ASTM E903-20

Standard Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres

SIGNIFICANCE AND USE
5.1 Solar-energy absorptance, reflectance, and transmittance are important in the performance of all solar energy systems ranging from passive building systems to central receiver power systems. This test method provides a means for determining these values under fixed conditions that represent an average that would be encountered during use of a system in the temperate zone.  
5.2 Solar-energy absorptance, reflectance, and transmittance are important for thermal control of spacecraft and the solar power of extraterrestrial systems. This test method also provides a means for determining these values for extraterrestrial conditions.  
5.3 This test method is designed to provide reproducible data appropriate for comparison of results among laboratories or at different times by the same laboratory and for comparison of data obtained on different materials.  
5.4 This test method has been found practical for smooth materials having both specular and diffuse optical properties. Materials that are textured, inhomogeneous, patterned, or corrugated require special consideration.  
5.4.1 Surface roughness may be introduced by physical or chemical processes, such as pressing, rolling, etching, or deposition of films or chemical layers on materials, resulting in textured surfaces.  
5.4.2 The magnitude of surface roughness with respect to the components of the spectrophotometer and attachments (light beam sizes, sphere apertures, sample holder configuration) can significantly affect the accuracy of measurements using this test method.  
5.4.3 Even if the repeatability, or precision of the measurement of textured materials is good, including repeated measurements at various locations within or orientations of the sample, the different characteristics of different spectrophotometers in different laboratories may result in significant differences in measurement results.  
5.4.4 In the context of 5.4.3, the term ‘significant’ means differences exceeding the calibration or m...
SCOPE
1.1 This test method covers the measurement of spectral absorptance, reflectance, and transmittance of materials using spectrophotometers equipped with integrating spheres.  
1.2 Methods of computing solar weighted properties from the measured spectral values are specified.  
1.3 This test method is applicable to materials having both specular and diffuse optical properties.  
1.4 This test method is applicable to material with applied optical coatings with special consideration for the impact on the textures of the material under test.  
1.5 Transmitting sheet materials that are inhomogeneous, textured, patterned, or corrugated require special considerations with respect to the applicability of this test method. Test Method E1084 may be more appropriate to determine the bulk optical properties of textured or inhomogeneous materials.  
1.6 For homogeneous materials this test method is preferred over Test Method E1084.  
1.7 This test method refers to applications using standard reference solar spectral distributions but may be applied using alternative selected spectra as long as the source and details of the solar spectral distribution and weighting are reported.  
1.8 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.  
1.9 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: 30-Sep-2020
• ICS: 77.140.80 - Iron and steel castings
• Technical Committee: E44 - Solar, Geothermal and Other Alternative Energy Sources
• Drafting Committee: E44.20 - Optical Materials for Solar Applications

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:E903 −20
Standard Test Method for
Solar Absorptance, Reflectance, and Transmittance of
1
Materials Using Integrating Spheres
This standard is issued under the fixed designation E903; 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
2
1.1 This test method covers the measurement of spectral
2.1 ASTM Standards:
absorptance, reflectance, and transmittance of materials using
E275 Practice for Describing and Measuring Performance of
spectrophotometers equipped with integrating spheres.
Ultraviolet and Visible Spectrophotometers
E424 Test Methods for Solar Energy Transmittance and
1.2 Methods of computing solar weighted properties from
Reflectance (Terrestrial) of Sheet Materials
the measured spectral values are specified.
E490 Standard Solar Constant and Zero Air Mass Solar
1.3 This test method is applicable to materials having both
Spectral Irradiance Tables
specular and diffuse optical properties.
E772 Terminology of Solar Energy Conversion
1.4 This test method is applicable to material with applied
E971 Practice for Calculation of Photometric Transmittance
optical coatings with special consideration for the impact on
and Reflectance of Materials to Solar Radiation
the textures of the material under test.
E1084 Test Method for Solar Transmittance (Terrestrial) of
Sheet Materials Using Sunlight
1.5 Transmitting sheet materials that are inhomogeneous,
E1175 Test Method for Determining Solar or Photopic
textured, patterned, or corrugated require special consider-
Reflectance, Transmittance, andAbsorptance of Materials
ations with respect to the applicability of this test method. Test
Using a Large Diameter Integrating Sphere
Method E1084 may be more appropriate to determine the bulk
E2554 Practice for Estimating and Monitoring the Uncer-
optical properties of textured or inhomogeneous materials.
tainty of Test Results of a Test Method Using Control
1.6 For homogeneous materials this test method is preferred
Chart Techniques
over Test Method E1084.
G173 TablesforReferenceSolarSpectralIrradiances:Direct
1.7 This test method refers to applications using standard
Normal and Hemispherical on 37° Tilted Surface
reference solar spectral distributions but may be applied using
G197 Table for Reference Solar Spectral Distributions: Di-
alternative selected spectra as long as the source and details of
rect and Diffuse on 20° Tilted and Vertical Surfaces
the solar spectral distribution and weighting are reported.
2.2 Other Documents:
3
1.8 This standard does not purport to address all of the
Federal Test Method Standard No. 141, Method 6101
4
safety concerns, if any, associated with its use. It is the
ASHRAE Standard 74-1988
responsibility of the user of this standard to establish appro-
CIE 38 Radiometric and Photometric Characteristics of Ma-
5
priate safety, health, and environmental practices and deter-
terials and their Measurement
5
mine the applicability of regulatory limitations prior to use.
CIE 44 Absolute Methods for Reflection Measurement
6
1.9 This international standard was developed in accor-
NIST SP 250-48 Spectral Reflectance
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mendations issued by the World Trade Organization Technical
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Barriers to Trade (TBT) Committee.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3
AvailablefromStandardizationDocuments,OrderDesk,Building4,SectionD,
700 Robbins Ave., Philadelphia, PA 19111-5049, Attn: NPODS.
1 4
This test method is under the jurisdiction of ASTM Committee E44 on Solar, Available from American Society of Heating, Refrigeration, and Air-
Geothermal and OtherAlternative Energy Sources and is the direct responsibility of Conditioning Engineers, Inc., 191 Tullie Circle, NE. Atlanta GA 30329.
5
Subcommittee E44.20 on Optical Materials for Solar Applications. Available from U.S. National Committee of the CIE (International Commission
Current edition approved Oct. 1, 2020. Published October 2020. Originally on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
approved in 1982. Last previous edition approved in 2012 as E903
...

