When FFU conducts air volume testing, how should filters be selected?

Straight answer: Air flow testing should use filters consistent with actual delivery of the project. First determine the HEPA or ULPA filtration requirements according to the cleanliness target, and then check the resistance, size and sealing method of the filter under the design air volume. The test record should indicate the filter model, status and FFU operating gear; after changing the filter level or model, the air volume of the entire machine needs to be re-verified.

FFU's filter not only affects air cleanliness, but also changes the fan operating point. If one type of filter is used to test the air volume, but another type of filter is installed upon delivery, the original test results may not represent the on-site air supply performance. Therefore, clean room and equipment-side projects should write the filter configuration into the FFU air volume test conditions.

Determine filter type according to cleanliness requirements

The project should first clarify the application area, particle control objectives and filter testing requirements, and then select the appropriateHEPA or ULPA air filter . When selecting, also check whether the filter's overall dimensions, frame and sealing method are consistent with theFFU fan filter unit matches.

For equipment-side projects with local high cleanliness requirements or limited space, the air supply direction, installation interface and filter replacement space should be checked at the same time. The filtration efficiency meets the requirements, but the installation seal cannot be guaranteed, and it is also not suitable as the final configuration.

Calculate FFU using resistance under design air volume

Filter resistance should be compared at defined test air volumes. The project needs to confirm whether the target air volume can be achieved under the agreed operating gear and system resistance conditions after the FFU is assembled with the selected filter. 'Maximum air volume without filter' or test data under different filter material conditions cannot be used to replace the actual configured data of the whole machine.

If the project usesFor ULPA filters , the filter resistance and fan performance should be rechecked instead of just checking whether the filter size is the same. Changes in filtration level may cause changes in the operating gear, power consumption or available static pressure at the target air volume.

Record filter status while testing

The prototype, factory and on-site air volume tests should use consistent filter configurations as much as possible, and record the model, installation status, resistance during testing, FFU gear and measurement method. This will explain the differences between the data at different stages.

The air volume measured by the new filter can be used as one of the basis for acceptance; for long-term operation projects, the ability of the FFU to maintain the target air supply in subsequent operations should also be checked based on the allowable resistance changes and maintenance requirements. When abnormalities are found in the air volume test, filter installation and sealing, resistance changes, and air inlet and return conditions should also be checked.

Aili Industrial’s supporting ideas

Aili Industry can match filters, fans, motors and cabinet structures based on cleanliness goals, filter requirements, target air volume and installation dimensions. For batch projects, it is recommended to first confirm the prototype configuration and test conditions, and then check the complete machine and on-site air volume according to the technical agreement. Specific filter specifications and FFU performance should be based on the test results under the agreed working conditions of the project.

When consulting Aili Industrial, it is recommended to provide cleanliness requirements, target air volume or wind speed, installation drawings, filter testing requirements and estimated quantities; if the air volume test method has been determined, it should also be stated together to facilitate the provision of comparable complete machine data.

Q: Can I test with a low-resistance filter first and then switch to the project-specified filter?
Answer: It can be used for internal debugging, but the result cannot be directly used as the air volume acceptance data for the final configuration. The test should be retested after changing equipment.

Q: Can filters of the same grade be directly interchanged?
Answer: Not necessarily. It is also necessary to check the resistance, size, frame, sealing method and overall air volume under the design air volume.

Q: What at least filter information should be stated in the air volume test report?
Answer: It is recommended to indicate the filter model, specifications, installation status and resistance during testing, and also record the FFU gear and testing method.