ISO 24448:2023

INTERNATIONAL ISO
STANDARD 24448
First edition
2023-07
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
LED light source for testing
semiconducting photocatalytic
materials used under indoor lighting
environment
Céramiques techniques — Source de lumière LED pour les essais
des matériaux photocatalytiques semi-conducteurs utilisés dans un
environnement d'éclairage intérieur
Reference number
ISO 24448:2023(E)
© ISO 2023

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ISO 24448:2023(E)
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© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 24448:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Light sources . 2
5 Illuminance meters .4
6 Measurement and use conditions . 4
7 Test report . 4
Annex A (informative) Relationship between photocatalytic performance and correlated
colour temperature of light source and indoor lighting environments .5
Annex B (informative) Difference in characteristics of white LED lamps in the same
product sold in the market . .7
Annex C (informative) Example of an irradiation box with a large uniform illuminance on
an irradiation surface .8
Annex D (informative) Characteristics of illuminance meters .11
Bibliography .14
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ISO 24448:2023(E)
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
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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 ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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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
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ISO 24448:2023(E)
Introduction
Photocatalytic performance depends on testing light sources. To fairly evaluate photocatalytic
performance, an ISO Standard on testing light sources for photocatalytic materials used under indoor
lighting environments was developed based on the lighting environment prevalent at the time of its
[1]
drafting (ISO 14605 ). Fluorescent lamps are specified as a testing light source in the document.
However, in order to achieve a low-carbon society and reduce the environmental load of mercury,
production of this type of lamp will stop in the near future. Light sources for indoor lighting will change
from this type of lamp to white LED lamps. According to a global lighting market report, the LED share
[11]
in general lighting was 45 % in 2016 and almost 70 % in 2020. Another report estimates the 2018
share of solid-state light products, including LEDs, as 64 %, and predicts that by 2030 this will rise to
[12]
96 %. This document has been developed based on this background.
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INTERNATIONAL STANDARD ISO 24448:2023(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — LED light source for testing semiconducting
photocatalytic materials used under indoor lighting
environment
1 Scope
This document specifies light emitting diodes (LED) for light source and radiometers used in the
performance evaluation of semiconducting photocatalytic materials under indoor LED lighting
environments in a laboratory. Light sources for indoor lighting environments do not include sunlight
passing through window glass.
[1]
This document does not replace ISO 14605. Either document can apply depending on the lighting
environment in which the photocatalytic material is used.
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
indoor lighting environment
lighting environment with artificial light source for general lighting service that does not include
sunlight
[1]
[SOURCE: ISO 14605:2013, 3.3 ]
3.2
light emitting diode
LED
solid-state device embodying a p-n junction, emitting incoherent optical radiation when excited by an
electric current
[3]
[SOURCE: IEC 60050-845:1987, 845-04-40 ]
3.3
correlated colour temperature
temperature of the Planckian radiator whose perceived colour most closely resembles that of a given
stimulus at the same brightness and under specified viewing conditions
Note 1 to entry: The correlated colour temperature is expressed in kelvins (K).
Note 2 to entry: The recommended method of calculating the correlated colour temperature of a stimulus is to
determine on a chromaticity diagram the temperature corresponding to the point on the Planckian locus that is
intersected by the agreed isotemperature line containing the point representing the stimulus.
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ISO 24448:2023(E)
Note 3 to entry: Reciprocal correlated colour temperature is used rather than reciprocal colour temperature
whenever correlated colour temperature is appropriate.
[3]
[SOURCE: IEC 60050-845:1987, definition 845-03-50 ]
3.4
colour rendering index
measure of the degree to which the psychophysical colour of an object illuminated by the test illuminant
conforms to that of the same object illuminated by the reference illuminant, suitable allowance having
been made for the state of chromatic adaptation
Note 1 to entry: In German, the term “Farbwiedergabe-Index” is also applied to colour reproduction.
[3]
[SOURCE: IEC 60050-845:1987, definition 845-02-61 ]
3.5
CIE 1974 general colour rendering index
Ra
mean of the CIE 1974 special colour rendering indices for a specified set of eight test colour samples
[3]
[SOURCE: IEC 60050-845:1987, definition 845-02-63 ]
3.6
spectral luminous efficiency
V (λ) for photopic vision
ratio of the radiant flux at wavelength λ to that at
m
wavelength λ such that both radiations produce equally intense luminous sensations under specified
photometric conditions and λ is chosen so that the maximum value of this ratio is equal to 1
m
Note 1 to entry: Unless otherwise indicated, the values used for the spectral luminous efficiency in photopic
vision are the values agreed internationally in 1924 by the CIE, completed by interpolation and extrapolation,
and recommended by the International Committee of Weights and Measures (CIPM) in 1972.
