ISO 17168-2:2025

Overview

ISO 17168-2:2025 - part of the ISO 17168 series on fine (advanced) ceramics - defines a standardized test method for measuring the air‑purification performance of semiconducting photocatalytic materials under indoor lighting, specifically for the removal of acetaldehyde. It covers materials with photocatalytic films or embedded ceramic photocatalysts (e.g., titanium dioxide‑based semiconducting oxides) in forms such as flat sheets, boards, plates, honeycomb structures, and plastic or paper composites containing ceramic microcrystals. The method uses continuous exposure of a test piece to model polluted air in a flow‑type photoreactor under controlled indoor‑light illumination to quantify acetaldehyde removal.

Key topics and technical requirements

• Scope and applicability

  • Applicable to indoor‑light‑active photocatalytic materials produced for air purification.
  • Not applicable to powder or granular photocatalytic materials.
  • Not intended to evaluate other attributes (self‑cleaning, antifogging, antibacterial action, or water contaminant decomposition).

• Test principle

  • Continuous flow photoreactor exposes a test piece to acetaldehyde (a representative VOC) under indoor‑light irradiation.
  • Photocatalytic oxidation of acetaldehyde is monitored; CO generation is measured to assess mineralization.
  • Dark tests are used to separate simple adsorption from photocatalytic removal.

• Apparatus and measurement

  • Test gas supply with controlled concentration, temperature and humidity; low‑adsorption tubing and components.
  • Photoreactor, indoor light source and UV sharp cut‑off filter to simulate indoor illumination (see ISO 14605 and ISO 24448 for light‑source specifications).
  • Analytical systems for acetaldehyde and CO measurement (referenced standards include ISO 16000‑3 and ISO 4224).
  • Procedures for pretreatment, pretest, main test, and calculation of removal percentage and converted CO (results expressed in removed quantity, µmol).

• Quality and verification

  • Method designed for reproducibility; interlaboratory test results are provided (Annex A).
  • Conformance to laboratory competence recommended (ISO/IEC 17025).

Practical applications and users

• Manufacturers of photocatalytic coatings, construction materials, honeycomb filters and composite materials - to validate and compare product performance for VOC removal under realistic indoor light.
• Independent testing laboratories and quality‑control teams - for routine performance testing and product certification.
• Indoor air quality specialists, specifiers, architects and regulators - to assess material claims, inform product selection, and support compliance or labeling of air‑purifying materials.
• R&D teams developing indoor‑light‑active photocatalysts - to benchmark formulations and optimize performance against acetaldehyde (a common indoor VOC).

Related standards

• ISO 17168‑1 - Part 1: Removal of nitric oxide (companion method for NO removal).
• ISO 14605 and ISO 24448 - light‑source specifications for indoor‑lighting tests.
• ISO 16000‑3 - sampling/analysis for carbonyls (incl. acetaldehyde).
• ISO 4224 - CO measurement (NDIR method).
• ISO/IEC 17025 - laboratory competence.

This standard supports reliable, comparable evaluation of indoor photocatalytic VOC removal performance (acetaldehyde), helping stakeholders make evidence‑based decisions on materials and product claims for improved indoor air quality.