1、Designation: C 1549 04Standard Test Method forDetermination of Solar Reflectance Near AmbientTemperature Using a Portable Solar Reflectometer1This standard is issued under the fixed designation C 1549; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a technique for determining thesolar reflectance of flat opaqu
3、e materials in a laboratory or inthe field using a commercial portable solar reflectometer. Thepurpose of the test method is to provide solar reflectance datarequired to evaluate temperatures and heat flows across sur-faces exposed to solar radiation.1.2 This test method does not supplant Test Metho
4、d E 903which measures solar reflectance over the wavelength range250 to 2500 nm using integrating spheres. The portable solarreflectometer is calibrated using specimens of known solarreflectance to determine solar reflectance from measurementsat four wavelengths in the solar spectrum: 380 nm, 500 nm
5、,650 nm, and 1220 nm. This technique is supported bycomparison of reflectometer measurements with measurementsobtained using Test Method E 903. This test method is appli-cable to specimens of materials having both specular anddiffuse optical properties. It is particularly suited to themeasurement of
6、 the solar reflectance of opaque materials.1.3 The values stated in SI units are to be regarded as thestandard. The values in parenthesis are for information only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the
7、user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents22.1 ASTM Standards:C 168 Terminology Relating to Thermal InsulationE 691 Practice for Conducting an Interlaboratory Study toDete
8、rmine the Precision of a Test MethodE 903 Test Method for Solar Absorptance, Reflectance, andTransmittance of Materials Using Integrating SpheresE 1980 Practice for Calculating Solar Reflectance Index ofHorizontal and Low-Sloped Opaque Surfaces2.2 Additional Reference:“Instructions for the Solar Spe
9、ctrum Reflectometer ModelSSR-ER,” Devices and Services Company33. Terminology3.1 DefinitionsFor definitions of some terms used in thetest method, refer to Terminology C 168.3.2 Definitions of Terms Specific to This Standard:3.2.1 air massair mass is related to the path length ofsolar radiation throu
10、gh the Earths atmosphere to the site ofinterest. Air mass 1 is for a path of normal solar radiation at theEarths equator while air mass 2 indicates two times this pathlength.3.2.2 solar reflectancethe fraction of incident solar radia-tion upon a surface that is reflected from the surface.3.3 Symbols
11、:A = area normal to incident radiation, m2Qabs= rate at which radiant heat is absorbed per m2ofarea, Wqsolar= solar flux, W/m2r = solar reflectance, dimensionless4. Summary of Test Method4.1 This test method employs a diffuse tungsten halogenlamp to illuminate a flat specimen for two seconds out of
12、aten-second measurement cycle. Reflected light is measured atan angle of 20 from the incident angle with four detectors.Each detector is equipped with color filters to tailor itselectrical response to a range of wavelengths in the solarspectrum. Software in the instrument combines the outputs ofthe
13、four detectors in appropriate proportions to approximate theresponse for incident solar radiation through air mass 0, 1, 1.5,or 2. The solar reflectance for the desired air mass is selectablefrom the instruments keypad. The reflectances measured bythe individual detectors are also available from the
14、 keypad and1This test method is under the jurisdiction of ASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurements.Current edition approved Sept. 1, 2004. Published October 2004. Originallyapproved in 2002. Last previous edition approved
15、in 2002 as C 1549 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of the appara
16、tus known to the committee at this timeis Devices reflectometer; solar reflectance;solar reflectometerTABLE 1 Solar Reflectances (%) of Roofing MaterialsPrecisionStatisticsMaterial Average SrSRrRA 5.79 0.10 0.15 0.29 0.43B 13.85 0.06 0.17 0.17 0.48C 28.93 0.17 0.72 0.47 2.01D 35.57 0.15 0.23 0.41 0.
17、65E 49.53 0.12 0.46 0.34 1.27F 76.00 0.14 0.51 0.38 1.42G 84.69 0.21 0.43 0.59 1.21TABLE 2 Bias of Test Method C 1549 for Solar Reflectance fromTest Method E 903Material E 903 C 1549 C 1549 E 903A 6.0 5.8 -0.2B 13.0 13.9 0.9C 26.0 28.9 2.9D 34.0 35.6 1.6E 47.0 49.5 2.5F 74.0 76.0 2.0G 83.0 84.7 1.7C
18、1549043ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such righ
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21、Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C1549044
