EN ISO 4892-1:2016

SLOVENSKI STANDARD
01-julij-2016
1DGRPHãþD
SIST EN ISO 4892-1:2001
Polimerni materiali - Metode izpostavljanja laboratorijskim virom svetlobe - 1. del:
Splošna navodila (ISO 4892-1:2016)
Plastics - Methods of exposure to laboratory light sources - Part 1: General guidance
(ISO 4892-1:2016)
Kunststoffe - Künstliches Bestrahlen oder Bewittern in Geräten - Teil 1: Allgemeine
Anleitung (ISO 4892-1:2016)
Plastiques - Méthodes d'exposition à des sources lumineuses de laboratoire - Partie 1:
Lignes directrices générales (ISO 4892-1:2016)
Ta slovenski standard je istoveten z: EN ISO 4892-1:2016
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 4892-1
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2016
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 4892-1:2000
English Version
Plastics - Methods of exposure to laboratory light sources -
Part 1: General guidance (ISO 4892-1:2016)
Plastiques - Méthodes d'exposition à des sources Kunststoffe - Künstliches Bestrahlen oder Bewittern in
lumineuses de laboratoire - Partie 1: Lignes directrices Geräten - Teil 1: Allgemeine Anleitung (ISO 4892-
générales (ISO 4892-1:2016) 1:2016)
This European Standard was approved by CEN on 15 April 2016.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4892-1:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 4892-1:2016) has been prepared by Technical Committee ISO/TC 61 “Plastics”
in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by
NBN.
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 November 2016, and conflicting national standards
shall be withdrawn at the latest by November 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 4892-1:2000.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 4892-1:2016 has been approved by CEN as EN ISO 4892-1:2016 without any
modification.
INTERNATIONAL ISO
STANDARD 4892-1
Third edition
2016-05-01
Plastics — Methods of exposure to
laboratory light sources —
Part 1:
General guidance
Plastiques — Méthodes d’exposition à des sources lumineuses de
laboratoire —
Partie 1: Lignes directrices générales
Reference number
ISO 4892-1:2016(E)
©
ISO 2016
ISO 4892-1:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 4892-1:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
4.1 General . 2
4.2 Significance . 3
4.3 Use of accelerated tests with laboratory light sources . 4
5 Requirements for laboratory exposure devices . 5
5.1 Irradiance . 5
5.2 Temperature . 6
5.3 Humidity and wetting . 8
5.4 Other requirements for the exposure device . 9
6 Test specimens.10
6.1 Form, shape and preparation .10
6.2 Number of test specimens .11
6.3 Storage and conditioning .11
7 Test conditions and procedure .11
7.1 Set points for exposure conditions .11
7.2 Property measurements on test specimens .12
8 Periods of exposure and evaluation of test results .13
8.1 General .13
8.2 Use of control materials .13
8.3 Use of results in specifications .13
9 Test report .14
Annex A (normative) Procedures for measuring the irradiance uniformity in the specimen
exposure area .16
Annex B (informative) Factors that decrease the degree of correlation between artificial
accelerated weathering or artificial accelerated irradiation exposures and actual-
use exposures .19
Annex C (informative) Solar spectral irradiance standards.22
Bibliography .24
ISO 4892-1:2016(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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 6, Ageing, chemical
and environmental resistance.
This third edition cancels and replaces the second edition (ISO 4892-1:1999), which has been technically
revised.
ISO 4892 consists of the following parts, under the general title Plastics — Methods of exposure to
laboratory light sources:
— Part 1: General guidance
— Part 2: Xenon-arc lamps
— Part 3: Fluorescent UV lamps
— Part 4: Open-flame carbon-arc lamps
iv © ISO 2016 – All rights reserved

ISO 4892-1:2016(E)
Introduction
Plastics are often used outdoors or in indoor locations where they are exposed to solar radiation or to
solar radiation behind glass for long periods. It is therefore very important to determine the effects of
solar radiation, heat, moisture and other climatic stresses on the colour and other properties of plastics.
Outdoor exposures to solar radiation and to solar radiation filtered by window glass are described in
[1]
ISO 877 (all parts). However, it is often necessary to determine more rapidly the effects of radiation,
heat and moisture on the physical, chemical and optical properties of plastics with artificial accelerated
weathering or artificial accelerated irradiation exposures that use specific laboratory light sources.
