ASTM G155-21

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: G155 − 13 G155 − 21
Standard Practice for
Operating Xenon Arc LightLamp Apparatus for Exposure of
Non-Metallic Materials
This standard is issued under the fixed designation G155; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*Scope
1.1 This practice is limited to the basic principles and procedures for operating a xenon arc lamp and water apparatus; on its own,
it does not deliver a specific result.
1.2 This practice covers the basic principles and operating procedures for using xenon arc light and water apparatus It is intended
to be used in conjunction with a practice or method that defines specific exposure conditions for an application along with a means
to evaluate changes in material properties. This practice is intended to reproduce the weathering effects that occur when materials
are exposed to sunlight (either direct or through window glass) and moisture as rain humidity, rain, or dew in actual use. This
practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. A number of exposure
procedures are listed in an appendix; however, this practice does not specify the exposure conditions best suited for the material
to be tested.
NOTE 1—A number of exposure procedures are listed in an appendix; however, this practice does not specify the exposure conditions best suited for the
material to be tested.
NOTE 2—Practice G151 describes performance criteria for all exposure devices that usegeneral procedures and performance requirements to be used when
exposing materials in an apparatus that uses laboratory light sources. This practice replaces Practice G26, which describes very specific designs for devices
used for xenon-arc exposures. The apparatus described in Practice G26 is covered by this practice.
1.3 Test specimens are exposed to filtered light from an optically-filtered xenon arc lightlamp under controlled environmental
conditions. Different types of optical filters in combination with xenon arc light sources and different filter combinations are
described.
1.4 Specimen preparation and evaluation of the results are covered in ASTM methods or specifications for specific materials.
General guidance is given in Practice G151 and ISO 4892-1. More specific information about methods for determining the change
in properties after exposure and reporting these results is described in Practice D5870.
NOTE 3—General information about methods for determining the change in properties after exposure and reporting these results is described in Practice
D5870.
1.5 This practice is not intended for corrosion testing of bare metals.
This practice is under the jurisdiction of ASTM Committee G03 on Weathering and Durability and is the direct responsibility of Subcommittee G03.03 on Simulated
and Controlled Exposure Tests.
Current edition approved June 1, 2013July 1, 2021. Published August 2013September 2021. Originally approved in 1997. Last previous edition approved in 20052013
as G155 – 05a.G155 – 13. DOI: 10.1520/G0155-13.10.1520/G0155-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G155 − 21
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.7 This practice is technically similar to the following ISO documents: ISO 4892-2, ISO 16474-2, ISO 105-B02, ISO 105-B04,
ISO 105-B05, ISO 105-B06, and ISO 105-B10.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of
the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.8.1 Should any ozone be generated from the operation of the lamp(s), it shall be carried away from the test specimens and
operating personnel by an exhaust system.
1.6 This practice is technically similar to the following ISO documents: ISO 4892-2, ISO 11341, ISO 105 B02, ISO 105 B04, ISO
105 B05, and ISO 105 B06.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D3980D2565 Practice for Interlaboratory Testing of Paint and Related MaterialsXenon-Arc Exposure of Plastics Intended for
Outdoor Applications (Withdrawn 1998)
D5870 Practice for Calculating Property Retention Index of Plastics
E691D6695 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodXenon-Arc Exposures
of Paint and Related Coatings
D7869 Practice for Xenon Arc Exposure Test with Enhanced Light and Water Exposure for Transportation Coatings
G26 Practice for Operating Light-Exposure Apparatus (Xenon-Arc Type) With and Without Water for Exposure of Nonmetallic
Materials (Discontinued 2001) (Withdrawn 2000)
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources
G153 Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials
G177 Tables for Reference Solar Ultraviolet Spectral Distributions: Hemispherical on 37° Tilted Surface
2.2 ASTM Adjuncts:
SMARTS2: Simple Model of the Atmospheric Radiative Transfer of Sunshine
2.3 CIE Standards:Standard:
CIE-Publ. No. 85: Recommendations for the Integrated Irradiance and the Spectral Distribution of Simulated Solar Radiation
for Testing Purposes
2.4 International Standards Organization ISO Standards:
ISO 113416474-2 PaintPaints and Varnishes—Artificial Weathering Exposure to Artificial Radiation to Filtered Xenon Arc
RadiationVarnishes—Methods of Exposure to Laboratory Light Sources—Part 2: Xenon-arc Lamps
ISO 105 B02105-B02 Textiles—Tests for Colorfastness—Part B02 Colorfastness to Artificial Light: Xenon Arc Fading Lamp
Test
ISO 105 B04105-B04 Textiles—Tests for Colorfastness—Part B04 Colorfastness to Artificial Weathering: Xenon Arc Fading
Lamp Test
ISO 105 B05105-B05 Textiles—Tests for Colorfastness—Part B05 Detection and Assessment of Photochromism
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from American National Standards Institute, 11 W.ASTM International Headquarters. Order Adjunct No. ADJG017342d St., 13th Floor, New York, NY
10036).
