SIST EN ISO 24444:2020

SLOVENSKI STANDARD
oSIST prEN ISO 24444:2019
01-maj-2019
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Cosmetics - Sun protection test methods - In vivo determination of the sun protection
factor (SPF) (ISO/DIS 24444:2019)
Kosmetik - Untersuchungsverfahren für Sonnenschutzmittel - In-vivo-Bestimmung des
Sonnenschutzfaktors (SSF) (ISO/DIS 24444:2019)
Cosmétiques - Méthodes d'essai de protection solaire - Détermination in vivo du facteur
de protection solaire (FPS) (ISO/DIS 24444:2019)
Ta slovenski standard je istoveten z: prEN ISO 24444
ICS:
71.100.70 .R]PHWLND7RDOHWQL Cosmetics. Toiletries
SULSRPRþNL
oSIST prEN ISO 24444:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 24444:2019

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oSIST prEN ISO 24444:2019
DRAFT INTERNATIONAL STANDARD
ISO/DIS 24444
ISO/TC 217 Secretariat: ISIRI
Voting begins on: Voting terminates on:
2019-03-20 2019-06-12
Cosmetics — Sun protection test methods — In vivo
determination of the sun protection factor (SPF)
Cosmétiques — Méthodes d'essai de protection solaire — Détermination in vivo du facteur de protection
solaire (FPS)
ICS: 71.100.70
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 24444:2019(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2019

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oSIST prEN ISO 24444:2019
ISO/DIS 24444:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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.
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2019 – All rights reserved

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oSIST prEN ISO 24444:2019
ISO/DIS 24444:2019(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Terms and definitions . 1
3 General principle . 3
4 Test subjects . 3
4.1 Selection of the test subjects . 3
4.1.1 General. 3
4.1.2 Skin colour of the test subjects . 3
4.1.3 Age restriction. 4
4.1.4 Frequency of participation in tests . 4
4.1.5 Ethics and consent. 4
4.2 Number of test subjects . 4
5 Apparatus and materials. 4
5.1 Source of ultraviolet radiation . 4
5.1.1 General. 4
5.1.2 Quality of ultraviolet radiation . 4
5.1.3 Total irradiance (UV, visible and near infrared rays) . 5
5.1.4 Uniformity of beam . 5
6 Maintenance and monitoring the UV solar simulator output . 7
6.1 Spectroradiometry . 7
6.2 Radiometry . 7
7 Reference sunscreen formulations . 8
7.1 General . 8
7.2 Reference standard to be used . 8
8 Procedure. 9
8.1 Main steps . 9
8.2 Test conditions . 9
8.3 Position of the test subjects . 9
8.4 Product application . 9
8.5 Procedure for MED assessment . .13
8.5.1 General.13
8.5.2 Time of assessment of MED .13
8.5.3 Data rejection criteria . .14
8.5.4 Test Failure Criteria .15
8.5.5 Expression of MEDs . .15
9 Calculation of the sun protection factor and statistics .15
9.1 Calculation of the individual SPF (SPFi) .15
9.2 Calculation of product SPF .15
9.3 Statistical criterion .15
9.4 Validation of the test .16
10 Test report .16
10.1 General Information .16
10.2 Data in tabular for each test subject .16
10.3 Statistics for the test products .17
Annex A (normative) Selection criteria for the test subjects .18
Annex B (normative) Definition of the UV solar simulator output .20
Annex C (normative) SPF reference sunscreen formulations .27
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Annex D (normative) Calculations and statistics .39
Annex E (normative) Colourimetric determination of skin colour typing and prediction
of the minimal erythemal dose (MED) without UV exposure .45
Annex F (informative) Visual Guidance For Erythema Grading.49
Annex G (normative) Sample Report Form .55
Bibliography .57
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oSIST prEN ISO 24444:2019
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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 ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 24444 was prepared by Technical Committee ISO/TC 217, Cosmetics.
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Introduction
The level of sun protection provided by sunscreen products has traditionally been estimated using the
sun protection factor or SPF test, which uses the erythemal response of the skin to ultraviolet (UV)
radiation. The SPF is a ratio calculated from the energies required to induce a minimum erythemal
response with and without sunscreen product applied to the skin of human test subjects. It uses
ultraviolet radiation usually from an artificial source.
