ASTM G154-23

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: G154 − 16 G154 − 23
Standard Practice for
Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for
Exposure of Nonmetallic Materials
This standard is issued under the fixed designation G154; 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.
1. Scope*
1.1 This practice is limited to the basic principles for operating a fluorescent UV lamp and water apparatus; on its own, it does
not deliver a specific result.
1.2 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 or dew in actual usage.
This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure.
NOTE 1—Practice G151 describes general procedures to be used when exposing nonmetallic materials in accelerated test devices that use laboratory light
sources.
NOTE 2—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.
1.3 Test specimens are exposed to fluorescent UV light under controlled environmental conditions. Different types of fluorescent
UV lamp sources are described.
NOTE 3—In this standard, the terms UV light and UV radiation are used interchangeably.
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.
NOTE 4—General information about methods for determining the change in properties after exposure and reporting these results is described in ISO 4582
and Practice D5870.
1.5 This practice is not intended for corrosion testing of bare metals.
1.6 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 standard is technically similar to ISO 4892-3 and ISO 16474-3.
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 March 1, 2016Jan. 1, 2023. Published September 2016January 2023. Originally approved in 1997. Last previous edition approved in 20122016
as G154 – 12a.G154 – 16. DOI: 10.1520/G0154-16.10.1520/G0154-23.
*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
G154 − 23
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.
1.7 This standard is technically similar to ISO 4892-3 and ISO 16474-3.
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:
D5870 Practice for Calculating Property Retention Index of Plastics
D6631 Guide for Committee D01 for Conducting an Interlaboratory Study for the Purpose of Determining the Precision of a Test
Method
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
G177 Tables for Reference Solar Ultraviolet Spectral Distributions: Hemispherical on 37° Tilted Surface
2.2 ISO Standards:
ISO 4582 Plastics—Determination of the Changes of Colour and Variations in Properties After Exposure to Daylight Under
Glass, Natural Weathering or Artificial Light
ISO 4892-1 Plastics—Methods of Exposure to Laboratory Light Sources—Part 1, Guidance
ISO 4892-3 Plastics—Methods of Exposure to Laboratory Light Sources—Part 3, Fluorescent UV lamps
ISO 16474-3 Paints and Varnishes—Methods of Exposure to Laboratory Light Sources—Part 3: Fluorescent UV Lamps
3. Terminology
3.1 Definitions—The definitions given in Terminology G113 are applicable to this practice.
3.2 Definitions of Terms Specific to This Standard—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.
3.2.1 Fluorescent Ultraviolet (UV) lamp Apparatus—an apparatus specifically designed for performing artificial accelerated
weathering and irradiation tests using fluorescent UV lamps as the light source and including a means to expose the test specimens
to moisture and controlled temperature.
4. Summary of Practice
4.1 Specimens are exposed to repetitive cycles of light and moisture under controlled environmental conditions.
4.1.1 Moisture is usually produced by condensation of water vapor onto the test specimen or by spraying the specimens with
demineralized/deionized water.
4.2 The exposure condition may be varied by selection of:
4.2.1 The fluorescent lamp,
4.2.2 The lamp’s irradiance level,
4.2.3 The type of moisture exposure,
4.2.4 The timing of the light, dark, and moisture periods, and
4.2.5 The temperature during each exposure condition.
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.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
G154 − 23
5. Significance and Use
5.1 The use of this apparatus is intended to induce property changes consistent with the end use conditions, including the effects
of the UV portion of sunlight, moisture, and heat. Typically, these exposures would include moisture in the form of condensing
humidity. 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. (Warning—Refer to Practice G151 for full cautionary guidance applicable to all laboratory weathering devices.)
5.2 This practice provides general procedures for operating fluorescent UV lamp weathering devices that allow for a wide range
of exposure conditions. Therefore, no reference shall be made to results from the use of this practice unless accompanied by a
report detailing the specific operating conditions in conformance with Section 10.
5.2.1 It is recommended that a similar material of known performance (a control) be exposed simultaneously with the test
specimen to provide a standard for comparative purposes. Generally, two controls are recommended: one known to have poor
durability and one known to have good durability. It is recommended that at least three replicates of each material evaluated be
exposed in each test to allow for statistical evaluation of results.
5.2.2 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.
5.2.3 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.tested (see Guide D6631 for guidance).
NOTE 5—See Guide D6631 for guidance.
6. Apparatus
6.1 Laboratory Light Source—The light source shall be one or more fluorescent UV lamps. A variety of fluorescent UV lamps can
be used for this procedure. Differences in lamp intensity or spectrum may cause significant differences in test results.