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.Available from American National
Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.IHS Markit, https://global.ihs.com.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland,
https://www.iso.org.
G155 − 21
ISO 105 B06105-B06 Textiles—Tests for Colorfastness—Part B06 Colorfastness to Artificial Light at High Temperatures:
Xenon Arc Fading Lamp Test
ISO 4892-1105-B10 Plastics—Methods of Exposure to Laboratory Light Sources, Part 1, General GuidanceTextiles—Tests for
Colorfastness—Part B10: Artificial Weathering—Exposure to Filtered Xenon Arc Radiation
ISO 4892-2 Plastics—Methods of Exposure to Laboratory Light Sources, Part 2, Xenon-Arc Sources
ISO TS 19022 Plastics—Method of Controlled Acceleration of Laboratory Weathering by Increased Irradiance
2.5 Society of Automotive Engineers’ SAE Standards:
SAE J2412 Accelerated Exposure of Automotive Interior Trim Components Using a Controlled Irradiance Xenon-Arc Apparatus
SAE J2527 Accelerated Exposure of Automotive Exterior Materials Using a Controlled Irradiance Xenon-Arc Apparatus
3. Terminology
3.1 Definitions—TheDefinitions—The definitions given in Terminology G113 are applicable to this practice.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 As used in this practice, the term sunlight is identical to the terms daylight and solar irradiance, global as they are defined
in Terminology G113.
4. Summary of Practice
4.1 Specimens are exposed to repetitive cycles of light and moisture under controlled environmental conditions.controlled light,
heat, and moisture.
4.1.1 Moisture is usually produced by spraying the test specimen with demineralized/deionized water or by condensation of water
vapor onto the specimen.
4.2 The exposure condition may be varied by selection of:
4.2.1 Lamp filter(s),The type of optical system used to adjust the spectrum, including xenon arc lamp(s), optical filter(s), and
reflector(s),
4.2.2 The lamp’s irradiance level,setpoint,
4.2.3 The type of moisture exposure,Optional moisture exposure in the form of (controlled) relative humidity within the apparatus,
spraying the test specimen(s) with demineralized/deionized water, immersing the specimens in water, or by condensation of water
vapor onto specimens,
4.2.4 The timing of the light and moisture exposure,sequence and duration of the various cycle step(s) (including light, dark,
moisture), and
4.2.5 The temperature of light exposure,and types of thermometers and other temperature sensor(s) used.
4.2.6 The temperature of moisture exposure, and
4.2.7 The timing of a light/dark cycle.
4.3 Comparison of results obtained from specimens exposed in the same model of apparatus should not be made unless
reproducibility has been established among devices for the material to be tested.
4.4 Comparison of results obtained from specimens exposed in different models of apparatus should not be made unless
correlation has been established among devices for the material to be tested.
5. Significance and Use
5.1 The use of this apparatus is intended to induce property changes associated with the end use conditions, including the effects
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http://www.sae.org.
G155 − 21
of sunlight, moisture, and heat. These exposures may include a means to introduce moisture to the test specimen. apparatus exposes
specimens to light, heat, and optionally moisture, often to attempt to replicate specimen property changes observed in outdoor and
indoor end-use environments. Exposures are not intended to simulate the deterioration caused by localized weather phenomena,
such as atmospheric pollution, biological attack, and saltwater exposure. Alternatively, the exposure may simulate the effects of
sunlight through window glass. Typically, these exposures would include moisture in the form of humidity.
NOTE 2—Caution: Refer to Practice G151 for full cautionary guidance applicable to all laboratory weathering devices.
5.2 Variation in results may be expected when operating conditions are varied within the accepted limits of this practice. This
practice allows a wide range of exposure conditions that may produce significantly different results. Therefore, no reference shall
be made to results from the use of this practice its use unless accompanied by a report in conformance with Section 10 detailing
the specific operating conditions in conformance with the Report Section.conditions.
5.2.1 It is recommended that a A control (a similar material of known performance (a control) performance) should be exposed
simultaneously with the test specimen to provide a standardreference for comparative purposes. It is best practice to use control
materials two different control materials: one known to have relatively poor and good durability. It is recommended that at
durability and one known to have relatively good durability. At least three replicates of each material evaluated be exposed in each
test to allow for test specimen and control material should be exposed concurrently to permit statistical evaluation of results.
5.3 Comparison of results obtained from specimens exposed in different apparatus (even if the apparatus is the same model) using
the identical setpoints and operational controls should not be made unless reproducibility has been established between apparatus
for the material to be tested.