Exposures in these laboratory devices are conducted under more controlled conditions than found
in natural environments and are intended to accelerate eventual polymer degradation and product
failures.
Relating results from accelerated weathering or artificial accelerated irradiation exposures to those
obtained in actual-use conditions is difficult because of variability in both types of exposure and
because laboratory tests never reproduce exactly all the exposure stresses experienced by plastics
exposed in actual-use conditions. No single laboratory exposure test can be specified as a total
simulation of actual-use exposures.
The relative durability of materials in actual-use exposures can be very different depending on
the location of the exposure because of differences in UV radiation, time of wetness, temperature,
pollutants and other factors. Therefore, even if results from specific accelerated weathering or
artificial accelerated irradiation exposures are found to be useful for comparing the relative durability
of materials exposed in a particular outdoor location or in particular actual-use conditions, it cannot
be assumed that they will be useful for determining the relative durability of materials exposed in a
different outdoor location or in different actual-use conditions.
INTERNATIONAL STANDARD ISO 4892-1:2016(E)
Plastics — Methods of exposure to laboratory light
sources —
Part 1:
General guidance
1 Scope
This part of ISO 4892 provides information and general guidance relevant to the selection and
operation of the methods of exposure described in detail in subsequent parts. It also describes
general performance requirements for devices used for exposing plastics to laboratory light sources.
Information regarding performance requirements is for producers of artificial accelerated weathering
or artificial accelerated irradiation devices.
NOTE In this part of ISO 4892, the term “light source” refers to radiation sources that emit UV radiation,
visible radiation, infrared radiation or any combination of these types of radiation.
This part of ISO 4892 also provides information on the interpretation of data from artificial accelerated
weathering or artificial accelerated irradiation exposures. More specific information about methods for
determining the change in the properties of plastics after exposure and reporting these results is given
in ISO 4582.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 293, Plastics — Compression moulding of test specimens of thermoplastic materials
ISO 294-1, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 1: General
principles, and moulding of multipurpose and bar test specimens
ISO 294-2, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 2: Small
tensile bars
ISO 294-3, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small plates
ISO 295, Plastics — Compression moulding of test specimens of thermosetting materials
ISO 2818, Plastics — Preparation of test specimens by machining
ISO 3167, Plastics — Multipurpose test specimens
ISO 4582, Plastics — Determination of changes in colour and variations in properties after exposure to
daylight under glass, natural weathering or laboratory light sources
ISO 4892-2, Plastics — Methods of exposure to laboratory light sources — Part 2: Xenon-arc lamps
ISO 4892-3, Plastics — Methods of exposure to laboratory light sources — Part 3: Fluorescent UV lamps
ISO 4892-4, Plastics — Methods of exposure to laboratory light sources — Part 4: Open-flame carbon-
arc lamps
ISO 4892-1:2016(E)
ISO 9370, Plastics — Instrumental determination of radiant exposure in weathering tests — General
guidance and basic test method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Definitions of other terms that are related to weathering tests are found in Reference [2].
3.1
control
material which is of similar composition and construction to the test material
and which is exposed at the same time for comparison with the test material
Note 1 to entry: An example of the use of a control material would be when a formulation different from one
currently being used is being evaluated. In that case, the control would be the plastic made with the original
formulation.
3.2
file specimen
portion of the material to be tested which is stored under conditions in which it is stable and which is
used for comparison between the exposed and unexposed states
3.3
artificial accelerated weathering
exposure of a material in a laboratory weathering device to conditions which may be cyclic and
intensified compared with those encountered in outdoor or in-service exposure
Note 1 to entry: This involves a laboratory radiation source, heat and moisture (in the form of relative humidity
and/or water spray, condensation or immersion) in an attempt to produce more rapidly the same changes that
occur in outdoor exposure.
Note 2 to entry: The device may include means for control and/or monitoring of the light source and other
weathering parameters. It may also include exposure to special conditions, such as acid spray to simulate the
effect of industrial gases.
3.4
artificial accelerated irradiation
exposure of a material to a laboratory radiation source intended to simulate window-glass-filtered
solar radiation or radiation from interior lighting sources and where specimens may be subjected to
relatively small changes in temperature and relative humidity in an attempt to produce more rapidly
the same changes that occur when the material is used in an indoor environment
Note 1 to entry: These exposures are commonly referred to as fading or lightfastness tests.
