INTERNATIONAL ISO

STANDARD 4892-2

Third edition
2013-03-01

Plastics — Methods of exposure to

laboratory light sources —
Part 2:
Xenon-arc lamps
Plastiques — Méthodes d’exposition à des sources lumineuses de
laboratoire —
Partie 2: Lampes à arc au xénon

Reference number
ISO 4892-2:2013(E)

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 ISO 4892-2:2013(E)


Contents Page

Foreword......................................................................................................................................................................................................................................... iv
1 Scope.................................................................................................................................................................................................................................. 1
2 Normative references....................................................................................................................................................................................... 1
3 Principle......................................................................................................................................................................................................................... 1
4 Apparatus...................................................................................................................................................................................................................... 2
4.1 Laboratory light source.................................................................................................................................................................... 2
4.2 Test chamber............................................................................................................................................................................................. 4
4.3 Radiometer.................................................................................................................................................................................................. 5
4.4 Black-standard/black-panel thermometer...................................................................................................................... 5
4.5 Wetting and humidity-control equipment....................................................................................................................... 5
4.6 Specimen holders.................................................................................................................................................................................. 5
4.7 Apparatus to assess changes in properties..................................................................................................................... 6
5 Test specimens........................................................................................................................................................................................................ 6
6 Exposure conditions.......................................................................................................................................................................................... 6
6.1 Radiation....................................................................................................................................................................................................... 6
6.2 Temperature............................................................................................................................................................................................... 6
6.3 Relative humidity of chamber air............................................................................................................................................ 7
6.4 Spray cycle................................................................................................................................................................................................... 7
6.5 Cycles with dark periods................................................................................................................................................................. 8
6.6 Sets of exposure conditions.......................................................................................................................................................... 8
7 Procedure..................................................................................................................................................................................................................... 9
7.1 General............................................................................................................................................................................................................ 9
7.2 Mounting the test specimens....................................................................................................................................................... 9
7.3 Exposure........................................................................................................................................................................................................ 9
7.4 Measurement of radiant exposure.......................................................................................................................................... 9
7.5 Determination of changes in properties after exposure...................................................................................... 9
8 Exposure report..................................................................................................................................................................................................... 9
Annex A (informative) Filtered xenon-arc radiation — Relative spectral irradiance.....................................10
Annex B (normative) Additional exposure cycles.................................................................................................................................11
Bibliography.............................................................................................................................................................................................................................. 13

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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75  % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO  4892-2 was prepared by Technical Committee ISO/TC  61, Plastics, Subcommittee SC  6, Ageing,
chemical and environmental resistance.
This third edition cancels and replaces the second edition (ISO 4892-2:2006), which has been technically
revised. It also cancels and replaces the Amendment ISO 4892-2:2006/Amd.1:2009.
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

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 INTERNATIONAL STANDARD ISO 4892-2:2013(E)

Plastics — Methods of exposure to laboratory light sources —

Part 2:
Xenon-arc lamps

1 Scope
This part of ISO  4892 specifies methods for exposing specimens to xenon-arc light in the presence
of moisture to reproduce the weathering effects (temperature, humidity and/or wetting) that occur
when materials are exposed in actual end-use environments to daylight or to daylight filtered through
window glass.
Specimen preparation and evaluation of the results are covered in other International Standards for
specific materials.
General guidance is given in ISO 4892-1.
NOTE Xenon-arc exposures of paints and varnishes are described in ISO 11341.

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  4582, Plastics — Determination of changes in colour and variations in properties after exposure to
daylight under glass, natural weathering or laboratory light sources
ISO 4892-1, Plastics — Methods of exposure to laboratory light sources — Part 1: General guidance
ISO  9370, Plastics — Instrumental determination of radiant exposure in weathering tests — General
guidance and basic test method

3 Principle

3.1 A xenon arc, fitted with filters, is used to simulate the relative spectral irradiance of daylight in the
ultraviolet (UV) and visible regions of the spectrum.

3.2 Specimens are exposed to various levels of light, heat, relative humidity and water (see 3.4) under
controlled environmental conditions.

3.3 The exposure conditions are varied by selection of

a) the light filter(s);

b) the irradiance level;
c) the temperature during exposure to light;
d) the relative humidity in the chamber during light and dark exposures, when exposure conditions
requiring control of humidity are used;
e) the way the test specimens are wetted (see 3.4);

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 ISO 4892-2:2013(E)


f) the water temperature and wetting cycle;

g) the relative lengths of the light and dark periods.

