ISO 17168-5:2025

Overview

ISO 17168-5:2025 specifies a standardized test method for assessing the air‑purification performance of semiconducting photocatalytic materials under indoor lighting, with a specific focus on the removal of methyl mercaptan (methanethiol). The standard applies to materials that contain a photocatalyst or have photocatalytic films on surfaces (commonly semiconducting metal oxides such as titanium dioxide and related fine ceramics) in flat sheet, board, plate or honeycomb forms, and to plastic/paper composites with ceramic microcrystals. It does not apply to powder or granular photocatalytic materials and is not intended for evaluating other photocatalytic attributes (self‑cleaning, antifogging, antibacterial).

Key topics and technical requirements

• Test principle: Continuous exposure of a test piece in a flow‑type photoreactor to a model pollutant (methyl mercaptan) under controlled indoor‑light illumination; performance derived from net pollutant removal and removal rate. Dark tests distinguish adsorption from photocatalytic oxidation.
• Apparatus & setup:
  • Test gas supply with flow controllers (flow rate accuracy ±5.0 %).
  • Photoreactor holding a planar test piece with a 5.0 mm ±0.5 mm air layer between piece and airtight optical window.
  • Light source: cool white fluorescent lamp with UV sharp cut‑off filter (per ISO 14605) or LED light source (per ISO 24448). Illuminance at sample: 6 000 lx ±300 lx, uniform within ±5 %.
  • Analytical measurement system for low pollutant concentrations and gas‑handling materials resistant to UV and adsorption (acrylic, stainless steel, glass, fluoropolymers).
• Test gases & concentrations: Standard methyl mercaptan cylinders typically balanced in nitrogen with volume fractions in the 100–1 000 µl/l range.
• Test piece dimensions and reactor geometry are specified (e.g., 99.0 mm × 49.0 mm test piece).
• Reporting & quality: Includes calculation of removal quantity and percentage, procedures for low‑performance samples, and requirements consistent with laboratory competence (ISO/IEC 17025 referenced).

Applications and users

• Who uses it: photocatalytic material manufacturers, product developers, independent testing laboratories, certification bodies, architects and specifiers, indoor air quality consultants, and regulatory agencies.
• Practical uses:
  • Product development and R&D for indoor‑active photocatalysts.
  • Quality control and batch comparison of air‑purifying materials.
  • Comparative performance claims and lab‑based certification for odor removal (sulfurous compounds).
  • Material selection for building interiors, ventilation components, and consumer products targeting odor control.

Related standards

• ISO 17168‑1 (Removal of nitric oxide) - foundational test methodology for indoor photocatalytic performance.
• ISO 14605 - light source for indoor testing (fluorescent + UV cut‑off).
• ISO 24448 - LED light source specification for indoor photocatalytic testing.
• ISO/IEC 17025 - laboratory competence and calibration requirements.

Keywords: ISO 17168-5:2025, fine ceramics, photocatalytic materials, air‑purification performance, methyl mercaptan, indoor lighting, titanium dioxide, photoreactor, ISO 14605, ISO 24448.