3.5
reference material
material of known performance
3.6
reference specimen
portion of the reference material that is to be exposed
4 Principle
4.1 General
Specimens of the samples to be tested are exposed to laboratory light sources under controlled
environmental conditions. The methods described include the requirements which have to be met for
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ISO 4892-1:2016(E)
the measurement of the irradiance and radiant exposure in the plane of the specimen, the temperature
of specified white and black sensors, the chamber air temperature and the relative humidity.
4.2 Significance
4.2.1 When conducting exposures in devices that use laboratory light sources, it is important to
consider how well the accelerated-test conditions simulate the actual-use environment for the plastic
being tested. In addition, it is essential to consider the effects of variability in both the accelerated test
and actual exposures when setting up exposure experiments and when interpreting the results from
artificial accelerated weathering or artificial accelerated irradiation exposures.
4.2.2 No laboratory exposure test can be specified as a total simulation of actual-use conditions. Results
obtained from artificial accelerated weathering or artificial accelerated irradiation exposures can be
considered as representative of actual-use exposures only when the degree of rank correlation has been
established for the specific materials being tested and when the type and mechanism of degradation are
the same. The relative durability of materials in actual-use conditions can be very different in different
locations because of differences in UV radiation, time of wetness, relative humidity, temperature,
pollutants and other factors. Therefore, even if results from a specific exposure test conducted in
accordance with any of the parts of this International Standard are found to be useful for comparing the
relative durability of materials exposed in a particular environment, it cannot be assumed that they will
be useful for determining the relative durability of the same materials in a different environment.
4.2.3 Even though it is very tempting, it is invalid to assign to all materials a “general acceleration
factor” relating “x” hours or megajoules of radiant exposure in an artificial accelerated weathering or
artificial accelerated irradiation exposure to “y” months or years of actual exposure. Such acceleration
factors are invalid for the following reasons.
a) Acceleration factors are material-dependent and can be significantly different for each material
and for different formulations of the same material.
b) Variability in the rate of degradation in both actual-use and artificial accelerated weathering
or artificial accelerated irradiation exposures can have a significant effect on the calculated
acceleration factor.
c) Acceleration factors calculated based on the ratio of irradiance between a laboratory light source
and solar radiation (even when identical passbands are used) do not take into consideration the
effects of temperature, moisture and differences in relative spectral irradiance between the
laboratory light source and solar radiation.
NOTE Acceleration factors determined for a specific formulation of a material are valid, but only if they
are based on data from a sufficient number of separate exterior or indoor environmental tests and artificial
accelerated weathering or artificial accelerated irradiation exposures so that results used to relate times to
failure in each exposure can be analysed using statistical methods. An example of a statistical analysis using
multiple laboratory and actual exposures to calculate an acceleration factor is described in Reference [3].
4.2.4 There are a number of factors that may decrease the degree of correlation between accelerated
tests using laboratory light sources and exterior exposures (more specific information on how each
factor may alter the stability ranking of materials is given in Annex B):
a) the differences in the relative spectral irradiance of the laboratory light source and solar radiation;
b) the irradiance levels higher than those experienced in actual-use conditions;
c) the exposure cycles that use continuous exposure to radiation from a laboratory light source
without any dark periods;
d) the specimen temperatures higher than those in actual conditions;
ISO 4892-1:2016(E)
e) the exposure conditions that produce unrealistic temperature differences between light- and dark-
coloured specimens;
f) the exposure conditions that produce very frequent cycling between high and low specimen
temperatures, or that produce unrealistic thermal shock;
g) the unrealistic levels of moisture in the accelerated test compared with actual-use conditions;
h) the absence of biological agents, pollutants or acidic precipitation or condensation.
4.3 Use of accelerated tests with laboratory light sources
4.3.1 Results from artificial accelerated weathering or artificial accelerated irradiation exposures
conducted in accordance with any of the parts of this International Standard are best used to compare the
relative performance of materials. Comparisons between materials can only be made when the materials
are tested at the same time in the same exposure device. Results can be expressed by comparing the
exposure time or radiant exposure necessary to reduce the level of a characteristic property to some
specified level. A common application of this is a test conducted to establish that the level of quality of
different batches does not vary from that of a control of known performance.
4.3.1.1 It is strongly recommended that at least one control be exposed with each test for the purpose
of comparing the performance of the test materials to that of the control. The control material should be
of similar composition and construction and be chosen so that its failure modes are the same as that of
the material being tested. It is preferable to use two controls, one with relatively good durability and one
with relatively poor durability.
