Standard Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials

SCOPE
1.1 This practice covers the basic principles and operating procedures for using enclosed carbon-arc light and water apparatus 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 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--Practice G151 describes performance criteria for all exposure devices that use laboratory light sources. This practice replaces Practice G23, which describes very specific designs for devices used for carbon-arc exposures. The apparatus described in Practice G23 is covered by this practice.
1.2 Test specimens are exposed to enclosed carbon arc light under controlled environmental conditions.
1.3 Specimen preparation and evaluation of the results are covered in various 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 ISO 4582.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
1.5.1 Should any ozone be generated from the operation of the light source, it shall be carried away from the test specimens and operating personnel by an exhaust system.

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ASTM G153-00 - Standard Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: G 153 – 00
Standard Practice for
Operating Enclosed Carbon Arc Light Apparatus for
Exposure of Nonmetallic Materials
This standard is issued under the fixed designation G 153; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 3980 Practice for Interlaboratory Testing of Paint and
Related Materials
1.1 This practice covers the basic principles and operating
E 691 Practice for Conducting Interlaboratory Study to
procedures for using enclosed carbon-arc light and water
Determine the Precision of a Test Method
apparatus intended to reproduce the weathering effects that
G 23 Practice for Operating Light-Exposure Apparatus
occur when materials are exposed to sunlight (either direct or
(Carbon-Arc Type) With and Without Water for Exposure
through window glass) and moisture as rain or dew in actual
of Nonmetallic Materials
use. This practice is limited to the procedures for obtaining,
G 113 Terminology Relating to Natural and Artificial
measuring, and controlling conditions of exposure. A number
Weathering Tests of Nonmetallic Materials
of exposure procedures are listed in an appendix; however, this
G 151 Practice for Exposing Nonmetallic Materials in Ac-
practice does not specify the exposure conditions best suited
celerated Test Devices that Use Laboratory Light Sources
for the material to be tested.
2.2 ISO Standards:
NOTE 1—Practice G 151 describes performance criteria for all exposure
ISO 4582, Plastics—Determination of the Changes of Co-
devices that use laboratory light sources. This practice replaces Practice
lour and Variations in Properties After Exposure to Day-
G 23, which describes very specific designs for devices used for carbon-
light Under Glass, Natural Weathering or Artificial Light
arc exposures. The apparatus described in Practice G 23 is covered by this
ISO 4892-1, Plastics—Methods of Exposure to Laboratory
practice.
Light Sources, Part 1, General Guidance
1.2 Test specimens are exposed to enclosed carbon arc light
ISO 4892-4, Plastics—Methods of Exposure to Laboratory
under controlled environmental conditions.
Light Sources, Part 4, Open-Flame Carbon Arc Lamp
1.3 Specimen preparation and evaluation of the results are
2.3 CIE Standards:
covered in various methods or specifications for specific
CIE-Publ. No. 85: Recommendations for the Integrated
materials. General guidance is given in Practice G 151 and ISO
Irradiance and the Spectral Distribution of Simulated
4892-1. More specific information about methods for deter-
Solar Radiation for Testing Purposes
mining the change in properties after exposure and reporting
these results is described in ISO 4582.
3. Terminology
1.4 The values stated in SI units are to be regarded as the
3.1 Definitions—The definitions that are applicable to this
standard.
practice are provided in Terminology G 113.
1.5 This standard does not purport to address all of the
3.1.1 As used in this practice, the term sunlight is identical
safety concerns, if any, associated with its use. It is the
to the terms daylight and solar irradiance, global as they are
responsibility of the user of this standard to establish appro-
defined in Terminology G 113.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Summary of Practice
1.5.1 Should any ozone be generated from the operation of
4.1 Specimens are exposed to repetitive cycles of light and
the light source, it shall be carried away from the test
moisture under controlled environmental conditions. Moisture
specimens and operating personnel by an exhaust system.
usually is produced by spraying the test specimen with
demineralized/deionized water or by condensation of water
2. Referenced Documents
vapor onto the specimen.
2.1 ASTM Standards:
Discontinued 1998; see 1998 Annual Book of ASTM Standards, Vol 06.01.
Annual Book of ASTM Standards, Vol 14.02.
This practice is under the jurisdiction of ASTM Committee G-3 on Weathering 4
Annual Book of ASTM Standards, Vol 14.04.
and Durability and is the direct responsibility of Subcommittee G03.03 on 5
Available from American National Standards Institute, 11 W. 42nd St., 13th
Simulated and Controlled Exposure Tests.
Floor, New York, NY 10036.
