ASTM D7251-11
(Specification)Standard Specification for Color and Appearance Retention of Variegated Color Plastic Siding Products (Withdrawn 2018)
Standard Specification for Color and Appearance Retention of Variegated Color Plastic Siding Products (Withdrawn 2018)
ABSTRACT
This specification establishes requirements and test methods for the color and appearance retention of variegated color plastic siding products. Color retention testing provides a method for estimating the acceptability of color change in a siding product over a period of years of service. Characterization of color and appearance for variegated colors is complicated by the presence of multiple colors in a random pattern. The procedure is based on using a template to reference 6 spots for color measurement. The color region for a color is determined by measuring the Hunter L, a, b color values for a sample population and calculating the average Hunter L, a, b color value. Ellipsoid Value Equations are used to determine the ellipsoid value representing the change in color due to weathering. Samples shall be exposed at three test sites: Temperate Northern represented by a site located in Louisville, KY or Cleveland, OH; hot, humid represented by a site located in Miami, FL, and hot, dry represented by a site located in Phoenix, Arizona. Materials shall be tested and the individual grades shall conform to specified values of ellipsoid value, color retention, and variegation change.
SCOPE
1.1 This specification establishes requirements and test methods for the color and appearance retention of variegated color 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.
1.3 Characterization of color and appearance for variegated colors is complicated by the presence of multiple colors in a random pattern. The procedure is based on using a template to reference six spots for color measurement.
1.4 Methods of indicating compliance with this specification are provided.
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.
Note 1—There is no known ISO equivalent to this standard.
WITHDRAWN RATIONALE
This specification establishes requirements and test methods for the color and appearance retention of variegated color plastic siding products.
Formerly under the jurisdiction of Committee D20 on Plastics, this specification was withdrawn in Mary 2018 and replaced by Specification D7856 for Color and Appearance Retention of Solid and Variegated Color Plastic Siding Products using CIELab Color Space.1
General Information
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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:D7251 −11 An American National Standard
Standard Specification for
Color and Appearance Retention of Variegated Color Plastic
1
Siding Products
This standard is issued under the fixed designation D7251; 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* G147 Practice for Conditioning and Handling of Nonmetal-
lic Materials for Natural and Artificial Weathering Tests
1.1 This specification establishes requirements and test
methods for the color and appearance retention of variegated
3. Terminology
color plastic siding products.
3.1 Definitions—Definitions are in accordance with termi-
1.2 Color retention testing provides a method for estimating
nologies in Terminologies D883 and D1600 unless otherwise
the acceptability of color change in a siding product over a
noted.
period of years of service.
3.2 Definitions of Terms Specific to This Standard:
1.3 Characterization of color and appearance for variegated
3.2.1 color region—parameters that define the color space
colors is complicated by the presence of multiple colors in a
for a siding sample, measured with Hunter Units, sphere
random pattern. The procedure is based on using a template to
geometry (di:8), Illuminant C, 2° Observer, specular compo-
reference six spots for color measurement.
nent included.
3.2.1.1 Discussion—The color values used to classify colors
1.4 Methods of indicating compliance with this specifica-
by region were established by measuring the Hunter L, a, b
tion are provided.
color values from the sample population, calculating the
1.5 This standard does not purport to address all of the
average for Hunter L, a, b, and then choosing the integer from
safety concerns, if any, associated with its use. It is the
the corresponding L, a, b average values (that is, by truncating
responsibility of the user of this standard to establish appro-
any fractional result) to be used to classify colors by region.
priate safety and health practices and determine the applica-
Thus, average values greater than zero are truncated down to
bility of regulatory limitations prior to use.
the next lowest integer, and average values less than zero are
NOTE 1—There is no known ISO equivalent to this standard.
truncated up to the next highest integer.All values greater than
-1 and less than +1 truncate to 0.
2. Referenced Documents
3.2.2 color retention standards—predictive color regions
2
2.1 ASTM Standards:
described by a three dimensional model which constitute
D883 Terminology Relating to Plastics
acceptable color retention levels resulting from weathering of
D1435 Practice for Outdoor Weathering of Plastics
a specific product type and color.
D1600 TerminologyforAbbreviatedTermsRelatingtoPlas-
3.2.2.1 Discussion—Color retention standards are defined
tics
by equations that describe the three dimensional ellipsoid
D2244 Practice for Calculation of Color Tolerances and
value.
Color Differences from Instrumentally Measured Color
3.2.3 ellipsoid value—a mathematical calculation derived
Coordinates
by inserting the measured ∆L, ∆a, and ∆b values of a
E805 Practice for Identification of Instrumental Methods of
weathered specimen into an ellipsoid equation.
Color or Color-Difference Measurement of Materials
3.2.4 temperate northern climate—in weathering testing,a
North American metropolitan area testing site located within
1
This specification is under the jurisdiction of ASTM Committee D20 on 73 to 100°W longitude and 37 to 45°N latitude.
Plastics and is the direct responsibility of Subcommittee D20.24 on Plastic Building
3.2.5 variegated plastic siding—siding having discrete
Products.
markings of different colors.
Current edition approved April 1, 2011. Published April 2011. Originally
approved in 2006. Last previous edition approved in 2010 as D7251 - 10. DOI:
4. Classification
10.1520/D7251-11.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.1 Definitions—Definitions are in accordance with termi-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
nology in Terminologies D883 and D1600 unless otherwise
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. noted.
*A Summary of Changes section appears at the end of this standard
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D7251−11
4.2 Color Regions—The color region for a color is deter- 4.2.13 Region 13—Dark Gray
mined by measuring the Hunter L, a, b color values at six
L = 25 to 49
...
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