4.3.1.2 Sufficient replicates of each control and each test material being evaluated are necessary in
order to allow statistical evaluation of the results. Unless otherwise specified, use a minimum of three
replicates for all test and control materials. When material properties are measured using destructive
tests, a separate set of specimens is needed for each exposure period.
4.3.2 In some specification tests, test materials are exposed at the same time as a weathering reference
material (e.g. blue wool test fabric). The property or properties of the test material are measured after
a defined property of the reference material reaches a specified level. If the reference material differs
in composition from the test material, it may not be sensitive to exposure stresses that produce failure
in the test material or it may be very sensitive to an exposure stress that has very little effect on the
test material. The variability in results for the reference material may be very different from that for the
test material. All these differences between the reference material and the test material can produce
misleading results when the reference material is used as a control or to determine the length of the
exposure period.
NOTE 1 Definitions of control and reference materials that are appropriate to weathering tests are given in
Clause 3.
NOTE 2 Weathering reference materials can also be used to monitor the consistency of the operating
conditions in an exposure test. Information about the selection and characterization of reference materials used
for this purpose can be found in Reference [4]. Reference [5] describes a procedure which uses the change in the
carbonyl index of a specific polyethylene weathering reference material to monitor conditions in both natural
weathering and artificial accelerated weathering exposures.
4.3.3 In some specification tests, properties of test specimens are evaluated after a specific exposure
time or radiant exposure using a test cycle with a prescribed set of conditions. Results from any
accelerated exposure test conducted in accordance with any of the parts of this International Standard
should not be used to make a “pass/fail” decision for materials, based on the level of a specific property
after a specific exposure time or radiant exposure, unless the combined reproducibility of the effects of a
particular exposure cycle and property measurement method has been established.
4 © ISO 2016 – All rights reserved

ISO 4892-1:2016(E)
5 Requirements for laboratory exposure devices
5.1 Irradiance
5.1.1 Laboratory light sources are used to provide irradiance for the test specimens. In ISO 4892-2, a
xenon-arc lamp is used to provide the irradiance for the specimens, in ISO 4892-3 a fluorescent UV lamp
and in ISO 4892-4 an open-flame sunshine carbon-arc lamp.
5.1.2 The exposure device shall provide for placement of specimens and any designated sensing
devices in positions that allow uniform irradiance from the radiation source.
NOTE The spectral irradiance produced in an artificial accelerated weathering device is very important.
Ideally, the relative spectral irradiance produced by the device is expected to be a very close match to that of
solar radiation, especially in the short-wavelength UV region. Annex C provides information about important
benchmark solar spectra that can be used for comparing the spectral irradiance produced in the artificial
accelerated exposure to that for solar radiation. Subsequent parts of this International Standard contain specific
requirements for the relative spectral irradiance produced in the devices described in those parts.
5.1.3 Exposure devices shall be designed such that the irradiance at any location in the area used for
specimen exposures is at least 70 % of the maximum irradiance measured in this area. Procedures for
measuring irradiance uniformity by the device manufacturers are given in Annex A.
NOTE The irradiance uniformity in exposure devices depends on several factors, such as deposits that
can develop on the optical system and chamber walls. In addition, irradiance uniformity can be affected by the
type of specimen and the number of specimens being exposed. The irradiance uniformity as guaranteed by the
manufacturer is valid for new equipment and well-defined measuring conditions.
5.1.4 If the minimum irradiance at any position in the area used for specimen exposure is between
70 % and 90 % of the maximum irradiance, specimens shall be periodically repositioned to reduce the
variability in radiant exposure. The repositioning procedure and schedule shall be agreed upon by all
interested parties.
NOTE Reference [6] describes several possible procedures, including random positioning of replicate
specimens, that can be used to reduce the variability in exposure stresses experienced by specimens during
exposure.
5.1.5 If the irradiance at any position in the area used for specimen exposure is at least 90 % of the
maximum irradiance, it is not necessary to use periodic repositioning of the specimens during exposure
to ensure uniform radiant exposure. While periodic repositioning of the specimens may not be necessary,
it is nevertheless good practice in order to be sure that the variability in exposure stresses experienced
during the exposure period is kept to the minimum.
NOTE 1 Depending on the specific sensitivity of the material, periodic repositioning of the specimens is good
practice to minimize variability in stresses experienced during the exposure.