3.4 Wetting is produced by spraying the test specimens with demineralized/deionized water, by
immersion in water or by condensation of water vapour onto the surfaces of the specimens.

3.5 The procedure includes measurements of the UV irradiance and UV radiant exposure in the plane
of the specimens.

3.6 It is recommended that a similar material of known performance (a control) be exposed

simultaneously with the test specimens to provide a standard for comparative purposes.

3.7 Intercomparison of results obtained from specimens exposed in different apparatus should not be
made unless an appropriate statistical relationship has been established between the apparatuses for the
particular material exposed.

4 Apparatus

4.1 Laboratory light source

4.1.1 General

The light source shall comprise one or more quartz-jacketed xenon-arc lamps which emit radiation from
below 270 nm in the ultraviolet through the visible spectrum and into the infrared. In order to simulate
daylight, filters shall be used to remove short-wavelength UV radiation (method A, see Table 1). Filters
to minimize irradiance at wavelengths shorter than 310 nm shall be used to simulate daylight through
window glass (method B, see Table 2). In addition, filters to remove infrared radiation may be used to
prevent unrealistic heating of the test specimens, which can cause thermal degradation not experienced
during outdoor exposures.
NOTE Solar spectral irradiance for a number of different atmospheric conditions is described in CIE Publication
No. 85. The benchmark daylight used in this part of ISO 4892 is that defined in Table 4 in CIE No. 85:1989.

4.1.2 Spectral irradiance of xenon-arc lamps with daylight filters

Filters are used to filter xenon-arc emissions in order to simulate daylight (CIE Publication No. 85:1989,
Table 4). The minimum and maximum levels of the relative spectral irradiance in the UV wavelength
range are given in Table 1 (see also Annex A).

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Table 1 — Relative spectral irradiance of xenon-arc lamps with daylight filtersab (method A)
Spectral passband Minimumc CIE No. 85:1989, Table 4de Maximumc
(λ = wavelength in nm) % % %
λ < 290 0,15
290 ≤ λ ≤ 320 2,6 5,4 7,9
320 < λ ≤ 360 28,2 38,2 39,8
360 < λ ≤ 400 54,2 56,4 67,5
a This table gives the irradiance in the given passband, expressed as a percentage of the total irradiance between 290 nm
and 400 nm. To determine whether a specific filter or set of filters for a xenon-arc lamp meets the requirements of this table,
the spectral irradiance must be measured from 250 nm to 400 nm. The total irradiance in each wavelength passband is then
summed and divided by the total irradiance from 290 nm to 400 nm. Typically, this is done in 2 nm increments.
b The minimum and maximum limits in this table are based on more than 100 spectral irradiance measurements with
water- and air-cooled xenon-arc lamps with daylight filters from different production lots and of various ages,[3] used in
accordance with the recommendations of the manufacturer. As more spectral irradiance data become available, minor
changes in the limits are possible. The minimum and maximum limits are at least three sigma from the mean for all the
measurements.
c The minimum and maximum columns will not necessarily sum to 100 % because they represent the minima and maxima
for the measurement data used. For any individual spectral irradiance, the percentages calculated for the passbands in this
table will sum to 100 %. For any individual xenon-arc lamp with daylight filters, the calculated percentage in each passband
shall fall within the minimum and maximum limits given. Exposure results can be expected to differ if obtained using
xenon-arc apparatus in which the spectral irradiances differ by as much as that allowed by the tolerances. Contact the
manufacturer of the xenon-arc apparatus for specific spectral irradiance data for the xenon-arc lamp and filters used.
d The data from Table 4 in CIE Publication No. 85:1989 is the global solar irradiance on a horizontal surface for an air
mass of 1,0, an ozone column of 0,34 cm at STP, 1,42 cm of precipitable water vapour and a spectral optical depth of aerosol
extinction of 0,1 at 500 nm. These data are target values for xenon-arc lamps with daylight filters.
e For the solar spectrum represented by Table 4 in CIE No. 85:1989, the UV irradiance (between 290 nm and 400 nm) is
11 % and the visible irradiance (between 400 nm and 800 nm) is 89 %, expressed as a percentage of the total irradiance
between 290 nm and 800 nm. The percentage of the UV irradiance and that of the visible irradiance incident on specimens
exposed in xenon-arc apparatus might vary due to the number of specimens being exposed and their reflectance properties.

