ISO 10820:2025

Fine ceramics (advanced ceramics, advanced technical ceramics) - Ultraviolet irradiation equipment using UV-A LEDs and optical radiometry for performance test of semiconducting photocatalytic materials

This document specifies the irradiation equipment using ultraviolet light emitting diode (UV-LED) and optical radiometry for testing the performance of semiconducting photocatalytic materials. The UV-LED irradiation equipment specified in this document uses UV-LEDs having a peak wavelength of 365 nm in the UV-A range and applies for a semiconductor photocatalyst exhibiting a photocatalytic function at this wavelength. This document applies only to irradiation equipment using UV-LED. ISO 10677[ REF Reference_ref_2 \r \h 2 08D0C9EA79F9BACE118C8200AA004BA90B0200000008000000100000005200650066006500720065006E00630065005F007200650066005F0032000000 ] is applicable for equipment using conventional UV light sources such as fluorescent lamps.

Titre manque

General Information

• Status: Published
• Publication Date: 17-Sep-2025
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206 - Fine ceramics
• Current Stage: 6060 - International Standard published
• Start Date: 18-Sep-2025
• Due Date: 13-Sep-2026
• Completion Date: 18-Sep-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.

Standards Content (Sample)

International
Standard
ISO 10820
First edition
Fine ceramics (advanced ceramics,
2025-09
advanced technical ceramics) —
Ultraviolet irradiation equipment
using UV-A LEDs and optical
radiometry for performance test
of semiconducting photocatalytic
materials
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Irradiation equipment . 3
4.1 UV-LED Chip properties .3
4.2 UV-LED irradiation equipment .4
4.3 UV-LED Chip replacement .4
5 UV radiometers and spectroradiometers . 4
5.1 General .4
5.2 UV radiometers .4
5.3 Spectroradiometers .4
6 Report of irradiation equipment in each application standard . 5
Annex A (informative) Irradiation equipment having multiple UV-LED chips . 6
Bibliography .11

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
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This document was prepared by Technical Committee ISO/TC 206, Fine Ceramics.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Photocatalytic materials are useful in the treatment of harmful environmental pollutants and
microorganisms. The market has been expanding significantly over the past 20 years, with the development
[1]
of test methods for various functions of photocatalyst, including ISO 27447 . Light irradiation equipment
[2]
is indispensable for testing photocatalytic materials, and ISO 10677 is widely used as a common UV light
source standard in various ISO performance test methods.
In recent years, LEDs that are highly efficient and do not use harmful substances such as mercury have
been rapidly developed even in the UV range, and conventional fluorescent lighting will be more difficult to
provision in the future. Since the characteristics of LEDs are significantly different from those of conventional
UV light sources, this document has been developed so that UV-LEDs can be used for performance testing of
various photocatalytic materials. UV-LEDs with a peak wavelength of 365 nm are chosen because they are
commonly available and good for photoexcitation of most of semiconductor photocatalysts.
Currently, no other ISO standard exists that uses UV-LED as the test light source for photocatalytic materials.
[2]
ISO 10677 will continue to be maintained for the time being for conventional light source users.

v
International Standard ISO 10820:2025(en)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Ultraviolet irradiation equipment using
UV-A LEDs and optical radiometry for performance test of
semiconducting photocatalytic materials
1 Scope
This document specifies the irradiation equipment using ultraviolet light emitting diode (UV-LED) and
optical radiometry for testing the performance of semiconducting photocatalytic materials. The UV-LED
irradiation equipment specified in this document uses UV-LEDs having a peak wavelength of 365 nm in
the UV-A range and applies for a semiconductor photocatalyst exhibiting a photocatalytic function at this
wavelength.
[2]
This document applies only to irradiation equipment using UV-LED. ISO 10677 is applicable for equipment
using conventional UV light sources such as fluorescent lamps.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
bandwidth
Δλ
measure of the width of a bandpass function defined by:
∫−b()λλ dλ
Δλ =
b λ
()
where
b(λ - λ ) is the bandpass function about the central wavelength, λ ;
0 0
b(λ ) is the bandpass function at the central wavelength, λ .
0 0
Note 1 to entry: In geometric terms, the bandwidth is the width of a rectangle with the same area as the bandpass
function and height the same as the bandpass function at the nominal centre wavelength, λ .
Note 2 to entry: For a triangular or trapezoid bandpass, the bandwidth is equal to the full width at half maximum (FWHM).
[5]
[SOURCE: CIE 233:2019, 3.3 ]
3.2
cut-off wavelength
wavelength for which spectral distribution of UV-LED is 5 %
Note 1 to entry: See Figure 1, Key D.
[8]
[SOURCE: CEN/TS 16599:2014, 3 ]
Key
X wavelength, nm
Y relative spectral irradiance
A maximum wavelength, nm
B full-width at half maximum (FWHM), nm
C cut-on wavelength, nm
D cut-off wavelength, nm
Figure 1 — Definitions of spectral characteristics of UV-LEDs
3.3
cut-on wavelength
wavelength for which spectral distribution of UV-LED is 2 %
Note 1 to entry: See Figure 1, Key C.
[8]
[SOURCE: CEN TS 16599:2014, 3 ]
3.4
directional response index (cosine response index) for irradiance
f
index describing the responsivity of the photometer to light incident at an angle other than normal (the
cosine law for general purpose illuminance meters)
[3]
[SOURCE: ISO/CIE 19476:2014, 3.2.5 ]
3.5
full-width at half maximum
FWHM
wavelength difference between the half-maximum points of the bandpass
Note 1 to entry: See Figure 1, Key B.
[5]
[SOURCE: CIE 233:2019, 3.4 ]
3.6
irradiation equipment
equipment for irradiation having a light source or multiple light sources
3.7
photocatalyst
substance that performs one or more catalytic functions based on oxidation or reduction reactions under
photoirradiation
Note 1 to entry: The functions include decomposition and removal of air and water contaminants, deodorization,
antibacterial, self-cleaning, and antifogging actions. A photocatalyst can also be used for light energy conversion.
3.8
spectral responsivity
s(λ)
quotient of the detector output, dY(λ), by the monochromatic detector input, dX (λ)=X (λ)dλ, in the
e e,λ
wavelength interval, dλ, as a function of wavelength, λ
dY()λ
s λ =
()
dX ()λ
e
[4]
Note 1 to entry: This entry was numbered 845-05
...