ASTM D7251-06
(Specification)Standard Specification for Color and Appearance Retention of Variegated Color Plastic Siding Products
Standard Specification for Color and Appearance Retention of Variegated Color Plastic Siding Products
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 6 spots for color measurement.
1.4 Methods of indicating compliance with this specification are provided.
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.
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An American National Standard
Designation: D 7251 – 06
Standard Specification for
Color and Appearance Retention of Variegated Color Plastic
Siding Products
This standard is issued under the fixed designation D 7251; 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 3. Terminology
1.1 This specification establishes requirements and test 3.1 Definitions—Definitions are in accordance with termi-
methods for the color and appearance retention of variegated nologies in Terminologies D 883 and D 1600 unless otherwise
color plastic siding products. noted.
1.2 Color retention testing provides a method for estimating 3.2 Definitions of Terms Specific to This Standard:
the acceptability of color change in a siding product over a 3.2.1 color region—parameters that define the color space
period of years of service. for a siding measured with Hunter Units, Illuminant C, 2°
1.3 Characterization of color and appearance for variegated Observer, specular component included.
colors is complicated by the presence of multiple colors in a 3.2.1.1 Discussion—Thecolorvaluesusedtoclassifycolors
random pattern. The procedure is based on using a template to by region will be established by measuring the Hunter L, a, b
reference 6 spots for color measurement. color values from the sample population, calculating the
1.4 Methods of indicating compliance with this specifica- average for Hunter L, a, b, and then choosing the integer from
tion are provided. the corresponding L, a, b average values (that is, no rounding
1.5 This standard does not purport to address all of the up or down) to be used to classify colors by region.
safety concerns, if any, associated with its use. It is the 3.2.2 color retention standards—predictive color regions
responsibility of the user of this standard to establish appro- described by a three dimensional model which constitute
priate safety and health practices and determine the applica- acceptable color retention levels resulting from weathering of
bility of regulatory limitations prior to use. a specific product type and color.
3.2.2.1 Discussion—Color retention standards are defined
NOTE 1—There is no known ISO equivalent to this standard.
by equations that describe the three dimensional ellipsoid
value.
2. Referenced Documents
2 3.2.3 ellipsoid value—a mathematical calculation derived
2.1 ASTM Standards:
by inserting the measured DL, Da, and Db values of a
D 883 Terminology Relating to Plastics
weathered specimen into an ellipsoid equation.
D 1435 Practice for Outdoor Weathering of Plastics
3.2.4 variegated plastic siding—siding having discrete
D 1600 Terminology for Abbreviated Terms Relating to
markings of different colors.
Plastics
D 2244 Practice for Calculation of Color Tolerances and
4. Classification
Color Differences from Instrumentally Measured Color
4.1 Definitions—Definitions are in accordance with termi-
Coordinates
nology in Terminologies D 883 and D 1600 unless otherwise
E 805 PracticeforIdentificationofInstrumentalMethodsof
noted.
Color or Color-Difference Measurement of Materials
4.2 Color Regions—The color region for a color is deter-
G 147 Practice for Conditioning and Handling of Nonme-
mined by measuring the Hunter L, a, b color values for a
tallic Materials for Natural andArtificial Weathering Tests
sample population and calculating the average Hunter L, a, b
color value. Use the integer value (by truncating any fractional
result)oftheaveragetodeterminethecolorregionforthecolor
This specification is under the jurisdiction of ASTM Committee D20 on
using the following region boundaries.
Plastics and is the direct responsibility of Subcommittee D20.24 on Plastic Building
Products. 4.2.1 Region 1—Brown
Current edition approved April 1, 2006. Published April 2006.
L = 20 to 49
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
a=–1to5
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
b=2to11
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 4.2.2 Region 2—Medium Blue
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7251–06
4.3 Ellipsoid Value Equations—Usethefollowingequations
L = 45 to 64
a=–8to1
to determine the ellipsoid value representing the change in
b = –12 to –2
color due to weathering. Use the equation that corresponds to
4.2.3 Region 3—Light Blue the color region determined for the specimen’s initial color
(prior to weathering) in 4.2.
