ASTM F520-97(2004)
(Test Method)Standard Test Method for Environmental Resistance of Aerospace Transparencies
Standard Test Method for Environmental Resistance of Aerospace Transparencies
SIGNIFICANCE AND USE
This test method, when applied to aerospace transparencies of either monolithic glass/plastic or laminated combinations, is a measure of the ability of the transparency to withstand the effects of artificially induced environments. The test may be used on configurations employing electrically conductive coatings, and also to evaluate the integrity of noncoated materials.
The resistance of the transparent enclosure to environmental effects may vary appreciably depending on the size, geometry, material of construction, coating integrity, coating density, and other factors.
SCOPE
1.1 This test method covers determination of the effects of exposure to thermal shock, condensing humidity, and simulated weather on aerospace transparent enclosures.
1.2 This test method is not recommended for quality control nor is it intended to provide a correlation to actual service life.
1.3 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.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
Designation:F520–97 (Reapproved 2004)
Standard Test Method for
Environmental Resistance of Aerospace Transparencies
ThisstandardisissuedunderthefixeddesignationF520;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope condensing humidity, and artificial weathering. Edge sealing
may be used if representative of the design.
1.1 This test method covers determination of the effects of
3.1.1 Type A specimens are used to determine the effect of
exposure to thermal shock, condensing humidity, and simu-
environmental exposure on electrical and optical properties.
lated weather on aerospace transparent enclosures.
3.1.2 Type B specimens are used to determine the effect of
1.2 Thistestmethodisnotrecommendedforqualitycontrol
environmental exposure on bond integrity.
nor is it intended to provide a correlation to actual service life.
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 This test method, when applied to aerospace transpar-
responsibility of the user of this standard to establish appro-
encies of either monolithic glass/plastic or laminated combi-
priate safety and health practices and determine the applica-
nations, is a measure of the ability of the transparency to
bility of regulatory limitations prior to use.
withstand the effects of artificially induced environments. The
2. Referenced Documents test may be used on configurations employing electrically
conductive coatings, and also to evaluate the integrity of
2.1 ASTM Standards:
noncoated materials.
D1003 Test Method for Haze and Luminous Transmittance
4.2 The resistance of the transparent enclosure to environ-
of Transparent Plastics
mental effects may vary appreciably depending on the size,
F521 TestMethodsforBondIntegrityofTransparentLami-
geometry, material of construction, coating integrity, coating
nates
density, and other factors.
G23 Practice for Operating Light-Exposure Apparatus
(Carbon-Arc Type) With and Without Water for Exposure
5. Test Specimens
of Nonmetallic Materials (Discontinued 2001)
5.1 Each Type A specimen shall be a 250 by 250-mm (9.8
G26 Practice for Operating Light-Exposure Apparatus
by 9.8-in.) cross section of the design and shall contain, as
(Xenon-Arc Type) With and Without Water for Exposure
43 applicable, surface coatings of operational, electrically con-
of Nonmetallic Materials (Discontinued 2001)
ducting coating systems complete with bus bars, braids, and
G53 Practice for Operating Light-and Water-Exposure Ap-
temperature sensors.
paratus(FluorescentUV-CondensationType)forExposure
4 5.1.1 Type A test specimens shall have a fully operational
of Nonmetallic Materials (Discontinued 2001)
coating system, when applicable, with an average resistivity
3. Summary of Test Method consistent with the average resistivity of the representative
design. Reproduction of multiphase electrical circuits is not
3.1 Two types of test specimens, duplicating the aerospace
required for these test specimens since this type of circuitry is
transparent enclosure design, are subjected to thermal shock,
only a design technique used to accommodate limited voltage
resources at installation.
5.2 Each Type B test specimen shall be 50 by 50 mm (2 by
This test method is under the jurisdiction of ASTM Committee F07 on
2 in.) and shall be of a cross section consistent with the edge
Aerospace andAircraft and is the direct responsibility of Subcommittee F07.08 on
configuration of the representative design. Type B test speci-
Transparent Enclosures and Materials.
Current edition approved Oct. 1, 2004. Published October 2004. Originally
mens are not intended to be operational electrically, but they
approved in 1977. Last previous edition approved in 1997 as F520–97. DOI:
shall be representative of the average resistivity of the design.
10.1520/F0520-97R04.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6. Preparation of Test Specimens
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
6.1 Prepare a minimum of three TypeAspecimens for each
the ASTM website.
design configuration. If the design contains an electrically
Withdrawn.
4 activated coating, only one temperature sensor per specimen is
Withdrawn. The last approved version of this historical standard is referenced
on www.astm.org. required.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F520–97 (2004)
6.2 Prepare a minimum of five Type B specimens for each 7.3.4 Monitor the current during gradual application of a dc
designconfiguration.Preparethespecimeninsuchamanneras voltage. Current in excess of 5 µA is objectionable. If the
to produce smooth edges and corners to prevent chipping current exceeds 5 µA dc before 500 V dc is reached, suspend
during testing. Polish at least one edge of each specimen to thetestanddeterminetheresistancebeforedecidingwhetherto
allow inspection of the internal bonded surfaces during tensile continue. Gradually apply and remove the potential at no
loading. Do not apply edge sealant to the specimens. greater rate than 500 V rms/s.
6.3 Condition all test specimens by exposing them to not
7.3.5 Electrically Conductive Coating Test—TesteachType
less than 40 h at 23 6 2°C (73.4 6 3.6°F) and 50 6 5% A specimen for electrically conductive coating uniformity by
relative humidity.
energizingwiththesamelevelofcontrolledpowerasproposed
in the design while viewing between polarized plates. Identify
7. Procedure alldetectablecoatinghotspotsduringthisheat-upcycle.These
thermally induced stress concentrations are generally charac-
7.1 Visual Examination—Carefully examine Type A and
terized by a “butterfly” shape and are to be noted for later
Type B specimens for any signs of material or manufacturing
specimen evaluation.
defects. A microscope or magnifying lens, dark background,
7.3.6 Overvoltage Test—Subject each of the electrical heat-
and cross lighting may be used, as appropriate, to assist in the
ing circuits of Type A specimens to the application of an
identification and classification of visible defects.
overvoltage of 150% maximum operating voltage for the
7.2 Optical Tests—Measure each Type A specimen for
circuit.Applythisvoltagetothepowerleadsforaminimumof
luminoustransmittanceandhazeinaccordancewithProcedure
5s.Afternolessthana2-minwait,applythesamevoltagefor
BofTestMethodD1003.Makeatleasttwomeasurements,one
a minimum of 5 s, observing the sample in a darkened room
in the center and one near the edge, on each specimen. Six
with specific emphasis being on the bus bars for signs of
measurements are preferred. If greater than 1% variation
arcing.
exists, prepare a template from polyester film or other suitable
7.3.7 Bond Integrity Test—Test individual Type B speci-
material to record these locations for indexing and correlation
mens in accordance with Test Methods F521.
to readings to be taken after environmental exposure.
7.4 Specimens that fail due to some obvious, non-
NOTE 1—Paragraphs 7.3-7.6 are applicable to systems using electri-
representative defect shall be disqualified and retests con-
cally conductive coatings.
ducted.
7.3 Electrical Tests:
7.5 Environmental Exposure:
7.3.1 Bus Bar-to-Bus Bar Resistance—Measure each Type
7.5.1 Artificial Weathering—Expose test specimens to arti-
Aspecimen for bus bar-to-bus bar resistance.Take precautions
ficial weathering in accordance with one of the two standards
to minimize the effects of variable contact resistance. Record
listed below.
results and repea
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