ASTM D5894-96

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Designation: D 5894 – 96
Standard Practice for
Cyclic Salt Fog/UV Exposure of Painted Metal, (Alternating
Exposures in a Fog/Dry Cabinet and a UV/Condensation
Cabinet)
This standard is issued under the fixed designation D 5894; 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 G 85 Standard Practice for Modified Salt Spray (Fog) Test-
ing
1.1 This practice covers basic principles and operating
practice for cyclic corrosion/UV exposure of paints on metal,
3. Summary of Practice
using alternating periods of exposure in two different cabinets:
3.1 The test specimens are exposed to alternating periods of
a cycling salt fog/dry cabinet, and a fluorescent UV/
one week in a fluorescent UV/condensation chamber and one
condensation cabinet.
week in a cyclic salt fog/dry chamber. The fluorescent UV/
1.2 This practice is limited to the methods of obtaining,
condensation cycle is 4-h UV at 60°C and 4-h condensation at
measuring, and controlling exposure conditions, and proce-
50°C,usingUVA-340lamps.Thefog/drychamberrunsacycle
dures. It does not specify specimen preparation nor evaluation
of 1-h fog at ambient temperature and 1-h dry-off at 35°C. The
of results.
fog electrolyte is a relatively dilute solution, with 0.05 %
1.3 This standard does not purport to address all of the
sodium chloride and 0.35 % ammonium sulfate.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Significance and Use
priate safety and health practices and determine the applica-
4.1 Theoutdoorcorrosionofpaintedmetalsisinfluencedby
bility of regulatory limitations prior to use.
many factors, including: corrosive atmospheres, rain, con-
densed dew, UV light, wet/dry cycling, and temperature
2. Referenced Documents
cycling. These factors frequently have a synergistic effect on
2.1 ASTM Standards:
one another. This practice is intended to provide a more
D 610 Test Method for Evaluating Degree of Rusting on
realistic simulation of the interaction of these factors than is
Painted Steel Surfaces
found in traditional tests with continuous exposure to a static
D 714 Test Method for Evaluating Degree of Blistering of
set of corrosive conditions.
Paints
4.2 Results obtained from this practice can be used to
D 1654 Test Method for Evaluation of Painted or Coated
compare the relative durability of materials subjected to the
Specimens Subjected to Corrosive Environments
specific test cycle used.
D 4587 Practice for Conducting Tests on Paint and Related
4.3 No single exposure test can be specified as a complete
Coatings and Materials Using a Fluorescent UV-
simulation of actual use conditions in outdoor environments.
Condensation Light-and-Water Exposure Apparatus
Results obtained from exposures conducted according to this
G 53 Practice for Operating Light-and-Water ExposureAp-
practice can be considered as representative of actual outdoor
paratus(FluorescentUV-CondensationType)forExposure
exposures only when the degree of rank correlation has been
of Nonmetallic Materials
established for the specific materials being tested. The relative
durability of materials in actual outdoor service can be very
different in different locations because of differences in UV
This practice is under the jurisdiction of ASTM Committee D-1 on Paint and radiation, time of wetness, temperature, pollutants, and other
Related Coatings, Materials, and Applications and is the direct responsibility of
factors. Therefore, even if results from a specific artificial test
Subcommittee D01.27 on Accelerated Testing.
condition are found to be useful for comparing the relative
Current edition approved Jan. 10, 1996. Published March 1996.
Annual Book of ASTM Standards, Vol 06.02.
Annual Book of ASTM Standards, Vol 06.01.
4 5
Annual Book of ASTM Standards, Vol 14.02. Annual Book of ASTM Standards, Vol 03.02.
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D 5894
durability of materials exposed in a particular exterior envi- similar composition to the test specimens. It is preferable to
ronment, it cannot be assumed that they will be useful for have two control materials: one of higher durability and one of
determining relative durability for a different environment. lower durability.
4.4 Even though it is very tempting, it is not recommended 6.5 It is recommended that at least three replicates of each
to calculate an “acceleration factor” relating x hours of specimen be tested, to compensate for variation within the
laboratory exposure toy months of exterior exposure. Different chambers and variation between specimens.
materials and different formulations of the same material can
have significantly different acceleration factors. The accelera- 7. Procedure
tion factor also varies depending on the variability in rate of
7.1 Fluorescent UV-Condensation Exposure:
degradation in the laboratory test and in actual outdoor
7.1.1 Start the exposure in the fluorescent UV-condensation
exposure.
chamber rather than the salt fog/dry chamber.
4.5 This practice is best used to compare the relative
NOTE 1—It has been found that in certain cases the exposure must start
performance of materials tested at the same time in the same
in the fluorescent UV in order to get realistic rusting and staining as well
exposure device. Because of possible variability between the
as faster corrosion. It is thought that the initial UV damage to the coating
same type of exposure devices, it is not recommended to
allows the subsequent salt fog to produce a more realistic corrosion attack
compare the amount of degradation in materials exposed for
on the substrate.
the same duration at separate times, or in separate devices
7.1.2 Perform the fluorescent UV-condensation exposure in
running the same test condition. This practice should not be
compliance with Practices D 4587 and G 53.
used to establish a “pass/fail” approval of materials after a
7.1.3 Program a cycle of 4-h UV at 60°C 6 3°
...