ASTM D7856-14
(Specification)Standard Specification for Color and Appearance Retention of Solid and Variegated Color Plastic Siding Products using CIELab Color Space
Standard Specification for Color and Appearance Retention of Solid and Variegated Color Plastic Siding Products using CIELab Color Space
SCOPE
1.1 This specification establishes requirements and test methods for the color and appearance retention of solid and variegated colored plastic siding products.
1.2 Color retention testing provides a method for estimating the acceptability of color change in a siding product over a period of years of service. The exposure locations and durations specified in this standard have been shown to provide a good estimation of the color change in a siding product over a period of years of service (see 2.2).
1.3 This specification is a successor to Specifications D6864 and D7251, which cover solid colors and variegated colors, respectively. This specification combines coverage for both, and has the same scope as those standards.
1.4 Specifications D6864 and D7251 use Hunter Lab color space for measurement of colors and evaluation of color change. These standards require classification of colors into regions based on the L, a, and b coordinates of the color, and evaluation of color changes is done using an ellipsoid value equation having unique coefficients for each color region. This specification uses CIE 1976 L* a* b* color space for measurement and evaluation of color change. Using this method, the need for separate color regions and evaluation equations has been eliminated.
1.5 Provisions for sample selection and preparation, and weathering are the same in this specification as in Specifications D6864 and D7251.
1.6 Characterization of color and appearance for variegated colors is complicated by the presence of multiple colors in a random pattern. The procedure for measuring variegated colors in this specification is based on using a template to reference six spots for color measurement.
1.7 This standard specifies outdoor weathering in three specific climate zones for a single 24-month exposure, and the color retention performance requirements under these conditions are established to predict acceptable performance for the expected service life. However, nothing in this standard precludes the use of different or additional climate zones, or different exposure durations, so long as those conditions are clearly specified in any reports.
1.8 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.9 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.Note 1—There is no known ISO equivalent to this standard.
General Information
Relations
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:D7856 −14
StandardSpecification for
Color and Appearance Retention of Solid and Variegated
Color Plastic Siding Products using CIELab Color Space
This standard is issued under the fixed designation D7856; 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 tions are established to predict acceptable performance for the
expected service life. However, nothing in this standard pre-
1.1 This specification establishes requirements and test
cludes the use of different or additional climate zones, or
methods for the color and appearance retention of solid and
different exposure durations, so long as those conditions are
variegated colored plastic siding products.
clearly specified in any reports.
1.2 Color retention testing provides a method for estimating
1.8 Units—The values stated in inch-pound units are to be
the acceptability of color change in a siding product over a
regarded as standard. The values given in parentheses are
period of years of service. The exposure locations and dura-
mathematical conversions to SI units that are provided for
tions specified in this standard have been shown to provide a
information only and are not considered standard.
good estimation of the color change in a siding product over a
1.9 This standard does not purport to address all of the
period of years of service (see 2.2).
safety concerns, if any, associated with its use. It is the
1.3 ThisspecificationisasuccessortoSpecificationsD6864
responsibility of the user of this standard to establish appro-
and D7251, which cover solid colors and variegated colors,
priate safety and health practices and determine the applica-
respectively. This specification combines coverage for both,
bility of regulatory limitations prior to use.
and has the same scope as those standards.
NOTE 1—There is no known ISO equivalent to this standard.
1.4 Specifications D6864 and D7251 use Hunter Lab color
space for measurement of colors and evaluation of color
2. Referenced Documents
change. These standards require classification of colors into
2.1 ASTM Standards:
regions based on the L, a, and b coordinates of the color, and
D660 Test Method for Evaluating Degree of Checking of
evaluation of color changes is done using an ellipsoid value
Exterior Paints
equation having unique coefficients for each color region. This
D661 Test Method for Evaluating Degree of Cracking of
specification uses CIE 1976 L* a* b* color space for measure-
Exterior Paints
ment and evaluation of color change. Using this method, the
D662 Test Method for Evaluating Degree of Erosion of
need for separate color regions and evaluation equations has
Exterior Paints
been eliminated.
D714 Test Method for Evaluating Degree of Blistering of
1.5 Provisions for sample selection and preparation, and
Paints
weathering are the same in this specification as in Specifica-
D772 Test Method for Evaluating Degree of Flaking (Scal-
tions D6864 and D7251.
ing) of Exterior Paints
D883 Terminology Relating to Plastics
1.6 Characterization of color and appearance for variegated
colors is complicated by the presence of multiple colors in a D1435 Practice for Outdoor Weathering of Plastics
D1600 Terminology forAbbreviatedTerms Relating to Plas-
randompattern.Theprocedureformeasuringvariegatedcolors
in this specification is based on using a template to reference tics
D2244 Practice for Calculation of Color Tolerances and
six spots for color measurement.