5.4 Refer to Practice G151 for cautionary guidance applicable to all laboratory weathering apparatus.
5.5 It is recommended that users follow good laboratory practices in order to reduce variability in exposures (1).
6. Apparatus
6.1 Laboratory Light Source—The light source shall be one or more quartz jacketed quartz-jacketed xenon arc lamps which emit
radiation from below 270 nm in the ultraviolet throughultraviolet, throughout the visible spectrum, and into the infrared. In order
for xenon arcs to simulate terrestrial daylight, optical filters must be used to remove reduce transmission of short wavelength UV
radiation. radiation below 295 nm, the terrestrial solar cut-on wavelength. Filters to reduce irradiance at wavelengths shorter than
310 nm must be used to simulate daylight filtered through window glass. In addition, filters to remove infrared radiation may be
used to prevent unrealistic excessive radiant heating of test specimens that can cause thermal degradation not experienced
commonly observed during outdoor exposures.
NOTE 4—While it is recognized that the visible and infrared wavelength outputs of the xenon arc lamp/optical system are essential for a complete
simulation of terrestrial sunlight, this practice sets requirements for only the ultraviolet and very short wavelength components (<400 nm). Users may
establish their own spectral power distribution requirements for longer wavelengths where needed.
6.1.1 The following factors can affect the spectral power distribution of optically filtered xenon arc light sources as used in these
apparatus:
6.1.1.1 Differences in the composition and thickness of filters canwill have large effects on the amount of short wavelength UV
radiation transmitted.UV radiation transmitted. Exposures conducted using different types or different combinations of optical
filters can produce different results.
Ketola, W., Skogland, T., Fischer, R., “Effects of Filter and Burner Aging on the Spectral Power Distribution of Xenon Arc Lamps,” Durability Testing of Non-Metallic
Materials, ASTM STP 1294, Robert Herling, Editor, ASTM, Philadelphia, 1995.
Searle, N. D., Giesecke, P., Kinmonth, R., and Hirt, R. C., “ Ultraviolet Spectral Distributions and Aging Characteristics of Xenon Arcs and Filters,” Applied Optics,
Vol. No. 8, 1964, pp. 923–927.
Ketola, W., Robbins, J. S., “UV Transmission of Single Strength Window Glass,” Accelerated and Outdoor Durability Testing of Organic Materials, ASTM STP 1202,
Warren D. Ketola and Douglas Grossman, Editors, ASTM, Philadelphia, 1993.
Gueymard, C., “Parameterized Transmittance Model for Direct Beam and Circumsolar Spectral Irradiance,” Solar Energy, Vol 71, No. 5, 2001, pp. 325-346.
Gueymard, C. A., Myers, D., and Emery, K., “Proposed Reference Irradiance Spectra for Solar Energy Systems Testing,” Solar Energy, Vol 73, No 6, 2002, pp. 443-467.
Myers, D. R., Emery, K., and Gueymard, C., “Revising and Validating Spectral Irradiance Reference Standards for Photovoltaic Performance Evaluation,” Transactions
of the American Society of Mechanical Engineers, Journal of Solar Energy Engineering, Vol 126, pp 567–574, Feb. 2004. The boldface numbers in parentheses refer to the
list of references at the end of this standard.
G155 − 21
TABLE X3.1 Common Exposure Conditions
Cycle Filter Irradiance Wavelength Exposure Cycle
1 Daylight 0.35 340 nm 102 min light
W/(m · nm) at 63°C
black panel
temperature
18 min light
and water
spray (air
temp. not
controlled)
2 Daylight 0.35 340 nm 102 min light
W/(m · nm) at 63°C
black panel
temperature
18 min light
and water
spray (air
temp. not
controlled)
repeated
nine times
for a total of
18h;
followed by
6 h dark at
95 (±4.0) %
RH, at 24°C
black panel
temperature
3 Daylight 0.35 340 nm 1.5 h light,
W/(m · nm) 70 % RH, at
77°C black
panel
temperature
0.5 h light
and water
spray (air
temp. not
controlled)
4 Window 0.30 340 nm 100 % light,
Glass W/(m · nm) 55 % RH, at
55°C black
panel
temperature
5 Window 1.10 420 nm 102 min
Glass W/(m · nm) light, 35 %
RH, at 63°C
black panel
temperature
18 min light
and water
spray (air
temp. not
controlled)
6 Window 1.10 420 nm 3.8 h light,
Glass W/(m · nm) 35 % RH, at
63 °C black
panel
temperature
1 h dark, 90
% RH, at 43
° C black
panel
temperature
6.1.1.2 Aging of optical filters from exposure can result in changes in filter transmission. The aging properties of filters can be
G155 − 21
Cycle Filter Irradiance Wavelength Exposure Cycle
7 Extended 0.55 340 nm 40 min light,
