1、Designation: E971 11Standard Practice forCalculation of Photometric Transmittance and Reflectanceof Materials to Solar Radiation1This standard is issued under the fixed designation E971; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes the calculation of luminous(photometric) transmittance and reflectance of mate
3、rials fromspectral radiant transmittance and reflectance data obtainedfrom Test Method E903.1.2 Determination of luminous transmittance by this prac-tice is preferred over measurement of photometric transmit-tance by methods using the sun as a source and a photometeras detector except for transmitti
4、ng sheet materials that areinhomogeneous, patterned, or corrugated.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
5、is theresponsibility of the 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 Documents2.1 ASTM Standards:2E772 Terminology Relating to Solar Energy ConversionG173 Tables for Reference Sol
6、ar Spectral Irradiances: Di-rect Normal and Hemispherical on 37 Tilted SurfaceE903 Test Method for Solar Absorptance, Reflectance, andTransmittance of Materials Using Integrating Spheres3E972 Test Method for Solar Photometric Transmittance ofSheet Materials Using SunlightE1175 Test Method for Determ
7、ining Solar or PhotopicReflectance, Transmittance, and Absorptance of MaterialsUsing a Large Diameter Integrating Sphere2.2 CIE Standard:4Standard Illuminator D653. Terminology3.1 DefinitionsFor definitions of other terms used in thispractice, refer to Terminology E772.3.1.1 illuminance, nluminous i
8、rradiance.3.1.2 luminous (photometric), adjreferring to a radiomet-ric quantity, indicates the weighted average of the spectralradiometric quantity, with the photopic spectral luminousefficiency function given in Annex A1 being the weightingfunction (see Appendix X1).3.1.3 radiant flux, F = dQ/dt Wa
9、tt(W), npower emitted,transferred, or received in the form of electromagnetic wavesor photons. See radiometric properties and quantities.3.1.4 solar irradiance at a point of a surface, Es=dF/dA,nthe quotient of the solar flux incident on an element of asurface containing the point, by the area of th
10、at element,measured in watts per square metre.3.1.5 solar, adj(1) referring to a radiometric term, indi-cates that the quantity has the sun as a source or is character-istic of the sun. (2) referring to an optical property, indicatesthe weighted average of the spectral optical property, with thesola
11、r spectral irradiance Eslused as the weighting function.3.1.6 spectral, adj(1) for dimensionless optical proper-ties, indicates that the property was evaluated at a specificwavelength, l, within a small wavelength interval, Dl about l.Symbol wavelength in parentheses, as L (350 nm, 3500), oras a fun
12、ction of wavelength, symbol L (l). (2) for a radiomet-ric quantity, indicates the concentration of the quantity per unitwavelength or frequency, indicated by the subscript lambda, asLl= dL/dl, at a specific wavelength. The wavelength at whichthe spectral concentration is evaluated may be indicated b
13、y thewavelength in parentheses following the symbol, Ll(350 nm).4. Summary of Practice4.1 Spectral transmittance or reflectance data betweenwavelengths of 380 and 760 nm (3800 to 7600 ), which havebeen obtained in accordance with Test Method E903, aremultiplied by solar spectral irradiance values pr
14、ovided in1These test methods are under the jurisdiction of ASTM Committee E44 onSolar, Geothermal and Other Alternative Energy Sources and is the direct respon-sibility of Subcommittee E44.05 on Solar Heating and Cooling Systems andMaterials.Current edition approved Aug. 15, 2011. Published Septembe
15、r 2011. Originallyapproved in 1983. Last previous edition approved in 2003 as E971 88(2003). DOI:10.1520/E0971-11.2For 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 th
16、e standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Available from Commission Internationale de lEclairage, Bureau Central de laCIE, 4 Av. du Recteur Poincar, 75-Paris, France.1Copyright ASTM Internation
17、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Standard Tables G173 and by the photopic spectral luminousefficiency function (see Annex A1). The resulting product isintegrated over the spectral range from 380 to 760 nm using asummation procedure to approximat
18、e the integral. This sum-mation procedure is then repeated with the product of the solarenergy spectral distribution and the photopic spectral luminousefficiency. The ratio of the two integrals is the solar luminous(photometric) transmittance or reflectance of the measuredsample.5. Significance and
19、Use5.1 Glazed apertures in buildings are commonly utilized forthe controlled admission of both light and solar radiant heatenergy into the structure. Other devices may also be used toreflect light and solar radiant heat into a building.5.1.1 Most of the solar radiant energy entering a building inthi
20、s manner possesses wavelengths that lie between 300 and2500 nm (3000 to 25 000 ). Only the portion between 380and 760 nm is visible radiation, however. In daylightingapplications, it is therefore important to distinguish the solarradiant energy transmittance and reflectance of these materialsfrom th
21、eir luminous (visual or photometric) transmittance andreflectance.5.2 For comparisons of the energy and illumination perfor-mances of building fenestration systems it is important that thecalculation or measurement, or both, of solar radiant andluminous transmittance and reflectance of materials use
22、d infenestration systems use the same incident solar spectralirradiance distribution.5.2.1 Solar luminous transmittance and reflectance are im-portant properties in describing the performance of compo-nents of solar illumination systems (for example, windows,clerestories, skylights, shading and refl
23、ecting devices) andother fenestrations that permit the passage of daylight as wellas solar energy into buildings.5.3 This practice is useful for determining the luminoustransmittance and reflectance of glazing materials and diffuselyor quasi-diffusely reflecting materials used in daylightingsystems.
