Overview
ISO 29463-3:2011 - "High-efficiency filters and filter media for removing particles in air - Part 3: Testing flat sheet filter media" - defines the standardized procedure for measuring the particle‑removal efficiency of flat sheet filter media. It is part of the ISO 29463 series (derived from EN 1822) and is intended to be used together with ISO 29463-1, -2, -4 and -5. The standard uses particle‑counting methods (mono‑disperse or poly‑disperse aerosols) to determine efficiency at the most penetrating particle size (MPPS) and includes requirements for sampling, apparatus, test air, measurement and reporting.
Key topics and technical requirements
- Scope and sampling
- Testing is performed on at least five specimens; samples must be flat, undamaged and clearly marked (designation and upstream side).
- Test principle
- Efficiency determined by particle counting upstream and downstream of a mounted flat sheet medium; produces an efficiency vs. particle‑size curve to identify the MPPS.
- Aerosol production
- Supports mono‑disperse test aerosols (generated via jet nebulizers, solvent evaporation, neutralization and a differential mobility analyser) and poly‑disperse aerosols (primary neutralized aerosols).
- Example aerosol substances and details (e.g., DEHS/DOP in iso‑propanol, DMA usage) are described for achieving the test size range (e.g., ~0.04 µm to 0.8 µm).
- Measurement equipment
- Condensation particle counters (CPC) for mono‑disperse total counts or optical particle counters for poly‑disperse size distributions.
- Use of a differential mobility analyser (DMA) for mono‑disperse sizing and dilution systems when upstream concentrations exceed counter ranges.
- Operational parameters
- Control and record filter medium face velocity, test volume flow rate, differential pressure (Δp), and environmental conditions (pressure, temperature, humidity).
- Evaluation and reporting
- Calculation of penetration and efficiency, determination of MPPS, statistical confidence limits, and specified test report content.
- Production and physical tests
- Annexes cover production testing, differential pressure measurement, HEPA media penetration tests and physical property tests.
Practical applications and users
ISO 29463-3 is used by:
- Filter manufacturers for media development and quality verification
- Independent testing laboratories performing certification or R&D
- Cleanroom and HVAC specifiers, procurement and QA teams verifying HEPA/ULPA media performance
- Pharmaceutical, semiconductor, healthcare and biosafety stakeholders requiring validated filter media performance
The standard enables consistent, reproducible measurement of filter media efficiency and supports classification and selection of HEPA/ULPA media based on MPPS and particle‑count results.
Related standards
- ISO 29463-1 - Classification, performance, testing and marking
- ISO 29463-2 - Aerosol production, measuring equipment, particle‑counting statistics
- ISO 29463-4 - Leak testing (scan method)
- ISO 29463-5 - Test method for filter elements
- ISO 29464 - Terminology for cleaning equipment for air and gases
Keywords: ISO 29463-3, flat sheet filter media testing, HEPA filter media, MPPS, condensation particle counter, differential mobility analyser, filter efficiency testing, aerosol generation, filter face velocity, differential pressure.