Is it necessary to use ULPA in non-unidirectional flow clean rooms?

Whether to use non-unidirectional flow clean roomULPA filters should be judged based on process particle targets, pollution loads, and system solutions. Room airflow patterns do not alone determine whether ULPA must be used or not. The characteristics of a non-unidirectional flow clean room are that the air flow is mixed and the direction is not fixed. The particles are gradually diluted after the air circulates multiple times. In this form of airflow, the role of the filter is to control the cleanliness of the incoming air, rather than to maintain directional protection. Whether ULPA is required depends on what level of cleanliness the incoming air needs to achieve and whether the system can withstand the corresponding resistance. Aili Industrial's product line covers different efficiency levelsHEPA/ULPA filter , also availableFFU fan filter unit andThe EFU equipment end fan filter unit is matched, and non-unidirectional flow scenarios can be matched between HEPA and ULPA according to process goals, rather than one-size-fits-all airflow patterns.

1. Confirm actual needs: Distinguish between room-wide goals and local sensitive areas

Distinguish between room-wide targets and local sensitive areas, evaluate contamination particle size, operating activities and process equipment, and avoid selecting filters just because of class name.

The cleanliness target of a non-unidirectional flow clean room is usually based on the particle concentration in the whole room as an indicator, but there may be local sensitive areas in the process - a certain work station, a certain piece of equipment or a certain operation step is more sensitive to particles. When the entire room is designed to ISO Class 6 or 7, local sensitive areas may require separate higher protection. Whether ULPA is used in the whole room or in part depends on the location and protection requirements of the sensitive area. Aili Industry isHEPA/ULPA filters, confirm the gear according to the particle size and protection range.When selecting Non-standard ULPA filter items can be customized according to local protection areas.The FFU fan filter unit can be used for reinforcement above local workstations. The relationship between levels and particle limits can be found inISO cleanliness level comparison。

2. Check system benefits and limitations: higher filtration performance requires system conditions to support

Higher filtration performance requires a combination of air volume, mixing, return air and pollution source control. The required air supply should still be maintained after increasing resistance.

ULPA is more efficient than HEPA, but the resistance is generally higher. The air supply volume of a non-unidirectional flow clean room is usually determined based on the number of air changes. If the filter resistance increases and the fan residual pressure is insufficient, the actual air supply volume will decrease, the number of air changes will not reach the design value, and the cleanliness will be affected. The prerequisite for using ULPA is that the system has residual pressure margin or the fan can be adjusted for speed compensation. Aili Industry isThe FFU fan filter unit supports EC DC speed regulation, which can compensate for the air volume after the filter resistance rises.The FFU computer group control system records changes in zone air volume and resistance. When ULPA is used in non-unidirectional flow scenarios, the system capability can be checked based on actual working points. The relationship between filter resistance and fan matching can be referred toHEPA FAQs and Selection Guide。

3. Compare whole-room and local solutions: local protection may be more economical

If necessary, configure independent protection for key workstations and pass corresponding status test evaluations. The final selection should be based on project validation rather than fixed matching rules.

The use of ULPA in the whole room and the local use of ULPA are two different investment methods. Whole-room use means that all air supply filters are upgraded, and the initial investment and operating resistance increase as a whole; local use means that ULPA is only configured inside key workstations or equipment, and HEPA is maintained in the background area. In non-unidirectional flow clean rooms, if sensitive areas are concentrated in a few workstations, a local solution may be more economical. Aili Industry isIn the EFU equipment end fan filter unit equipment end matching, local ULPA protection can be configured according to the work station or equipment.Tank seal ULPA filter andThe partitionless ULPA ultra-high efficiency filter can match the structure according to the local protection space. For comparison between whole-room and partial solutions, please refer toULPA ultra-high efficiency filter FAQ and selection guide。

4. When only one device in the mixed airflow room is more sensitive to particles, local protection and whole-room modification can be compared.

When only one piece of equipment in a mixed airflow room is more sensitive to particles, the effectiveness and maintenance conditions of local protection versus full room modification can be compared. The investment in local protection is concentrated and has little impact on the overall system; the whole-room renovation involves all air supply filters and fans, which has a large impact.

Aili Industry isNon-standard ULPA filters andIn the EFU equipment-side fan filter unit equipment-side solution, local ULPA protection is configured according to the equipment structure.The FFU fan filter unit can be used for local reinforcement above the workstation. Both methods can add a local protective layer under the existing non-unidirectional flow background. The design points of the local protection scheme can be referred toEFU FAQ and technical support。

5. Related questions and answers

Is it a waste to use ULPA for non-unidirectional flow?
It is not possible to generalize, but should look at the actual process goals, system matching and verifiable effects.

Which one is better, ULPA for the whole room or ULPA for local use in a non-unidirectional flow clean room?
Depends on sensitive area distribution and system conditions. The local solution may be more economical when the sensitive areas are concentrated, and the whole-room solution is more straightforward when the whole-room target is high.

Can the airflow pattern determine whether to use ULPA?
cannot. Airflow patterns influence how particles are distributed, but filter gearing should be determined by particle control objectives and system capabilities.

6. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

No partition ULPA ultra high efficiency filter

EFU equipped with ULPA ultra-high efficiency filter

HEPA FAQs and Selection Guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industrial's product line covers different efficiency levelsHEPA/ULPA filter , also availableFFU fan filter unit andThe EFU equipment end fan filter unit is matched, and non-unidirectional flow scenarios can be matched between HEPA and ULPA according to process objectives.HEPA/ULPA filter selection is based on the determined particle size and protection range.The FFU fan filter unit supports EC DC speed regulation, which can compensate for the air volume after the filter resistance rises.The FFU computer group control system records changes in zone air volume and resistance. When ULPA is used in non-unidirectional flow scenarios, the system capability can be checked based on actual working points.Non-standard ULPA filters can be customized according to local protection areas.The fan filter unit at the EFU equipment end can be configured with local ULPA protection according to workstations or equipment.Tank seal ULPA filter andThe partitionless ULPA ultra-high efficiency filter can match the structure according to the local protection space. Provide process objectives, installation drawings, operating conditions and acceptance requirements, and can further communicate ULPA standard specifications, non-standard interfaces, samples and batch matching. The specific parameters and test range are based on the confirmed model and technical documents.