Should ULPA be graded by filter material or finished product efficiency?

This question often arises in procurement and acceptance. The answer itself is not complicated: the grade determination should be based on the finished product test results, and the filter material data is raw material information.

However, in actual projects, the boundaries between the two are often confused. Some people use a filter media report as proof of complete machine qualification, while others use filter media data to 'calculate' the grade when the finished product report is missing. These practices will cause problems during acceptance.

What can filter material samples prove?

The object of filter media testing is the material itself, usually a sample removed from the filter media.

What it can tell is: how efficiently this material filters particles of a specific size under specified test conditions. This is an important reference in the material selection stage and can help determine whether a certain filter material is suitable for the performance requirements of the project.

What it cannot explain is: the performance of a filter made of this filter material under actual installation and use conditions. Because there are several processes in between from filter material to finished product, each of which may change the final result.

The filter material report has its scope of application and cannot be expanded at will. The report should indicate that the test object is the filter material sample and the test conditions. This information is critical when interpreting the data.

Why the finished product may be different

Just because the filter material has qualified performance when it leaves the factory does not mean that it will perform the same after it is made into a filter.

folding process. The filter material is stressed when pleated. If the process is not properly controlled, local damage or uneven pleats may occur.

Edge sealing process. If the colloid between the filter material and the frame is not continuously distributed or is not firmly bonded, air may bypass the filter material from these locations.

Frame assembly. The dimensional accuracy, flatness and structural strength of the outer frame affect the matching state of the filter element and the installation frame.

Shipping and handling. During transportation from the factory to the site, the filter element may be subject to vibration, collision, or extrusion, which affects the condition of the filter material and sealing structure.

Therefore, the purpose of finished product inspection is to incorporate these processing and assembly factors into the evaluation. The grade of the finished product should be judged based on the test results of the complete filter. For specific test items, please refer to the relevant instructions of ULPA factory inspection.

How to request information when purchasing

Clearly identify the objects to be tested. It should be clearly written in the procurement documents whether the grade is determined based on the finished product report or the filter material report. If the project requires finished product testing, acceptance will be based on the finished product report.

Request the finished product report corresponding to the model or number. Reports should relate to specific products rather than a batch average. If traceability is required, the report must also correspond to each device.

Filter media certificate as supplement. Filter media data can help understand material performance but is not a substitute for finished product reporting. Both can be provided together, each with its own purpose.

Subsequent changes need to be evaluated. If the filter material or structure is changed, it should be re-inspected according to the scope of impact. If the same batch of filter media is used to make two filters with different structures, the raw material certificate cannot be used to determine that both finished products reach the same level. involving HEPA/ULPA air filter products of different grades have the same data requirements, and the criteria are implemented according to the corresponding standards.

Project judgment example

The information provided by the supplier only contains efficiency data of the filter material and no finished product test report.

In this case, this information cannot be used as the basis for ULPA grade determination. It is necessary to obtain the finished product report of the corresponding model from the supplier to confirm: test standards, test air volume, overall efficiency and local leak detection results.

If the supplier does not have the ability or data to test finished products, whether to accept it or not needs to be judged according to the project requirements. Finished product reports are often necessary for projects with strict grade requirements and traceability. For general purposes, specific requirements shall be subject to the contract.

Supporting FFU fan filter unit or The actual performance of the filter element used in the fan filter unit of the EFU equipment after installation must be confirmed through on-site leak detection and regional testing. The finished product report is only one link in the verification chain.

Selection and Acceptance Checklist

About Aili Industrial’s testing data cooperation

The boundaries between finished product testing and filter material testing should be clearly stated in the documentation, so there will be no disputes during acceptance.

Aili Industrial's manufacturing system covers filters, motors, fans, control systems and complete machine assembly, and can provide ULPA ultra-high efficiency filter and supporting air supply equipment. The finished product testing data of the corresponding model can be provided according to the project agreement, indicating the testing objects and testing conditions. filter with When the FFU fan filter unit and EFU are delivered together, the corresponding relationship between the finished product data and the filter element data can be uniformly checked.

Clarifying the basis for grade determination and reporting form when making an inquiry will help confirm the acceptance data. Specific information shall be subject to the project agreement and contract documents.