Cosmetics - Determination of sunscreen UVA photoprotection in vitro (ISO 24443:2021, Corrected version 2022-02)

This document specifies an in vitro procedure to characterize the UVA protection of sunscreen products. Specifications are given to enable determination of the spectral absorbance characteristics of UVA protection in a reproducible manner.
In order to determine relevant UVA protection parameters, the method has been created to provide an UV spectral absorbance curve from which a number of calculations and evaluations can be undertaken. These include calculation of the Ultraviolet-A protection factor (UVA-PF) [correlating with in vivo UVA-PF from the persistent pigment darkening (PPD) testing procedure], critical wavelength and UVA absorbance proportionality. These computations are optional and relate to local sunscreen product labelling requirements. This method relies on the use of static in vivo SPF results for scaling the UV absorbance curve.
This document is not applicable to powder products such as pressed powder and loose powder products.

Kosmetische Mittel - In-vitro-Bestimmung des UVA Schutzes von Sonnenschutzmitteln (ISO 24443:2021, korrigierte Fassung 2022-02)

Dieses Dokument legt ein In vitro Verfahren zur Charakterisierung des UVA Schutzes von Sonnenschutz¬mitteln fest. Es werden Spezifikationen angegeben, die eine reproduzierbare Bestimmung der spektralen Extinktionseigenschaften des UVA Schutzes ermöglichen.
Zur Bestimmung von für den UVA Schutz relevanten Kenngrößen wurde ein Verfahren zur Aufstellung einer Kurve der spektralen Extinktion im UV Bereich entwickelt, auf dessen Grundlage eine Reihe von Berechnungen und Bewertungen vorgenommen werden können. Diese umfassen die Berechnung des UVA Schutzfaktors (UVA PF) [korreliert mit dem In vivo UVA Schutzfaktor aus dem Persistent-Pigment-Darkening (PPD) Prüfverfahren], der kritischen Wellenlänge und des UVA-Extinktionsverhältnisses. Diese Berechnungen sind optional und beziehen sich auf die örtlichen Anforderungen an die Kennzeichnung von Sonnenschutzmitteln. Dieses Verfahren basiert auf der Verwendung von statischen In vivo SPF Ergebnissen für die Skalierung der UV Extinktionskurve.
Dieses Dokument ist nicht anwendbar für pulverförmige Produkte, die z. B. gepresst oder lose vorliegen.

Cosmétiques - Détermination in vitro de la photoprotection UVA (ISO 24443:2021, Version corrigée 2022-02)

Le présent document spécifie un mode opératoire in vitro pour caractériser la protection UVA apportée par les produits de protection solaire. Des spécifications sont fournies pour permettre de déterminer les caractéristiques d’absorbance spectrale de la protection UVA de façon reproductible.
Afin de déterminer les paramètres de protection UVA pertinents, la méthode a été mise au point de sorte à fournir une courbe d’absorbance spectrale UV à partir de laquelle des calculs et des évaluations peuvent être effectués. Ces calculs comprennent le calcul du facteur de protection contre les ultraviolets A (FPUVA) [corrélé au FPUVA in vivo du mode opératoire d’essai de pigmentation persistante (PPD)], de la longueur d’onde critique et de la proportionnalité de l’absorbance des UVA. Ces calculs sont facultatifs et sont liés aux exigences d’étiquetage locales des produits de protection solaire. Cette méthode repose sur les résultats du FPS in vivo statique pour élaborer la courbe d’absorbance des UV.
Le présent document n’est pas applicable aux produits sous forme de poudre tels que les produits en poudre compacte ou en poudre libre.

Kozmetika - Določevanje zaščitnega faktorja UVA in vitro (ISO 24443:2021, popravljena izdaja 2022-02)

General Information

Status
Published
Public Enquiry End Date
01-Jul-2020
Publication Date
15-Jun-2022
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
21-Apr-2022
Due Date
26-Jun-2022
Completion Date
16-Jun-2022

RELATIONS

Buy Standard

Standard
SIST EN ISO 24443:2022 - BARVE na PDF-str 26,28,29,47
English language
45 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day
Draft
oSIST prEN ISO 24443:2020
English language
39 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN ISO 24443:2022
01-julij-2022
Nadomešča:
SIST EN ISO 24443:2012
Kozmetika - Določevanje zaščitnega faktorja UVA in vitro (ISO 24443:2021,
popravljena izdaja 2022-02)

Cosmetics - Determination of sunscreen UVA photoprotection in vitro (ISO 24443:2021,

Corrected version 2022-02)

Kosmetische Mittel - In-vitro-Bestimmung des UVA Schutzes von Sonnenschutzmitteln

