ISO 17168-2:2018

Overview

ISO 17168-2:2018 specifies a laboratory test method for evaluating the air‑purification performance of semiconducting photocatalytic materials under indoor lighting, focusing on the removal of acetaldehyde, a representative volatile organic compound (VOC). The standard applies to photocatalytic materials and surface films (commonly titanium dioxide and other ceramic semiconductors) in consolidated forms - e.g., flat sheets, boards, plates, honeycomb structures, and plastic/paper composites containing ceramic microcrystals. It excludes powder or granular photocatalysts and is not intended to assess other attributes (self‑cleaning, antifogging, antibacterial or water contaminant decomposition).

Key topics and technical requirements

• Principle: Continuous exposure of a test piece in a flow‑type photoreactor to a model acetaldehyde‑containing air stream under controlled indoor‑light irradiation; photocatalytic oxidation and adsorption are distinguished by dark tests.
• Photoreactor design: Planar test piece held parallel to an airtight optical window with a specified 5.0 mm ± 0.5 mm air gap; gas flows only through this gap to the active surface.
• Test gas supply & control:
  • Use of mass‑flow controllers and humidifier to deliver pollutant concentration, temperature and humidity within specified limits (flow stability within ±5%).
  • Typical controller capacities cited (pollutant gas ~100 mL/min; dry/wet air ~1 000 mL/min).
  • Standard acetaldehyde cylinder concentrations normally 50–250 µl/l for dilution.
• Illumination & filters: Indoor‑light source and UV sharp‑cutoff filter per ISO 14605 to simulate realistic indoor spectra.
• Analytical measurements:
  • Quantify acetaldehyde removal (µmol, removal percentage) and, where applicable, monitor CO conversion as an oxidation product.
  • Use low‑adsorption materials in the test system and validated analytical methods for acetaldehyde and CO.
• Procedure elements: Pretreatment, pretest stabilization, dark control runs, calculation methods (removal quantity, percent removal, CO conversion) and reporting requirements.
• Validation: Interlaboratory test results included (Annex A) to support method reproducibility.

Applications and who uses it

• Manufacturers and R&D teams developing indoor‑light‑active photocatalytic surfaces and advanced ceramic coatings.
• Accredited test laboratories performing performance verification for product claims related to indoor air quality (IAQ) and VOC removal.
• Building materials suppliers, architects and specifiers assessing materials for low‑VOC/air‑purifying interior finishes.
• Regulators, certification bodies and product certifiers needing standardized, comparable test data for market surveillance and labeling.

Related standards

• ISO 17168-1 (Part 1 - Removal of nitric oxide)
• ISO 14605 (Light source for indoor photocatalyst testing)
• ISO 16000-3 (Determination of carbonyls in indoor air)
• ISO 4224 (CO determination - NDIR method)
• ISO/IEC 17025 (Laboratory competence)

Keywords: ISO 17168-2, photocatalytic materials, acetaldehyde removal, indoor‑light, fine ceramics, air‑purification performance, titanium dioxide, photoreactor, VOC removal, indoor air quality.