4.1.3 Spectral irradiance of xenon-arc lamps with window glass filters

Filters are used to filter the xenon-arc lamp emissions in order to simulate daylight which has passed
through window glass. The minimum and maximum levels of the relative spectral irradiance in the UV
region are given in Table 2 (see also Annex A).

Table 2 — Relative spectral irradiance for xenon-arc lamps with window glass filtersab (method B)

CIE No. 85:1989, Table 4, plus

Spectral passband Minimumc Maximumc
effect of window glassde
(λ = wavelength in nm) % %
%
λ < 300 0,29
300 ≤ λ ≤ 320 0,1 ≤ 1 2,8
320 < λ ≤ 360 23,8 33,1 35,5

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 ISO 4892-2:2013(E)


Table 2 (continued)
CIE No. 85:1989, Table 4, plus
Spectral passband Minimumc Maximumc
effect of window glassde
(λ = wavelength in nm) % %
%
360 < λ ≤400 62,4 66,0 76,2
a This table gives the irradiance in the given passband, expressed as a percentage of the total irradiance
between 290 nm and 400 nm. To determine whether a specific filter or set of filters for a xenon-arc lamp meets
the requirements of this table, the spectral irradiance must be measured from 250 nm to 400 nm. The total
irradiance in each passband is then summed and divided by the total irradiance between 290 nm and 400 nm.
Typically, this is done in 2 nm increments.
b The minimum and maximum limits in this table are based on more than 30 spectral irradiance meas-
urements with water- and air-cooled xenon-arc lamps with window glass filters from different production lots
and of various ages,[3] used in accordance with the recommendations of the manufacturer. As more spectral
irradiance data become available, minor changes in the limits are possible. The minimum and maximum limits
are at least three sigma from the mean for all the measurements.
c The minimum and maximum columns will not necessarily sum to 100 % because they represent the
minima and maxima for the data used. For any individual spectral irradiance, the percentages calculated for
the passbands in this table will sum to 100 %. For any individual xenon-arc lamp with window glass filters, the
calculated percentage in each passband shall fall within the minimum and maximum limits given. Exposure
results can be expected to differ if obtained using xenon-arc apparatus in which the spectral irradiances differ
by as much as that allowed by the tolerances. Contact the manufacturer of the xenon-arc apparatus for specific
spectral irradiance data for the xenon-arc lamp and filters used.
d The data from Table 4 in CIE No. 85:1989 plus the effect of window glass was determined by mul-
tiplying the CIE No. 85:1989, Table 4, data by the spectral transmittance of 3-mm-thick window glass (see
ISO 11341). These data are target values for xenon-arc lamps with window glass filters.
e For the CIE No. 85:1989 plus window glass data, the UV irradiance between 300 nm and 400 nm is typ-
ically about 9 % and the visible irradiance (between 400 nm and 800 nm) is typically about 91 %, expressed as
a percentage of the total irradiance between 300 nm and 800 nm. The percentage of the UV irradiance and that
of the visible irradiance incident on specimens exposed in xenon-arc apparatus might vary due to the number
of specimens being exposed and their reflectance properties.

4.1.4 Irradiance uniformity

The irradiance at any position in the area used for specimen exposure shall be at least 80  % of the
maximum irradiance. Requirements for periodic repositioning of specimens when this requirement is
not met are described in ISO 4892-1.
NOTE For some materials of high reflectivity, high sensitivity to irradiance and temperature, periodic
repositioning of specimens is recommended to ensure uniformity of exposures, even when the irradiance
uniformity in the exposure area is within the limits so that repositioning is not required.

4.2 Test chamber

The design of the test chamber may vary, but it shall be constructed from inert material. In addition
to the controlled irradiance, the test chamber shall provide for control of temperature. For exposures
that require control of humidity, the test chamber shall include humidity-control facilities that meet
the requirements of ISO 4892-1. When required by the exposure used, the apparatus shall also include
facilities for the provision of water spray or the formation of condensate on the surface of the test
specimens, or for the immersion of the specimens in water. Water used for water spray shall meet the
requirements of ISO 4892-1.
The light source(s) shall be located, with respect to the specimens, such that the irradiance at the
specimen surface complies with 6.1.
NOTE If the lamp system (one or more lamps) is centrally positioned in the chamber, the effect of any
eccentricity of the lamp(s) on the uniformity of exposure can be reduced by using a rotating frame carrying the
specimens or by repositioning or rotating the lamps.