NOTE 2 Random placement of replicate specimens is also good practice to reduce the effect of any variability
in the conditions within the exposure area.
5.1.6 Follow the device manufacturer’s instructions for lamp and filter replacement and for pre-ageing
of lamps and/or filters.
5.1.7 A radiometer that complies with the requirements outlined in ISO 9370 may be used to measure
the irradiance, E, or spectral irradiance, E , and the radiant exposure, H, or spectral radiant exposure, H ,
λ λ
in the plane of the specimen surface.
5.1.7.1 If used, the radiometer shall be mounted so that it receives the same radiation as the specimen
surface. If it is not positioned in the specimen plane, it shall have a sufficiently wide field of view and be
calibrated for irradiance at the specimen distance. The radiometer shall be calibrated using a light source
ISO 4892-1:2016(E)
filter combination of the same type that will be used for testing or an appropriate spectral mismatch
factor has been taken into account. The calibration shall be checked in accordance with the radiation
measuring instrument manufacturer’s instructions. A full calibration of the radiometer that is traceable
to a recognized radiometric standards body shall be conducted at least once per year. More frequent
calibrations are recommended.
For fluorescent UVB lamps, field radiometers shall be calibrated with lamps that have a spectral power
distribution which is identical to that of the lamps that will be used for testing.
NOTE 1 Reference [7] provides specific guidance on the calibration of radiometers using spectroradiometers.
This method can be used to calibrate the instrument radiometer(s).
NOTE 2 Refer to ISO 9370 for definitions of field and reference radiometers.
5.1.7.2 When measured, the irradiance in the wavelength range agreed upon by all interested parties
shall be reported. Some types of device provide for measuring irradiance in a specific wavelength range
(e.g. 300 nm to 400 nm or 300 nm to 800 nm) or in a narrow passband that is centred around a single
wavelength (e.g. 340 nm).
5.2 Temperature
5.2.1 The surface temperature of exposed materials depends primarily on the amount of radiation
absorbed, the emissivity of the specimen, the amount of thermal conduction within the specimen and
the amount of heat transmission between the specimen and the air or between the specimen and the
specimen holder. Since it is not practical to monitor the surface temperature of individual test specimens,
a specified black-panel sensor is used to measure and control the temperature within the exposure
chamber. The black panel of the black surface temperature sensor shall be mounted within the specimen
exposure area so that it is in the same plane and orientation and receives the same radiation and
experiences the same cooling conditions as a flat test panel surface. For three-dimensional specimens,
the black panel shall be in a plane and orientation that best represents the majority of the specimen
surface of interest or at the plane of the primary surface of interest.
5.2.2 Two types of black surface temperature sensors may be used: black-standard thermometer (BST)
and black-panel thermometer (BPT).
5.2.2.1 Black-standard thermometers, consisting of a plane (flat) stainless-steel plate with a thickness
of 0,5 mm to 1,2 mm. A typical length and width is about 70 mm by 40 mm. The surface of this plate facing
the radiation source shall be coated with a black layer which has good resistance to ageing. The coated
black plate shall reflect no more than 10 % of all incident flux up to 2 500 nm. A thermally sensitive
element such as a platinum resistance sensor shall be attached to the centre of the plate, in good thermal
contact with the plate, on the side opposite the radiation source. This side of the metal plate shall be
attached to a 5 mm thick baseplate made of unfilled poly(vinylidene fluoride) (PVDF). A small space
sufficient to hold the platinum resistance sensor shall be machined in the PVDF baseplate. The distance
between the sensor and this recess in the PVDF plate shall be about 1 mm. The length and width of the
PVDF plate shall be sufficient so that no metal-to-metal thermal contact exists between the black-coated
metal plate and the mounting holder into which it is fitted. The metal mounts of the holder of the insulated
black panel shall be at least 4 mm from the edges of the metal plate. Black-standard thermometers which
differ in construction from that specified above are permitted as long as the temperature indicated by
the alternative construction is within ±1,0 °C of that of the specified construction at all steady-state
temperature and irradiance settings the exposure device is capable of attaining. In addition, the time
needed for an alternative black-standard thermometer to reach the steady-state shall be within 10 % of
the time needed for the specified black-standard thermometer to reach the steady-state.
NOTE Black-standard thermometers are sometimes referred to as insulated black-panel thermometers.
