Can ordinary FFU be changed to FFU with chemical filtration?

It can be evaluated, but not all ordinary FFU are suitable for modification.

The core issue of the transformation is: under the original fan and structural conditions, can a chemical filtration section be installed while maintaining the target air volume and wind speed. If the fan margin is insufficient, the space cannot be installed, and the sealing cannot be guaranteed, forced installation may lead to a decrease in air volume, bypass air leakage, or maintenance difficulties. For specific evaluation logic, please refer to Discussion of what localized contamination can be treated by FFU plus chemical filter .

Determine gas requirements

Before modification, first confirm what gases will be processed.

Contamination components and sources. Is it released inside the equipment, input from adjacent areas, or brought in by fresh air from the outside? Different sources correspond to different processing locations and filter segment configurations. For specific investigation methods, please refer to whether to do air sampling before choosing a chemical filter . Discuss

Target gas and concentration range. Is it acid gas, alkaline gas, organic vapor or mixed pollution? What is the approximate entrance concentration? This information determines the media type and amount used. For specific principles, please refer to ~!phoenix_var88_0!~ ~!phoenix_var88_1!~

Export requirements. What concentration level is desired? Is it to improve odor, or to protect sensitive equipment? The stricter the export requirements, the higher the design and replacement cycle requirements of the filter section.

Confirm whether loop filtering can cover the main path. If the pollution source is downstream of the FFU, or the airflow bypasses the FFU, the effect of adding a filter section will be compromised. Before modification, it is necessary to understand the airflow organization in the area. For specific judgment methods, please refer to Discussion of what localized contamination can be treated by FFU plus chemical filter .

Check structure and resistance

With the gas demand in mind, check the engineering conditions for the transformation.

Available space. The internal space of ordinary FFU is usually full: fan, particle filter, and box structure. Adding a chemical filtration section requires additional height or depth. If there is insufficient space, it may be necessary to adjust the structure or use a thin chemical filter section. For specific configuration, please refer to Discussion of how to determine configuration when chemical filter thickness is limited .

Fan margin. Chemical filtration sections increase system resistance. Whether the original fan can maintain the target air volume under the new resistance needs to be calculated according to the fan curve. If the fan is already running at high speed, the margin may be insufficient. For specific accounting methods, please refer to Discussion of how much the added resistance of the chemical filter will increase the fan's electricity consumption .

Weight and support. The weight of the chemical filter section and media needs to be borne by the FFU box and ceiling supports. If the weight increases significantly, determine whether the supporting structure needs to be reinforced.

Wind speed target. After adding a filter section, the wind speed distribution on the air outlet surface may change. It is necessary to confirm whether the wind speed is uniform after modification and whether it meets the requirements of clean areas. For specific measurement methods, please refer to Discussion on how to check the target wind speed after FFU is equipped with a chemical filter .

Filter section installation method

Where the chemical filtration section is installed in the FFU affects the transformation plan and effect.

In front of the air inlet. The chemical filtration section is installed before the particle filter to first treat the gas and then control the particles. This method protects the particle filter from the chemical media falling off. However, the space in front of the air inlet may be limited, and installation conditions need to be confirmed.

After particle filter. The chemical filtration section is installed after the particle filter. In this method, special attention should be paid to whether the chemical medium will produce dust or outgassing, because this part of the air is sent directly to the clean area. For specific verification methods, please refer to Discussion on how to verify the low outgassing requirements of ULPA .

Integrated structure. Some retrofit solutions integrate particulate filtration and chemical filtration into a single frame. This structure is compact, but replacement and maintenance methods need to be confirmed.

No matter where it is installed, the seal must be reliable. Frame bypass allows untreated air to bypass the filter material, affecting the outlet concentration. For specific inspection methods, please refer to Discussion on how to check frame bypass after chemical filter installation .

Verify run after completion

After the transformation is completed, you cannot just look at 'installed', you must verify the actual operating status.

Air volume measurement. Measure the wind speed and air volume on the air outlet surface in the working gear to confirm that the design requirements can still be met after modification. If the air volume drops significantly, you need to go back and check the fan operating point or filter section resistance.

Wind speed uniformity. Measure the wind speed on the wind outlet surface at multiple points to confirm that the distribution is even. If the local wind speed is low, it may affect the airflow coverage in the clean area.

Outlet concentration detection. Detect the target gas outlet concentration according to project requirements to confirm the treatment effect. You cannot judge the effect simply by 'installing a chemical filter'.

Particle cleanliness. If the FFU was originally responsible for particle control, the particle cleanliness cannot be reduced after the transformation. Leak detection and particle detection shall be carried out according to the original requirements.

Maintain path. Confirm that the replacement of the chemical filter section is feasible. The internal space of the equipment is limited, and replacing the filter element may require disassembly of other parts. Maintenance access and operating spaces should be confirmed in the renovation plan. involving The system, interfaces and maintenance methods of the FFU supporting chemical filter need to be checked together during the planning stage.

Project judgment example

A clean room originally had ordinary FFU and was operating normally. Later, the process was adjusted, and a slight organic smell appeared in the area, but there was no problem with particle control.

The initial idea is to install a layer of chemical filter material in front of the FFU air inlet. After the evaluation, it was found that the original FFU air inlet space was insufficient, and the resistance increased by about 30% after installation. The fan margin was insufficient and the air volume would decrease significantly.

Adjustment plan: Replace with FFU with chemical filter section design, the fan static pressure is higher, and the structure reserves space for the installation of the filter section. After the transformation, the air volume and wind speed meet the requirements, and the outlet concentration and odor are significantly improved. The original FFU is used in other areas without gas treatment requirements.

This case illustrates: Ordinary FFU transformation depends on the engineering conditions and is not simply adding a layer of filter material. involving For the configuration of the chemical filter product series , it is recommended that the FFU parameters, gas requirements and space conditions be provided to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s FFU transformation package

When FFU installs a chemical filtration section, the core is to check the fan margin, structural space, sealing interface and wind speed target.

Aili Industrial has independent manufacturing capabilities in filters, motors, fans, control systems and sheet metal processing, and can provide chemical filter product series and supporting air supply equipment. For FFU transformation projects, we can assist in checking the filter section configuration and transformation plan based on the original unit parameters, gas demand, installation space and operation requirements. When the filter is matched with FFU, EFU and other equipment, the resistance, interface and maintenance methods can be confirmed uniformly.

Related products:Chemical filter product series、FFU matching chemical filter、MAU box chemical filter . Providing the original FFU parameters, gas requirements and system conditions during the inquiry will help confirm the appropriate modification plan. The specific selection is subject to the technical documents and test results confirmed by the project.