UV W/(m ·nm) 50 % RH, at
70 (±2) °C
black panel
temperature
and 47 (±2)
°C chamber
air
temperature
20 min light
and water
spray on
specimen
face
60 min light,
50 % RH, at
70 (±2) °C
black panel
temperature;
and 47 (±2)
°C chamber
air
temperature
60 min dark
and water
spray on
specimen
front and
back, 95
%RH, 38
(±2) °C
black panel
temperature
and 38 (±2)
°C chamber
air
temperature
7A 340 nm 40 min light,
50 (±5.0) %
RH, at 70
(±2) °C
black panel
temperature
and 47 (±2)
0.55
Daylight °C chamber
W/(m ·nm)
air
temperature
20 min light
and water
spray on
specimen
face;
60 min light,
50 % RH, at
70 (±2) °C
black panel
temperature;
and 47 (±2)
°C chamber
air
temperature
60 min dark
and water
spray on
specimen
front and
back, 95 %
RH, 38 (±2)
°C black
panel
temperature
and 38 (±2)
°C chamber
air
temperature
G155 − 21
Cycle Filter Irradiance Wavelength Exposure Cycle
8 Extended 0.55 340 nm
UV W/m ·nm
3.8 h light,
1.0 h dark,
50 % RH, at
95 % RH,
89 (±3) °C
at 38 (±2)
black panel
°C black
temperature
panel
and 62 (±2)
temperature
°C chamber
and 38 (±2)
air
°C chamber
temperature
air
temperature
9 Daylight 180 W/m 300–400 102 min light
nm at 63°C
black panel
temperature
18 min light
and water
spray
(temperature
not
controlled)
10 Window 162 W/m 300–400 nm 100 % light,
Glass 50 % RH, at
89°C black
panel
temperature
11 Window 1.5 W/(m · 420 nm Continuous
Glass nm) light at 63°C
black panel
temperature,
30 % RH
12 Daylight 0.35 340 nm 18 h
W/(m · nm) consisting of
continuous
light at 63°C
black panel
temperature
30 % RH
6 h dark at
90 % RH, at
35°C
chamber air
temperature
A
TABLE 1 Relative Ultraviolet Spectral Power Distribution Specification for Xenon Arc Lamp(s) with Daylight Filters
Spectral Bandpass Benchmark Solar Radiation
B C D
General Type I Type II
F,G,H
Wavelength λ in nm Percent
E E E E E E
Min. % Max % Min. % Max % Min. % Max %
I
λ < 300 0 0.2 0.2 1.1
2.6 8.1 5.8
300 # λ # 320 2.6 6 3.5 7.0
320 < λ # 340 10.0 17.0 10.0 17.0
28.3 40.0 40.0
340 < λ # 360 18.3 23.2 18.3 23.2
360 < λ # 380 25.0 30.5 25.0 30.5
54.2 67.5 54.2
380 < λ # 400 29.2 37.0 29.2 37.0
A
Data in Table 1 are the irradiance in the given bandpass expressed as a percentage of the total irradiance from 290 to 400 nm. The manufacturer shall ensure
conformance to Table 1. Annex A1 states how to determine relative spectral irradiance.
B
The data in this column is based on the approximate rectangular integration of 112 spectral power distributions for water and air cooled xenon-arcs with daylight filters
of various lots and ages measured in the 1990s. The spectral power distribution data is for filters and xenon arc lamps within the recommended operating lifetime of the
apparatus manufacturer. The minimum and maximum data are at least three sigma limits from the mean for all measurements.
C
Type I filters more closely match the spectrum of noon summer sunlight. This designation was obtained by reviewing the spectral performance of commercially available
optical filter systems with a cut-on wavelength of ~295 nm from various manufacturers.
D
Type II filters transmit more shortwave UV than noon summer sunlight. These filters more closely match the daylight filters that have historically been used in xenon arc
lamp apparatus and are more likely to give a similar performance for correlation to historic test conditions. This designation was obtained by reviewing the spectral
performance of commercially available optical filter systems with a cut-on wavelength shorter than 295 nm from various manufacturers.
E
The minimum and maximum columns will not necessarily sum to 100 % because they represent the minimum and maximum for the data used. For any individual spectral
power distribution, the calculated percentage for the bandpasses in Table 1 will sum to 100 %. For any individual xenon arc lamp with daylight filters, the calculated
percentage in each bandpass must fall within the minimum and maximum limits of Table 1. Test results can be expected to differ between exposures using xenon arc
apparatus in which the spectral power distributions differ by as much as that allowed by the tolerances. Contact the manufacturer of the xenon arc lamp apparatus for
spectral power distribution data for the xenon arc lamp/optical filter system used.
F
The benchmark solar radiation data is defined in ASTM G177 and is for atmospheric conditions and altitude chosen to maximize the fraction of short wavelength solar
UV. This data is provided for comparison purposes only.