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Should any ozone be generated from operation of the lamp(s), the lamp(s) shall be isolated from the test
specimens and operating personnel. If the ozone is in an air stream, it shall be vented directly to the
outside of the building.

4.3 Radiometer
When a radiometer is used, it shall comply with the requirements outlined in ISO 4892-1 and ISO 9370.

4.4 Black-standard/black-panel thermometer

The black-standard or black-panel thermometer used shall comply with the requirements for these
devices given in ISO 4892-1.
The preferred maximum surface temperature device is the black-standard thermometer. The relevant
cycles are described in Table 3 and Table B.1.

4.5 Wetting and humidity-control equipment

4.5.1 General

Specimens may be exposed to moisture in the form of water spray or condensation, or by immersion.
Specific exposure conditions using water spray are described in Table 3 (see also Table B.1) and Table 4
(see also Table B.2). If condensation, immersion or other methods are used to expose the specimens to
moisture, details of the procedures and exposure conditions used shall be included in the exposure report.
Table 3 and Table 4 also describe exposure conditions in which the relative humidity is controlled.
Table B.1 and Table B.2 describe exposure conditions in which humidity control is not required.
NOTE The relative humidity of the air can have a significant influence on the photodegradation of polymers.

4.5.2 Relative-humidity control equipment

For exposures where relative-humidity control is required, the location of the sensors used to measure
the humidity shall be as specified in ISO 4892-1.

4.5.3 Spray system

The test chamber may be equipped with a means of directing an intermittent water spray onto the fronts
or backs of the test specimens under specified conditions. The spray shall be uniformly distributed
over the specimens. The spray system shall be made from corrosion-resistant materials that do not
contaminate the water employed.
The water sprayed onto the specimen surfaces shall have a conductivity below 5 µS/cm, contain less
than 1 µg/g dissolved solids and leave no observable stains or deposits on the specimens. Care shall
be taken to keep silica levels below 0,2 µg/g. A combination of deionization and reverse osmosis can be
used to produce water of the desired quality.

4.6 Specimen holders

Specimen holders may be in the form of an open frame, leaving the backs of the specimens exposed, or
they may provide the specimens with a solid backing. They shall be made from inert materials that will
not affect the results of the exposure, for example non-oxidizing alloys of aluminium or stainless steel.
Brass, steel or copper shall not be used in the vicinity of the test specimens. The backing used might
affect the results, as might any space between the backing and the test specimen, particularly with
transparent specimens, and shall be agreed on between the interested parties.

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4.7 Apparatus to assess changes in properties

If an International Standard relating to the determination of the properties chosen for monitoring the
changes in properties exists (see, in particular, ISO 4582), the apparatus specified by the International
Standard concerned shall be used.

5 Test specimens
Make reference to ISO 4892-1.

6 Exposure conditions

6.1 Radiation
Unless otherwise specified, control the irradiance at the levels indicated in Table 3 (see also Table B.1) and
Table 4 (see also Table B.2). Other irradiance levels may be used when agreed on by the interested parties.
The irradiance, and the pass band in which it was measured, shall be included in the exposure report.

6.2 Temperature

6.2.1 Black-standard and black-panel temperature

For referee purposes, Table 3 and Table B.1 specify black-standard temperatures. For normal work, black-
panel thermometers may be used in place of black-standard thermometers (see Table 4 and Table B.2).
The black-panel temperatures specified in Table 4 and the black-standard temperatures specified in
Table 3 are those most commonly used, but have no relationship to each other. Therefore, test results
obtained with the two tables might not be comparable.
NOTE 1 If a black-panel thermometer is used, the temperature indicated will be 3 °C to 12 °C lower than that
indicated by a black-standard thermometer under typical exposure conditions.

If a black-panel thermometer is used, then the panel material, the type of temperature sensor and the
way in which the sensor is mounted on the panel shall be included in the exposure report.
NOTE 2 If higher temperatures are used as specified in Table 3 and Table 4 for special exposures, the tendency
for specimens to undergo thermal degradation will increase and this might affect the results of such exposures.