L = 65 to 89
a=–8to1
4.3.1 Region 1—Brown
b = –12 to –2
2 2 2
DL – 1.6! Da 1 1.0! Db – 0.5!
~ ~ ~
4.2.4 Region 4—Green 1 1 5 Ellipsoid Value
2 2 2
~5.2! ~3.0! ~2.5!
L = 50 to 84
a = –12 to –1 4.3.2 Region 2—Medium Blue
b=–1to10
2 2 2
~DL 1 1.0! ~Da 1 0.6! ~Db – 0.8!
1 1 5 Ellipsoid Value
4.2.5 Region 5—Medium Beige
2 2 2
6.0 2.9 5.4
~ ! ~ ! ~ !
L = 50 to 74 L = 50 to 64 L = 65 to 74
4.3.3 Region 3—Light Blue
a=0to1 a=–2to1 a=–7to0
b=4to12 b=11to14 b=11to12
2 2 2
~DL 1 0.3! ~Da 1 0.1! ~Db – 0.8!
1 1 5 Ellipsoid Value
4.2.6 Region 6—Light Beige 2 2 2
~6.4! ~2.7! ~4.3!
L = 75 to 84 L = 85 to 93 L = 75 to 84
4.3.4 Region 4—Green
a=0to1 a=–7to1 a=–7to–1
b=4to12 b=4to12 b=11to12
2 2 2
DL – 0.2 Da – 0.8 Db – 0.2
~ ! ~ ! ~ !
1 1 5 Ellipsoid Value
2 2 2
4.2.7 Region 7—Gold
~5.9! ~4.8! ~5.6!
L = 65 to 93
4.3.5 Region 5—Medium Beige
a=0to4
b=13to30 2 2 2
~DL 1 0.1! ~Da – 0.0! ~Db – 0.4!
1 1 5 Ellipsoid Value
2 2 2
4.2.8 Region 8—Yellow
~6.1! ~2.8! ~3.9!
L = 65 to 93
4.3.6 Region 6—Light Beige
a = –10 to –1
2 2 2
b=13to30
~DL – 0.0! ~Da – 0.2! ~Db – 0.3!
1 1 5 Ellipsoid Value
2 2 2
~5.0! ~2.6! ~5.4!
4.2.9 Region 9—White
L = 85 to 100 All L = 94 to 100
4.3.7 Region 7—Gold
a=–2to1
2 2 2
b=–1to3
~DL 1 0.6! ~Da 1 0.3! ~Db 1 0.4!
1 1 5 Ellipsoid Value
2 2 2
~6.6! ~3.4! ~4.7!
4.2.10 Region 10—Light Gray
L = 65 to 84 4.3.8 Region 8—Yellow
a=0to1
2 2 2
~DL 1 0.3! ~Da – 1.0! ~Db 1 0.1!
b=–1to3
1 1 5 Ellipsoid Value
2 2 2
~5.5! ~3.3! ~5.5!
4.2.11 Region 11—Mauve
4.3.9 Region 9—White
L = 65 to 93 L = 65 to 93 L = 50 to 64
a=2to11 a=5to11 a=2to11
2 2 2
~DL – 0.6! ~Da 1 0.0! ~Db – 1.9!
b=2to12 b=13to15 b=2to15
1 1 5 Ellipsoid Value
2 2 2
~8.2! ~3.3! ~5.3!
4.2.12 Region 12—Medium Gray
4.3.10 Region 10—Light Gray
L = 50 to 64
a=0to1
2 2 2
~DL 1 1.8! ~Da – 0.2! ~Db – 1.3!
b=–1to3
1 1 5 Ellipsoid Value
2 2 2
7.0! 2.1! 4.0!