[1-3]
Different standard methods are available and described in the technical report ISO/TR 26369 . For
this version of ISO 24444, these references have been updated in the Bibliography section.
Since publication of the first version of this Standard, harmonization has been achieved in many
member countries. The objective of this updated version is to further improve reproducibility between
test sites, so as to obtain the same SPF value.
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oSIST prEN ISO 24444:2019
DRAFT INTERNATIONAL STANDARD ISO/DIS 24444:2019(E)
Cosmetics — Sun protection test methods — In vivo
determination of the sun protection factor (SPF)
1 Scope
This International Standard specifies a method for the in vivo determination of the sun protection
factor (SPF) of sunscreen products. This International standard is applicable to products that contain
any component able to absorb, reflect or scatter ultraviolet (UV) rays and which are intended to be
placed in contact with human skin.
It provides a basis for the evaluation of sunscreen products for the protection of human skin against
erythema induced by solar ultraviolet rays.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
ultraviolet radiation
UVR
electromagnetic radiation in the range of 290 nm to 400 nm
2.1.1
ultraviolet B
UVB
electromagnetic radiation in the range of 290 nm to 320 nm
2.1.2
ultraviolet A
UVA
electromagnetic radiation in the range of 320 nm to 400 nm
Note 1 to entry: UVA II = 320 nm to 340 nm; UVA I = 340 nm to 400 nm.
2.1.3
Erythemal effective irradiance E
er
radiometric quantity derived by multiplying the spectral irradiance E(λ) of the solar simulator with
[4]
the erythema action spectrum s (λ) at each wavelength λ and integrating over wavelength range of
er
290 nm to 400 nm
400
2
E = Es()λλ()dλ   unit: W/m (eff.)
er er
∫
290
2.1.4
Erythemal effective radiant exposure (erythemal dose) H
er
radiometric quantity defined as time integral of erythemal effective irradiance E (t)
er
2
H = Et()dt   unit: J/m (eff.)
er er
∫
t
2.2
erythema
reddening of the skin caused by UV radiation
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2.3
sunscreen products
products containing any component able to absorb, reflect or scatter UV rays, which are intended to
be placed on the surface of human skin with the purpose of protecting against erythema and other
ultraviolet induced damage
2.4
minimal erythemal dose
MED
lowest erythemal effective radiant exposure (H ) that produces the first perceptible unambiguous
er
erythema with defined borders appearing over more than 50% of UV exposure subsite, 16 h to 24 h
after UV exposure. Annex F contains visual references and colourimetric guidance for the acceptable
MED appearance
2.4.1
MED
u
MED on unprotected skin.
2.4.1.1
MED
iu
MED of an individual subject on unprotected skin
2.4.2
MED
p
MED on product protected skin
2.4.2.1
MED
ip
MED of an individual subject on protected skin
2.5
individual sun protection factor
SPF
i
ratio of the individual minimal erythemal dose on product protected skin (MED ) to the (individual)
ip
minimal erythemal dose on unprotected skin (MED ) of the same subject:
iu
MED
MED
iprotected
() ip
SPF ==
i
MED MED
iu
iunprotected
()
Note 1 to entry: SPFi is expressed to one decimal place by truncation.
2.6
sun protection factor of a product: SPF
arithmetic mean of all valid individual SPFi values obtained from all subjects in the test
Note 1 to entry: SPF is expressed to one decimal place by truncation.
2.7
test area
on the back between the scapula line and the waist. Skeletal protrusions and extreme areas of curvature
should be avoided
2.8
test site
area of the skin where a product is applied or the site used for the determination of the unprotected MED
2.9
exposure sub-sites
areas of skin that are exposed to UV-irradiation
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2.10
individual typology angle
ITA°
value characterizing the skin colour of the subject as measured by a skin contact reflectance
spectrophotometer or skin colourimeter. Refer to Annex E for the detailed requirements of the
equipment / measurement
3 General principle
The SPF test method is a laboratory method that utilizes a xenon arc lamp solar simulator (or equivalent)
of defined and known output to determine the protection provided by sunscreen products on human
skin against erythema induced by solar ultraviolet rays.