6.1.1 Do not mix different types of lamps. Mixing different types of lamps (as described in 6.1.4) in a fluorescent UV apparatus
may produce causes major inconsistencies in the light falling on the samples, unless the apparatus has been specifically designed
to ensure a uniform spectral distribution.to the radiation received by the samples.
6.1.1.1 A detailed description of the type(s) of lamp(s) used shall be stated in the test report. The particular testing application
determines which lamp is used. See Appendix X1 for lamp application guidelines.
6.1.2 The apparatus should include an irradiance control system to monitor and control the irradiance. In apparatuses without
irradiance control, the actual irradiance levels at the test specimen surface may vary due to the type of lamps, manufacturer of the
lamps, age of the lamps, accumulation of dirt or other residue on the lamps, distance to the lamp array, air temperature within the
chamber and ambient laboratory temperature.
NOTE 5—In general, in apparatuses without irradiance control, lamp output will decrease with increasing chamber or laboratory temperature, or both.
6.1.3 Fluorescent lamps age with extended use. Follow the apparatus manufacturer’s instructions on the procedure necessary to
maintain desired irradiance (1, 2).
6.1.4 Standard Fluorescent UV Lamps—Fluorescent UV lamps are available with a choice of spectral power distributions that vary
significantly. The more common are identified as UVA-340, UVA-351, and UVB-313. These numbers represent the characteristic
nominal wavelength (in nm) of peak emission for each of these lamp types. The actual peak emissions are at 343 nm, 350 nm,
and 313 nm, respectively.
6.1.4.1 Spectral Power Distribution (also known as Spectral Irradiance) of UVA-340 Lamps for Daylight UV—The spectral power
distribution of UVA-340 fluorescent lamps shall comply with the requirements specified in Table 1.
The boldface numbers in parentheses refer to a list of references at the end of this standard.
G154 − 23
TABLE 1 Relative Ultraviolet Spectral Power Distribution
A,B
Specification for Fluorescent UVA-340 Lamps for Daylight UV
Spectral
Bandpass Minimum Benchmark Solar Maximum
C D,E C
Wavelength λ in Percent Radiation Percent Percent
nm
λ < 290 0.01
290 # λ # 320 5.9 5.8 9.3
320 < λ # 360 60.9 40.0 65.5
360 < λ # 400 26.5 54.2 32.8
A
Data in Table 1 are the irradiance in the given bandpass expressed as a
percentage of the total irradiance from 290 nm to 400 nm. The manufacturer is
responsible for determining conformance to Table 1. Annex A1 states how to
determine relative spectral irradiance.
B
The data in Table 1 are based on the rectangular integration of 65 spectral power
distributions for fluorescent UV devices operating with UVA 340 lamps of various
lots and ages. The spectral power distribution data is for lamps within the aging
recommendations of the device manufacturer. The minimum and maximum data
are at least the three sigma limits from the mean for all measurements.
C
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 fluorescent UVA-340 lamp, 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 devices
with fluorescent UVA-340 lamps in which the spectral power distributions differ by
as much as that allowed by the tolerances. Contact the manufacturer of the
fluorescent UV devices for specific spectral power distribution data for the
fluorescent UVA-340 lamp used.
D
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. While this data is provided for comparison purposes only, it
is desirable for the laboratory accelerated light source to provide a spectrum that
is a close match to the benchmark solar spectrum.
E
For the benchmark daylight spectrum, the UV irradiance (290 nm to 400 nm) is
9.8%9.8 % and the visible irradiance (400 nm to 800 nm) is 90.2%90.2 %
expressed as a percentage of the total irradiance from 290 nm to 800 nm. Because
the primary emission of fluorescent UV lamps is concentrated in the 290 nm to 400
nm bandpass, there are limited visible light emissions from fluorescent UV lamps.
NOTE 6—The main application for UVA-340 lamps is for simulation of the short and middle UV wavelength region of daylight.
6.1.4.2 Spectral Power Distribution of UVA-351 Lamps for Daylight UV Behind Window Glass—The spectral power distribution
of UVA-351 lamp for Daylight UV behind Window Glass shall comply with the requirements specified in Table 2.
NOTE 7—The main application for UVA-351 lamps is for simulation of the short and middle UV wavelength region of daylight that has been filtered
through window glass (3).
6.1.4.3 Spectral Power Distribution of UVB-313 Lamps—The spectral power distribution of UVB-313 fluorescent lamps shall
comply with the requirements specified in Table 3. Fluorescent UVB lamps have the spectral distribution of radiation peaking near
the 313-nm mercury line, and as such, are not recommended for sunlight simulation.
