ISO 10820:2025

Overview

ISO 10820:2025 specifies ultraviolet (UV) irradiation equipment and optical radiometry for performance testing of semiconducting photocatalytic materials, with a focus on UV-A LEDs. The standard defines spectral, electrical and measurement requirements for UV‑LED sources (peak wavelength 365 nm ± 5 nm) and for the radiometric instruments used to quantify irradiance and dose. ISO 10820 is intended for testing photocatalysts that are excited at 365 nm and complements existing standards for conventional lamps (see Related Standards).

Key topics and requirements

• UV‑LED spectral characteristics
  • Peak wavelength: 365 nm ± 5 nm
  • Full width at half maximum (FWHM): ≤ 10 nm
  • Cut-on wavelength: 345 nm ± 5 nm (recommended)
  • Cut-off wavelength: 385 nm ± 5 nm (recommended)
• LED drive and stability
  • UV‑LED chips shall be driven by direct current (DC) only.
  • UV irradiance stability requirement: ≤ 1.25 %/h (measured at start, end and each 1‑h interval during tests).
  • Replacement: replace UV‑LED chips when irradiance falls to 70% of initial value.
• Irradiation uniformity
  • Uniformity U = |Eav − Emin| / Eav × 100 (%), where Eav is average and Emin is minimum irradiance on the sample surface.
  • For multi‑chip arrays, use identical chips (same manufacturer/catalogue) and consider wavelength selection to ensure uniform spectral output.
• Optical radiometry requirements
  • UV radiometers: spectral responsivity should be constant over 310–400 nm or calibrated against a matching spectral source; measurements traceable to national metrology.
  • Spectroradiometers: bandwidth ≤ 5 nm, calculation interval = bandwidth, and UV irradiance calculated by E = ∫315–400 E(λ) dλ. Calibration traceable to national spectral irradiance standards.
  • Directional response (cosine) index f ≤ 8% (can be waived for parallel optics or single‑chip sources).
• Reporting
  • Test reports must include reference to ISO 10820:2025, equipment type/manufacturer/catalogue, radiometer/spectroradiometer details, and measured UV irradiance at the sample.

Applications and users

ISO 10820 is intended for laboratories, test houses, manufacturers of photocatalytic materials (including fine/advanced ceramics), LED irradiation system designers, research institutions and conformity assessment bodies performing standardized performance tests (e.g., antibacterial testing, pollutant decomposition) on semiconducting photocatalysts that respond at 365 nm UV‑A. It supports reproducible, comparable performance testing using modern mercury‑free UV‑LED technology.

Related Standards

• ISO 10677 - for irradiation equipment using conventional UV sources (fluorescent lamps).
• Application standards such as ISO 27447 (antibacterial performance testing) reference UV irradiation requirements and can adopt ISO 10820 for LED‑based light sources.

Keywords: ISO 10820, UV‑LED, UV‑A 365 nm, photocatalytic materials, semiconducting photocatalyst, optical radiometry, UV radiometer, spectroradiometer, irradiation equipment, fine ceramics.