The test shall be restricted to the area of the back of selected human subjects.
A section of each subject’s skin is exposed to ultraviolet light without any protection and another
(different) section is exposed after application of the sunscreen product under test. One further section
is exposed after application of an SPF reference sunscreen formulation which is used for validation of
the procedure.
To determine the sun protection factor, incremental series of delayed erythemal responses are induced
on a number of small sub-sites on the skin. These responses are visually assessed for presence of
erythema 16 to 24 hours after UV radiation, by the judgment of a trained and competent evaluator.
The individual minimal erythemal dose for unprotected skin (MED ) and the individual MED obtained
iu
after application of a sunscreen product (MED ) shall be determined on the same subject on the same
ip
day. An individual sun protection factor (SPF ) for each subject tested is calculated as the ratio of
i
individual MED on product protected skin divided by the individual MED on unprotected skin, as in the
equation of item 2.5.
The sun protection factor for the product (SPF) is the arithmetic mean of all valid SPF results from
i
each subject in the test expressed to one decimal place.
4 Test subjects
4.1 Selection of the test subjects
4.1.1 General
There are strict requirements governing the inclusion and non-inclusion of test subjects which should
be adhered to. The criteria are set out in Annex A
4.1.2 Skin colour of the test subjects
Test subjects included in the SPF test shall have an ITA° value of at least 28° by colourimetric methods
(see Annexes A and E) and be untanned on the test area.
The average of the subjects making up a test panel shall have an ITA° between 41° and 55°, and there
shall be at least one subject from each ITA° band 28-40°, 41-55°, and >56°.
A trained and competent scientist or technician should examine each subject to ensure that there is no
condition which might put the subject at risk and that the outcome of the test cannot be compromised
by adverse skin conditions such as sun damage, pigmentation marks and previous history of abnormal
response to the sun (see Annex A).
The test sites intended for UV exposure shall be free from blemishes and hair, and have an even colour
tone with no variation in ITA° greater than 5° from each other or the MEDu test area.
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4.1.3 Age restriction
Test subjects below the locally regulated age of consent or older than 70 years shall not be included in
the SPF test panel.
4.1.4 Frequency of participation in tests
Subjects may participate in a test provided that at least 8 weeks have elapsed since they participated
in a previous UV exposure study (i.e. SPF, UVA-PF, photoallergy, phototoxicity test), and all skin tanned
marks from that previous test have cleared from the test sites on the back and are no longer visible.
4.1.5 Ethics and consent
[7]
All testing shall be done in accordance with the Declaration of Helsinki and national regulations
regarding human studies, if any.
Informed, written (signature) consent shall be obtained from all test subjects and retained.
4.2 Number of test subjects
The minimum number of valid SPFi results shall be 10 and the maximum number of valid SPFi results
shall be 20. In order to achieve between 10 and 20 valid results, a maximum of five individual invalid
results may be excluded from the calculation of the mean SPF. Consequently the actual number of test
subjects used will fall between a minimum of 10 and a maximum of 25 subjects (i.e. a maximum of 20
valid results plus 5 rejected invalid results).
Results may only be declared invalid and excluded from the calculation of the mean SPF according to
8.6.4 or because of non-compliance with the related protocol.
In order to determine the number of test subjects, the 95 % confidence interval (95 % CI) on the mean
SPF shall be taken into account. A minimum of 10 subjects shall be tested. The test shall be considered
valid for the first 10 subjects if the resulting range of the 95 % CI of the mean SPF shall be within ±17 %
of the mean SPF. If it s not within ±17 % of the mean SPF, the number of subjects shall be increased
stepwise from the minimum number of 10 until the 95 % CI statistical criterion is met (up to a maximum
of 20 valid results from a maximum of 25 subjects tested). If the statistical criterion has not been met
after 20 valid results from a maximum of 25 subjects, then the test shall be rejected. For details on
statistical definitions, sequential procedure and calculations, refer to Annex D.
5 Apparatus and materials
5.1 Source of ultraviolet radiation
5.1.1 General
The artificial light source used shall comply with the source spectral specifications as described in
5.1.2 and Annex B. A xenon arc solar simulator with appropriate filters shall be used.