NOTE 8—Fluorescent UVB lamps have the spectral distribution of radiation peaking near the 313-nm mercury line, and as such, are not recommended
for sunlight simulation. They 313 lamps emit significant amounts of radiation below 295 nm, the nominal cut on wavelength of global solar radiation,
that may result in aging processes not occurring outdoors. See Table 3.
6.2 Test Chamber—The design of the test chamber maycan vary, but it shouldshall be constructed from corrosion and UV resistant
material and, in addition to the light source, may if required 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.
NOTE 9—Most commercially available apparatus used for testing in accordance with this practice do not control relative humidity.
6.2.1 The light source(s) shall be located with respect to the specimens such that the uniformity of irradiance at the specimen face
complies with the requirements in Practice G151.
G154 − 23
TABLE 2 Relative Spectral Power Distribution Specification for
Fluorescent UVA-351 Lamps for Daylight UV Behind Window
A,B
Glass
Spectral
Window Glass
Bandpass Minimum Maximum
Filtered
C C
Wavelength λ in Percent Percent
D,E
Daylight Percent
nm
λ < 300 0.0 0.2
300 # λ # 320 1.1 # 0.5 3.3
320 < λ # 360 60.5 34.2 66.8
360 < λ # 400 30.0 65.3 38.0
A
Data in Table 2 are the irradiance in the given bandpass expressed as a
percentage of the total irradiance from 300 nm to 400 nm. The manufacturer is
responsible for determining conformance to Table 1. Annex A1 states how to
determine relative spectral irradiance.
B
The data in Table 2 are based on the rectangular integration of 21 spectral power
distributions for fluorescent UV devices operating with UVA 351 lamps of various
lots and ages. The spectral power distribution data is for lamps within the aging
recommendations of the device manufacturer. The minimum and maximum data
are at least the three sigma limits from the mean for all measurements.
C
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
2 will sum to 100 %. For any individual fluorescent UV device operating with UVA
351 lamps, 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 fluorescent UV devices in which the spectral power
distributions differ by as much as that allowed by the tolerances. Contact the
manufacturer of the fluorescent UV devices for specific spectral power distribution
data for the lamps used.
D
The window glass filtered solar radiation data is for a solar spectrum with
atmospheric conditions and altitude chosen to maximize the fraction of short
wavelength 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 (3).
While this data is provided for comparison purposes only, it is desirable for the
laboratory accelerated light source to provide a spectrum that is a close match to
this benchmark window glass filtered solar spectrum.
E
For the benchmark window glass filtered solar spectrum, the UV irradiance (300
nm to 400 nm) is 8.2 % and the visible irradiance (400 nm to 800 nm) is 91.8 %
expressed as a percentage of the total irradiance from 300 nm to 800 nm. Because
the primary emission of fluorescent UV lamps is concentrated in the 290 nm to 400
nm bandpass, there are limited visible light emissions from fluorescent UV lamps.
6.2.2 Lamp replacement, lamp rotation, and specimen repositioning maycan be required to obtain uniform exposure of all
specimens to UV radiation and temperature. Follow manufacturer’s recommendation for lamp replacement and rotation.
6.2.3 Specimens in the extreme left and right side of the exposure area (at the ends of the lamps) experience a lower irradiance
than other specimens (4). While these positions do meet the irradiance requirements in G151 when repositioning is used (see 9.5),
it is recommended that these positions are excluded when test and control specimens do not completely fill the specimen racks (see
Fig. 1).
6.3 Calibration—To ensure standardization and accuracy, the instruments associated with the exposure apparatus (for example,
timers, thermometers, UV sensors, and radiometers) require periodic calibration to ensure repeatability of test results. Calibration
schedule and procedure shall be in accordance with manufacturer’s instructions. Calibration should be traceable to a national
metrological institute (NMI).
6.4 Radiometer—The use of a radiometer to monitor and control the amount of radiant energy received at the sample is
recommended. If a radiometer is used, it shall comply with the requirements in Practice G151.
6.5 Thermometer—Either insulated or un-insulated black or white panel thermometers may be used. The un-insulated
thermometers may be made of either steel or aluminum. Thermometers shall conform to the descriptions found in Practice G151.
NOTE 10—Typically, these devices control by un-insulated black panel thermometer only.are controlled by black-panel thermometer, and not by chamber
air temperature.
