High‑efficiency particulate air (HEPA) and ultra‑low penetration air (ULPA) filters are key components of modern cleanroom technology in microelectronics, pharmaceutical manufacturing, medical device production, and advanced HVAC systems. Ensuring their reliable performance over the full lifecycle requires harmonized laboratory classification, production quality control, and in‑situ qualification in operating cleanrooms.

This contribution presents a structured, standards‑based approach that links type testing and production control of HEPA/ULPA filters according to ISO 29463‑4 and ‑5 with on‑site performance verification in accordance with ISO 14644‑3. ISO 29463 provides a framework for the determination of fractional efficiency and the most penetrating particle size (MPPS), the execution of scan‑based local efficiency and leak tests, and the measurement of integral efficiency to assign filters to defined efficiency classes. Building on this framework, we discuss the implementation of both local and integral measurements for different filter classes and geometries, highlighting the transition from flat‑sheet medium characterization to full‑size filter element testing.

Experimentally, we employ modular test stands designed for HEPA/ULPA filter evaluation, including manual and automated scanning systems as well as robot‑assisted setups for complex three‑dimensional filter geometries. These systems enable reproducible aerosol generation, well‑defined flow conditions and high‑resolution spatial mapping of local leakage and efficiency, while generating standardized digital test reports suitable for integration into quality management systems. We outline the methodology for transferring these laboratory and production concepts to in‑situ testing in installed cleanroom systems, with a focus on the selection of challenge aerosols, sampling strategies, scan patterns, and acceptance criteria (filter leak test) that are compatible with ISO 14644‑3 and practical constraints in operational facilities.

The paper concludes by proposing a consistent qualification strategy that spans initial filter development, series production, and periodic on‑site requalification...