G
Versions of this standard dated 2000 and earlier used solar radiation data from Table 4 of CIE Publication Number 85. See Appendix X4 for more information comparing
the solar radiation data used in this standard with that for CIE 85 Table 4.
G155 − 21
H
For the benchmark solar spectrum, the UV irradiance (290 to 400 nm) is 9.8 % and the visible irradiance (400 to 800 nm) is 90.2 % expressed as a percentage of the
total irradiance from 290 to 800 nm. The percentages of UV and visible irradiances on samples exposed in xenon arc apparatus may vary due to the number and reflectance
properties of specimens being exposed.
I
In addition to the maximum specification for wavelengths shorter than 300 nm in Table 1, transmission of wavelengths shorter than 290 nm should not exceed 0.15 %
of the total irradiance from 290 to 400 nm, for all Daylight filters.
TABLE 2 Relative Ultraviolet Spectral Power Distribution
Specification for Xenon-Arc Xenon Arc Lamp(s) with Window
A,B
Glass Filters
Window Glass Filtered
Spectral Bandpass Minimum Maximum
Solar Radiation
C C
Wavelength λ in nm Percent Percent
D,E,F
Percent
λ < 300 0.0 0.29
300 # λ # 320 0.1 # 0.5 2.8
320 < λ # 360 23.8 34.2 35.5
360 < λ # 400 62.5 65.3 76.1
A
Data in Table 2 are the irradiance in the given bandpass expressed as a
percentage of the total irradiance from 300 to 400 nm. The manufacturer is
responsible for determining shall ensure conformance to Table 2. Annex A1 states
how to determine relative spectral irradiance.
B
The data in Table 2 are based on the rectangular integration of 36 spectral power
distributions for water cooled and air cooled xenon-arcs with window glass filters
of various lots and ages. ages measured in the 1990s. The spectral power
distribution data is for filters and xenon-burners xenon arc lamps within the aging
recommendations of the deviceapparatus manufacturer. The minimum and maxi-
mum data are at least the three sigma limits from the mean for all measurements.
C
The The minimum and maximum columns will not necessarily sum to 100 %
because they represent the minimum and maximum for the data used. For any
individual spectral power distribution, the calculated percentage for the band-
passes in Table 2 will sum to 100 %. For any individual xenon-lamp with window
glass filters, the calculated percentage in each bandpass must fall within the
minimum and maximum limits of Table 2. Test results can be expected to differ
between exposures using xenon arc devices lamp apparatus in which the spectral
power distributions differ by as much as that allowed by the tolerances. Contact the
manufacturer of the xenon-arc devices xenon arc lamp apparatus for specific
spectral power distribution data for the xenon-arc and filters xenon arc lamp/optical
filter system used.
D
The The window glass filtered solar data is for a solar spectrum with atmo-
spheric conditions and altitude chosen to maximize the fraction of short wave-
length solar UV (defined in ASTM G177) that has been filtered by window glass.
The glass transmission is the average for a series of single strength window
glasses tested as part of a research study for ASTM Subcommittee G3.02.G03.02
(8). While this data is provided for comparison purposes only, it is desirable for a
xenon-arc with window glass filters to provide a spectrum that is a close match to
this window glass filtered solar spectrum.
E
Previous versions Versions of this standard dated 2000 and earlier used window
glass filtered solar radiation data based on Table 4 of CIE Publication Number 85.
See Appendix X4 for more information comparing the solar radiation data used in
the standard with that for CIE 85 Table 4.
F
For the benchmark window glass filtered solar spectrum, the UV irradiance (300
to 400 nm) is 8.2 % and the visible irradiance (400 to 800 nm) is 91.8 % expressed
as a percentage of the total irradiance from 300 to 800 nm. The percentages of UV
and visible irradiances on samples exposed in xenon arc devices lamp apparatus
with window glass filters may vary due to the number and reflectance properties of
specimens being exposed, and the UV transmission of the window glass filters
used.
influenced by the composition. Aging of filters can result spectral transmission, resulting in a significant reduction in the short
wavelength UV emission of a xenon burner.UV radiation emitted by the xenon arc lamp/optical filter system.
6.1.1.3 Accumulation of deposits deposits, dirt, or other residue on filters can effect filter transmission.the optical filters or xenon
arc lamp can affect the UV radiation emitted by the xenon arc lamp/optical filter system.
6.1.1.4 Aging of the xenon burner itself arc lamp from use can result in changes in lamp output. Changes in lamp output may also
be caused by accumulation of dirt or other residue in or on the burner envelope.spectral output of the lamp.
NOTE 5—More information on the effects of composition, aging, and deposits on a xenon arc lamp/optical filter system can be found in Refs (2-7).
