistance → Determine the fan operating point

Rather than just comparing 'maximum air volume'.

8. Should FFU choose AC, DC or EC?

FFU can adopt AC, DC or EC power solutions according to different projects.

It is recommended to consider comprehensively when making a specific choice:

For FFU projects that run for a long time and require speed adjustment, different operating states can be further considered.

For example:

Normal production → Working speed | Low demand period → Reduce speed | Shutdown or maintenance → Adjust operating status according to cleanliness requirements

Therefore, there is no unified answer for AC, DC, and EC out of working conditions.

What really needs to be compared is:

Which option is more suitable for the project under the target air volume and actual system resistance conditions.

9. How to control hundreds or tens of thousands of FFUs?

If the clean room only has a small amount of FFU, control is relatively simple.

However, a large-scale clean project may have hundreds, tens of thousands or even more FFUs.

If all relies on manual operation one by one, the later management will be more complicated.

At this time, it can be configured according to the project scale.FFU group control system is implemented according to the system design:

Area division | Unified start and stop | Speed ​​adjustment | Working mode | Duty mode | Single machine control | Running status management

Aili Industrial can configure corresponding control solutions according to FFU and EFU projects of different sizes.

For FFU projects with a large number of projects, it is recommended to plan the control system together in the early selection stage instead of waiting for all FFU installations to be completed before considering control issues.

10. When should you consider ultra-thin EFU?

If it is a traditional clean room ceiling application, conventional FFU can usually be configured according to the ceiling structure.

However, the internal space of semiconductor equipment, EFEM, SMT equipment, and other automation equipment may be limited.

The equipment may already have:

Mechanical structure | Electrical system | Manipulator | Pipeline | Process module | Other functional components

There is not much space left for the air filter unit.

At this time, it is important to confirm:

Available height of equipment | Air volume requirements | Filter thickness | Fan size | Air inlet method | Control interface | Maintenance space

If conventional FFU cannot meet the equipment height restriction, you can further consider ultra-thin EFU。

Ai Li industrial partThe overall height of the ultra-thin EFU solution can be about 70 mm. By overall matching of fans, motors, filters, internal air ducts and control components, it can be used in applications where the internal installation space of the equipment is limited.

Things to note are:

Being ultra-thin does not mean simply lowering the FFU cabinet.

After the overall height is reduced, the fans, motors, filters and internal air flow channels all need to be rematched.

Therefore, the selection logic of the device-side EFU should be:

Equipment space → Cleanliness requirements → Air volume and speed → HEPA/ULPA → Fan → Control system → Overall machine structure

11. Why should semiconductor FFU pay attention to wind speed uniformity?

For ordinary clean areas, total air volume is usually an important parameter.

However, in semiconductor equipment, precision manufacturing and some high-cleaning applications, it may also be necessary to pay attention to the uniformity of the wind speed on the FFU air outlet surface.

Factors affecting wind speed uniformity include:

Fan structure | Fan position | Air duct inside the box | HEPA/ULPA filter structure | Air outlet area | Actual operating air volume

Therefore, device-side FFU or EFU items cannot only provide:

'Need 1000 m³/h.'

If the project has clear requirements for airflow uniformity, these should also be raised during the selection stage.

In this way, the fan, filter and box structure design can be considered simultaneously.

12. How to choose the FFU cabinet material?

The material of the FFU cabinet should be determined based on the actual use environment.

Conventional clean projects can use corresponding metal boxes according to the clean environment and structural requirements.

For some special use environments, stainless steel FFU or other structural solutions may also need to be considered.

The main considerations for material selection are:

Usage environment → Cleanliness requirements → Corrosion risk → Installation structure → Customer technical specifications

Therefore, there is no one box material suitable for all FFU projects.

It should be selected according to the actual application.

13. What parameters are recommended to be prepared before purchasing FFU?

If you are ready to inquire from the manufacturer or select an FFU model, you can first organize the parameters according to the table below.

If you cannot determine all the parameters at the moment, you can also prepare first:

Equipment drawings + installation space + cleanliness requirements + target air volume + usage environment

Then determine the specific configuration item by item based on the project.

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

Because the same external dimensions do not mean the same internal configuration.

Different fans → air volume and pressure may be different

Different motors → power, efficiency and speed control methods may be different

HEPA/ULPA is different → Filtration efficiency and resistance may be different

Different control systems→different single machine control and group control capabilities

The box structure is different → the installation method and internal air flow state may be different

Therefore, when comparing FFU purchases, it is recommended to unify the technical conditions first:

Same size + same target air volume + same filtration level + same residual pressure requirements + same control requirements

Then compare the different options.

