ISO 11155-2:2009

Overview

ISO 11155-2:2009 - Road vehicles - Air filters for passenger compartments - Part 2: Test for gaseous filtration - defines laboratory test methods for measuring dynamic gas adsorption of cabin air filters. The standard applies to air filters that reduce gaseous, odorous or hazardous components from ambient or re‑circulated air in vehicle passenger compartments. It provides procedures to measure gas/vapour removal characteristics and air pressure loss, enabling reproducible evaluation of filter performance against specific gaseous contaminants.

Key topics and technical requirements

• Test scope and purpose: Dynamic laboratory tests to determine gaseous filtration efficiency, breakthrough, capacity and optional desorption behaviour.
• Mandatory and optional contaminants:
  • Mandatory: n‑butane and toluene (set point ~80 ± 8 ppm, purity ≥ 99.5%).
  • Optional: SO2 (set point ~30 ± 3 ppm) for acid gas representation. Annex D covers conversion factors and other gases.
• Measurement accuracy and conditions:
  • Flow rate accuracy ±3 %, differential pressure ±2 %, temperature ±0.5 °C, relative humidity ±2 %.
  • Conditioning of challenge gas: (23 ± 3) °C and (50 ± 2) % RH.
  • Influent concentration stability maintained within ±3 % of set point.
• Definitions & metrics: Efficiency (percentage removal), influent/effluent concentrations, time zero (t0) and lag time, capacity (mass adsorbed), and test duration criteria.
• Test equipment and validation: Requirements for test stand layout, air supply, contaminant generation, sampling/analysis and system validation (flow uniformity, concentration stability). Normative annexes provide test stand configuration and calculation details.
• Output: Test report contents, data analysis methods, and optional desorption testing.

Applications and who uses this standard

ISO 11155-2:2009 is used by:

• Automotive filter manufacturers for product development and quality control of cabin air filters (activated carbon and other adsorption media).
• Vehicle OEMs to specify cabin air filter performance for passenger comfort and safety.
• Independent test laboratories performing standardized gaseous filtration testing and certification.
• Regulators and procurement teams evaluating air quality performance for vehicles, fleets and public transport.

Practical applications include evaluating activated-carbon based filters for removal of hydrocarbons, aromatics and acidic gases, assessing pressure drop impact on HVAC performance, and comparing filter capacity and service life under controlled challenge gas exposure.

Related standards

• ISO 11155-1: Test for particulate filtration (companion part).
• ISO 11841-1 / ISO 11841-2: Filter vocabulary and characteristics definitions.

Keywords: ISO 11155-2:2009, gaseous filtration, cabin air filters, automotive air filters, challenge gas, breakthrough, capacity, efficiency, activated carbon.