Overview
EN ISO 29461-2:2022 - Air intake filter systems for rotary machinery - Test methods - Part 2: Filter element endurance test in fog and mist environments (ISO 29461-2:2022) specifies laboratory test methods to determine water endurance performance of air filter elements used in air intake systems for rotary machinery (for example, stationary gas turbines, compressors and stationary internal combustion engines). The document is published by CEN as the European adoption of ISO 29461-2:2022.
Key points:
- Defines general test requirements, test rig and equipment, test materials, test procedure and reporting.
- Evaluates filter behaviour in controlled fog and mist (high-humidity/water droplet) environments.
- Emphasises that laboratory results cannot, by themselves, be directly or quantitatively extrapolated to predict in-service lifetime or water endurance.
Key topics and technical requirements
The standard covers technical elements necessary to run reproducible water-endurance tests:
- Test rig and equipment: design and configuration of the test duct, water spray and humidifying devices, and water collection systems.
- Test media: specifications for test air and test water used to generate fog/mist.
- Qualification of apparatus: checks such as pressure-system integrity, air leakage, air velocity uniformity, empty-duct pressure drop, wet-environment stability, droplet-size distribution, and water tightness.
- Test procedure:
- Preparation of filter elements and measurement of initial pressure drop.
- Wet equilibrium pre-treatment to simulate pre-wetted conditions (where applicable).
- Controlled water fog test sequence and monitoring.
- Measurement of water penetration ratio and performance metrics.
- Reporting requirements: recommended test report contents, summaries, and interpretation guidance.
- Informative and normative annexes detail calculations, vertical-installation testing, tests without wet pre-treatment, penetration-ratio methods, leak detection, and example reports.
Applications and users
EN ISO 29461-2:2022 is intended for:
- Filter manufacturers validating product resistance to fog/mist and developing water-tolerant designs.
- OEMs (gas turbine, compressor and engine manufacturers) specifying intake filtration performance and procurement criteria.
- Independent test laboratories performing standardized endurance testing and issuing reports.
- Maintenance and reliability engineers assessing risk of water-induced pressure-rise or performance loss in intake systems.
- Procurement and certification bodies requiring harmonized test data for supplier evaluation.
Practical applications include product development, comparative performance assessment, supplier qualification and specification of intake filtration systems for high-humidity or coastal/industrial locations.
Related standards
- ISO 29461 series (other parts covering filter system test methods and requirements)
- Coordination with ISO/TC 142 (Cleaning equipment for air and other gases) and applicable CEN adoption documents.
Keywords: EN ISO 29461-2:2022, air intake filter systems, filter element endurance test, fog and mist environments, water endurance, rotary machinery, stationary gas turbines, compressors, test rig, water penetration ratio.