24、 For the results of this practice to be meaningful,inhomogeneities or corrugations in the sample must not belarge. Test Method E1175 (or Test Method E972) is availablefor sheet materials that do not satisfy this criterion.6. Procedure6.1 MeasurementsMeasure spectral transmittance datat(li) or spectr
25、al reflectance data r(li) from 380 nm to 760 nmas described in Test Method E903.6.2 CalculationsCalculate the photometric transmittancetvor reflectance rvusing Eq 1 as follows:rvor tv5 (i 5 1Nrli! or t li!#EliVliDli/(i 5 1NEliVli(1)where:Eli= terrestrial direct normal solar spectral irradiance forai
26、r mass 1.5 provided in Tables G173,Vl= photopic spectral luminous efficiency function givenin Annex A1, andN = number of wavelengths for which Elis knownbetween 380 nm and 760 nm.6.2.1 For the purposes of this practice, the difference Dlibetween adjacent wavelengths (liand li+1) shall be less than15
27、 nm for any i, N shall be greater than 25, and the first and lastwavelength (l1and lN) shall be within 30 nm of 380 and 760nm, respectively.6.2.2 The standard spectral irradiance distribution Elusedin this calculation shall be the direct normal irradiance for airmass 1.5 provided in Standard Tables
28、G173.NOTE 1The spectral distribution of CIE standard illuminant D-65 issimilar to the spectral irradiance distribution provided in Tables G173.Calculations of solar photometric transmittance and reflectance of avariety of different samples using the D-65 spectral irradiance values forEl above have s
29、hown a maximum difference of 0.004 in absolutetransmittance of reflectance from those calculated using the spectralirradiance specified in this practice. For chromaticity calculations, refer tostandards governing these calculations under the jurisdiction of ASTMCommittee E12.7. Report7.1 The report
30、shall include the following:7.1.1 Photometric transmittance or reflectance, or both, tothe nearest 0.01 (1 %).7.1.2 A copy of the test report resulting from execution ofthe procedures described in Test Method E903.8. Keywords8.1 clerestories; fenestration; glazing materials; photometricreflectance;
31、photometric transmittance; skylights; solar radia-tion; windowsE971 112ANNEX(Mandatory Information)A1. INFORMATION ON THE CIE PHOTOPIC SPECTRAL LUMINOUS EFFICIENCY Vl AND THE LUMINOUSEFFICACY CONSTANT KmA1.1 Values for the spectral luminous efficiency functionVlfor photopic vision, as adopted by the
32、 International Com-mission on Illumination in 1924 and by the InternationalCommittee for Weights and Measures in 1933 (column forstandard values) and intermediate interpolated values (othercolumns) are given in Table A1.1.NOTE A1.1The International Committee for Weights and Measures,meeting at the I
33、nternational Bureau of Weights and Measures near Paris,France, on Sept. 2022, 1977, approved the value of 683 lm/W for thespectral luminous efficacy constant Km. This constant is for monochro-matic radiation at a wavelength 555 nm (5550 ) (where Vlhas itsmaximum value of 1.0002) in standard air for
34、photopic vision.E971 113APPENDIX(Nonmandatory Information)X1. INFORMATION ON SOLAR ILLUMINANCEX1.1 If Elis the solar spectral irradiance given in Wm2nm1, then the solar irradiance Eewill be given as follows:Ee5*OEldl Wm22# (X1.1)X1.2 If Vlis the CIE spectral luminous efficiency function(see Annex A1
35、), then the corresponding solar illuminance Evwill be given as follows:Ev5 Km*380760VlEldl 1mm22# (X1.2)TABLE A1.1 Values for the Spectral Luminous Efficiency Function V (l)AWave-length,nmStandardValuesValues Interpolated at Intervals of 1 nm123456789380 0.00004 0.000045 0.000049 0.000054 0.000059 0
