ASTM D4329-99

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D4329–99
Standard Practice for
Fluorescent UV Exposure of Plastics
This standard is issued under the fixed designation D 4329; 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* Weathering Tests of Nonmetallic Materials
G 141 Guide forAddressingVariability in ExposureTesting
1.1 This practice covers specific procedures and test condi-
on Nonmetallic Materials
tionsthatareapplicableforfluorescentUVexposureofplastics
G 147 Practice for Conditioning and Handling of Nonme-
conducted in accordance with Practices G 151 and G 154.This
tallic Materials for Natural andArtificial Weathering Tests
practice also covers the preparation of test specimens, the test
G 151 Practice for Exposing Nonmetallic Materials in Ac-
conditions best suited for plastics, and the evaluation of test
celerated Test Devices That Use Laboratory Light Sources
results.
G 154 Practice for Operating Fluorescent Light Apparatus
NOTE 1—Previous versions of this practice referenced fluorescent UV
for UV Exposure of Nonmetallic Materials
devices described by Practice G 53, which described very specific
2.2 ISO Standard:
equipment designs. Practice G 53 is being replaced by Practice G 151,
ISO 4892-3 Plastics—Methods of Exposure to Laboratory
which describes performance criteria for all exposure devices that use
Light Sources — Part 3, Fluorescent UV Lamps
laboratory light sources and by Practice G 154, which gives requirements
for exposing nonmetallic materials in fluorescent UV devices. Practice
3. Terminology
G 53 will be balloted for withdrawal before December 2000.
3.1 The definitions in Terminology G 113 are applicable to
1.2 ThevaluesstatedinSIunitsareberegardedasstandard.
this practice.
The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 The ability of a plastic material to resist deterioration of
responsibility of the user of this standard to establish appro-
its electrical, mechanical, and optical properties caused by
priate safety and health practices and determine the applica-
exposure to light, heat, and water can be very significant for
bility of regulatory limitations prior to use.
many applications.This practice is intended to induce property
NOTE 2—This practice is technically equivalent to ISO 4892-3.
changes associated with end-use conditions, including the
effects of sunlight, moisture, and heat. The exposure used in
2. Referenced Documents
thispracticeisnotintendedtosimulatethedeteriorationcaused
2.1 ASTM Standards:
by localized weather phenomena, such as, atmospheric pollu-
D 3980 Practice for Interlaboratory Testing of Paint and
tion, biological attack, and saltwater exposure.
Related Materials
4.2 Caution—Variation in results may be expected when
D 5870 Practice for Calculating Property Retention Index
operating conditions are varied within the accepted limits of
of Plastics
this practice. Therefore, no reference to the use of this practice
E 691 Practice for Conducting an Interlaboratory Study to
should be made unless accompanied by a report prepared in
Determine the Precision of a Test Method
accordance with Section 8 that describes the specific operating
G 53 Practice for Operating Light- and Water-Exposure
conditions used. Refer to Practice G 151 for detailed informa-
Apparatus (Fluorescent UV-CondensationType) for Expo-
tion on the caveats applicable to use of results obtained in
sure of Nonmetallic Materials
accordance with this practice.
G 113 Terminology Relating to Natural and Artificial
NOTE 3—Additional information on sources of variability and on
strategies for addressing variability in the design, execution, and data
analysis of laboratory-accelerated exposure tests is found in Guide G 141.
ThispracticeisunderthejurisdictionofASTMCommitteeD20onPlasticsand
is the direct responsibility of Subcommittee D20.50 on Permanence Properties.
4.3 Reproducibility of test results between laboratories has
Current edition approved Jan. 10, 1999. Published April 1999. Originally
been shown to be good when the stability of materials is
published D 4329 – 84. Last previous edition D 4329 – 92.
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 Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036.
*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.