(ISO 24443:2021, korrigierte Fassung 2022-02)
Cosmétiques - Détermination in vitro de la photoprotection UVA (ISO 24443:2021,
Version corrigée 2022-02)
Ta slovenski standard je istoveten z: EN ISO 24443:2021
ICS:
71.100.70 Kozmetika. Toaletni Cosmetics. Toiletries
pripomočki
SIST EN ISO 24443:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 24443:2022
---------------------- Page: 2 ----------------------
SIST EN ISO 24443:2022
EN ISO 24443
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2021
EUROPÄISCHE NORM
ICS 71.100.70 Supersedes EN ISO 24443:2012
English Version
Cosmetics - Determination of sunscreen UVA
photoprotection in vitro (ISO 24443:2021, Corrected
version 2022-02)

Cosmétiques - Détermination in vitro de la Kosmetische Mittel - In-vitro-Bestimmung des UVA

photoprotection UVA (ISO 24443:2021, Version Schutzes von Sonnenschutzmitteln (ISO 24443:2021,

corrigée 2022-02) korrigierte Fassung 2022-02)
This European Standard was approved by CEN on 17 October 2021.

This European Standard was corrected and reissued by the CEN-CENELEC Management Centre on 16 March 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N
EUROPÄISCHES KOMITEE FÜR NORMUN G
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 24443:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 24443:2022
EN ISO 24443:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 24443:2022
EN ISO 24443:2021 (E)
European foreword

This document (EN ISO 24443:2021) has been prepared by Technical Committee ISO/TC 217

"Cosmetics" in collaboration with Technical Committee CEN/TC 392 “Cosmetics” the secretariat of

which is held by AFNOR.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by June 2022, and conflicting national standards shall be

withdrawn at the latest by June 2022.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 24443:2012.

This document has been prepared under a Standardization Request given to CEN by the European

Commission and the European Free Trade Association.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 24443:2021, Corrected version 2022-02 has been approved by CEN as

EN ISO 24443:2021 without any modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 24443:2022
---------------------- Page: 6 ----------------------
SIST EN ISO 24443:2022
INTERNATIONAL ISO
STANDARD 24443
Second edition
2021-12
Corrected version
2022-02
Cosmetics — Determination of
sunscreen UVA photoprotection in
vitro
Cosmétiques — Détermination in vitro de la photoprotection UVA
Reference number
ISO 24443:2021(E)
© ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .............................................................................................................................................................................................................................. vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms, definitions, symbols and abbreviated terms .................................................................................................... 1

3.1 Terms and definitions ...................................................................................................................................................................... 1

3.2 Symbols and abbreviated terms ............................................................................................................................................. 2

4 Principle ........................................................................................................................................................................................................................ 3

5 Apparatus .................................................................................................................................................................................................................... 3

5.1 Spectrophotometer specifications ........................................................................................................................................ 3

5.2 Calibration of the spectrophotometer ............................................................................................................................... 4

5.3 Calibration of the UV exposure source ............................................................................................................................. 4

5.4 Monitoring of the UV exposure source ............................................................................................................................. 5

5.5 Calibration of the UVA radiometer used to monitor the test sample irradiation ........................ 5

5.6 Substrate/plate ...................................................................................................................................................................................... 5

6 Test method ............................................................................................................................................................................................................... 6

6.1 Outline of the test procedure ..................................................................................................................................................... 6

6.2 Equipment calibration and validation of test plates ............................................................................................. 6

6.3 Absorption measurements through the plate ............................................................................................................ 6

6.4 Sample application .............................................................................................................................................................................. 7

6.5 Absorbance measurements of the product-treated plate ................................................................................ 8

6.6 Number of determinations .......................................................................................................................................................... 8

6.7 Determination of initial calculated SPF (SPF ), “C” value, initial UVA-PF
in vitro,0

(UVA-PF ), and UV exposure dose ......................................................................................................................................... 8

6.7.1 Determination of initial in vitro SPF (SPF ) ............................................................................... 8

in vitro,0

6.7.2 Determination of “C” value ........................................................................................................................................ 8

6.7.3 Determination of initial UVA protection factor before UV exposure (UVA-

PF ) ................................................................................................................................................................................................. 9

6.7.4 Determination of the UV exposure dose .................................................................................................... 10

6.8 UV exposure of sample plates ................................................................................................................................................ 10

6.9 Calculation of UVA-PF of plates after UV exposure of the sample ......................................................... 10

6.10 Calculation of critical wavelength of plates after UV exposure of the sample ........................... 11

7 Procedure using the spreadsheet in this document ...................................................................................................11

8 Product reference sunscreen ..............................................................................................................................................................12

8.1 Formula S2............................................................................................................................................................................................... 12

8.2 Standard P8 ............................................................................................................................................................................................12

9 Test report ...............................................................................................................................................................................................................12

Annex A (normative) Calibration of spectrophotometer and plate transmission test ...............................14

Annex B (normative) Radiometer calibration to spectroradiometric irradiance procedure .............18

Annex C (normative) Computation values: PPD and erythema action spectra and UVA and

UV‑SSR spectral irradiances .................................................................................................................................................................20

Annex D (normative) PMMA substrate plate surface specifications ..............................................................................23

Annex E (normative) Product reference sunscreen formulations ....................................................................................26

Annex F (informative) Statistical calculations ......................................................................................................................................32

Annex G (informative) Definition and examples of valid results/Factor “C” .........................................................35

Bibliography .............................................................................................................................................................................................................................36

iii
© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(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

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.