[3]
[SOURCE: IEC 60050-845:1987, definition 845-01-22, modified ]
3.7
general V(λ) mismatch index
f’
1
index describing the deviation of the relative spectral responsivity of the photometer from the V(λ)
function
[2]
[SOURCE: ISO/CIE 19476:2014, 3.2.2 ]
3.8
directional response index (cosine response index) for illuminance
f
2
index describing the responsivity of the photometer to light incident at an angle other than normal (the
cosine law for general purpose illuminance meters)
[2]
[SOURCE: ISO/CIE 19476:2014, 3.2.5 ]
4 Light sources
The following requirements apply to white LED lamps used as a testing light source of photocatalytic
materials under indoor LED lighting environments.
a) A phosphor-type LED lamp with a peak wavelength of optical radiation emitting from solid of
450 nm ± 10 nm shall be used (see A.1 for additional information).
b) A phosphor-type LED lamp with a CIE 1974 general colour rendering index Ra of 80 ≤ Ra < 90 shall
be used.
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ISO 24448:2023(E)
c) Correlated colour temperature of a white phosphor-type LED lamp shall be defined by a national
testing light source standard for photocatalytic materials, a regional (e.g. EU) light source standard
for photocatalytic materials or a light source standard of each national photocatalytic association.
Where these standards are not published, correlated colour temperature of the white phosphor-
type LED lamp shall be between 3 800 K and 4 500 K (F4000, cool white). Lighting environments in
different countries are described in A.2 for additional information.
d) A phosphor-type LED lamp shall be driven by direct current (DC). An alternating current (AC)-
driven phosphor-type LED lamp is not permitted.
e) If a phosphor-type LED lamp with a reflection plate is selected for the testing light source, the
colour of the reflection plate shall be white.
f) If multiple white LED lamps are used to achieve a large uniform irradiation surface, at least the
same white LED lamp (the same manufacturer and the same catalogue number) shall be used. A
selection of white LED lamps with a peak wavelength of optical radiation emitting from solid is
strongly recommended.
If the spectral distribution data of LED lamps is not obtained from the manufacturer, the peak
wavelength of the optical radiation emitting from a solid shall be evaluated with a spectral irradiance
meter or a spectral illuminance meter. The spectral response of a spectral irradiance meter or a spectral
illuminance meter shall be calibrated with a spectral irradiance standard lamp which is traceable to
the national standard.
A typical spectral distribution of white LED lamps specified by this document is shown in Figure 1.
Key
X wavelength, nm
Y relative radiant power
Figure 1 — An example of spectral power distribution of a white LED in which the correlated
colour temperature is 4 000 K and CIE 1974 general colour rendering index Ra is 80
NOTE 1 White LEDs sold in the market are divided into two types by method of white light generation. The
first is RGB type. This type of white LEDs has three LED chips which emit red, green and blue light in one LED
package. The second is phosphor-type. This type of white LEDs generates white light by fluorescence of phosphor
which is excited by violet light (405 nm) or blue light (450 nm) emitting from solid. The phosphor-type white
LEDs using phosphors excited by blue light are commonly used in lighting environments.
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ISO 24448:2023(E)
NOTE 2 An example of the different characteristics of white LED lamps in the same product sold in the market
is shown in Annex B. An example of an irradiation box with a large uniform irradiation surface is shown in
Annex C.
5 Illuminance meters
Illuminance (E) shall be measured by an illuminance meter. The following specifications apply.
a) A conventional filter-type illuminance meter shall be used. A spectral radiometer or a spectral
illuminance meter shall not be used as an illuminance meter.
b) A conventional filter-type illuminance meter with a general V(λ) mismatch index f’ of ≤ 6 % shall
1
be used.
c) A conventional filter-type illuminance meter with a directional response index (cosine response
index) for illuminance f of ≤ 4 % shall be used.
2
d) A conventional filter-type illuminance meter which has been calibrated by a national calibration
laboratory or with a standard lamp which is traceable to the national measurement standard shall
be used.
The importance of defining the characteristics of illuminance meters is described in Annex D.
6 Measurement and use conditions
a) The illumina
...