D4329–99
evaluated in terms of performance ranking compared to other 6.4 Seal any holes in specimens larger than 2 mm and any
4,5
materials or to a control. Therefore, exposure of a similar openings larger than 1 mm around irregularly shaped speci-
material of known performance (a control) at the same time as mens to prevent loss of water vapor. Attach porous specimens
the test materials is strongly recommended. It is recommended to a solid backing such as aluminum that can act as a vapor
that at least three replicates of each material be exposed to barrier.
allow for statistical evaluation of results. 6.5 Unless otherwise specified, expose at least three repli-
4.4 Test results will depend upon the care that is taken to cate specimens of each test and control material.
operate the equipment in accordance with Practice G 154. 6.6 Follow the procedures described in Practice G 147 for
Significant factors include regulation of line voltage, tempera- identification, conditioning, and handling of specimens of test,
ture of the room in which the device operates, temperature control, and reference materials prior to, during, and after
control, and condition and age of the lamp. exposure.
6.7 Do not mask the face of a specimen for the purpose of
5. Apparatus
showing on one panel the effects of various exposure times.
5.1 Use of fluorescent UV apparatus that conforms to the Misleading results may be obtained by this method, since the
masked portion of the specimen is still exposed to temperature
requirements defined in Practices G 151 and G 154 is required
and humidity cycles that in many cases will affect results.
to conform to this practice.
6.8 Since the thickness of a specimen may markedly affect
5.2 Unless otherwise specified, the spectral power distribu-
the results, thickness of test and control specimens shall be
tion of the fluorescent UV lamp shall conform to the require-
within 610 % of the nominal dimensions.
ments in Practice G 154 for a UVA 340 lamp.
5.3 Test Chamber Location:
NOTE 4—This is especially important when mechanical properties are
5.3.1 Locatetheapparatusinanareamaintainedbetween18
being investigated.
and 27°C (65 and 80°F). Measure ambient temperature at a
6.9 Incident energy at the extremes of the specimen expo-
maximum distance of 150 mm (6 in.) from the plane door of
sure area in older equipment may be only 70 % of that at the
the apparatus. Control of ambient temperature is particularly
center.Iftheirradianceatanypositionwithintheexposurearea
critical when one apparatus is stacked above another, because
is less than 90 % of the peak irradiance, follow one of the
the heat generated from the lower unit can interfere with the
procedures outlined in Practice G 154 to ensure either equal
operation of the units above.
radiant exposure or compensation for differences in radiant
5.3.2 Place the apparatus at least 300 mm from walls or
exposure.
other apparatus. Do not place the apparatus near a heat source
6.10 Retain a supply of unexposed file specimens of all
such as an oven.
materials evaluated.
5.3.3 Ventilate the room in which the apparatus is located to
6.10.1 When destructive tests are run, ensure that sufficient
remove heat and moisture.
file specimens are retained so that the property of interest can
be determined on unexposed file specimens each time exposed
6. Test Specimen
materials are evaluated.
6.1 The size and shape of specimens to be exposed will be
6.11 Specimens should not be removed from the exposure
determined by the specifications of the particular test method
apparatus for more than 24 h and then returned for additional
used to evaluate the effects of the exposure on the specimens;
tests, since this does not produce the same results on all
the test method shall be determined by the parties concerned.
materials as tests run without this type of interruption. When
Where practical, it is recommended that specimens be sized to
specimensareremovedfromtheexposureapparatusfor24hor
fit specimen holders and racks supplied with the exposure
more and then returned for additional exposure, report the
apparatus. Unless supplied with a specific backing as an
elapsed time as noted in accordance with Section 9.
integral part of the test, specimens shall be mounted so that
NOTE 5—Since the stability of the file specimen may also be time-
only the minimum specimen area required for support by the
dependent, users are cautioned that over prolonged exposure periods, or
holder shall be covered. This unexposed surface must not be
where small differences in the order of acceptable limits are anticipated,
used as part of the test area.
comparisonofexposedspecimenswiththefilespecimenmaynotbevalid.
6.2 For specimens of insulating materials, such as foams,
Instrumental measurements are recommended whenever possible.
maximum specimen thickness is 20 mm in order to allow for
adequate heat transfer for condensation.
7. Procedure
6.3 To provide rigidity, attach flexible specimens to a
7.1 When the test and control specimens do not completely
backing panel made of aluminum, 0.635 mm (0.025 in.) thick.
fill the specimen racks, fill all empty spaces with blank panels
Suggested aluminum alloys are 5052, 6061, or 3003.
to maintain the test conditions within the chamber.