6.1.2 Follow the device As a result of the potential for significant changes in spectral irradiance due to effects described in 6.1.1.2,
G155 − 21
6.1.1.3, and 6.1.1.4, users should follow the apparatus manufacturer’s instructions for recommended maintenance.maintenance and
replacement of xenon arc lamps and optical filters.
6.1.3 Spectral Irradiance of Xenon Arc Lamp(s) with Daylight Filters—Filters Optical filters are used to filtermodify xenon arc
lamp emissions in a simulation of terrestrial sunlight. The to simulate terrestrial sunlight. Any xenon arc lamp/optical filter system
,
with a spectral power distribution of xenon arcs with new or pre-aged filtersthat complies with the ultraviolet spectral shall comply
with the requirements specified in Table 1. is considered a “Daylight” filter. The manufacturer shall ensure compliance for the
xenon arc lamp/optical filter systems, prior to initial use.
6.1.3.1 General Daylight Filters—These filters meet the requirements in the General column of Table 1. The General column
represents the broad definition for Daylight filters found in previous versions of this standard. Both Type I and Type II filters are
subsets of General Daylight filters.
6.1.3.2 Type 1 Daylight Filters—These filters meet both the requirements in the General column and the Type I column of Table
1. They are designed to best represent a match to the terrestrial solar cut-on at approximately 295 nm of outdoor noon summer
sunlight.
NOTE 6—Type I Daylight filters include optical filters defined in Practice D7869.
6.1.3.3 Type II Daylight Filters—These filters meet both the requirements in General column and Type II column of Table 1. They
transmit appreciable ultraviolet radiation at wavelengths below the terrestrial solar cut-on at ~295 nm.
NOTE 7—Type II Daylight filters include the borosilicate glass filters that were among the first optical filters that were designed to represent an outdoor
solar spectrum, representing the best technology available at the time. Type I Daylight filters were subsequently developed to provide a better match to
outdoor sunlight. Results may differ between tests conducted with Type I and Type II Daylight filters.
6.1.4 Spectral Irradiance of Xenon Arc Lamp(s) With Window Glass Filters—Filters are used to filtermodify xenon arc lamp
emissions in a simulation of sunlight filtered through window glass.glassTable 2 shows(8 the relative spectral power distribution
limits for xenon arcs filtered with window glass filters. The ). Any xenon arc lamp/optical filter system with a spectral power
distribution of xenon arcs with new or pre-aged filters shall comply with the that complies with the ultraviolet spectral requirements
specified in Table 2. is considered a “Window” or “Window Glass” filter. The manufacturer shall ensure compliance for the xenon
arc lamp/optical filter systems, prior to initial use.
6.1.5 Spectral Irradiance of Xenon Arc Lamp(s) With Extended UV Filters—Filter that transmit more short wavelength UV are
sometimes used to accelerate test result. Optical filters are used to modify xenon arc lamp emissions to transmit more UV radiation
below 295 nm. Although this type of filter has beenoptical system is specified in some tests, they transmit significant radiant energy
below 300 nm (the typical cut-on wavelength for terrestrial sunlight) and tests to accelerate degradation, it may result in aging
processes that do not occurring outdoors. The spectral irradiance for a xenon arc with extended UV filters shall comply with the
requirements of occur outdoors. Any xenon arc lamp/optical filter system with a spectral power distribution that complies with the
ultraviolet spectral requirements specified in Table 3. is considered an “Extended UV” filter. The manufacturer shall ensure
compliance for the xenon arc lamp/optical filter systems, prior to initial use.
6.1.6 The laboratory light source(s) shall be located with respect to the specimens such that the irradiance at the specimen plane
complies with Practice G151.
6.1.7 The actual irradiance at the tester’s specimen plane is a function of the number of xenon burners arc lamps used, the power
applied to each, and the the optical filter(s) used, the distance between the test specimens and the xenon burner. If appropriate,
report the arc lamp(s), and the reflective properties of any test specimens. The irradiance and the bandpass in which it was
measured.measured should be recorded.
6.2 Test Chamber—The design of the test chamber may vary, but it should be constructed from corrosion resistant material and,
in addition to the radiant source, may provide for means of controlling temperature and relative humidity. When required, provision
shall be made for the spraying of water on the test specimen, for the formation of condensate on the exposed face of the specimen
or for the immersion of the test specimen in water.material.
6.2.1 The radiation source(s) shall be located with respect to the specimens such that the irradiance at the specimen face complies
with the requirements in Practice G151.
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TABLE 3 Relative Ultraviolet Spectral Power Distribution
A,B
Specification for Xenon Arc Lamp(s) with Extended UV Filters
Spectral Bandpass Minimum Benchmark Solar Maximum
C D,E,F C
Wavelength λ in nm Percent Radiation Percent Percent
250 # λ < 290 0.1 0.7
290 # λ # 320 5.0 5.8 11.0
320 < λ # 360 32.3 40.0 37.0
360 < λ # 400 52.0 54.2 62.0
A
Data in Table 3 are the irradiance in the given bandpass expressed as a
percentage of the total irradiance from 250 to 400 nm. The manufacturer is
responsible for determining shall ensure conformance to Table 3. Annex A1 states
how to determine relative spectral irradiance.
