How to rebalance the air volume after ULPA replacement and layout adjustment?

After the ULPA filter is replaced or the layout is adjusted, each module and system air volume may need to be rebalanced. The recovery of a single reading does not mean that the whole room distribution, pressure and process point protection are restored at the same time. The difficulty in rebalancing the air volume is that 'partial correctness does not mean overall correctness': after replacing a filter element, the air volume of a single unit returns to the design value, but other modules sharing the air duct may have air volume deviations due to changes in resistance; when the air supply in one area is adjusted, the pressure difference in adjacent areas may change accordingly. Rebalancing solves the distribution problem at the system level. Aili Industry isFFU fan filter unit andThe fan filter unit on the EFU equipment side supports zone speed regulation.The FFU computer group control system records the air volume, pressure and operating status of each module. After replacement or layout adjustment, it can be gradually rebalanced according to the partition data.

1. Establish a comparison with the same working conditions: record the replacement point, model and settings first

Record the replacement point, filter element model, fan or damper settings, unify door, equipment and exhaust status, and then measure the total volume and partition data.

The prerequisite for rebalancing is comparable data. Which unit was replaced, what model was replaced, whether the fan or damper settings were changed, and what the status of the door and equipment was during the test. These should be recorded clearly before adjustment. If the working conditions before and after are inconsistent, it is impossible to determine whether the change in air volume data is caused by replacement or changes in working conditions. Aili Industry isIn the HEPA/ULPA filter replacement plan, the operating parameters before replacement are recorded according to the original system conditions.The FFU computer group control system records the partition air volume and settings before and after replacement. Only comparisons with consistent working conditions are meaningful. The relationship between levels and filtering requirements can be found inISO cleanliness level comparison。

2. Gradually adjust according to system relationships: the impact of shared air ducts and group control partitions

Identify independent FFU, shared air ducts and group control areas to avoid adjusting one module without affecting adjacent modules without reviewing it.

Air volume rebalancing is not about adjusting all modules again, but adjusting them sequentially according to the system relationship. Adjustment of independently operating FFU will have little impact on neighbors. Adjustment of one module in a shared air duct will cause the air volume of adjacent modules to change. Adjustment of one module in a group control zone will affect other modules in the same zone. Aili Industry isIn the group control scheme of FFU fan filter unit, it is managed by partition.The FFU computer group control system records the affiliation and operating status of each module. When rebalancing, it first adjusts the independent modules, then processes the shared air duct and partition linkage, and retests the data of adjacent modules after each step of adjustment. For the relationship between shared air duct and module linkage, please refer toHEPA FAQs and Selection Guide。

3. Closed-loop confirmation of performance: look at distribution, pressure and process points together

Retest distribution, pressure and necessary process area items, and retain the final settings. If there are changes in materials or interfaces, corresponding integrity confirmation needs to be completed.

Air volume recovery does not equal system recovery. After rebalancing, three things need to be confirmed: whether the air volume distribution of each module returns to the design range, whether the pressure gradient between areas is maintained, and whether the wind speed and particle concentration at the process protection point meet the standards. Aili Industry isIn the ULPA ultra-high efficiency filter replacement project, the integrity is confirmed according to the status after replacement.The FFU computer group control system records the air volume, pressure and operating parameters after rebalancing.In the EFU equipment-side fan filter unit equipment-side scenario, the local air volume can be confirmed based on the machine back pressure. Please refer to the confirmation items after rebalancing.ULPA ultra-high efficiency filter FAQ and selection guide。

4. After replacing the filter element in one area, it will absorb more air volume and the other ends of the shared air duct will decrease. The overall balance should be

If one area absorbs more air volume after replacing the filter element, the other ends of the shared air duct will decrease. The overall balance should be maintained rather than just adjusting the new filter element. When the resistance of the new filter element is lower than that of the old filter element, the air volume passing through it at the same fan speed will increase, the flow distribution in the shared air duct will change accordingly, and the air volume in other branches may decrease.

Aili Industry isNon-standard ULPA filters andIn the FFU fan filter unit replacement project, the rebalancing plan is evaluated based on the system relationship of the shared air duct.The FFU fan filter unit supports EC DC speed regulation, and can adjust operating parameters according to the actual air volume of each branch during rebalancing.The FFU computer group control system records the air volume changes of each branch to facilitate overall balance rather than local repair. For the scenario of shared air ducts on the equipment side, please refer toEFU FAQ and technical support。

5. Related questions and answers

Is it okay to just adjust the speed back to the original value?
The resistance and layout of the old and new ones may be different. The original speed does not guarantee the original air volume and should be confirmed by actual measurement.

Does the recovery of air volume on a single unit mean that rebalancing is complete?
not enough. Also confirm that room-wide distribution, pressure gradient and process point protection are restored at the same time.

Do I need to re-check the integrity after adjusting the layout?
If changes in installation status are involved, the completeness should be confirmed according to project requirements, and the records before adjustment cannot be used.

6. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

FFU computer group control system

FFU FAQ and technical support

HEPA FAQs and Selection Guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industry isFFU fan filter unit andThe fan filter unit on the EFU equipment side supports zone speed regulation.The FFU computer group control system records the air volume, pressure, operating status and affiliation of each module. After replacement or layout adjustment, it can be gradually rebalanced according to the partition data.HEPA/ULPA filter replacement plan records the operating parameters before replacement according to the original system conditions.The FFU computer group control system records the air volume and settings of the partitions before and after replacement; when rebalancing, the independent modules are first adjusted, and then the shared air duct and partition linkage are processed, and the adjacent module data is retested after each step of adjustment.The ULPA ultra-high efficiency filter replacement project confirms the completeness according to the status after replacement.The FFU computer group control system records the air volume, pressure and operating parameters after rebalancing.EFU equipment side fan filter unit equipment side scene confirms the local air volume according to the machine back pressure;Non-standard ULPA filters andThe FFU fan filter unit replacement project evaluates the rebalancing plan based on the relationship between the shared air duct system.The FFU fan filter unit supports EC DC speed regulation, and can adjust operating parameters according to the actual air volume of each branch during rebalancing. 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.