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 documents 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).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 217 Cosmetics, in collaboration with

the European Committee for Standardization (CEN) Technical Committee CEN/TC 392, Cosmetics, in

accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 24443:2012), which has been technically

revised.
The main changes compared to the previous edition are as follows:

— acceptance of moulded and sandblasted PMMA plates, according to specifications described in

Annex D;
— product application fitted to 1,2mg/cm for sandblasted plates;
— description of application gesture according to tested products;
— introduction of a new high UVA PF standard P8;
— introduction of critical wavelength calculation;

— calculation of coefficient "C" accepted from in vivo screening SPF, with specific conditions based on

SEM and percentage of variability, and new range proposed from 0,6 to 1,6;
— limitation of UVA irradiation dose to 36 J/cm .

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.
This corrected version of ISO 24443:2021 incorporates the following corrections:
— Formulae (2) and (4) have been corrected;
— in 6.7.2, the significance of SEM has been explained;
© ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)

— in A.5.1, the transmission values for sandblasted PMMA plates have been corrected;

— Bibliographic references have been corrected.
© ISO 2021 – All rights reserved
---------------------- Page: 11 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)
Introduction

This document specifies the procedure to determine the ultraviolet protection factor (UVA-PF) of a

sunscreen product using the in vitro UVA-PF according to the principles recommended by the European

Cosmetic and Perfumery Association (COLIPA) in 2011. The outcome of this test method can be used

to determine the UVA classification of topical sunscreen products according to local regulatory

requirements.

Topical sunscreen products are primarily rated and labelled according to their ability to protect against

sunburn, using a test method to determine the in vivo sun protection factor (see ISO 24444). This

rating evaluates filtration of sunburn generating radiation across the electromagnetic UV spectrum

(290 nm to 400 nm). However, knowledge of the sun protection factor (SPF) rating does not provide

explicit information on the magnitude of the protection provided specifically in the UVA range of

the spectrum (320 nm to 400 nm), as it is possible to have high SPF products with very modest UVA

protection (e.g. SPF 50 with a UVA-PF of only 3 to 4). There is a demand among medical professionals,

as well as knowledgeable consumers, to have fuller information on the UVA protection provided by

their sunscreen product, in addition to the SPF, in order to make a more informed choice of product,

providing a more balanced and broader-spectrum protection. Moreover, there is also a demand to

prevent UVA-induced darkening of the skin from a cultural point of view even without sunburn. The

UVA-PF value of a product provides information on the magnitude of the protection provided explicitly

in the UVA portion of the spectrum, independent of the SPF values.

The test method outlined in this document is derived primarily from the in vitro UVA-PF test method as

developed by COLIPA.
© ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 24443:2022
INTERNATIONAL STANDARD ISO 24443:2021(E)
Cosmetics — Determination of sunscreen UVA
photoprotection in vitro
1 Scope

This document specifies an in vitro procedure to characterize the UVA protection of sunscreen

products. Specifications are given to enable determination of the spectral absorbance characteristics of

UVA protection in a reproducible manner.

In order to determine relevant UVA protection parameters, the method has been created to provide an

UV spectral absorbance curve from which a number of calculations and evaluations can be undertaken.

These include calculation of the Ultraviolet-A protection factor (UVA-PF) [correlating with in vivo

UVA-PF from the persistent pigment darkening (PPD) testing procedure], critical wavelength and UVA

absorbance proportionality. These computations are optional and relate to local sunscreen product

labelling requirements. This method relies on the use of static in vivo SPF results for scaling the UV

absorbance curve.

This document is not applicable to powder products such as pressed powder and loose powder products.

2 Normative references
There are no normative references in this document.
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological 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/
3.1.1
ultraviolet radiation
electromagnetic radiation in the range of 290 nm to 400 nm
3.1.2
UVB
ultraviolet B
electromagnetic radiation in the range of 290 nm to 320 nm
3.1.3
UVA
ultraviolet A
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.
© ISO 2021 – All rights reserved
---------------------- Page: 13 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)
3.1.4
spectral absorbance
ai(λ)

logarithm to base 10 of the reciprocal of the spectral internal transmittance, ai(λ)=−log10 τi(λ)

Note 1 to entry: In the context of this standard the absorption or transmission of sunscreen is used.