G154 − 23
TABLE 3 Relative Spectral Power Distribution Specification for
A,B
Fluorescent UVB 313 lamps
Spectral
Bandpass Minimum Benchmark Solar Maximum
C D,E C
Wavelength λ in Percent Radiation Percent Percent
nm
λ < 290 1.3 5.4
290 # λ # 320 47.8 5.8 65.9
320 < λ # 360 26.9 40.0 43.9
360 < λ # 400 1.7 54.2 7.2
A
Data in Table 3 are the irradiance in the given bandpass expressed as a
percentage of the total irradiance from 250 nm to 400 nm. The manufacturer is
responsible for determining 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 44 spectral power
distributions for fluorescent UV devices operating with UVB 313 lamps of various
lots and ages. The spectral power distribution data is for lamps within the aging
recommendations of the device manufacturer. The minimum and maximum data
are at least the three sigma limits from the mean for all measurements.
C
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
3 will sum to 100 %. For any individual UVB 313 lamp, 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 conducted in fluorescent UV
devices using UVB 313 lamps in which the spectral power distributions differ by as
much as that allowed by the tolerances. Contact the manufacturer of the
fluorescent UV device for specific spectral power distribution data for the device
operated with the UVB 313 lamp used.
D
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.
E
For the benchmark solar spectrum, the UV irradiance (290 nm to 400 nm) is
9.8%9.8 % and the visible irradiance (400 nm to 800 nm) is 90.2 % expressed as
a percentage of the total irradiance from 290 nm to 800 nm. Because the primary
emission of fluorescent UV lamps is concentrated in the 290 nm to 400 nm
bandpass, there are limited visible light emissions from fluorescent UV lamps.
6.5.1 Uninsulated black-panel thermometers are recommended for use with highly thermally-conductive or very thin specimens.
Insulated black-panel thermometers are recommended for use with insulating or thick specimens. Different types of black-panel
thermometers can result in significantly different temperature profiles in the test chamber.
6.5.2 The thermometer shall be mounted on the specimen rack so that its surface is in the same relative position and subjected
to the same influences as the test specimens.
6.5.3 The apparatus may provide chamber air temperature control. Positioning and calibration of chamber air temperature sensors
shall be in accordance with the descriptions found in Practice G151.
6.6 Moisture—A means for exposing the specimen to moisture shall be provided. The moisture may be in the form of water spray,
condensation, or humidity.
6.6.1 Water Spray—The test chamber may be equipped with a means to introduce intermittent water spray onto the test specimens
under specified conditions. The spray shall be uniformly distributed over the samples.specimens. The spray system shall be made
from corrosion resistant materials that do not contaminate the water used.
NOTE 11—Temperature is typically not controlled in spray segments.
6.6.1.1 Spray Water Quality—Spray water shall have a conductivity below 5 μS/cm, contain less than 1-ppm solids, and leave no
observable stains or deposits on the specimens. 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 0.2 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.
6.6.2 Condensation—The test chamber may be equipped with a means to cause condensation to form on the face of the test
G154 − 23
FIG. 1 Typical Exposure Area of a UV-lamp Apparatus with Useable and Recommended Specimen Positions Marked.
specimen exposed to test chamber conditions (front side). Typically, water vapor is generated by heating water and filling the
chamber with hot vapor, which then is made to condense on the test specimens by convective cooling on the back side of the
specimens.
NOTE 12—The temperature and amount of condensate forming on the specimens is influenced by the specimen thickness, thermal conductance, and the
temperature differential between the test chamber and the room. Condensation may be difficult to achieve for highly thermally-insulative or very thick
specimens.
6.6.3 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.
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 copper shall not be
used in the vicinity of the test specimens.
7. Test Specimen
7.1 Refer to Practice G151 for guidance on test specimen form and preparation, number of test specimens, and specimen storage
and conditioning.
8. Exposure Conditions
8.1 The user shall define the exposure conditions appropriate for their application. Any exposure conditions may be used as long
as the exact conditions are detailed in the report. Appendix X2 lists exposure conditions taken from several material test methods.
These conditions are provided for reference only; none are specifically preferred and no recommendations are implied. This
practice is not intended as a primary means for defining exposure cycles for a given application. Refer to the appropriate
international standard for defining an appropriate exposure cycle.
9. Procedure
9.1 Identify each test specimen by suitable indelible marking, but not on areas used in testing.
9.2 Determine which property of the test specimens will be evaluated. Prior to exposing the specimens, quantify the appropriate
properties in accordance with recognized ASTM or international standards. If required (for example, destructive testing), use
unexposed file specimens to quantify the property. See ISO 4582 for detailed guidance.
9.3 Mounting of Test Specimens—Attach the specimens to the specimen holders in the equipment in such a manner that the
specimens are not subject to any unnecessary applied stress
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