5.1.2 Quality of ultraviolet radiation
5.1.2.1 The solar UV simulator shall emit a continuous spectrum with no gaps or extreme peaks of
emission in the UV region. The output from the solar UV simulator shall be stable, uniform across the
whole output beam and suitably filtered to create a spectral quality that complies with the required
acceptance limits (see Table B.1).
5.1.2.2 To ensure that appropriate amounts of UVA radiation are included in the spectrum of the
solar UV simulator, the total radiometric proportion of the UVA II (320 nm to 340 nm) irradiance of the
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simulator shall be ≥ 20 % of the total UV (290 nm to 400 nm) irradiance. Additionally, the UVA I region
(340 nm to 400 nm) irradiance shall be ≥ 60 % of the total UV irradiance.
5.1.2.3 The source spectral specification is described in terms of cumulative erythemal effective
irradiance by successive wavelength bands from < 290 nm up to 400 nm. The erythemal effective
irradiance of each wavelength band is expressed as a percentage of the total erythemal effective
irradiance from < 290 nm to 400 nm, or as the percentage relative cumulative erythemal effectiveness
(% RCEE). The definition and calculation of % RCEE values is described in Annex B and the acceptance
limits are given in Table B.1.
5.1.3 Total irradiance (UV, visible and near infrared rays)
If total irradiance is too intense, an excessive feeling of heat or pain may be induced in the irradiated
skin of subjects and heat induced erythema may result. Therefore, total irradiance shall not exceed
2 2
1600 W/m . When total irradiance is < 1600 W/m , it shall still be confirmed, prior to conducting an
SPF test, that the irradiance to be used (UV, visible and near-infrared rays) will not induce an excessive
feeling of heat in the skin. The output of the solar simulator shall be measured with a broad spectrum
sensor (capable of measuring between 280 and 1600nm) calibrated against a standard reference
source over the range of 280 to 1600nm. Alternatively, the source may be measured with a calibrated
spectroradiometer over this same wavelength range to determine the total irradiance.
5.1.4 Uniformity of beam
Uniformity of the beam shall be measured periodically depending on the solar simulator type using
either UV sensitive film or UV sensor methods (see 5.1.4.3 and 5.1.4.4). Solar simulators with large
beams (>1,3 cm diameter) or with multiple output ports shall be measured at least every 6 months,
or when any modifications are made to the lamp optical components, or when non-uniform erythema
spots are seen in test subsites. Solar simulators with a single output port beam (≤1,3 cm diameter)
shall be measured at least every 1 month, or when any modifications are made to the lamp optical
components, or when non-uniform erythema spots are seen in test subsites.
Uniformity measurements may be conducted using UV sensitive paper that darkens with exposure, or
by using a UV sensor that is smaller in active area compared to the beam size by a ratio of at least 1:4.8
with sufficient measurements to cover more than 75% of the beam area.
Measurements are to be made using the orientation of the source output as used for subject exposures.
5.1.4.1 Large beam source: When a large-beam UV source is used to simultaneously expose several
sub-sites (i.e. at least two sub-sites) within an irradiation series by varying the exposure time, the
intensity of the beam shall be as uniform as possible. A UV film densitometry method or a UV radiometer
method may be used. The minimum number of sample sites of equal area within the beam (Area of
Interest – AOI) to be assessed shall be determined by dividing the area of the beam by 6.45. (For example,
2
if the beam is 232 cm in area, then the minimum number of measurements shall be 36).
5.1.4.1.1 UV film densitometry method: The UV sensitive film at least as large as the beam shall be
exposed by the entire beam so that the entire beam fits inside the borders of the film. See 5.1.4.3 for
further details.
5.1.4.1.2 UV Radiometer method: A UV radiometer sensor may be used to sample the beam intensity
at multiple sites. Measurements shall be made at equally distributed points
5.1.4.1.3 The uniformity shall be ≥ 90% as calculated by the equation:
(1-(max-min)/(average))% ≥ 90% (tentative pending data)
If the uniformity is less than 90%, then optical components should be adjusted or appropriate
compensation for different irradiance shall be made in the exposure time on each sub-site.
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