In fields such as semiconductors, biopharmaceuticals, and sterile medical devices—fields crucial to human health and cutting-edge technology—high-efficiency/ultra-high-efficiency air filters are the ultimate barrier to cleanliness. However, even the most sophisticated physical designs cannot guarantee flawless operation during the complex processes of manufacturing, transportation, and installation. A pinhole-sized defect in the filter media, or a barely perceptible flaw in the frame seal, can render this defense ineffective, leading to cross-contamination, a sharp drop in product yield, and even biosafety risks.
Therefore, the superior capture capabilities of filters require an equally superior “validation system” to “testify” to their effectiveness. The IEST-RP-CC034: HEPA and ULPA Filter Leak Tests recommended by the Institute for Environmental Sciences and Technology (IEST) is the globally recognized gold standard for providing authoritative “diagnostic” services for filter integrity.
What is IEST-RP-CC034?
The latest version of IEST-RP-CC034 (CC034.5, released in July 2022) systematically covers the entire lifecycle of testing, from factory production to in-situ installation, clearly defining definitions, equipment, and operating procedures. Its testing philosophy is simulation and challenge: by artificially generating aerosol challenge particles with known properties upstream (such as PAO , DEHS , and other environmentally friendly media, replacing earlier DOP ), and then systematically scanning downstream with high-sensitivity detectors, the invisible “leakage” is transformed into a quantifiable and locatable physical signal.
The IEST-RP-CC034 core testing methods primarily consist of two methods, acting like eyes with different “visions” to meet the stringent requirements of different filter grades.
1. Photometer Scanning Method: Primarily measures changes in the mass concentration of downstream aerosols. The testing equipment includes an aerosol generator, a photometer, and a scanning probe. Suitable for HEPA filters (e.g., H13, H14 grades), with leakage rates typically not exceeding 0.03% (e.g., H13/H14 grades). Advantages include speed, intuitiveness, and lower cost; disadvantages include insufficient sensitivity for extremely low leakage in ULPA-grade filters.
2. Particle Counting Scanning Method: Primarily counts changes in the number of downstream particles of a specific size. The testing equipment includes an aerosol generator, a high-sensitivity particle counter , and a scanning probe. Suitable for ULPA filters and even higher-efficiency HEPA filters, with a leakage threshold as low as 0.0001% (i.e., penetration rate not exceeding 0.0001%). Advantages include extremely high sensitivity; disadvantages include higher cost, more complex operation, and susceptibility to interference from environmental background particles.
These two methods together constitute a progressively precise verification system. In practice, testers must use a speed not exceeding 5 cm per second, holding the probe 1-3 cm from the filter media surface, to perform a slow and meticulous “Z”-shaped scan of every inch of the filter media, all edges, and the seal between the filter and the mounting frame. Once a signal exceeding a preset threshold (e.g., a leakage rate exceeding 0.01% in critical areas) is detected, the instrument will alarm, and the leak point will be immediately marked.
The Value of IEST-RP-CC034
IEST-RP-CC034 defines a quality assurance framework that spans the entire lifecycle of the filter.
- 1. Pre-shipment “Certification”: At the factory, it ensures that every filter leaving the factory is free of manufacturing defects.
- 2. Post-installation “In-situ Approval”: This is the most critical step. The standard clearly distinguishes between factory testing and field testing because human intervention during transportation and installation can introduce new risks. Post-installation field leakage testing is an indispensable part of cleanroom acceptance testing.
- 3.Regular “Check-ups” During Operation: In accordance with industry regulations (such as pharmaceutical GMP, AMG Berlin) and ISO 14644, installed filters require regular leak testing (typically every 6 to 24 months) to monitor their long-term operational integrity and prevent potential problems.
Trenntech believes that the IEST-RP-CC034 leak test is more than just a technical specification. It is a bridge of trust between precision manufacturing and the need for absolute reliability, a certification ceremony that gives HEPA/ULPA filters “authoritative status,” and a safeguarding procedure that ensures industries that concern the future and lives can steadily move forward on a truly pure foundation.