Other temperatures may be used when agreed on by the interested parties, but shall be stated in the
exposure report.
If water spray is used, the temperature requirements apply to the end of the dry period. If the
thermometer does not reach a steady state during the dry period after the short water-spray part of
the cycle, check whether the specified temperature is reached during a longer dry period, and consider
using this longer dry period.
NOTE 3 During the water-spray part of the cycle, the black-standard or black-panel temperature will be close
to that of the water used.

NOTE  4 The additional measurement of a white-standard/white-panel temperature with a

white-standard/white-panel thermometer in accordance with ISO 4892-1 gives important information on the
range of surface temperatures of differently coloured test specimens.

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6.2.2 Chamber air temperature

Exposures can be run either with the chamber air temperature controlled at a specified level (see Table 3
and Table 4) or allowing the air temperature to find its own level (see Table B.1 and Table B.2).
NOTE The possible specimen surface temperature has as its lower limit the temperature of the air surrounding
the specimens (i.e. the chamber temperature) and as its upper limit the black-standard temperature specified. It
is assumed that the actual specimen temperature lies somewhere between these two limits.

6.3 Relative humidity of chamber air

Exposures can be conducted either with the relative humidity controlled at a specified level (see Table 3
and Table 4) or allowing the relative humidity to find its own level (see Table B.1 and Table B.2).

Table 3 — Exposure cycles with temperature control by black-standard thermometer (BST)a

Method A — Exposures using daylight filters (artificial weathering)

Irradianceb
Black-stand-
Broadband Chamber Relative
Cycle Narrowband ard tempera-
Exposure period (300 nm to temperature humidity
No. (340 nm) ture
400 nm) °C %
W/(m2⋅nm) °C
W/m2
102 min dry
60 ± 2 0,51 ± 0,02 65 ± 3 38 ± 3 50 ± 10c
1 18 min water
60 ± 2 0,51 ± 0,02 — — —
spray
Method B — Exposures using window glass filters
Irradiance
Black-stand-
Broadband Chamber Relative
Cycle Narrowband ard tempera-
Exposure period (300 nm to temperature humidity
No. (420 nm) ture
400 nm) °C %
W/(m2⋅nm) °C
W/m2
2 Continuously dry 50 ± 2 1,10 ± 0,02 65 ± 3 38 ± 3 50 ± 10c
3 Continuously dry 50 ± 2 1,10 ± 0,02 100 ± 3 65 ± 3 20 ± 10
NOTE 1 The ± tolerances given for irradiance, black-standard temperature and relative humidity are the allow-
able fluctuations of the parameter concerned about the given value under equilibrium conditions. This does not
mean that the value may vary by plus/minus the amount indicated from the given value.
NOTE 2 For exposures in which the chamber temperature and humidity are not controlled (see Table B.1), it
could be useful to report the measured values of both in the exposure report.
a This table gives the conditions for exposures conducted with daylight filters (method A) and with win-
dow glass filters (method B) using a black-standard thermometer, whereas in Table 4 temperature control is by
means of a black-panel thermometer.
b The irradiance values given are those that have historically been used. In apparatus capable of produc-
ing higher irradiances, the actual irradiance might be significantly higher than the stated values, e.g. up to
180 W/m2 (300 nm to 400 nm) for xenon-arc lamps with daylight filters or 162 W/m2 (300 nm to 400 nm) for
xenon-arc lamps with window glass filters.
c For materials sensitive to humidity, the use of (65 ± 10) % RH is recommended.

6.4 Spray cycle

The spray cycle used shall be as agreed between the interested parties, but should preferably be that in
Table 3 (or Table B.1) for method A and Table 4 (see also Table B.2) method A.

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6.5 Cycles with dark periods

The conditions in Table 3 and Table B.1 (see also Table 4 and Table B.2) are valid for continuous presence
of radiant energy from the source. More complex cycles may be used. These could include dark periods
that might involve high humidity and/or the formation of condensate on the surfaces of the specimens.
Such programmes shall be given, with full details of the conditions, in the exposure report.