3.1.5
irradiance

fluence rate per unit area, expressed in W/m , for a defined range of wavelengths

Note 1 to entry: From 290 nm to 400 nm for UVA + UV-B irradiance; from 320 nm to 400 nm for UVA irradiance.

3.1.6
spectral irradiance
I(λ)
irradiance (3.1.5) per unit wavelength, I(λ), expressed in W/m /nm
Note 1 to entry: Spectral irradiance can refer to PPD testing or SPF testing.
3.1.7
spectrophotometer

equipment for measuring the reflection or transmission properties of a material as a function of

wavelength limited to ultraviolet, visible and short infrared ranges in this document

3.1.8
spectroradiometer
device designed to measure the spectral density of illuminants
3.1.9
radiometer
device for measuring the radiant flux (power) of electromagnetic radiation
3.1.10
product reference sunscreen
reference sunscreen product used to validate the testing procedure
3.1.11
solar simulator
equipment used to simulate the solar irradiance and spectrum
3.1.12
plate
substrate
material to which the test product is to be applied
3.2 Symbols and abbreviated terms
3.2.1
UVA-PF
in vitro ultraviolet A protection factor

in vitro UVA protection factor of a sun protection product against UVA radiation, which can be derived

mathematically with in vitro spectral modelling
3.2.2
SPF
in vitro
in vitro sun protection factor

in vitro protection factor of a sun protection product against erythema-inducing radiation calculated

with spectral modelling
© ISO 2021 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)
3.2.3
critical wavelength
CWL

wavelength at which the area under the absorbance curve represents 90 % of the total area under the

curve in the UV region
Note 1 to entry: Calculated from spectral data.
3.2.4
erythema action spectrum
E(λ)

relative effects of individual spectral bands of an exposure source for an erythema response

3.2.5
PPD action spectrum
P(λ)

relative effects of individual spectral bands of an exposure source for a persistent pigment response

4 Principle

The test is based on the assessment of UV-transmittance through a thin film of sunscreen sample spread

on a roughened substrate, before and after exposure to a controlled dose of radiation from a defined UV

exposure source.

Because of several variables that cannot be controlled with typical thin film spectroscopic techniques,

each set of sunscreen transmission data is mathematically adjusted so that the in vitro SPF data yield

the same measured in vivo SPF value that was determined by in vivo testing. As in vivo method can

raise ethical consideration, any alternative SPF method, published as an ISO method, may be used.

Samples are exposed to a specific measured dose of UV radiation to account for the photostability

characteristics of the test product.

The resulting spectral absorbance data have been shown to be a useful representation of both the

width and height of the UVA protection characteristics of the sunscreen product being tested. The

mathematical modelling procedure has been empirically derived to correlate with human in vivo

(persistent pigment darkening) test results.
5 Apparatus
5.1 Spectrophotometer specifications

The spectrophotometer wavelength range shall span the primary waveband of 290 nm to 400 nm. The

wavelength increment step shall be 1 nm.

A spectrophotometer that does not have a monochromator after the test sample should employ a

fluorescence rejection filter.

The spectrophotometer input optics should be designed for diffuse illumination and/or diffuse

collection of the transmitted irradiance through the roughened polymethylmethacrylate (PMMA)

substrate, with and without the sunscreen layer spread on its surface.

The size of the diameter of the entrance port of the spectrophotometer probe shall be smaller than the

size of the light spot to be measured at the sample level (in order to account for stray light).

The area of each reading site should be at least 0,5 cm in order to reduce the variability between

readings and to compensate for the lack of uniformity in the product layer.
© ISO 2021 – All rights reserved
---------------------- Page: 15 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)

The wavelength should be accurate to within 1 nm, as checked using a holmium-doped filter (see

Annex A). The ability of an instrument to accurately measure absorbance is limited by the sensitivity of

the instrument. The minimum required dynamic range for this methodology is 2,2 absorbance units as

determined according to Annex A.

The maximum measured absorbance should be within the dynamic range of the device used. If

the test measurements yield absorbance curves that exceed the determined upper limit of the

spectrophotometer, the product should be re-tested using an instrument with increased sensitivity and

dynamic range.

The lamp in the spectrophotometer that is used to measure the transmittance shall emit continuous

radiation over the range of 290 nm to 400 nm, and the level of irradiance should be sufficiently low, so

that the photostability of the product is not unduly challenged (a xenon lamp is a convenient solution).

Therefore, the UV dose during one measurement cycle should not exceed 0,2 J/cm .

NOTE A spectrophotometer is used to measure the absorbance properties of the sunscreen on the test

plates. A spectroradiometer is used to measure the spectral energy distribution and intensity of the UV exposure

source or the spectrophotometer during the absorbance measurement of the sunscreen on the test plate.

Coupled with an UV source, the spectroradiometer can give similar results to a spectrophotometer.

