ASTM C1549-02

Standard Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer

SCOPE
1.1 This test method covers a technique for determining the solar reflectance of flat opaque materials in a laboratory or in the field using a commercial portable solar reflectometer. The purpose of the test method is to provide solar reflectance data required to evaluate temperatures and heat flows across surfaces exposed to solar radiation.
1.2 This test method does not supplant Test Method E 903 which measures solar reflectance over the wavelength range 250 to 2500 nm using integrating spheres. The portable solar reflectometer is calibrated using specimens of known solar reflectance to determine solar reflectance from measurements at four wavelengths in the solar spectrum: 380 nm, 500 nm, 650 nm, and 1220 nm. This technique is supported by comparison of reflectometer measurements with measurements obtained using Test Method E 903. This test method is applicable to specimens of materials having both specular and diffuse optical properties. It is particularly suited to the measurement of the solar reflectance of opaque materials.
1.3 The values stated in SI units are to be regarded as the standard. The values in parenthesis are for information only.
1.4 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.

General Information

• Status: Historical
• Publication Date: 09-Oct-2002
• ICS: 27.160 - Solar energy engineering
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.30 - Thermal Measurement

Relations

• Replaced By: ASTM C1549-04 - Standard Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer
• Effective Date: 01-Sep-2004
• Referred By: ASTM D7897-18(2023) - Standard Practice for Laboratory Soiling and Weathering of Roofing Materials to Simulate Effects of Natural Exposure on Solar Reflectance and Thermal Emittance
• Effective Date: 10-Oct-2002
• Referred By: ASTM D3794-22 - Standard Guide for Testing Coil Coatings
• Effective Date: 10-Oct-2002
• Referred By: ASTM C1864-17(2022) - Standard Test Method for Determination of Solar Reflectance of Directionally Reflective Material Using Portable Solar Reflectometer
• Effective Date: 10-Oct-2002
• Referred By: ASTM D2824/D2824M-18 - Standard Specification for Aluminum-Pigmented Asphalt Roof Coatings, Nonfibered, and Fibered without Asbestos
• Effective Date: 10-Oct-2002
• Referred By: ASTM E2813-18 - Standard Practice for Building Enclosure Commissioning
• Effective Date: 10-Oct-2002

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: C 1549 – 02
Standard Test Method for
Determination of Solar Reflectance Near Ambient
1
Temperature Using a Portable Solar Reflectometer
This standard is issued under the fixed designation C 1549; 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.
5
1. Scope Horizontal and Low-Sloped Opaque Surfaces
2.2 Additional Reference:
1.1 This test method covers a technique for determining the
“Instructions for the Solar Spectrum Reflectometer Model
solar reflectance of flat opaque materials in a laboratory or in
6
SSR-ER,” Devices and Services Company
the field using a commercial portable solar reflectometer. The
purpose of the test method is to provide solar reflectance data
3. Terminology
required to evaluate temperatures and heat flows across sur-
3.1 Definitions—For definitions of some terms used in the
faces exposed to solar radiation.
test method, refer to Terminology C 168.
1.2 This test method does not supplant Test Method E 903
3.2 Definitions of Terms Specific to This Standard:
which measures solar reflectance over the wavelength range
3.2.1 air mass—air mass is related to the path length of
250 to 2500 nm using integrating spheres. The portable solar
solar radiation through the Earth’s atmosphere to the site of
reflectometer is calibrated using specimens of known solar
interest. Air mass 1 is for a path of normal solar radiation at the
reflectance to determine solar reflectance from measurements
Earth’s equator while air mass 2 indicates two times this path
at four wavelengths in the solar spectrum: 380 nm, 500 nm,
length.
650 nm, and 1220 nm. This technique is supported by
3.2.2 solar reflectance—the fraction of incident solar radia-
comparison of reflectometer measurements with measurements
tion upon a surface that is reflected from the surface.
obtained using Test Method E 903. This test method is appli-
3.3 Symbols:
cable to specimens of materials having both specular and
2
A = area normal to incident radiation, m
diffuse optical properties. It is particularly suited to the
2
Q = rate at which radiant heat is absorbed per m of
abs
measurement of the solar reflectance of opaque materials.
area, W
1.3 The values stated in SI units are to be regarded as the
2
q = solar flux, W/m
solar
standard. The values in parenthesis are for information only.
r = solar reflectance, dimensionless
1.4 This standard does not purport to address all of the
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-
4.1 This test method employs a diffuse tungsten halogen
priate safety and health practices and determine the applica-
lamp to illuminate a flat specimen for two seconds out of a
bility of regulatory limitations prior to use.
ten-second measurement cycle. Reflected light is measured at
2. Referenced Documents an angle of 20° from the incident angle with four detectors.
Each detector is equipped with color filters to tailor its
2.1 ASTM Standards:
2 electrical response to a range of wavelengths in the solar
C 168 Terminology Relating to Thermal Insulation
spectrum. Software in the instrument combines the outputs of
E 691 Practice for Conducting an Interlaboratory Study to
3 the four detectors in appropriate proportions to approximate the
Determine the Precision of a Test Method
response for incident solar radiation through air mass 0, 1, 1.5,
E 903 Test Method for Solar Absorptance, Reflectance, and
4
or 2. The solar reflectance for the desired air mass is selectable
Transmittance of Materials Using Integrating Spheres
from the instrument’s keypad. The reflectances measured by
E 1980 Practice for Calculating Solar Reflectance Index of
the individual detectors are also available from the keypad and
digital readout. The instrument is calibrated using a black body
1
This test method is under the jurisdiction of ASTM Committee C16 on Thermal
5
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal Annual Book of ASTM Standards, Vol 04.12.
6
Measurements. The sole source of supply of the apparatus known to the committee at this time
Current edition approved Oct. 10, 2002. Published October 2002. is Devices & Services Company, 10024 Monroe Drive, Dallas, TX 75229. If you are
2
Annual Book of ASTM Standards, Vol 04.06. aware of alternative suppliers, please provide this information to ASTM Interna-
3
Annual Book of ASTM Standards, Vol 14.02. tional Headquarters. Your comments will receive careful consideration at a meeting
4
1
Annual Book of ASTM Standards, Vol 12.02. of the responsible technical committee , which you may
...