Otherwise, it may appear that we are comparing the same FFU, but in fact we may be comparing different technical configurations.

15. How does Aili Industry conduct FFU selection and matching?

FFU is not a simple combination of several independent parts.

There is a direct relationship between air volume, air pressure, filter resistance, motor, fan and control system.

Aili Industrial has formed a R&D and manufacturing system from core components to complete machines around FFU, EFU and clean air equipment, covering:

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

When project requirements change, configuration can be made from the perspective of the entire machine.

This matching method is especially suitable for semiconductor equipment, equipment-side cleanliness, ultra-thin EFU, high wind speed FFU and other non-standard clean air projects.。

16. Frequently asked questions about FFU selection

1.What are the most important parameters for FFU selection?

FFU selection usually requires consideration of installation size, air volume, wind speed, filtration level, system resistance, power supply, motor, control method and application environment.。

No single parameter determines the entire FFU configuration.

2. Can I purchase the FFU directly after the size is determined?

Not recommended.

FFUs of the same size can use different fans, motors, HEPA/ULPA filters and control methods, so the target air volume, wind speed and actual operating conditions need to be further confirmed.

If you are not familiar with the basic structure and working principle of FFU, you can read first:

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

Then combine this article to make specific selections.

3. Is the larger the FFU air volume, the better?

no.

FFU air volume should be determined based on the actual clean environment and production process, taking into account wind speed, power, noise and air flow organization.

4.Should FFU choose H13 or H14?

It needs to be determined according to the cleanliness requirements and process requirements of the project.

At the same time, you should also confirm the resistance of different filters and whether the FFU fan can meet the required air volume under the target working conditions.

5.Can FFU be configured with ULPA filter?

Can.

For higher particle control requirements, ULPA filters such as U15, U16, and U17 can be configured according to the project, but the filter resistance and the actual working status of the FFU fan need to be confirmed simultaneously.

6. When should you choose ultra-thin EFU?

When the internal installation height of semiconductor equipment, EFEM, SMT equipment or other automation equipment is limited and conventional FFU cannot meet the space requirements, ultra-thin EFU can be considered based on the equipment structure.

7. How to control hundreds or tens of thousands of FFUs?

The FFU group control system can be configured according to the project scale to achieve partitioning, start-stop, speed regulation, work/duty mode and operating status management.

8. Can FFU be customized according to the equipment drawings?

Non-standard structural matching can be carried out according to the equipment installation space, target air volume, wind speed, filtration level, interface, material and control requirements.

Specific plans should be determined based on actual project parameters.

17. Quick summary of FFU selection

If you don’t want to remember too many parameters, you can remember the following logic:

First determine where it will be used → then determine how big it can be installed → then determine how much wind is required → determine the HEPA/ULPA level → confirm the system resistance → match the fan and motor → determine the control method → ​​finally confirm the FFU complete machine parameters

Ordinary clean rooms can start from standard FFU.

For space-constrained applications such as semiconductor equipment, EFEM, and SMT , ultra-thin FFU or ultra-thin EFU can be further considered。

For higher particle control requirements, the matching relationship between the ULPA filter and the FFU fan needs to be further confirmed.。

For clean systems composed of dozens or hundreds of FFUs, the FFU group control system should be planned simultaneously.。

Therefore, the final selection of FFU is not simply to select a model from the parameter list, but to complete the matching of the whole machine according to the actual project conditions.

18. Choose the appropriate FFU solution for your cleaning project

Different clean projects for FFU size, air volume, wind speed, static pressure, filtration efficiency, box material and control method .have different requirements

Aili Industry covers motors, fans, control systems, sheet metal, HEPA/ULPA filters, and complete machine assembly and testing. It can select FFU, EFU and supporting products based on clean rooms, semiconductor equipment, electronic manufacturing, lithium batteries, photovoltaics, biomedicine and other equipment-side clean applications.

Standard projects can be configured according to existing product parameters; requirements such as ultra-thin EFU, high-wind speed FFU, equipment-side FFU, non-standard sizes, special filtration levels, and multiple FFU group control can be further confirmed based on equipment drawings and actual working conditions.

Learn about FFU products and technical parameters:
Aili Industrial FFU fan filter unit

Related reading

What is FFU? Structure, working principle, application scenarios and selection guide | What are the main parts of FFU? Detailed explanation of fans, filters, and control systems | What is the relationship between FFU air volume and wind speed? ｜ What do you think of FFU wind pressure and static pressure? ｜ FFU choose AC, DC or EC?