5.2 Calibration of the spectrophotometer

The spectrophotometer shall be validated every month by measurements of reference materials.

A three-fold test is required, as described in Annex A:
— dynamic range of the spectrophotometer;
— linearity test of the spectrophotometer;
— wavelength accuracy test.
5.3 Calibration of the UV exposure source

The spectral irradiance at the exposure plane of the UV exposure source that is used for irradiation

(to take into account any photoinstability) shall be as similar as possible to the irradiance at ground

[5] [6]

level under a standard zenith sun . As defined by COLIPA , the reference standard sun has a total

2 2

irradiance of 51,4 W/m to 63,7 W/m and a UVA to UVB irradiance ratio of 16,9 to 17,5.

Therefore, the UV irradiance shall be within the following acceptance limits (measured at sample

distance).
Table 1 — UV exposure source specifications
UV exposure source specifications as measured with a spectroradiometer
2 2
Total UV irradiance (290 nm to 400 nm) 40 W/m to 200 W/m
a b
Irradiance ratio of UVA to UVB 11-22
320 nm to 400 nm.
290 nm to 320 nm.

In broad-beam UV-sources, spectra from different locations under the beam shall be recorded over at

least 5 different locations (a location is defined for each plate) in order to account for uniformity.

The uniformity shall be ≥ 90 % as calculated by Formula (1):
U = (1-(max-min)/(X̅)) (1)
© ISO 2021 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 24443:2022
ISO 24443:2021(E)
where
U is the uniformity in percentage;
X̅ is the average.

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 plate.

The UV exposure source device should h
...

SLOVENSKI STANDARD
oSIST prEN ISO 24443:2020
01-junij-2020
Kozmetika - Določevanje zaščitnega faktorja UVA in vitro (ISO/DIS 24443:2020)
Determination of sunscreen UVA photoprotection in vitro (ISO/DIS 24443:2020)

In vitro Bestimmung des UVA-Schutzes von Sonnenschutzmitteln (ISO/DIS 24443:2020)

Détermination in vitro de la photoprotection UVA (ISO/DIS 24443:2020)
Ta slovenski standard je istoveten z: prEN ISO 24443 rev
ICS:
71.100.70 Kozmetika. Toaletni Cosmetics. Toiletries
pripomočki
oSIST prEN ISO 24443:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 24443:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 24443:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 24443
ISO/TC 217 Secretariat: ISIRI
Voting begins on: Voting terminates on:
2020-04-30 2020-07-23
Determination of sunscreen UVA photoprotection in vitro
Détermination in vitro de la photoprotection UVA
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 24443:2020(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 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 3

5 Apparatus ..................................................................................................................................................................................................................... 3

5.1 UV spectrophotometer specifications ................................................................................................................................. 3

5.2 Calibration of the UV spectrophotometer........................................................................................................................ 4

5.3 Calibration of the UV exposure source ............................................................................................................................... 4

5.4 Monitoring of the UV exposure source ............................................................................................................................... 4

5.5 Calibration of the UVA radiometer used to monitor the test sample irradiation .......................... 5

5.6 Substrate/plate ....................................................................................................................................................................................... 5

6 Test method ............................................................................................................................................................................................................... 5

6.1 Outline of the test procedure ...................................................................................................................................................... 5

6.2 Equipment calibration and validation of test plates............................................................................................... 6

6.3 Absorption measurements through the plate .............................................................................................................. 6

6.4 Sample application .............................................................................................................................................................................. 6

6.5 Absorbance measurements of the product-treated plate .................................................................................. 7

6.6 Number of determinations ........................................................................................................................................................... 7

6.7 Determination of initial calculated SPF (SPF ), “C” value, initial UVA-PF (UVA-

in vitro

PF ), and UV exposure dose ......................................................................................................................................................... 7

6.7.1 Determination of SPF ......................................................................................................................................

in vitro 7

6.7.2 Determination of “C” value ...................................................................................................................................... 8

6.7.3 Determination of initial UVA protection factor before UV exposure (UVA-PF ) ....... 8

6.7.4 Determination of the UV exposure dose...................................................................................................... 9

6.8 UV exposure ............................................................................................................................................................................................... 9

6.9 Measurement of final adjusted absorbance spectrum ......................................................................................... 9

6.10 Calculation of UVA-PF of plates after UV exposure of the sample ...........................................................10

6.11 Calculation of critical wavelength of plates after UV exposure of the sample ..............................10

7 Procedure using the spreadsheet in this document .....................................................................................................10

8 Product reference sunscreen ...............................................................................................................................................................11

8.1 Formula S2 ...............................................................................................................................................................................................11

8.2 Standard P8 .............................................................................................................................................................................................11

9 Test report ................................................................................................................................................................................................................12

Annex A (normative) Calibration of UV spectrophotometer and plate transmission test.........................13

Annex B (normative) Radiometer calibration to spectroradiometric irradiance procedure ................17

Annex C (normative) Computation values: PPD and erythema action spectra and UVA and

UV-SSR spectral irradiances ...................................................................................................................................................................19

Annex D (normative) PMMA test plate surface specifications ................................................................................................22

Annex E (normative) UVA Product reference sunscreen S2 ......................................................................................................25

Annex F (informative) Statistical calculations .........................................................................................................................................31

Bibliography .............................................................................................................................................................................................................................34

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(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

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.

