What items need to be retested after changing batches of ULPA filter media?

This problem is often encountered in actual production: the filter material supplier has changed batches, or the supplier itself has not changed but the production batches are different. If the material model name is the same, will the performance be the same? Cannot default.

During the production process of filter media, parameters such as fiber diameter, weight, and porosity may fluctuate from batch to batch. These differences may not affect most applications, but for products of ULPA level, it is necessary to evaluate the impact scope of the change to confirm whether it affects the performance and consistency of the finished product.

What should be checked for incoming raw materials?

The first step in batch change is incoming material inspection.

Lot number and specifications. Whether the batch number, model, and specifications of the new batch are consistent with the original ones. This is the most basic check.

Media performance data. Ask the supplier for new batch performance data, including efficiency, resistance, MPPS and other parameters. Compare the data of the old and new batches to see if the difference is within the acceptable range.

Statement applies. Are there any special instructions for the new batch of materials, such as applicable environment, storage conditions, usage restrictions, etc.

For process-sensitive materials, agreed contamination control information should also be compared. For example, in semiconductor applications, it is necessary to confirm whether the new batch meets the requirements for the content of boron and metal ions. This part of information should be stipulated in the purchase agreement and should not be requested on an ad hoc basis.

What effects does finished product verification cover?

Just because the incoming materials pass the inspection does not mean that the finished product is fine. Batch changes in filter media may affect subsequent processing and finished product performance.

Efficiency testing. Under the same folding structure and testing conditions, it is confirmed that the efficiency of the finished product is consistent with that of the original batch. The test conditions and judgment standards are implemented according to the project documents. For details, please refer to the relevant instructions of ULPA factory inspection.

Resistance data. The resistance of new batches of filter media may change. Compare the resistance of the finished product at the target air volume. If the resistance deviates, you need to check whether the operating point of the system fan still meets the requirements. For details, please refer to the relevant instructions on resistance calculation.

Edge sealing and gluing. Different batches of filter media may have different bonding properties with colloids. Check the edge sealing quality and confirm that the colloid and filter material are firmly combined.

Local leak detection. Conduct leak detection on finished products according to project requirements to confirm completeness. Batch differences cannot be judged by appearance alone. For specific methods, please refer to the instructions on overall and local efficiency.

Records must be complete. The test data, comparison results and confirmation conclusions of the new batch should be saved. When problems occur later, it can be traced back to which batch of materials and which change.

Change notifications and records

Whether batch changes need to be notified to the project party depends on the contract.

When involving agreed materials, performance boundaries or process risks, they should be confirmed according to the change process. You cannot replace materials without informing them. Especially for industries that have special requirements for materials such as semiconductors and pharmaceuticals, unconfirmed changes may affect the process.

Keep records of samples and first articles. The first piece inspection data and sample retention of the new batch should be recorded. During mass production, unit-by-unit records should also be retained.

If the impact of the change is significant, revalidation may be required. For example, the efficiency or resistance of a new batch of filter media is significantly different from the original one, or the folding process needs to be adjusted to adapt to the new material. In this case, it may be necessary to re-test the finished product, or even re-confirm the matching of the installation interface and the system.

Project judgment example

After a certain batch of ULPA filter media was replaced, the resistance of the finished product shifted somewhat, but was still within the limit.

In this case, we cannot simply say 'it will be fine if you pass the exam'. Several aspects need to be checked: whether the offset is within the acceptable range, whether the fan still has sufficient margin under the final resistance condition, and whether the resistance consistency of multiple products meets the requirements. If only a single unit is qualified, but the consistency of the entire batch becomes poor, the problem of uneven air volume distribution may occur when used in parallel.

The basis for acceptance shall be based on the contract and project confirmation documents. involving For products of different grades of HEPA/ULPA air filters , the retest items may be different and shall be carried out according to the corresponding standards. Supporting FFU fan filter unit or fan filter unit at the EFU equipment end and the matching of the whole machine must also be re-confirmed. The filter element used in the

Selection and Acceptance Checklist

About Aili Industrial’s batch management cooperation

The key to batch changes is whether the recording and confirmation process is clear.

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. For projects involving material changes, the scope of impact can be confirmed according to the agreed process and corresponding testing data can be provided. filter with When the FFU fan filter unit and EFU are delivered together, the impact assessment of batch changes can be carried out uniformly.

When making an inquiry or signing an agreement, clarify the confirmation process and re-inspection requirements for material changes, which will help orderly execution of subsequent batch switching. Specific information shall be subject to the project agreement and contract documents.