Color Differences from Instrumentally Measured Color
1.7 This standard specifies outdoor weathering in three
Coordinates
specific climate zones for a single 24-month exposure, and the
D4214 Test Methods for Evaluating the Degree of Chalking
color retention performance requirements under these condi-
of Exterior Paint Films
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.24 on Plastic Building For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Products. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Feb. 1, 2014. Published February 2014. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D7856-14. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7856−14
D6864 Specification for Color andAppearance Retention of 4.3.3 Specimens shall be a flat section and a minimum of 2
Solid Colored Plastic Siding Products by 3 ⁄4 in. (51 by 95 mm). If the normally-exposed surface of
D7251 Specification for Color andAppearance Retention of the siding is heavily textured to the extent that correct or
Variegated Color Plastic Siding Products consistent color measurements cannot be obtained, weathering
E29 Practice for Using Significant Digits in Test Data to test exposure of the back surface or other surface is permitted,
Determine Conformance with Specifications so long as the surface is representative of the exposed surface.
E805 Practice for Identification of Instrumental Methods of
4.4 Variegated Color Specimens:
Color or Color-Difference Measurement of Materials
4.4.1 Prepare a minimum of four specimens per sample per
G147 Practice for Conditioning and Handling of Nonmetal-
test site to allow for three test specimens and one file specimen
lic Materials for Natural and Artificial Weathering Tests
for each sample evaluated.
2.2 Other Reference: 4.4.2 The file specimen will be used for a visual assessment
VS2W Vinyl Siding Institute (VSI) Technical Research Re-
of variegation/contrast change. The test specimens will be
port for Weatherability of Vinyl Siding Products measured for color and weathered.
4.4.3 Specimens shall be a flat section and a minimum of 3
NOTE 2—The report cited in 2.2 supports the conclusion that commer-
by 10 in. (76 by 254 mm). The variegated pattern shall be
cial vinyl siding products which demonstrate weathering behavior within
parallel to the long edge of the specimen.
conformance to these standards during a two year test program can be
anticipated to provide acceptable color retention properties for the
4.4.4 Use the Variegated Color Measurement Template to
expected life of the product.
identify the six spots on each test specimen for color retention
testing.ThecenterpointsofthesesixspotsarespecifiedinFig.
3. Terminology
1. The diameter of the six spots is specified as 0.50 in. (12.2
3.1 Definitions—Definitions are in accordance with Termi-
mm) minimum.The actual diameter used shall be large enough
nologies D883 and D1600 unless otherwise noted. to admit the aperture plate of the instrument used without
extraneous light leakage.
3.2 Definitions of Terms Specific to This Standard:
4.4.5 The exact locations of these test spots must be
3.2.1 temperate northern climate—in weathering testing, a
determined and recorded for each test specimen to allow
North American metropolitan area testing site within 73 to
measurement of color change following exposure testing. The
100°W longitude and 37 to 45°N latitude.
locations and spot sizes identified in 4.4.4 for each test
3.2.2 variegated plastic siding—siding having discrete
specimen shall not change once the exposure test is started.
markings of different colors.
5. Procedure
4. Sampling and Specimen Preparation
5.1 Outdoor Weathering:
4.1 Samples shall be representative of the product to be
5.1.1 Samplesshallbeexposedatthreetestsites:Temperate
evaluated. Samples shall be taken either from commercial
NorthernrepresentedbyasitelocatedinnearLouisville,KYor
products or from laboratory samples. Laboratory samples shall
Cleveland, OH; hot, humid represented by a site located near
be produced in the same manner as the commercial products to
Miami, FL; and hot, dry represented by a site located near
be evaluated.
Phoenix, AZ. Actual test locations are not limited to these
representative cities so long as the location is representative of
NOTE3—Productionoflaboratorysamplesinthesamemannerincludes
use of the same method of forming the product. For example, if the the indicated climate zone.
commercial product is extruded, the laboratory specimen shall be ex-
5.2 Color Measurement (General):
truded; if the commercial product is injection molded, the laboratory
5.2.1 All color measurements are to be made in accordance
specimen shall be injection molded, and so forth.
with this section. Obtain test and file specimens in accordance
4.2 Mark each specimen permanently to ensure retention of
with 4.3 or 4.4. The following procedure is used at each of the
identity during and after exposure testing. Ensure that the
three weathering locations.
identification marking is small and does not interfere with the
5.2.2 Color is measured using 8° sphere geometry, diffuse
color measuring area.
illumination, specular component included (di:8), Illuminant
NOTE 4—Use of a vibratool leaves a permanent mark that satisfies this
D65, and 10° observer, in accordance with Practice E805. For
criterion.
solid colors make at least three separate measurements on the
4.3 Solid Color Specimens: specimen and average them. For variegated colors take one
4.3.1 Prepare a minimum of four specimens per sample per
reading at each of the six spots identified in 4.4.4, and average
test site to allow for three test specimens and one file specimen them.
for each sample evaluated.
5.2.3 Calculate the CIE 1976 L*a*b* units in accordance
4.3.2 The file specimen will be measured for color at each
with the “CIE 1976 L* a* b* Uniform Color Space and
testlocationandwillserveasthereferencecolorforevaluation
Color-Difference Equation” in Test Method D2244, using the
of color changes in the three replicates after weathering.
average of the replicate measurements, and record them in a
permanent record.
5.2.4 Measured specimen color values shall be reported to
no more than two decimal places,
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.