36、.000064 0.000071 0.000080 0.000090 0.000104390 0.00012 0.000138 0.000155 0.000173 0.000193 0.000215 0.000241 0.000272 0.000308 0.000350400 0.0004 0.00045 0.00049 0.00054 0.00059 0.00064 0.00071 0.00080 0.00090 0.00104410 0.0012 0.00138 0.00156 0.00174 0.00195 0.00218 0.00244 0.00274 0.00310 0.003524
37、20 0.0040 0.00455 0.00515 0.00581 0.00651 0.00726 0.00806 0.00889 0.00976 0.01066430 0.0116 0.01257 0.01358 0.01463 0.01571 0.01684 0.01800 0.01920 0.02043 0.02170440 0.023 0.0243 0.0257 0.0270 0.0284 0.0298 0.0313 0.0329 0.0345 0.0362450 0.038 0.0399 0.0418 0.0438 0.0459 0.0480 0.0502 0.0525 0.0549
38、 0.0574460 0.060 0.0627 0.0654 0.0681 0.0709 0.0739 0.0769 0.0802 0.0836 0.0872470 0.091 0.0950 0.0992 0.1035 0.1080 0.1126 0.1175 0.1225 0.1278 0.1333480 0.139 0.1448 0.1507 0.1567 0.1629 0.1693 0.1761 0.1833 0.1909 0.1991490 0.208 0.2173 0.2270 0.2371 0.2476 0.2586 0.2701 0.2823 0.2951 0.3087500 0
39、.323 0.3382 0.3544 0.3714 0.3890 0.4073 0.4259 0.4450 0.4642 0.4836510 0.503 0.5229 0.5436 0.5648 0.5865 0.6082 0.6299 0.6511 0.6717 0.6914520 0.710 0.7277 0.7449 0.7615 0.7776 0.7932 0.8082 0.8225 0.8363 0.8495530 0.862 0.8739 0.8851 0.8956 0.9056 0.9149 0.9238 0.9320 0.9398 0.9471540 0.954 0.9604
40、0.9661 0.9713 0.9760 0.9803 0.9840 0.9873 0.9902 0.9928550 0.995 0.9969 0.9983 0.9994 1.0000 1.0002 1.0001 0.9995 0.9984 0.9969560 0.995 0.9926 0.9898 0.9865 0.9828 0.9786 0.9741 0.9691 0.9638 0.9581570 0.952 0.9455 0.9386 0.9312 0.9235 0.9154 0.9069 0.8981 0.8890 0.8796580 0.870 0.8600 0.8496 0.838
41、8 0.8277 0.8163 0.8046 0.7928 0.7809 0.7690590 0.757 0.7449 0.7327 0.7202 0.7076 0.6949 0.6822 0.6694 0.6565 0.6437600 0.631 0.6182 0.6054 0.5926 0.5797 0.5668 0.5539 0.5410 0.5282 0.5156610 0.503 0.4905 0.4781 0.4658 0.4535 0.4412 0.4291 0.4170 0.4049 0.3929620 0.381 0.3690 0.3570 0.3449 0.3329 0.3
42、210 0.3092 0.2977 0.2864 0.2755630 0.265 0.2548 0.2450 0.2354 0.2261 0.2170 0.2082 0.1996 0.1912 0.1830640 0.175 0.1672 0.1596 0.1523 0.1452 0.1382 0.1316 0.1251 0.1188 0.1128650 0.107 0.1014 0.0961 0.0910 0.0862 0.0816 0.0771 0.0729 0.0688 0.0648660 0.061 0.0574 0.0539 0.0506 0.0475 0.0446 0.0418 0
43、.0391 0.0366 0.0343670 0.032 0.0299 0.0280 0.0263 0.0247 0.0232 0.0219 0.0206 0.0194 0.0182680 0.017 0.01585 0.01477 0.01376 0.01281 0.01192 0.01108 0.01030 0.00956 0.00886690 0.0082 0.00759 0.00705 0.00656 0.00612 0.00572 0.00536 0.00503 0.00471 0.00440700 0.0041 0.00381 0.00355 0.00332 0.00310 0.0
44、0291 0.00273 0.00256 0.00241 0.00225710 0.0021 0.001954 0.001821 0.001699 0.001587 0.001483 0.001387 0.001297 0.001212 0.001130720 0.00105 0.000975 0.000907 0.000845 0.000788 0.000736 0.000688 0.000644 0.000601 0.000560730 0.00052 0.000482 0.000447 0.000415 0.000387 0.000360 0.000335 0.000313 0.0002
45、91 0.000270740 0.00025 0.000231 0.000214 0.000198 0.000185 0.000172 0.000160 0.000149 0.000139 0.000130750 0.00012 0.000111 0.000103 0.000096 0.000090 0.000084 0.000078 0.000074 0.000069 0.000064760 0.00006 0.000056 0.000052 0.000048 0.000045 0.000042 0.000039 0.000037 0.000035 0.000032AIES Lighting
46、 Handbook, 1981 Reference Volume, Illuminating Engineering Society of North America, 345 East 47th Street, New York, NY 10017, Figs. 37, pp. 35,is the source for this table.E971 114ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item
47、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 rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical commit
48、tee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a mee
49、ting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM 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 (