7.2 Unlessotherwisespecified,programthedevicetooneof
the following test cycles. Operate the device continuously.
Fischer, R., “Results of Round Robin Studies of Light- and Water-Exposure
7.2.1 Cycle A:
Standard Practices,” Accelerated and Outdoor Durability Testing of Organic
8 h UV with uninsulated black panel temperature controlled at 60 6
Materials, ASTM STP 1202, Warren D. Ketola and Douglas Grossman, eds.,
3°C
American Society for Testing and Materials, Philadelphia, 1993.
4 h condensation with uninsulated black panel temperature con-
Ketola, W., and Fischer, R., “Characterization and Use of Reference Materials
trolled at 506 3°C
in Accelerated Durability Tests,” VAMAS Technical Report No. 30, available from
(Used for most general applications)
NIST, Gaithersburg, MD.
D4329–99
7.2.2 Cycle B: test materials themselves. All concerned parties must agree on
the control material used.
8 h UV with uninsulated black panel temperature controlled at 70 6
3°C
7.6.1 Identification of any control specimen used shall
4 h condensation with uninsulated black panel temperature con-
accompany the report.
trolled at 506 3°C
(Typically used for automotive applications)
8. Periods of Exposure and Evaluation of Test Results
7.2.3 Cycle C:
8.1 In most cases, periodic evaluation of test and control
8 h UV with uninsulated black panel temperature controlled at 50 6
materials is necessary to determine the variation in magnitude
3°C
anddirectionofpropertychangeasafunctionofexposuretime
4 h condensation with uninsulated black panel temperature con-
trolled at 506 3°C
or radiant exposure.
(Typically used for plastic building products)
8.2 The time or radiant exposure necessary to produce a
7.3 Practice G 154 lists several other exposure cycles that defined change in a material property can be used to evaluate
are used for fluorescent UV exposures of nonmetallic materi- or rank the stability of materials.This method is preferred over
als.Obtainmutualagreementbetweenallconcernedpartiesfor evaluating materials after an arbitrary exposure time or radiant
the specific exposure cycle used. exposure.
7.4 In order to minimize any effects from temperature or 8.2.1 Exposure to an arbitrary time or radiant exposure may
UV light variation, reposition the specimens as follows. Fig. 1 be used for the purpose of a specific test if agreed upon
shows a diagram of the specimen repositioning. between the parties concerned or if required for conformance
7.4.1 Reposition the specimens horizontally once per week to a particular specification. When a single exposure period is
used, select a time or radiant exposure that will produce the
by(1)movingthetwoextremeright-handholderstothefarleft
of the exposure area, and (2) sliding the remaining holders to largest performance differences between the test materials or
between the test material and the control material.
the right.
7.4.2 Repositionthespecimensverticallysothateachspeci- 8.2.2 The minimum exposure time used shall be that nec-
essary to produce a substantial change in the property of
men spends the same amount of exposure time in each vertical
position within the specimen holder. For instance, if two interest for the least stable material being evaluated. An
exposure time that produces a significant change in one type of
specimens are stacked vertically in each holder, then the top
and bottom specimens should switch places halfway through material cannot be assumed to be applicable to other types of
the test. If four specimens are stacked vertically, then the materials.
specimens should be repositioned vertically three times during 8.2.3 The relation between time to failure in an exposure
the test. conducted in accordance with this practice and service life in
7.5 Water Purity—The purity of water used for specimen an outdoor environment requires determination of a valid
spray is very important. Follow the purity requirements in acceleration factor. Do not use arbitrary acceleration factors
Practice G 151 for water sprayed on specimen surfaces. It is relating time in an exposure conducted in accordance with this
recommended that deionized water be used for water used to practice and time in an outdoor environment because they can
produce condensation. giveerroneousinformation.Theaccelerationfactorismaterial-
7.6 It is recommended that a control material be exposed at dependent and is only valid if it is based on data from a
the same time as the test specimens for compariso
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