Table 4 — Exposure cycles with temperature control by black-panel thermometer (BPT)

Method A — Exposures using daylight filters (artificial weathering)
Irradiancea
Broadband Black-panel Chamber Relative
Cycle Narrowband
Exposure period (300 nm to temperature temperature humidity
No. (340 nm)
400 nm) °C °C %
W/(m2⋅nm)
W/m2
102 min dry
60 ± 2 0,51 ± 0,02 63 ± 3 38 ± 3 50 ± 10b
4 18 min water
60 ± 2 0,51 ± 0,02 — — —
spray
Method B — Exposures using window glass filters
Irradiancea
Broadband Black-panel Chamber Relative
Cycle Narrowband
Exposure period (300 nm to temperature temperature humidity
No. (420 nm)
400 nm) °C °C %
W/(m2⋅nm)
W/m2
5 Continuously dry 50 ± 2 1,10 ± 0,02 63 ± 3 38 ± 3 50 ± 10b
6 Continuously dry 50 ± 2 1,10 ± 0,02 89 ± 3 65 ± 3 20 ± 10
NOTE 1 The ± tolerances given for irradiance, black-panel temperature and relative humidity are the allowable
fluctuations of the parameter concerned about the given value under equilibrium conditions. This does not
mean that the value may vary by plus/minus the amount indicated from the given value.
NOTE 2 For exposures in which the chamber temperature and humidity are not controlled (see Table B.2), it
could be useful to report the measured values of both in the exposure report.
a The irradiance values given are those that have historically been used. In apparatus capable of produc-
ing higher irradiances, the actual irradiance might be significantly higher than the stated values, e.g. up to
180 W/m2 (300 nm to 400 nm) for xenon-arc lamps with daylight filters or 162 W/m2 (300 nm to 400 nm) for
xenon-arc lamps with window glass filters.
b For materials sensitive to humidity, the use of (65 ± 10) % RH is recommended.

6.6 Sets of exposure conditions

Table 3 (see also Table B.1) and Table 4 (see also Table B.2) lists various sets of conditions for exposures
conducted with daylight filters (method A) and those conducted with window glass filters (method B).
If no other exposure conditions are specified, use cycle No. 1 (BST control) or cycle No. 4 (BPT control).
Table 3 specifies three exposure cycles in which the black-standard temperatures are controlled
(for additional cycles, see Table B.1). In Table 4 (for additional cycles see Table B.2), black-panel
temperatures are given.
The black-panel temperatures specified in Table 4 and Table B.2 and the black-standard temperatures
specified in Table 3 and Table B.1 are the ones most commonly used, but have no relationship to each
other. The exposure results might therefore not be comparable.
Black-standard thermometers may also be used instead of black-panel thermometers to ensure that
the temperature requirements in Table 4 and Table B.2 are met. However, in this case the actual
temperature difference between the different types of thermometer shall be determined and the

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 ISO 4892-2:2013(E)


temperature measured by each shall be used as the equivalent set point temperature to compensate for
the differences in the thermal conductivity between the two thermometer types.

7 Procedure

7.1 General
It is recommended that at least three test specimens of each material evaluated be exposed in each run
to allow statistical evaluation of the results.

7.2 Mounting the test specimens

Attach the specimens to the specimen holders in the equipment in such a manner that the specimens
are not subject to any applied stress. Identify each test specimen by suitable indelible marking, avoiding
areas to be used for subsequent testing. As a check, a plan of the test-specimen positions may be made.
If desired, in the case of specimens used to determine change in colour and appearance, a portion of each
test specimen may be shielded by an opaque cover throughout the exposure. This gives an unexposed
area adjacent to the exposed area for comparison. This is useful for checking the progress of the exposure,
but the data reported shall always be based on a comparison with file specimens stored in the dark.

7.3 Exposure
Before placing the specimens in the test chamber, be sure that the apparatus is operating under the
desired conditions (see Clause 6). Programme the apparatus with the selected conditions to operate
continuously for the required number of cycles at the selected exposure conditions. Maintain these
conditions throughout the exposure, keeping any interruptions to service the apparatus and to inspect
the specimens to a minimum.
Expose the test specimens and, if used, the irradiance-measuring instrument for the specified period.
Repositioning of the specimens during exposure is desirable and might be necessary. Follow the guidance
in ISO 4892-1.
If it is necessary to remove a test specimen for periodic inspection, take care not to touch the exposed
surface or alter it in any way. After inspection, return the specimen to its holder or to its place in the test
chamber with its exposed surface oriented in the same direction as before.