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 documents 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).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 217 Cosmetics.

This second edition cancels and replaces the first edition (ISO 24443:2012), which has been technically

revised.

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 © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)
Introduction

This International Standard specifies the procedure to determine the Ultraviolet A Protection Factor

(UVAPF) of a sunscreen product using the in vitro UVAPF according to the principles recommended

by COLIPA in 2011. The outcome of this test method can be used to determine the UVA classification of

topical sunscreen products according to local regulatory requirements.

Topical sunscreen products are primarily rated and labelled according to their ability to protect against

sunburn, using a test method to determine the in vivo Sun Protection Factor (see ISO 24444). This

rating evaluates filtration of sunburn generating radiation across the electromagnetic UV spectrum

(290 nm to 400 nm). However, knowledge of the Sun Protection Factor (SPF) rating does not provide

explicit information on the magnitude of the protection provided specifically in the UVA range of

the spectrum (320 nm to 400 nm), as it is possible to have high SPF products with very modest UVA

protection (e.g. SPF 50 with a UVAPF of only 3 to 4). There is demand among medical professionals,

as well as knowledgeable consumers, to have fuller information on the UVA protection provided by

their sunscreen product, in addition to the SPF, in order to make a more informed choice of product,

providing a more balanced and broader-spectrum protection. Moreover, there also a demand to prevent

UVA-induced darkening of the skin from a cultural point of view even without sunburn. The UVAPF

value of a product provides information on the magnitude of the protection provided explicitly in the

UVA portion of the spectrum, independent of the SPF values.

The test method outlined in this International Standard is derived primarily from the in vitro UVAPF

test method as developed by COLIPA.
© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 24443:2020
---------------------- Page: 8 ----------------------
oSIST prEN ISO 24443:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 24443:2020(E)
Determination of sunscreen UVA photoprotection in vitro
1 Scope

This document specifies an in vitro procedure to characterize the UVA protection of sunscreen products.

Specifications are proposed to enable determination of the spectral absorbance characteristics of UVA

protection in a reproducible manner.

In order to determine relevant UVA protection parameters, the method has been created to provide an

UV spectral absorbance curve from which a number of calculations and evaluations can be undertaken.

Results from this measurement procedure can be used for other computations, as required by local

regulatory authorities. These include calculation of the Ultraviolet-A protection factor (UVA-PF)

[correlating with in vivo UVA-PF from the persistent pigment darkening (PPD) testing procedure],

critical wavelength and UVA absorbance proportionality. These computations are optional and relate

to local sunscreen product labelling requirements. This method relies on the use of static in vivo SPF

results for scaling the UV absorbance curve.

This document is not applicable to powder products such as pressed powder and loose powder products.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 24444, Cosmetics — Sun protection test methods — In vivo determination of the sun protection

factor (SPF)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
in vitro UVA protection factor
UVA-PF

in vitro UVA protection factor of a sun protection product against UVA radiation, which can be derived

mathematically with in vitro spectral modelling
3.2
in vitro protection factor

SPF , protection factor of a sun protection product against erythema-inducing radiation calculated

in vitro
with spectral modelling
3.3

critical wavelength, calculated from spectral data. It corresponds to the wavelength at which the area

under the absorbance curve represents 90 % of the total area under the curve in the UV region

© ISO 2020 – All rights reserved 1
---------------------- Page: 9 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)
3.4
[1]
action spectrum for erythema [2].
E(λ)

relative effects of individual spectral bands of an exposure source for an erythema response

3.5
[3]
action spectrum for PPD [4].
P(λ)

relative effects of individual spectral bands of an exposure source for a persistent pigment response

3.6
monochromatic absorbance

sunscreen absorbance at wavelength, λ, related to the sunscreen transmittance, T , by

ATλ =−log

where transmittance, T , is the fraction of incident irradiance transmitted by the sunscreen film

3.7
irradiance

fluence rate per unit area, expressed in W/m , for a defined range of wavelengths

EXAMPLE From 290 nm to 400 nm for UVA + UV-B irradiance; from 320 nm to 400 nm for UVA irradiance.

