ISO 29461-2:2022

Overview

ISO 29461-2:2022 - "Air intake filter systems for rotary machinery - Test methods - Part 2: Filter element endurance test in fog and mist environments" defines a repeatable laboratory water endurance test for air filter elements used in rotary machinery (for example, stationary gas turbines, compressors and stationary internal combustion engines). The standard specifies general requirements, the test rig and equipment, test materials and the test procedure and report needed to determine how filter elements perform when exposed to fog, mist and high-humidity conditions. Results are intended for comparison and development; they are not, by themselves, quantitative predictors of in-service lifetime.

Key topics and technical requirements

• Test scope and purpose: evaluate water endurance performance of air filter elements under controlled laboratory conditions (fog/mist environments).
• Test rig and equipment: requirements for test duct, water spray device, humidifying device, water collection, and two-fluid nozzles.
• Qualification of apparatus: pressure system and air leakage tests, air velocity uniformity, pressure-drop baseline, water tightness, droplet size distribution and fog mass concentration checks.
• Test procedure:
  • Preparation of the filter element and measurement of initial pressure drop.
  • Wet equilibrium pre-treatment (where applicable).
  • Controlled water fog test to assess pressure-drop rise and water handling.
  • Measurement of water penetration ratio (see Annex D - normative).
• Measurements and reporting: record initial and final pressure drop, water fog mass, penetration ratio, test duration and environmental conditions; include standardized test report templates (informative annexes).
• Annexes: examples of completed test reports, vertical-installation testing guidance, apparatus checks and detection procedures.

Practical applications and who uses this standard

ISO 29461-2:2022 is useful for:

• Filter manufacturers: product development, design validation and R&D of water-enduring media.
• Media suppliers: assessing new filter media formulations for fog and mist resistance.
• End users and asset owners (power plants, compressor stations): supplier selection, procurement specifications and comparative evaluation of filter options for humid environments.
• Test laboratories and certification bodies: reproducible laboratory method for benchmarking and quality assurance.
• Maintenance and reliability engineers: understanding how filters behave under water-laden intake air and informing operational risk assessments.

Related standards

• ISO 29461 series (other parts address system-level requirements).
• ISO 16890-2:2022 (referenced for fractional efficiency and airflow resistance measurement).

Keywords: ISO 29461-2:2022, air intake filter, water endurance test, fog and mist environments, filter element testing, rotary machinery, gas turbine filters, compressor intake filters, pressure drop, water penetration ratio.