5.2.2.2 Black-panel thermometers, consisting of a plane (flat) metal plate that is resistant to corrosion.
Typical dimensions are about 150 mm long, 70 mm wide and 1 mm thick. The surface of this plate
6 © ISO 2016 – All rights reserved

ISO 4892-1:2016(E)
that faces the radiation source shall be coated with a black layer which has good resistance to ageing.
The coated black plate shall reflect no more than 10 % of all incident flux up to 2 500 nm. A thermally
sensitive element shall be firmly attached to the centre of the exposed surface. This thermally sensitive
element can be a black-coated stem-type bimetallic dial sensor, a resistance-based sensor, a thermistor
or a thermocouple. The back side of the metal panel shall be open to the atmosphere.
NOTE 1 As convection cooling acts from both sides, installation geometry influences the stability of black
panel thermometers.
NOTE 2 Black-panel thermometers are sometimes referred to as uninsulated black-panel thermometers.
5.2.2.3 Unless otherwise specified, temperatures shall be measured using either of the thermometer
designs described above. If other means are used to measure the temperature of black or white panels,
the exact construction of the black or white panel shall be included in the test report.
5.2.3 The temperature indicated by the black-panel or black-standard thermometer depends on the
irradiance produced by the laboratory light source and the temperature and speed of the air moving
in the exposure chamber. Black-panel temperatures generally correspond to those for dark coatings on
metal panels without thermal insulation on the rear side. Black-standard thermometer temperatures
generally correspond to those for the exposed surface of dark samples with poor thermal conductivity.
At conditions used in typical exposures, the temperature indicated by a black-standard thermometer will
be 3 °C to 12 °C higher than that indicated by a black-panel thermometer. The actual difference between
a black-panel temperature and a temperature measured with a black-standard thermometer should,
however, preferably be determined for each exposure condition. Because black-standard thermometers
are insulated, their response time for temperature changes is slightly slower than for a black-panel
thermometer.
5.2.4 At low irradiance levels, the difference between the temperature indicated by a black-panel or
black-standard thermometer and the real specimen temperature may be small. When radiation sources
that emit very little infrared radiation are used, there will generally be only very small differences in the
temperatures indicated by the two types of black panel or between light- and dark-coloured specimens.
5.2.5 In order to evaluate the range of surface temperatures of the exposed specimens and to better
control the irradiance or the conditions in the exposure chamber, the use of a white-panel or white-
standard thermometer, in addition to the black-panel or black-standard thermometer, is recommended.
The white-panel or white-standard thermometer shall be constructed in the same way as the
corresponding black-panel or black-standard thermometer, except for the use of a white coating with
a good resistance to ageing. The reflectance of the white coating shall be at least 60 % between 450 nm
and 800 nm and at least 30 % between 800 nm and 1 500 nm.
5.2.6 Manufacturers of exposure devices shall ensure that devices designed to meet the requirements
of this part of ISO 4892 are able to meet the following requirements for control of the temperature of the
black or white temperature sensor at the position where it is intended to operate. These requirements
apply to equilibrium conditions.
Table 1 — Requirements for set-point temperature of the black or white temperature sensor at
the position where it is intended to operate
Allowable deviation of the sensor temperature at
Set-point temperature
the position in which sensor operates
≤70 °C ±3 °C
>70 °C ±4 °C
5.2.7 Manufacturers of exposure devices shall ensure that devices designed to meet the requirements
of this part of ISO 4892 are able to meet the following requirements for control of the temperature of a
ISO 4892-1:2016(E)
black or white temperature sensor at any position within the allowed exposure area. These requirements
apply to equilibrium conditions.
Table 2 — Requirements for set-point temperature of the black or white temperature sensor at
any position within the allowed exposure area
Allowable deviation of the sensor temperature
Set-point temperature
when sensor placed anywhere in the exposure area
≤70 °C ±5 °C
>70 °C ±7 °C
NOTE For some materials, differences in degradation rate may occur between devices operating within the
allowable temperature ranges. Periodic repositioning of specimens or random positioning of replicate specimens
during exposure will reduce the variability caused by differences in temperature within the exposure area.
5.2.8 The test report shall indicate whether a black-standard or black-panel thermometer and whether
a white-standard or white panel thermometer was used.
NOTE Different temperatures may be indicated by a single type of black-standard or black-panel
thermometer, depending on the specific design of the device supplied by different manufacturers.
5.2.9
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