Current edition approved Feb 10, 2000. Published May 2000. Originally 6
Available from Secretary, U.S. National Committee, CIE, National Institute of
published as G 153 – 97. Last previous edition G 153 – 98.
Standards and Technology, Gaithersburg, MD 20899.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G 153
TABLE 1 Typical Relative Spectral Power Distribution for
4.2 The exposure condition may be varied by selection of
Enclosed Carbon Arc with Daylight Filters (Representative Data)
the following:
Ultraviolet Wavelength Region
4.2.1 Filter,
Irradiance as a Percentage of Total Irradiance from 300 to 400 nm
4.2.2 The type of moisture exposure,
Enclosed Carbon Arc
4.2.3 The timing of the light and moisture exposure,
A B
Bandpass (nm) Daylight Filters Sunlight
4.2.4 The temperature of light exposure, and
250–280 0 % 0 %
4.2.5 The timing of a light/dark cycle. 281–290 0 % 0 %
291–300 0 % 0 %
4.3 Comparison of results obtained from specimens exposed
301–320 0 % 5.6 %
in same model of apparatus should not be made unless
321–340 0.3 % 18.5 %
341–360 20.2 % 21.7 %
reproducibility has been established among devices for the
361–380 28.0 % 26.6 %
material to be tested.
381–400 51.5 % 27.6 %
4.4 Comparison of results obtained from specimens exposed
Ultraviolet and Visible Wavelength Region
in different models of apparatus should not be made unless
C
Irradiance as a Percentage of Total Irradiance from 300 to 800 nm
correlation has been established among devices for the material
to be tested.
Enclosed Carbon Arc
A D
Bandpass (nm) Daylight Filters Sunlight
5. Significance and Use 300–400 53.5 % 11 %
401–700 30.5 % 72 %
5.1 The use of this apparatus is intended to induce property
A
Carbon Arc Data—This data are for a typical spectral power distribution for an
changes associated with the end use conditions, including the
enclosed carbons arc with borosilicate glass globe. Not enough spectral data is
effects of sunlight, moisture, and heat. These exposures may available for meaningful analysis to develop a specification. ASTM Subcommittee
G03.03 is working to collect sufficient data in order to develop a specification.
include a means to introduce moisture to the test specimen.
B
Sunlight Data—The sunlight data is for global irradiance on a horizontal surface
Exposures are not intended to simulate the deterioration caused
with an air mass of 1.2, column ozone 0.294 atm cn, 30 % relative humidity,
by localized weather phenomena, such as atmospheric pollu- altitude 2100 m (atmospheric pressure of 787.8 mb), and an aerosol represented
by an optical thickness of 0.081 at 300 nm and 0.62 at 400 nm.
tion, biological attack, and saltwater exposure. Alternatively,
C
Data from 701 to 800 nm is not shown.
the exposure may simulate the effects of sunlight through D
Sunlight Data—The sunlight data is from Table 4 of CIE Publication No. 85,
global solar irradiance on a horizontal surface with an air mass of 1.0, column
window glass. Typically, these exposures would include mois-
ozone of 0.34 atm cm, 1.42 cm water vapor, and an aerosol represented by an
ture in the form of humidity.
optical thickness of 0.1 at 500 nm.
5.2 Cautions—Refer to Test Method G 151 for full caution-
ary guidance applicable to all laboratory weathering devices.
distribution of enclosed carbon arc light sources:
5.2.1 Variation in results may be expected when operating
6.1.3.1 Differences in the composition and thickness of
conditions are varied within the accepted limits of this practice.
filters can have large effects on the amount of short wavelength
Therefore, no reference shall be made to results from the use of
UV radiation transmitted.
this practice unless accompanied by a report detailing the
6.1.3.2 Aging (solarization) of filters can result in changes
specific operating conditions in conformance with Section 10.
in filter transmission. The aging properties of filters can be
5.2.2 It is recommended that a similar material of known
influenced by the composition. Aging of filters can result in a
performance, a control, be exposed simultaneously with the
significant reduction in the short wavelength UV emission of a
test specimen to provide a standard for comparative purposes.
burner.
It is recommended that at least three replicates of each material
6.1.3.3 Accumulation of dirt or other residue on filters can
evaluated be exposed in each test to allow for statistical
affect filter transmission.
evaluation of results.