~ ~ ~
4.2.13 Region 13—Dark Gray
4.3.11 Region 11—Mauve
L = 25 to 49
2 2 2
a=–1to5
~DL – 0.4! ~Da – 0.8! ~Db – 1.1!
b=–1to1
1 1 5 Ellipsoid Value
2 2 2
~6.5! ~4.0! ~4.5!
4.2.14 Region 14—Dark Blue
4.3.12 Region 12—Medium Gray
L = 25 to 44
2 2 2
a=–8to3
DL 1 1.0 Da 1 0.3 Db – 1.2
~ ! ~ ! ~ !
b = –12 to –2 1 1 5 Ellipsoid Value
2 2 2
~6.6! ~2.5! ~3.7!
4.2.15 Region 15—Dark Green
4.3.13 Region 13—Dark Gray
L = 25 to 49
2 2 2
a = –20 to –2 ~DL – 0.1! ~Da 1 0.8! ~Db 1 0.1!
1 1 5 Ellipsoid Value
b=–1to11
2 2 2
~5.1! ~3.4! ~3.0!
4.2.16 Region 16—Dark Red
4.3.14 Region 14—Dark Blue
L = 25 to 49
2 2 2
DL – 0.3! Da – 1.0! Db 1 1.3!
~ ~ ~
a=6to30
1 1 5 Ellipsoid Value
2 2 2
b=–1to25
~5.2! ~3.6! ~4.5!
D7251–06
4.3.15 Region 15—Dark Green 5.3.1 Measured specimen color values shall be reported to
one decimal place.
2 2 2
~DL – 0.0! ~Da 1 0.4! ~Db 1 0.2!
1 1 5 Ellipsoid Value
5.3.2 Calculation of color units shall be reported to one
2 2 2
5.0! 3.0! 3.8!
~ ~ ~
decimal place.
4.3.16 Region 16—Dark Red
5.4 Practice:
2 2 2
~DL – 0.4! ~Da – 0.8! ~Db – 0.2! 5.4.1 Obtain test and file specimens in accordance with 5.2.
1 1 5 Ellipsoid Value
2 2 2
5.4 4.0 3.0 5.4.2 MeasuretheoriginaltristimulusX,Y,andZvaluesfor
~ ! ~ ! ~ !
the 6 spots identified in 5.2.5 for each test specimen. Color is
5. Procedure for Measuring Color Retention measured using sphere geometry (D8), illuminant C, 2° ob-
server, specular component included in accordance with Prac-
5.1 Test Site Setup and Exposure Duration Test Times:
tice E 805. The minimum aperture size for color measurement
5.1.1 Samplesshallbeexposedatthreetestsites:Temperate
0.50 in. (12.2 mm).
Northern represented by a site located in Louisville, KY or
5.4.3 Calculate the Hunter L, a, and b units in accordance
Cleveland, OH; hot, humid represented by a site located in
with the equations in the section on “Hunter L, a, and b Color
Miami, FL, and hot, dry represented by a site located in
Space and Color-Difference Equation” in Test Method D 2244
Phoenix,Arizona.Additional test sites are permitted as agreed
using the average of the six measurements and record in a
upon by the buyer and the seller.
permanent record.
5.1.2 All exposures shall be conducted at an angle of 45°
5.4.4 The measured average color of each test specimen is
facing South and backed using unpainted plywood in accor-
the specimen’s initial color and is used to determine color
dance with Practices D 1435 and G 147.
change after specified periods of exposure testing.
5.1.3 Remove test specimens for color measurement at
5.4.5 Repeat steps 5.4.2 through 5.4.4 for each test speci-
24-monthexposure.Insomecases,24monthsarenotsufficient
men.
to distinguish material durability differences and longer expo-
sure periods are necessary. Additional exposure times are 5.4.6 Calculate the average color in Hunter L, a, b for the
testspecimenstodeterminetheircolorregionasdefinedin4.2.
permitted as agreed upon by the buyer and the seller.
5.2 Sampling and Specimen Preparation:
5.4.6.1 Calculate the overall average color of the 3 test
5.2.1 Samples shall be represe
...
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