ASTM D7990-15

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D7990 −15
Standard Test Method for
Using Reflectance Spectra to Produce an Index of
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Temperature Rise in Polymeric Siding
This standard is issued under the fixed designation D7990; 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 E903 Test Method for Solar Absorptance, Reflectance, and
Transmittance of Materials Using Integrating Spheres
1.1 This test method uses reflectance spectra from the
E1331 Test Method for Reflectance Factor and Color by
ultraviolet, visible, and near infrared region to produce an
Spectrophotometry Using Hemispherical Geometry
index of the temperature rise of polymeric siding above
ambient temperature that occurs due to absorption of the sun’s
3. Terminology
energy.
3.1 Definitions of Terms Specific to This Standard:
1.2 The test method determines the intensity factor of a
3.1.1 fractional absorptance—one minus Fractional
sample color. The intensity factor is a function of the sample’s
Reflectance,1–R.
reflectance spectra and the energy output of the heat lamp used
3.1.2 fractional reflectance—the percentage of energy re-
in the test method Test Method D4803.
flected by a sample at a given wavelength, divided by 100.
1.3 Appendix X1 provides a method for using the intensity
3.1.3 intensity factor—an indicator of a specimen’s heat
factor to determine the maximum temperature rise of a sample
buildupbasedonitsreflectancespectrumandtheenergyoutput
under severe solar exposure.
of the IR lamp used in Test Method D4803.
1.3.1 A correlation between intensity factor and heat
3.1.3.1 Discussion—The intensity factor is a summation
buildup (temperature rise) as predicted by Test Method D4803
product of the heat lamp’s relative intensity and the specimen’s
exists.
fractional absorptance at 20 nm intervals between 200 and
1.3.2 The heat buildup (temperature rise) for a polymeric
2,500 nm.
building product specimen is determined from its reflectance
3.1.4 heat buildup—the temperature rise above that of
spectra and the correlation’s regression equation.
ambient air due to the amount of energy absorbed from the sun
1.4 Units—The values stated in SI units are to be regarded
by a specimen.
as standard. No other units of measurement are included in this
3.1.5 relative intensity (of heat lamp)—the lamp’s spectral
standard.
output across the range of 200 nm to 2500 nm, normalized to
1.5 This standard does not purport to address all of the
a value of 100 at the lamp’s maximum output.
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.1 The specimen’s size must cover the spectrophotometer’s
bility of regulatory limitations prior to use.
measurement port, typically 25.4 mm in diameter. Typical
sample dimensions are 102 by 102 by 1.3 mm.
2. Referenced Documents
4.2 Ablackbackercardorplaqueisuseddirectlybehindthe
2.1 ASTM Standards:
specimen to absorb any radiant energy transmitted through the
D2244 Practice for Calculation of Color Tolerances and
specimen.
Color Differences from Instrumentally Measured Color
4.3 The spectral reflectance curve of the test specimen is
Coordinates
measured to determine the amount of energy the specimen
D4803 Test Method for Predicting Heat Buildup in PVC
absorbs at each wavelength.
Building Products
4.4 The intensity factor of the test specimen is the result of
a series summation for the specimen’s spectral absorptance and
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This test method is under the jurisdiction ofASTM Committee D20 on Plastics
the relative intensity of the IR lamp used in Test Method
and is the direct responsibility of Subcommittee D20.24 on Plastic Building
D4803.Theproductofthespecimen’sspectralabsorptanceand
Products.
relative intensity is determined for the spectral region of 200 –
Current edition approved Dec. 1, 2015. Published December 2015. DOI:
10.1520/D7990–15 2,500 nm at an interval of 20 nm
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7990−15
4.5 Appendix X1 provides a method for using the intensity 6. Apparatus
factor to determine the maximum temperature rise of a sample
6.1 UV/VIS/NIR Spectrophotometer—The spectral reflec-
under severe solar exposure.
tance data are obtained using a spectrophotometer equipped
4.5.1 A correlation of intensity factors and heat buildup
with a PTFE-coated integrating sphere detector, capable of
(temperature rise) results from Test Method D4803 for a
reading
...