ISO 17168-3:2018

Overview

ISO 17168-3:2018 specifies a laboratory test method to determine the air‑purification performance of semiconducting photocatalytic materials with respect to toluene removal under an indoor lighting environment. It applies to photocatalytic films and materials (flat sheets, boards, plates, honeycomb structures, and composites containing ceramic microcrystals), typically based on semiconducting metal oxides such as titanium dioxide. The standard excludes powders and granular photocatalysts and is focused specifically on gas‑phase VOC removal (toluene), not on water treatment, self‑cleaning, antifogging or antibacterial properties.

Key Topics

• Test principle: Continuous exposure of a prepared test piece to a model toluene‑contaminated air stream in a flow‑type photoreactor while illuminated by indoor light; measurement of toluene removal (photocatalytic oxidation vs. adsorption).
• Apparatus and setup: Test gas supply (humidified, controlled concentration), photoreactor with airtight optical window, light source (cool white halophosphate lamp), UV sharp cut‑off filter, and analytical measurement system.
• Controlled parameters: illuminance at test surface (e.g., 6 000 lx ± 300 lx), air layer gap between window and sample (5.0 mm ± 0.5 mm), and standard toluene supply concentrations (typical pre‑diluted cylinder 10–50 µl/l).
• Measurement and evaluation: determination of toluene volume fraction at reactor exit, calculation of toluene removed (μmol) and removal percentage, and separate dark tests to assess adsorption vs. photocatalytic activity.
• Quality and reproducibility: requirements for flow control (thermal mass‑flow controllers), low‑adsorption reactor materials, uniform illumination, and interlaboratory comparison guidance.

Applications

• Who uses this standard:
  • Photocatalytic material manufacturers evaluating indoor‑light‑active products
  • Construction material producers (coatings, panels, honeycomb substrates)
  • Accredited testing laboratories and R&D groups validating VOC removal performance
  • Product certification bodies and specifiers assessing air‑purification claims
• Practical uses:
  • Validate effectiveness of photocatalytic coatings for indoor VOC reduction (toluene as representative aromatic VOC)
  • Compare product performance under standardized indoor lighting conditions
  • Support product development, quality control and marketing claims with reproducible test data

Related Standards

• ISO 17168-1 (Removal of nitric oxide) - companion method in the same series
• ISO 14605 - light source specification for indoor photocatalytic testing
• ISO 22197 series - related photocatalytic performance methods
• ISO/IEC 17025 - laboratory competence and calibration requirements
• ISO 6145-7, ISO 80000-1 - gas calibration and units

Keywords: ISO 17168-3:2018, photocatalytic materials, fine ceramics, toluene removal, indoor lighting, air‑purification test method, semiconducting photocatalyst, VOC removal, photoreactor.