ASTM D7990-21

Standard Test Method for Using Reflectance Spectra to Produce an Index of Temperature Rise in Polymeric Siding

SIGNIFICANCE AND USE
5.1 Heat buildup of polymeric building products due to absorption of energy from the sun may lead to distortion problems. Test Method Test Method D4803 was developed to predict a building product’s heat buildup (temperature rise). It compares the relative temperature changes of a pigmented PVC product and a PVC panel containing carbon black when exposed to an infrared heat lamp. Based on experimental results that determined the maximum temperature for this black panel under both solar exposure and in the laboratory test, a method for determining the exterior temperature rise and heat buildup for a test panel was developed. This test has shown to be useful and reliable but is time consuming and requires controlled conditions to minimize sources of variation.  
5.2 This test method uses a spectrophotometer to measure a specimen’s reflectance in the ultraviolet, visible, and near infrared region and uses the spectral power distribution of the heat lamp specified in Test Method D4803 to determine an intensity factor, which is an index of the relative spectral energy absorption by the specimen.  
5.2.1 The temperature rise that would occur under an Test Method D4803 test is proportional to this intensity factor. An equation has been derived from the correlation of the intensity factor and temperature rise data obtained from Test Method D4803 testing of samples with a wide range of color and lightness. A total of 99 samples were studied and represent samples with the lowest to highest temperature rise. Linear regression analysis yields a R2 correlation coefficient of 0.98.  
5.2.2 The procedure in Appendix X1 allows prediction of temperature rise that would result from testing of the same sample under Test Method D4803.  
5.2.3 As this procedure is a correlation to results obtained by Test Method D4803, it is a method that yields a relative temperature rise compared to black under certain defined severe conditions, but does not predict actual field application tempera...
SCOPE
1.1 This test method uses reflectance spectra from the ultraviolet, visible, and near infrared region to produce an index of the temperature rise of polymeric siding above ambient temperature that occurs due to absorption of the sun’s energy.  
1.2 The test method determines the intensity factor of a sample color. The intensity factor is a function of the sample’s reflectance spectra and the energy output of the heat lamp used in the test method Test Method D4803.  
1.3 Appendix X1 provides a method for using the intensity factor to determine the maximum temperature rise of a sample under severe solar exposure.  
1.3.1 A correlation between intensity factor and heat buildup (temperature rise) as predicted by Test Method D4803 exists.  
1.3.2 The heat buildup (temperature rise) for a polymeric building product specimen is determined from its reflectance spectra and the correlation’s regression equation.  
1.4 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 83.140.99 - Other rubber and plastics products
• ICS: 91.060.10 - Walls. Partitions. Facades
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.24 - Plastic Building Products