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: E903 − 12 E903 − 20
Standard Test Method for
Solar Absorptance, Reflectance, and Transmittance of
1
Materials Using Integrating Spheres
This standard is issued under the fixed designation E903; 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
1.1 This test method covers the measurement of spectral absorptance, reflectance, and transmittance of materials using
spectrophotometers equipped with integrating spheres.
1.2 Methods of computing solar weighted properties from the measured spectral values are specified.
1.3 This test method is applicable to materials having both specular and diffuse optical properties.
1.4 This test method is applicable to material with applied optical coatings with special consideration for the impact on the textures
of the material under test.
1.5 Transmitting sheet materials that are inhomogeneous, textured, patterned, or corrugated require special considerations with
respect to the applicability of this test method. Test Method E1084 may be more appropriate to determine the bulk optical
properties of textured or inhomogeneous materials.
1.6 For homogeneous materials this test method is preferred over Test Method E1084.
1.7 This test method refers to applications using standard reference solar spectral distributions but may be applied using alternative
selected spectra as long as the source and details of the solar spectral distribution and weighting are reported.
1.8 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.
1.9 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
2.1 ASTM Standards:
1
This test method is under the jurisdiction of ASTM Committee E44 on Solar, Geothermal and Other Alternative Energy Sources and is the direct responsibility of
Subcommittee E44.20 on Glass Optical Materials for Solar Applications.
Current edition approved Dec. 1, 2012Oct. 1, 2020. Published December 2012October 2020. Originally approved in 1982. Last previous edition approved in 19962012
as E903–96 which was withdrawn August 2005 and reinstated in December 2012. DOI: 10.1520/E0903-12.–12. DOI: 10.1520/E0903-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E903 − 20
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
E424 Test Methods for Solar Energy Transmittance and Reflectance (Terrestrial) of Sheet Materials
E490 Standard Solar Constant and Zero Air Mass Solar Spectral Irradiance Tables
E772 Terminology of Solar Energy Conversion
E971 Practice for Calculation of Photometric Transmittance and Reflectance of Materials to Solar Radiation
E1084 Test Method for Solar Transmittance (Terrestrial) of Sheet Materials Using Sunlight
E1175 Test Method for Determining Solar or Photopic Reflectance, Transmittance, and Absorptance of Materials Using a Large
Diameter Integrating Sphere
E2554 Practice for Estimating and Monitoring the Uncertainty of Test Results of a Test Method Using Control Chart Techniques
G173 Tables for Reference Solar Spectral Irradiances: Direct Normal and Hemispherical on 37° Tilted Surface
G197 Table for Reference Solar Spectral Distributions: Direct and Diffuse on 20° Tilted and Vertical Surfaces
2.2 Other Documents:
3
Federal Test Method Standard No. 141, Method 6101
4
ASHRAE Standard 74-1988
5
CIE 38 Radiometric and Photometric Characteristics of Materials and their Measurement
5
CIE 44 Absolute Methods for Reflection
...