B
The data in Table 3 are based on the rectangular integration of 81 spectral power
distributions for water cooled and air cooled xenon-arcs with extended UV filters of
various lots and ages. ages measured in the 1990s. The spectral power distribu-
tion data is for filters and xenon-burners xenon arc lamps within the aging
recommendations of the deviceapparatus manufacturer. The minimum and maxi-
mum data are at least the three sigma limits from the mean for all measurements.
C
The The minimum and maximum columns will not necessarily sum to 100 %
because they represent the minimum and maximum for the data used. For any
individual spectral power distribution, the calculated percentage for the band-
passes in Table 3 will sum to 100 %. For any individual xenon-arc lamp with
extended UV filters, the calculated percentage in each bandpass must fall within
the minimum and maximum limits of Table 3. Test results can be expected to differ
between exposures using xenon arc devices lamp apparatus in which the spectral
power distributions differ by as much as that allowed by the tolerances. Contact the
manufacturer of the xenon-arc devices xenon arc lamp apparatus for specific
spectral power distribution data for the xenon-arc and filters xenon arc lamp/optical
filter system used.
D
The The benchmark solar radiation data is defined in ASTM G177 and is for
atmospheric conditions and altitude chosen to maximize the fraction of short
wavelenghtwavelength solar UV. This data is provided for comparison purposes
only.
E
Previous versions Versions of this standard dated 2000 and earlier used solar
radiation data from Table 4 of CIE Publication Number 85. See Appendix X4 for
more information comparing the solar radiation data used in the standard with that
for CIE 85 Table 4.
F
For the benchmark solar spectrum, the UV irradiance (290 to 400 nm) is 9.8 %
and the visible irradiance (400 to 800 nm) is 90.2 % expressed as a percentage of
the total irradiance from 290 to 800 nm. The percentages of UV and visible
irradiances on samples exposed in xenon arc devices lamp apparatus may vary
due to the number and reflectance properties of specimens being exposed.
6.3 Instrument Calibration—To ensure standardization and accuracy, the instruments associated with the exposure apparatus (that
is,(such as timers, thermometers, wet bulb sensors, dry bulb sensors, humidity sensors, UV sensors, radiometers) require periodic
calibration to ensure repeatability of test results. Whenever possible, Instrument calibration should be traceable to national or
international standards. Calibration schedulefrequency and procedure should be in accordance with manufacturer’s instruction-
s.instructions and good laboratory practices.
NOTE 8—For guidance on good laboratory practices for instrument calibration, see NIST GMP-11 (9).
6.4 Radiometer—The use of a An integrated radiometer to monitor and control the amount of radiant energy received at the
specimen is recommended. plane should be used. If a radiometer is used, it shall comply with the requirements in Practice ASTM
G151.
6.5 Thermometer—Either insulated or un-insulated black or white panel thermometers may be used. Thermometers shall conform
to the descriptions and requirements found in Practice G151. The type of thermometer used, the method of mounting (for example,
on a specimen holder,holder), and the exposure temperature shall be stated in the test report.
6.5.1 The thermometer shall be mounted onwithin the specimen rack exposure area so that its surface is in it receives the same
relative position and subjected to the same influences as theradiation and cooling conditions as a flat test panel surface per the
recommended configuration in Practice G151test specimens.
6.5.2 Some test specifications may require chamber air temperature control. Positioning and calibration of any chamber air
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temperature sensors shall be in accordance with the descriptions found in Practice G151. Controlling chamber air temperature
allows better and more reproducible specimen temperatures and may reduce test variability (10).
6.5.3 Aspects of the apparatus’ design, along with its heating, cooling, and control systems and ambient laboratory conditions, can
have a significant impact on the amount of time it takes for the apparatus’ thermometer to reach steady-state temperature during
an exposure step. As a result, this affects how long specimens remain at the desired temperature, since exposure steps are typically
fixed in total duration. The rate and magnitude of specimen degradation during exposure can be significantly impacted by these
factors. Users are cautioned when comparing results from apparatus with different thermometer time-to-steady-state temperature
characteristics.
6.6 Moisture—The test specimens may be exposed to moisture in the form of water spray, condensation, immersion, or high
humidity.humidity, or a combination thereof.
6.6.1 Water Spray—The test chamber may be equipped with a means to introduce intermittent water spray onto the front or the
back 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 corrosion-resistant materials that do not contaminate the spray water employed.(11).