6.1.3.4 Differences in chemical composition of carbons.
6. Apparatus
6.1.4 Spectral Irradiance for Enclosed Carbon with Day-
6.1 Laboratory Light Source—Enclosed carbon arc light light Filters—The data in Table 1 are representative of the
sources typically use carbon rods which contain a mixture of spectral irradiance received by a test specimen mounted in the
metal salts. An electric current is passed between the carbon specimen plane.
rods which burn and give off ultraviolet, visible, and infrared 6.2 Test Chamber—The design of the test chamber may
radiation. Use carbon rods recommended by the device manu- vary, but it should be constructed from corrosion resistant
facturer. material, and in addition to the radiant source, may provide for
means of controlling temperature and relative humidity. When
6.1.1 Filter—The most commonly used filters are borosili-
cate glass globes which fit around the carbon burners. Other required, provision shall be made for the spraying of water on
the test specimen or for the formation of condensate on the
filters may be used by mutual agreement by the interested
parties as long as the filter type is reported in conformance with exposed face of the specimen.
the report section in Test Method G 151. 6.2.1 The radiant source(s) shall be located with respect to
6.1.2 The emission spectra of the enclosed carbon arc shows the specimens such that the irradiance at the specimen face
strong emission in the long wavelength ultraviolet region. complies with the requirements in Test Method G 151.
Emissions in the visible, infrared, and short wavelength ultra- 6.3 Instrument Calibration—To ensure standardization and
violet below 350 nm generally are weaker than in sunlight (see accuracy, the instruments associated with the exposure appa-
Table 1). ratus, for example, timers, thermometers, wet bulb sensors, dry
6.1.3 The following factors can affect the spectral power bulb sensors, humidity sensors, UV sensors and radiometers,
G 153
require periodic calibration to ensure repeatability of test provide the specimen with a solid backing. Any backing used
results. Whenever possible, calibration should be traceable to may affect test results and shall be agreed upon in advance
national or international standards. Calibration schedule and between the interested parties.
procedure should be in accordance with manufacturer’s in- 6.7 Apparatus to Assess Changes in Properties—The nec-
structions. essary apparatus required by ASTM or ISO relating to the
6.4 Thermometer—Either insulated or uninsulated black or determination of the properties chosen for monitoring (see also
white panel thermometers may be used. Thermometers shall ISO 4582) shall be used.
conform to the descriptions found in Test Method G 151. The
7. Test Specimen
type of thermometer used, the method of mounting on speci-
men holder, and the exposure temperature shall be stated in the 7.1 Refer to Test Method G 151.
test report.
8. Test Conditions
NOTE 2—Typically, these devices control by black panel temperature
8.1 Any exposure conditions may be used, as long as the
only.
exact conditions are detailed in the report. Appendix X1 lists
6.4.1 Some specifications may require chamber air tempera-
some representative exposure conditions. These are not neces-
ture control. Positioning and calibration of chamber air tem-
sarily preferred and no recommendation is implied. These
perature sensors shall be in accordance with the descriptions
conditions are provided for reference only.
found in Test Method G 151.
6.4.2 The thermometer shall be mounted on the specimen 9. Procedure
rack so that its surface is in the relative position and subjected
9.1 Identify each test specimen by suitable indelible mark-
to the same influences as the test specimens.
ing, but not on areas to be used in testing.
6.5 Moisture—The test specimens may be exposed to mois-
9.2 Determine which property of the test specimens will be
ture in the form of water spray, condensation, or high humidity.
evaluated. Prior to exposing the specimens, quantify the
6.5.1 Water Spray—The test chamber may be equipped with
appropriate properties in accordance with recognized ASTM or
a means to introduce intermittent water spray onto the test
international standards. If required, for example, destructive
specimens under specified conditions. The spray shall be
testing, use unexposed file specimens to quantify the property.
applied so that the specimens are uniformly wetted. The spray
See ISO 4582 for detailed guidance.
system shall be made from corrosion resistant materials that do
9.3 Mounting of Test Specimens. Attach the specimens to the
not contaminate the water used.
specimen holders in the equipment in such a manner that the
6.5.1.1 Quality of Water for Sprays—Spray water must have
specimens are not subject to any applied stress. To assure
a conductivity below 5 μS/cm, contain less than 1-ppm solids,
uniform exposure conditions, fill all of the spaces, using blank
and leave no observable stains or deposits on the specimens.
panels of corrosion resistant material if necessary.
Very low levels of silica in spray water can cause significant
NOTE 3—Evaluation of color and appearance changes of exposed
deposits on the surface of test specimens. Care should be taken
materials must be made based on comparisons to unexposed specimens of
to keep silica levels below 0.1 ppm. In addition to distillation,
the same material, which have been stored in the dark. Masking or
a combination of deionization and reverse osmosis can effec-
shielding the face of test specimens with an opaque cover for the purpose
tively produce water of the required quality. The pH of the
of showing the effects of exposure on one panel is not recommended.
water
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