ISO 27447:2019

Overview

ISO 27447:2019 defines a standardized test method for the antibacterial activity of semiconducting photocatalytic materials. The method measures bacterial survival (enumeration of viable bacteria) on materials that contain or are coated with a photocatalyst under ultraviolet (UV) irradiation. It is intended for flat construction-type forms (sheets, boards, plates) and textiles, and excludes powders, granules and porous/permeable surfaces. The standard is commonly applied to photocatalytic materials produced for antibacterial effects - often based on titanium dioxide (TiO2) - but does not assess other photocatalytic functions (antifungal, antiviral, self‑cleaning, air or water purification).

Key topics and technical requirements

• Test principle: Enumeration of viable bacteria before and after controlled UV irradiation to quantify antibacterial effect.
• Test specimen types: Flat sheets, boards, plates and textiles; powders, granules and porous materials are excluded.
• Two covering methods: Film cover method and glass cover method for placing bacterial inoculum on the test surface.
• Bacterial preparation and media: Defined procedures for bacterial strains, inoculum, and use of nutrient broths, nutrient agar and SCDLP neutralizer.
• Apparatus and light source:
  • UV light source and irradiance measurement specified (use of UV radiometer).
  • Light source and radiometer requirements referenced to ISO 10677.
• Environmental and procedural controls:
  • Specified UV irradiation conditions and laboratory conditions (e.g., test environment temperature noted).
  • Limits on storage and handling of bacterial suspensions and media.
• Data handling and calculation: Procedures to calculate the photocatalyst antibacterial activity value from viable counts; requirements for test reporting.
• Safety note: Microbial handling requires trained personnel and appropriate biosafety procedures.
• Informative annexes: Examples of test results and reference data for cover films/glasses and UV damage to bacteria.

Practical applications and who uses this standard

• Manufacturers of photocatalytic ceramics, glass, coatings and textiles who need validated antibacterial performance claims.
• Independent testing laboratories and quality assurance teams performing standardized antibacterial efficacy testing.
• Product developers and R&D teams assessing photocatalyst formulations (e.g., TiO2 coatings) for building materials and interior finishes.
• Specifiers, procurement officers, and regulatory authorities requiring reproducible, comparable test data for antimicrobial materials used in construction and healthcare environments.

Related standards

• ISO 10677 - Ultraviolet light source for testing semiconducting photocatalytic materials
• ISO 80000-1 - Quantities and units (general)

Keywords: ISO 27447, antibacterial activity, photocatalytic materials, semiconducting photocatalyst, UV irradiation, bacteria enumeration, TiO2, testing protocol, construction materials.