ISO 22197-3:2019

Overview

ISO 22197-3:2019 defines a standardized laboratory test method for the air‑purification performance of semiconducting photocatalytic materials - specifically measuring the removal of toluene, a representative aromatic volatile organic compound (VOC). The standard applies to materials that incorporate or are coated with photocatalysts (commonly titanium dioxide or other semiconducting metal oxides) in planar forms (sheets, boards, plates), structured filters (honeycomb, woven/non‑woven), and composite plastics or papers that contain ceramic microcrystals. It excludes powders/granular photocatalysts and does not address other photocatalytic functions (e.g., water‑phase decomposition, self‑cleaning, antifogging, antibacterial).

Key topics and technical requirements

• Test principle: Continuous flow photoreactor exposes a defined test piece to toluene‑containing air under UV‑A irradiation; photocatalytic oxidation and adsorption are quantified.
• Pollutant and metrics: Uses toluene as a model VOC; removal is reported in micromoles (µmol) and as removal percentage. Dark tests evaluate adsorption separate from photocatalysis.
• Photoreactor design: Test piece placed with a controlled air gap (nominal 5.0 mm ±0.5 mm) between sample and optical window; flow is limited to the gap region.
• Light source: UV‑A irradiation in the 300–400 nm range (black‑light/BL(B) fluorescent lamps or filtered xenon), with specified irradiance at the sample surface (document specifies a target irradiance and uniformity requirement).
• Gas supply and flow control: Continuous test gas with controlled toluene concentration, temperature and humidity; thermal mass‑flow controllers and low‑adsorption materials are required for accurate low‑concentration testing.
• Analytical system: Sensitive pollutant measurement to detect low toluene concentrations and calculate removed amount; system construction must minimize background adsorption.
• Procedure elements: Sample pretreatment (including removal of water‑soluble contaminants), dark adsorption check, UV exposure testing, calculation and acceptance criteria for adsorption/performance.
• Scope limits: Not suitable for powder/granular materials or for assessing non‑air purification photocatalytic properties.

Applications

• Performance evaluation of photocatalytic building materials (tiles, panels), air‑purification coatings and structured photocatalytic filters.
• Quality control and R&D for manufacturers of fine/advanced ceramics and photocatalytic composites.
• Comparative testing in product development and certification programs where toluene or aromatic VOC removal is a target.
• Laboratory method for researchers studying VOC degradation by semiconductor photocatalysts.

Who should use this standard

• Material manufacturers (ceramics, coatings, composite panels)
• Filter and HVAC component producers integrating photocatalytic functions
• Independent testing and calibration laboratories (ISO/IEC 17025 accredited)
• Product certifiers, specifiers, and researchers evaluating VOC air‑purification performance

Related standards

• ISO 22197 series (other parts for different pollutants)
• ISO 10677 (UV light source for photocatalytic testing)
• ISO 4892‑3 (fluorescent UV lamps)
• ISO/IEC 17025 (laboratory competence)

Keywords: ISO 22197‑3:2019, photocatalytic materials, air‑purification performance, toluene removal, fine ceramics, titanium dioxide, UV‑A photoreactor, VOC testing, photocatalyst test method.