What is the difference between overall efficiency testing and scanning leak detection?

These two tests often appear side by side in project documents, but they serve different purposes and are occasionally understood as the same thing.

The overall efficiency test answers 'How is the overall performance of this filter?', and the scanning leak detection answers 'Where are the local leaks?' One looks at the overall indicators, and the other looks for specific locations. Both may be required during project acceptance, but each solves different problems.

Overall efficiency looks at the performance of the entire product

The overall efficiency test examines a complete filter and measures its ability to remove test particles.

The efficiency data on the report should be read in conjunction with the test air volume, method used and particle conditions. The same product may have different efficiency readings under different test air volumes. When purchasing, don’t just extract a percentage from the report. You should also check whether the product specifications corresponding to the report are consistent with the actual order model.

This test is usually completed during the product delivery stage, and the supplier provides a report. For projects that require unit-by-unit reporting, each product should have independent test results and corresponding numbers. involving HEPA/ULPA air filter products of different grades may have different test standards and efficiency requirements. The verification shall be carried out according to the corresponding documents.

Scanning leak detection looks for local weak points

Scanning leak detection has different detection methods, and the purpose is to locate local abnormalities.

The detection probe moves along the filter material surface and peripheral seams, measuring point by point, focusing on identifying locations with high local readings. Pinholes in the filter material, discontinuous glue filling, and poor sealing fit may all be found here.

Scanning leak detection after on-site installation will also extend the inspection scope to the sealing path between the filter, frame and box. This part is not within the scope of factory inspection because the filter and installation structure have not been assembled together before leaving the factory.

For device-side applications such as The EFU equipment-end fan filter unit has a compact internal structure, and the accessibility of the scanning path needs to be planned in advance. If the diffuser plate or diversion structure blocks the frame, it may need to be disassembled and assembled during leak detection. This should be made clear in the project plan.

The two results cannot be substituted for each other

The overall efficiency is qualified, but it does not mean that there are no local leaks. A product may pass the overall test but have an uncovered bypass in a corner. Leak scanning is designed to find just this type of problem.

On the other hand, passing the scanning leak detection does not mean that the overall efficiency must meet the requirements. A scan is a location-specific spot check, with different coverage and sampling methods than a holistic test.

It is recommended in the project document that the two requirements be written separately: who will provide the overall efficiency test and what form the report will be; who will perform the on-site scanning and leak detection, and what methods and criteria will be used to determine it. In this way, when a problem occurs, it can be determined whether it is a problem on the product side or the installation side. Supporting For the FFU fan filter unit system, the division of responsibilities for complete machine inspection and on-site leak detection should also be clarified in the planning stage.

Testing requirements must be included in the delivery documents

Make it clear who will provide the factory inspection data, who will be responsible for on-site leak detection, when to re-inspect, and how to deal with leaks when leaks are discovered.

During the factory delivery stage, the supplier usually provides an overall efficiency report and necessary local testing data; after installation is completed, the project party or a designated agency performs on-site leak detection. The records of these two links must be able to correspond to the same product and the same installation location.

The handling method after a leak is discovered also needs to be agreed upon: the handling methods for filter material leaks and seal leaks are different, and the attribution of responsibility may also be different. Reports should be recorded separately to avoid confusion.

Suggestions for archiving data

File the complete machine factory report, on-site installation leak detection record and room cleanliness report separately, corresponding to their respective product numbers and location numbers.

Three types of information solve problems at different levels: whether the product itself is qualified, whether the installation is sealed, and whether the cleanliness of the space meets the standards. If they are mixed together and filed together, it will be difficult to locate them during subsequent verification. For batch projects, it is recommended to set the fields of product number, installation location, report number and leak detection results in the delivery form to form a complete traceability chain.

About Aili Industrial’s testing cooperation

Aili Industrial can provide filter product information and testing cooperation according to the project agreement. filter with FFU fan filter unit、The EFU equipment-end fan filter unit is matched in the same manufacturing system, and the factory inspection data and on-site installation interface can be uniformly checked during the delivery stage.

When ordering, please specify the test standards, air volume, report form and serial number requirements to facilitate subsequent installation and acceptance traceability. The specific testing methods and judgment standards are subject to the project plan.