6.6.1.1 Quality of Water for Sprays and Immersion—Spray To minimize stains or deposits on specimens, spray water must have
a conductivity below 5 μS/cm, μS/cm and contain less than 1-ppm solids, and leave no observable stains or deposits on the
specimens. Very 1 ppm solids. Care should be taken to keep silica levels below 0.1 ppm because even very low levels of silica
in spray water can cause significant deposits on the surface of test specimens. Care should be taken to keep silica levels below 0.1
ppm. In addition to distillation, a combination of deionization and reverse osmosis can effectively produce water of the required
quality. The pH of the water used should be reported. See Practice G151 for detailed water quality instructions.requirements.
6.6.1.2 Condensation—A spray system designed to cool the specimen by spraying the back surface of the specimen or specimen
substrate during a dark condition (that is, with the lamps off) may be required when the exposure program specifies periods of
condensation.
NOTE 9—The mechanism used to form condensation on the face of specimens is to cool the back side of thermally conductive specimens with a cool water
back spray during warm, humid, dark conditions. Condensation is created by cooling the specimen surface temperature below the test chamber air’s
dewpoint. Refer to Note X3.3 in Appendix X3 for more information on the implementation of backspray in historical xenon arc test methods.
6.6.2 Relative Humidity—The test chamber may be equipped with a means to measure and control the relative humidity. Such
instruments shall be shielded from the lamp radiation.direct radiation and water spray. Controlling relative humidity allows better
reproducibility of exposure conditions and may reduce test variability.
6.6.3 Water Immersion—The test chamber may be equipped with a means to immerse specimens in water under specified
conditions. conditions (for example, controlled water temperature). The immersion system shall be made from corrosion resistant
corrosion-resistant materials that do not contaminate the water employed.immersion water.
6.7 Specimen Holders—Holders for test specimens shall be made from corrosion resistant materials that will not affect the test
results. Corrosion resistant alloys of aluminum or stainless steel have been found acceptable. Brass, steel, or copperto be
acceptable. Specimen holders shall not be used in the vicinity of the test specimens.made from brass, steel (non-stainless), or
copper.
6.7.1 The specimen holders are typically, but not necessarily, may be mounted on a revolving cylindrical rack that is rotated around
the lamp system at a speed dependent on the type of equipment and that is centered both horizontally and vertically with respect
to the exposure area.or a flat tray.
6.7.1.1 If mounted on a revolving cylindrical rack, the rack shall be centered both horizontally and vertically with respect to the
exposure area. The rotation speed may be varied.
6.7.2 Specimen holders may be in the form of an open frame, leaving the back of the specimen exposed, or they may provide the
specimen with a solid backing. Any backing used may affect test results and shall be agreed upon in advance between the interested
parties.
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6.7.3 Specimen holders may rotate on their own axis. When these holders are used, they may be filled with specimens placed back
to back. Rotation of the holder on its axis alternately exposes each specimen to direct radiation from the xenon burner.
6.8 Apparatus to Assess Changes in Properties—Use the apparatus required by the ASTM or other standard that describes
determination of the property or properties being monitored.
7. Test Specimen
7.1 Refer to Practice G151.
8. TestExposure Conditions
8.1 Any exposure conditions may be used as long as the exact conditions optical filter system, irradiance control, and exposure
conditions for each step in the cycle are detailed in the report. Appendix X1X3 lists some representative exposure conditions. These
are not necessarily preferred conditions are provided for reference only and no recommendation is implied. These conditions are
provided for reference only.
8.2 Transition times between different thermometer temperature, chamber air temperature, and relative humidity conditions in an
exposure cycle can affect test results. Variations in these transition times can adversely affect repeatability and reproducibility. The
significance of this effect is dependent upon the exposure cycle used, the specimens under test, and how the specimens are mounted
in the apparatus. Transition times are not specified in this standard. Apparatus where the specimen conditions reach and maintain
steady state faster may produce different degradation results. Users are cautioned when comparing results from apparatus with
different specimen-time-temperature characteristics.
NOTE 10—For information regarding how to determine transition times for your apparatus, consult with the manufacturer or the apparatus’ technical
manual.
9. Procedure
9.1 Identify each test specimen by suitable indelible marking, but not on areas to be used in testing.marking that shall not interfere
with subsequent property measurements.
9.2 Determine which propertyproperties of the test specimens will are to be evaluated. Prior to exposing the specimens, quantify
the appropriate properties If applicable, measure the properties of interest in accordance with recognized international standards.
appropriate test methods prior to exposing specimens. If required (for example, destructive testing), use unexposed file specimens
to quantifyspecimens, stored in the dark and in appropriate humidity and temperature conditions, to measure the property. See
Practice D5870 for detailed guidance.guidance on calculating property retention indices.
9.3 Mounting of Test Specimens—Attach the specimens to the specimen holders in the equipment test apparatus in such a manner
that the specimens are not subject to any applied stress.
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