3.8
spectral irradiance for SPF testing or PPD testing
I(λ)
irradiance per unit wavelength, I(λ), expressed in W/m /nm
3.9
spectrophotometer

equipment for measuring the reflection or transmission properties of a material as a function of

wavelength limited to ultraviolet, visible and short infrared ranges in this document

3.10
spectroradiometer
device designed to measure the spectral density of illuminants
3.11
radiometer
device for measuring the radiant flux (power) of electromagnetic radiation
3.12
reference product
reference sunscreen product used to validate the testing procedure
3.13
solar simulator
Equipment used to simulate the solar irradiance and spectrum.
3.14
substrate plate
Material to which the test product is to be applied.
2 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)
4 Principle

The test is based on the assessment of UV-transmittance through a thin film of sunscreen sample spread

on a roughened substrate, before and after exposure to a controlled dose of radiation from a defined UV

exposure source.

Because of the several variables that cannot be controlled with typical thin film spectroscopic

techniques, each set of sunscreen transmission data is mathematically adjusted so that the in vitro

SPF data yield the same measured in vivo SPF value that was determined by in vivo testing. As in vivo

method could raise ethical consideration, any alternative SPF method, published as an ISO method, may

be used.

Samples are then exposed to a specific measured dose of UV radiation to account for the photostability

characteristics of the test product.

The resulting spectral absorbance data have been shown to be a useful representation of both the

width and height of the UVA protection characteristics of the sunscreen product being tested. The

mathematical modelling procedure has been empirically derived to correlate with human in vivo

(persistent pigment darkening) test results.
5 Apparatus
5.1 UV spectrophotometer specifications

The UV spectrophotometer wavelength range shall span the primary waveband of 290 nm to 400 nm.

The wavelength increment step shall be 1 nm.

A UV spectrophotometer that does not have a monochromator after the test sample should employ a

fluorescence rejection filter.

The UV spectrophotometer input optics should be designed for diffuse illumination and/or diffuse

collection of the transmitted irradiance through the roughened polymethylmethacrylate (PMMA)

substrate, with and without the sunscreen layer spread on its surface.

The size of the diameter of the entrance port of the UV spectrophotometer probe shall be smaller than

the size of the light spot to be measured at the sample level (in order to account for stray light).

The area of each reading site should be at least 0,5 cm in order to reduce the variability between

readings and to compensate for the lack of uniformity in the product layer.

The wavelength should be accurate to within 1 nm, as checked using a holmium-doped filter (see Annex

A). The ability of an instrument to accurately measure absorbance is limited by the sensitivity of the

instrument. The minimum required dynamic range for this methodology is 2,2 absorbance units as

determined according to Annex A.

The maximum measured absorbance should be within the dynamic range of the device used. If

the test measurements yield absorbance curves that exceed the determined upper limit of the UV

spectrophotometer, the product should be re-tested using an instrument with increased sensitivity and

dynamic range.

The lamp in the UV spectrophotometer that is used to measure the transmittance shall emit continuous

radiation over the range of 290 nm to 400 nm, and the level of irradiance should be sufficiently low, so

that the photostability of the product is not unduly challenged (a xenon lamp is a convenient solution).

Therefore, the UV dose during one measurement cycle should not exceed 0,2 J/cm .

NOTE A UV spectrophotometer is used to measure the absorbance properties of the sunscreen on the test

plates. A spectroradiometer is used to measure the spectral energy distribution and intensity of the UV exposure

source or the UV spectrophotometer during the absorbance measurement of the sunscreen on the test plate.

Coupled with an UV source, the radiometer can give similar results to a spectrophotometer.

© ISO 2020 – All rights reserved 3
---------------------- Page: 11 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)
5.2 Calibration of the UV spectrophotometer

The UV spectrophotometer shall be validated every month by measurements of reference materials.

A three-fold test is required, as described in Annex A:
— dynamic range of the UV spectrophotometer;
— linearity test of the UV spectrophotometer;
— wavelength accuracy test.
5.3 Calibration of the UV exposure source

The spectral irradiance at the exposure plane of the UV exposure source that is used for irradiation

(to take into account any photoinstability) shall be as similar as possible to the irradiance at ground

[1] [2]

level under a standard zenith sun. As defined by COLIPA, the reference standard sun has a total

irradiance of 51.4 to 63.7 W/m2 and a UVA to UVB irradiance ratio of 16.9 to 17.5.

Therefore, the UV irradiance shall be within the following acceptance limits (measured at sample

distance).
Table 1 — UV exposure source specifications
UV exposure source specifications as measured with a spectroradiometer
2 2
Total UV irradiance (290 nm to 400 nm) 40 W/m to 200 W/m
a b
Irradiance ratio of UVA to UVB 11-22
320 nm to 400 nm.
290 nm to 320 nm.

In broad-beam UV-sources, spectra from different locations under the beam shall be recorded over at

least 5 different locations (a location is defined for each plate) in order to account for uniformity.

The uniformity shall be ≥ 90% as calculated by the equation:
(1-(max-min)/(average))% ≥ 90% *

*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 plate.

