IEST-RP-CC001 is a recommended practice published by the Institute of Environmental Sciences and Technology. It provides guidance on the terminology, classification, construction, performance and testing of HEPA and ULPA filters.
Unlike EN 1822 and ISO 29463, IEST-RP-CC001 should not be presented as an identical filter-classification system. The required test method, aerosol, measurement instrument and acceptance criteria should be selected according to the specified filter type, application and contractual requirement.




Filter Performance Testing
Filter performance is evaluated by challenging the filter with a specified test aerosol and comparing the upstream and downstream concentrations. The test method must match the filter type, required efficiency level and specified measurement range.
Depending on the applicable procedure, particle-counting or photometric methods may be used. The aerosol and instrument should therefore not be selected independently from the required test method.
Overall Efficiency and Penetration
Overall efficiency represents the average performance of the complete filter under the specified airflow and test conditions. The report should identify the aerosol, airflow, measurement method and particle-size basis used for the test.
Local leak testing is used to identify defects in the filter media, media-pack seal or frame connection. The scanning method, probe movement, sampling flow and acceptance criterion must follow the selected procedure.
Overall efficiency testing and local leak testing serve different purposes. Passing an overall efficiency test does not by itself confirm that the filter has no local defect.
| Standard or Practice | Main Role |
| IEST-RP-CC001 | Recommended practice covering HEPA and ULPA filter terminology, classification, performance and testing |
| EN 1822 | European classification and testing of EPA, HEPA and ULPA filters using MPPS-based methods |
| ISO 29463 | International classification and testing of high-efficiency filters and filter media using MPPS-based methods |
| ISO 14644-3 | Test methods used for cleanroom and clean-zone performance verification, including installed filter-system leakage testing |
These documents are related but not interchangeable. The standard or recommended practice specified by the customer, project or regulatory requirement should be used for acceptance.




Following standardized procedures ensures consistent filter performance and reliable contamination control.
Manufacturers may use the applicable procedures for:
IEST-RP-CC001 plays an important role in maintaining cleanroom performance by providing recommended practices for verifying filter integrity and efficiency.
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