7.4 Measurement of radiant exposure

If used, mount and calibrate the radiometer so that it measures the irradiance at the exposed surface of
the test specimen.
When radiant exposures are used, express the exposure interval in terms of incident radiant energy per
unit area of the exposure plane, in joules per square metre (J/m2), in the wavelength band from 300 nm to
400 nm, or in joules per square metre per nanometre [J/(m2⋅nm)] at the wavelength selected (e.g. 340 nm).

7.5 Determination of changes in properties after exposure

These shall be determined as specified in ISO 4582 in as far as possible. Other properties may be used if
agreed upon by all interested parties.

8 Exposure report
Make reference to ISO 4892-1.

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 ISO 4892-2:2013(E)


Annex A
(informative)

Filtered xenon-arc radiation — Relative spectral irradiance

A.1 General
CIE Publication No. 85:1989 provides data on spectral solar irradiance for typical atmospheric conditions,
and this data can be used as a basis for comparing laboratory light sources with daylight. The data used
for filtered xenon-arc radiation are given in Table 4 in CIE No. 85:1989. However, CIE No. 85:1989 has
a number of disadvantages: The global solar spectral energy distribution which it gives does not start
until 305 nm, the increments are rather approximate and the calculation code is no longer available.
Therefore, efforts have been under way for several years to revise CIE No. 85. The revision is based on
more recent measurements and an improved calculation model (SMARTS2[4]). CIE No. 85:1989, Table 4,
may continue to be employed when recalculated using the SMARTS2 model.[5]

A.2 Spectral irradiance specification (UV region)

A.2.1 Xenon-arc lamps with daylight filters
The data given in CIE No. 85:1989, Table 4, for the UV region (≤ 400 nm) represent the irradiance benchmark
for xenon-arc lamps with daylight filters. Table 1 gives the CIE No. 85:1989, Table 4, benchmark data.

A.2.2 Xenon-arc lamps with window glass filters

The benchmark spectral data for xenon-arc lamps with window glass filters given in Table 2 were
determined by modifying the data in the UV region given in CIE No.  85:1989, Table 4, to allow for
the transmission of typical window glass. The window glass transmittance used was based on the
transmittance of a specific 3-mm-thick window glass as given in Table B.2 of ISO 11341:2004. The CIE
No. 85:1989, Table 4, irradiance was multiplied by the appropriate transmittance of the window glass to
determine the irradiance in each passband.
NOTE Note that Table 2 allows very different spectral distributions, even spectral distributions overlapping
with those in Table 1. To achieve a spectral distribution meeting the minimum and maximum limits for window
glass, a spectral transmittance for window glass of between 0,1 and 0,2 at 320 nm and a minimum of 0,8 at 380 nm
is preferred.

A.2.3 Specification limits

The spectral irradiance specifications given in Tables 1 and 2 are based on spectral irradiance data
provided by 3M, Atlas Material Testing Technology, Q‑Lab Corporation, and Suga Test Instruments. The
irradiance in each passband was totalled and then expressed as a percentage of the total irradiance
between 290 nm and 400 nm. The specification limits given in Tables 1 and 2 are based on plus and
minus 3 standard deviations from the mean of the data available. Assuming that the measurements are
representative of the xenon-arc apparatus population, this range encompasses 99 % of this population.

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 ISO 4892-2:2013(E)


Annex B
(normative)

Additional exposure cycles

Table B.1 — Additional exposure cycles with temperature control by black-standard