The UV exposure source device should have the ability to maintain samples within the range of 27 °C

to 32 °C, with intra laboratory temperature ± 2 °C. It is important that the temperature of the sample

itself on the plate shall be measured and not just the surrounding air temperature. Therefore, the

measurement of the temperature shall be on plate level.

To maintain samples at required temperature, a filter system that particularly reduces Infrared

radiation shall be used to achieve the specified temperature range. Cooling trays for the sample plates

or ventilators shall be used to maintain a temperature lower than 32 °C and warming devices to

maintain samples at or above 27 °C.

Measurement to be made using a sensor that is traceable to a national or an international calibration

standard, within the range of use.
5.4 Monitoring of the UV exposure source

The emission of the UV exposure source used for exposure shall be checked for compliance with the

given acceptance limits by a suitably qualified expert (at least) every 12 months, or 2500 hours of lamp

running time. The inspection should be conducted with a spectroradiometer that has been calibrated

against a standard lamp that is traceable to a national or an international calibration standard provided

4 © ISO 2020 – All rights reserved
---------------------- Page: 12 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)

by an accredited ISO17025 laboratory. In addition to the spectroradiometric inspection, the intensity of

the UV exposure source used for exposure shall be checked prior to each use.

This can be done using either a spectroradiometer or a radiometer with sensitivity in the UVA,

calibrated for the same UV exposure source spectrum used for the exposure step of the procedure,

applying the coefficient of calibration to adjust for variance between the UVA radiometer and the

reference spectroradiometer.

5.5 Calibration of the UVA radiometer used to monitor the test sample irradiation

If a UVA radiometer is used, this device shall have been suitably calibrated. This requires that it be

calibrated to the spectroradiometer used to measure the exposure source (as during annual solar

simulator calibration).

Calibration shall be conducted in terms of UVA irradiance (320 nm to 400 nm) and shall be at the

same level at which the test plates are exposed. Once calibrated with the spectroradiometer, the UVA

radiometer may be used to determine the UV doses to be used during the exposure procedure on a day-

to-day basis. Annex B provides the step-by-step calibration procedure.
5.6 Substrate/plate

The substrate/plate is the material to which the test product is to be applied. For this method, PMMA

plates with one rough side of the substrate are to be used and are commercially available. The size of

the substrate should be chosen such that the application area is not less than 16 cm .

[9]

The specifications and preparation of this type of plate are described in Annex D.

6 Test method
6.1 Outline of the test procedure

6.1.1 Conduct the calibration and validation of the test equipment, including the UV spectrophotometer

used for transmission/absorbance measurements and the UVA radiometer (or spectroradiometer) used

to measure the UV exposure source, and verify the transmission properties of the test plates as described

in Annex D.

6.1.2 Conduct blank measurements of a glycerin-treated or Vaseline-treated plate for the reference

“blank”, which will be used in the subsequent absorbance measurements.

6.1.3 Conduct in vitro absorbance measurements of the sunscreen product spread on a PMMA plate,

prior to any UV irradiation. Acquire the initial mAf spectrum with A (λ) data.

6.1.4 Conduct the mathematical adjustment of the initial UV absorbance spectrum using coefficient

“C” (see the calculation in 6.7.2) to achieve an in vitro SPF (no UV dose) equal to the measured static in

vivo SPF. Initial UVA-PF is calculated using A (λ) and C. A single UV exposure dose, D, is calculated, equal

0 0
to 1,2 × UVA-PF in J/cm , for each plate

6.1.5 Conduct UV exposure of the same sample as in 6.1.3, according to the calculated UV exposure

dose D.

6.1.6 Measure the in vitro absorbance of the sunscreen product after UV exposure. Acquire the second

UV spectrum with A(λ) data.
© ISO 2020 – All rights reserved 5
---------------------- Page: 13 ----------------------
oSIST prEN ISO 24443:2020
ISO/DIS 24443:2020(E)

6.1.7 Conduct the mathematical adjustment of the second mAf spectrum (following UV exposure) by

multiplying with the same “C” coefficient, previously determined in 6.1.4. The resulting absorbance curve

is the final adjusted absorbance values.
6.2 Equipment calibration and validation of test plates

Test procedures as described in Annex A are to be completed to validate the wavelength accuracy,

linearity and absorbance limits of the UV spectrophotometer/spectroradiometer to be used for the test

procedure. Validation of the UV properties of the test PMMA plates shall also be conducted as described

in Annex D.
6.3 Absorption measurements through the plate

It is necessary to first determine the absorbance of UV radiation through a “blank” PMMA plate.

Prepare a “blank” plate by spreading a few microlitres of glycerin/vaseline on the roughened side of the

plate. Choose the amount of glycerine/vaseline such that the entire surface is just completely covered

(approximately 15 μl for a 50 mm × 50 mm plate).
Any excess of
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.