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D7990 −21 An American National Standard
Standard Test Method for
Using Reflectance Spectra to Produce an Index of
1
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* 2. Referenced Documents
1.1 This test method uses reflectance spectra from the 2.1 ASTM Standards:
ultraviolet, visible, and near infrared region to produce an
D2244 Practice for Calculation of Color Tolerances and
index of the temperature rise of polymeric siding above Color Differences from Instrumentally Measured Color
ambient temperature that occurs due to absorption of the sun’s
Coordinates
energy. D4803 Test Method for Predicting Heat Buildup in PVC
Building Products
1.2 The test method determines the intensity factor of a
E903 Test Method for Solar Absorptance, Reflectance, and
sample color. The intensity factor is a function of the sample’s
Transmittance of Materials Using Integrating Spheres
reflectance spectra and the energy output of the heat lamp used
E1331 Test Method for Reflectance Factor and Color by
in the test method Test Method D4803.
Spectrophotometry Using Hemispherical Geometry
1.3 Appendix X1 provides a method for using the intensity
factor to determine the maximum temperature rise of a sample
3. Terminology
under severe solar exposure.
3.1 Definitions of Terms Specific to This Standard:
1.3.1 A correlation between intensity factor and heat
3.1.1 fractional absorptance—one minus Fractional
buildup (temperature rise) as predicted by Test Method D4803
Reflectance,1–R.
exists.
3.1.2 fractional reflectance—the percentage of energy re-
1.3.2 The heat buildup (temperature rise) for a polymeric
flected by a sample at a given wavelength, divided by 100.
building product specimen is determined from its reflectance
spectra and the correlation’s regression equation.
3.1.3 intensity factor—an indicator of a specimen’s heat
buildupbasedonitsreflectancespectrumandtheenergyoutput
1.4 Units—The values stated in SI units are to be regarded
of the IR lamp used in Test Method D4803.
as standard. No other units of measurement are included in this
3.1.3.1 Discussion—The intensity factor is a summation
standard.
product of the heat lamp’s relative intensity and the specimen’s
1.5 This standard does not purport to address all of the
fractional absorptance at 20 nm intervals between 200 and
safety concerns, if any, associated with its use. It is the
2,500 nm.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3.1.4 heat buildup—the temperature rise above that of
ambient air due to the amount of energy absorbed from the sun
mine the applicability of regulatory limitations prior to use.
by a specimen.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.1.5 relative intensity (of heat lamp)—the lamp’s spectral
ization established in the Decision on Principles for the
output across the range of 200 nm to 2500 nm, normalized to
Development of International Standards, Guides and Recom-
a value of 100 at the lamp’s maximum output.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 The specimen’s size must cover the spectrophotometer’s
measurement port, typically 25.4 mm in diameter. Typical
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
sample dimensions are 102 by 102 by 1.3 mm.
and is the direct responsibility of Subcommittee D20.24 on Plastic Building
Products.
4.2 Ablackbackercardorplaqueisuseddirectlybehindthe
Current edition approved April 1, 2021. Published April 2021. Originally
specimen to absorb any radiant energy transmitted through the
approved in 2015. Last previous edition approved in 2015 as D7990 – 15. DOI:
10.1520/D7990–21. specimen.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D7990−21
4.3 The spectral reflectance curve of the test specimen is influenced by incident angle of the sun, clouds, wind speed,
measured to determine the amount of energy the specimen insulation, installation behind glass, etc.
absorbs at each wavelength.
5.3 Th
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7990 − 15 D7990 − 21 An American National Standard
Standard Test Method for
Using Reflectance Spectra to Produce an Index of
1
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 Scope*
1.1 This test method uses reflectance spectra from the ultraviolet, visible, and near infrared region to produce an index of the
temperature rise of polymeric siding above ambient temperature that occurs due to absorption of the sun’s energy.
1.2 The test method determines the intensity factor of a sample color. The intensity factor is a function of the sample’s reflectance
spectra and the energy output of the heat lamp used in the test method Test Method D4803.
1.3 Appendix X1 provides a method for using the intensity factor to determine the maximum temperature rise of a sample under
severe solar exposure.
1.3.1 A correlation between intensity factor and heat buildup (temperature rise) as predicted by Test Method D4803 exists.
1.3.2 The heat buildup (temperature rise) for a polymeric building product specimen is determined from its reflectance spectra and
the correlation’s regression equation.
1.4 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
D4803 Test Method for Predicting Heat Buildup in PVC Building Products
E903 Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres
E1331 Test Method for Reflectance Factor and Color by Spectrophotometry Using Hemispherical Geometry
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.24 on Plastic Building Products.
Current edition approved Dec. 1, 2015April 1, 2021. Published December 2015April 2021. Originally approved in 2015. Last previous edition approved in 2015 as
D7990 – 15. DOI: 10.1520/D7990–1510.1520/D7990–21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7990 − 21
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 fractional absorptance—one minus Fractional Reflectance, 1 – R.
3.1.2 fractional reflectance—the percentage of energy reflected by a sample at a given wavelength, divided by 100.
3.1.3 intensity factor—an indicator of a specimen’s heat buildup based on its reflectance spectrum and the energy output of the
IR lamp used in Test Method D4803.
3.1.3.1 Discussion—
The intensity factor is a summation product of the heat lamp’s relative intensity and the specimen’s fractional absorptance at 20
nm intervals between 200 and 2,500 nm.
3.1.4 heat buildup—the temperature rise above that of ambient air due to the amount of energy absorbed from the sun by a
specimen.
3.1.5 relative intensity (of heat lamp)—the lamp’s spectral output across the range of 200 nm to 2500 nm, normalized to a value
of 100 at the lamp’s maximum output.
4. Summary of Test Method
4.1 The specimen’s size must cover the spectrophotometer’s measurement port, typically 25.4 mm in diameter. Typical sample
dimensions are 102 by 102 by 1.3 mm.
4.2 A black backer card or plaque is used directly behind the specimen to absorb any radiant energy transmitted through the
specimen.
4.3 The spectral reflectance curve of the te
...