thermometer (BST)
Method A — Exposures using daylight filters (artificial weathering)
Irradiancea
Black-stand-
Broadband Chamber Relative
Cycle Narrowband ard tempera-
Exposure period (300 nm to temperature humidity
No. (340 nm) ture
400 nm) °C %
W/(m2⋅nm) °C
W/m2
102 min dry
60 ± 2 0,51 ± 0,02 65 ± 3 Not controlled Not controlled
B1 18 min water
60 ± 2 0,51 ± 0,02 — — —
spray
Method B — Exposures using window glass filters
Irradiancea
Black-stand-
Broadband Chamber Relative
Cycle Narrowband ard tempera-
Exposure period (300 nm to temperature humidity
No. (420 nm) ture
400 nm) °C %
W/(m2⋅nm) °C
W/m2
B2 Continuously dry 50 ± 2 1,10 ± 0,02 65 ± 3 Not controlled Not controlled
B3 Continuously dry 50 ± 2 1,10 ± 0,02 100 ± 3 Not controlled Not controlled
NOTE 1 The ±  tolerances given for irradiance, black-standard temperature and relative humidity are the allowable
fluctuations of the parameter concerned about the given value under equilibrium conditions. This does not mean that the
value may vary by plus/minus the amount indicated from the given value.
NOTE 2 For exposures in which the chamber temperature and humidity are not controlled, it could be useful to report the
measured values of both in the exposure report.
NOTE 3 Types of exposure apparatus that do not control chamber temperature but do control the humidity shall be set to a
relative humidity of (50  ± 10) %.
a The irradiance values given are those that have historically been used. In apparatus capable of producing higher
irradiances, the actual irradiance might be significantly higher than the stated values, e.g. up to 180  W/m2 (300 nm to
400 nm) for xenon-arc lamps with daylight filters or 162 W/m2 (300 nm to 400 nm) for xenon-arc lamps with window glass
filters.

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 ISO 4892-2:2013(E)


Table B.2 — Additional exposure cycles with temperature control by black-panel

thermometer (BPT)
Method A — Exposures using daylight filters (artificial weathering)
Irradiancea
Broadband Black-panel Chamber Relative
Cycle Narrowband
Exposure period (300 nm to temperature temperature humidity
No. (340 nm)
400 nm) °C °C %
/(m2⋅nm)
W/m2
102 min dry
60 ± 2 0,51 ± 0,02 63 ± 3 Not controlled Not controlled
B4 18 min water
60 ± 2 0,51 ± 0,02 — — —
spray
102 min dry
60 ± 2 0,51 ± 0,02 83 ± 3 Not controlled Not controlled
B5 18 min water
60 ± 2 0,51 ± 0,02 — — —
spray
102 min dry
60 ± 2 0,51 ± 0,02 89 ± 3 Not controlled 20 ± 10
B6 18 min water
60 ± 2 0,51 ± 0,02 — — —
spray
Method B — Exposures using window glass filters
Irradiancea
Broadband Black-panel Chamber Relative
Cycle Narrowband
Exposure period (300 nm to temperature temperature humidity
No. (420 nm)
400 nm) °C °C %
W/(m2⋅nm)
W/m2
B7 Continuously dry 50 ± 2 1,10 ± 0,02 63 ± 3 Not controlled Not controlled
B8 Continuously dry 50 ± 2 1,10 ± 0,02 89 ± 3 Not controlled Not controlled
NOTE 1 The ± tolerances given for irradiance, black-panel temperature and relative humidity are the allowable fluctuations
of the parameter concerned about the given value under equilibrium conditions. This does not mean that the value may vary
by plus/minus the amount indicated from the given value.
NOTE 2 For exposures in which the chamber temperature and humidity are not controlled, it could be useful to report the
measured values of both in the exposure report.
NOTE 3 Types of exposure apparatus that do not control chamber temperature but do control the humidity shall be set to a
relative humidity of (50  ± 10) %.
a The irradiance values given are those that have historically been used. In apparatus capable of producing higher
irradiances, the actual irradiance might be significantly higher than the stated values, e.g. up to 180  W/m2 (300 nm to
400 nm) for xenon-arc lamps with daylight filters or 162 W/m2 (300 nm to 400 nm) for xenon-arc lamps with window glass
filters.

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 ISO 4892-2:2013(E)


Bibliography

[1] CIE Publication No. 85:1989, Solar spectral irradiance

[2] ISO 11341:2004, Paints and varnishes — Artificial weathering and exposure to artificial radiation —
Exposure to filtered xenon-arc radiation
[3] ASTM  G155, Standard Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-
Metallic Materials
[4] Gueymard C. SMARTS2 — A Simple Model of the Atmospheric Radiation Transfer of Sunshine:
Algorithms and Performance Assessment, Professional Paper FSEC-PF-270-95, Florida Solar Energy
Center, 1679 Clearlake Road. Cocoa, FL, 1995, pp. 32922.
[5] Schönlein A. Accelerated Weathering Test of Plastics and Coatings — New Technologies and
Standardization, European Coatings Congress, Nuremberg, Germany, 2009

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 ISO 4892-2:2013(E)


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