1、Designation: E 971 88 (Reapproved 2003)Standard Practice forCalculation of Photometric Transmittance and Reflectanceof Materials to Solar Radiation1This standard is issued under the fixed designation E 971; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the 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 practice describes the calculation of luminous(photometric) transmittance an
3、d reflectance of materials fromspectral radiant transmittance and reflectance data obtainedfrom Test Method E 903.1.2 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
4、 except for transmitting sheet materials that areinhomogeneous, patterned, or corrugated.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practice
5、s and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 772 Terminology Relating to Solar Energy Conversion2E 891 Tables for Terrestrial Direct Normal Solar SpectralIrradiance for Air Mass 1.53E 903 Test Method for Solar Absorptance, Refl
6、ectance, andTransmittance of Materials Using Integrating Spheres2E 972 Test Method for Solar Photometric Transmittance ofSheet Materials Using Sunlight2E 1175 Test Method for Determining Solar or PhotopicReflectance, Transmittance, and Absorptance of MaterialsUsing a Large Diameter Integrating Spher
7、e22.2 CIE Standard:Standard Illuminator D6543. Terminology3.1 DefinitionsFor definitions of other terms used in thispractice, refer to Terminology E 772.3.1.1 illuminance, nluminous irradiance.3.1.2 luminous (photometric), adjreferring to a radiomet-ric quantity, indicates the weighted average of th
8、e 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 Watt(W), npower emitted,transferred, or received in the form of electromagnetic wavesor photons. See radiometric proper
9、ties 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 that element,measured in watts per square metre.3.1.5 solar, adj(1) referring to a radiometric term, indi-cates that th
10、e 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 thesolar spectral irradiance Eslused as the weighting function.3.1.6 spectral, adj(1) for dimensionless optical proper-ties,
11、 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 function of wavelength, symbol L (l). (2) for a radiomet-ric quantity, indicates the concentration of the quantity per u
12、nitwavelength 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 by thewavelength in parentheses following the symbol, Ll(350 nm).4. Summary of Practice4.1 Spectral transmittance or r
13、eflectance data betweenwavelengths of 380 and 760 nm (3800 to 7600 ), which havebeen obtained in accordance with Test Method E 903, aremultiplied by solar spectral irradiance values provided inStandard Tables E891 and by the photopic spectral luminousefficiency function (see Annex A1). The resulting
14、 product isintegrated over the spectral range from 380 to 760 nm using asummation procedure to approximate 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 i
15、s the solar luminous(photometric) transmittance or reflectance of the measuredsample.1These test methods are under the jurisdiction of ASTM Committee E44 onSolar, Geothermal, and Other Alternative Energy Sources and is the directresponsibility of Subcommittee E44.05 on Solar Heating and Cooling Subs
16、ystemsand Systems.Current edition approved Aug. 26, 1988. Published December 1988. Originallyapproved in 1983. Last previous edition approved in 1996 as E 971 85(1996)e1.2Annual Book of ASTM Standards, Vol 12.02.3Annual Book of ASTM Standards, Vol 14.02.4Available from Commission Internationale de l
17、Eclairage, Bureau Central de laCIE, 4 Av. du Recteur Poincar, 75-Paris, France.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 Glazed apertures in buildings are commonly utilized forthe controlled admission
18、 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 inthis manner possesses wavelengths that lie between 300 and2500 nm (3000 to 25 000 ). Only
19、 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 their luminous (visual or photometric) transmittance andreflectance.5.2 For comparisons
20、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 used infenestration systems use the same incident solar spectralirradiance distribution.5
21、.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 reflecting devices) andother fenestrations that permit the passage of daylight as wellas s
22、olar 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. For the results of this practice to be meaningful,inhomogeneities or corrugations in
23、the sample must not belarge. Test Method E 1175 (or Test Method E 972) is availablefor sheet materials that do not satisfy this criterion.6. Procedure6.1 MeasurementsMeasure spectral transmittance datat(li) or spectral reflectance data r(li) from 380 nm to 760 nmas described in Test Method E 903.6.2
24、 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 forair mass 1.5 provided in Tables E891,Vl= photopic spectral luminous efficiency func
25、tion 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 nm for any i, N shall be greater than 25, and the first and lastwavelength (l1an
26、d 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 E891.NOTE 1The spectral distribution of CIE standard illuminant D-65 issimilar to
27、 the spectral irradiance distribution provided in Tables E891.Calculations of solar photometric transmittance and reflectance of avariety of different samples using the D-65 spectral irradiance values forEl above have shown a maximum difference of 0.004 in absolutetransmittance of reflectance from t
28、hose calculated using the spectralirradiance specified in this practice. For chromaticity calculations, refer tostandards governing these calculations under the jurisdiction of ASTMCommittee E-12.37. Report7.1 The report shall include the following:7.1.1 Photometric transmittance or reflectance, or
29、both, tothe nearest 0.01 (1 %).7.1.2 A copy of the test report resulting from execution ofthe procedures described in Test Method E 903.8. Keywords8.1 clerestories; fenestration; glazing materials; photometricreflectance; photometric transmittance; skylights; solar radia-tion; windowsANNEX(Mandatory
30、 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 International Com-mission on Illumination in 1924 and by the InternationalCommittee f
31、or 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 International Bureau of Weights and Measures near Paris,France, on Sept. 2022, 1977, ap
32、proved 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 photopic vision.E 971 88 (2003)2APPENDIX(Nonmandatory Information)X1. INFORMATION ON S
33、OLAR 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), then the corresponding solar illuminance Evwill be given as follows:Ev5 Km*
34、380760VlEldl1mm22# (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 0.000064 0.000071 0.000080 0.000090 0.000104390 0.00012 0.000138 0.000155 0.0001
35、73 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 0.00352420 0.0040 0.00455 0.00515 0.00581 0.00651 0.00726 0.00806 0.00889 0.00976 0.010
36、66430 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 0.0574460 0.060 0.0627 0.0654 0.0681 0.0709 0.0739 0.0769 0.0802 0.0836 0.0872
37、470 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 0.323 0.3382 0.3544 0.3714 0.3890 0.4073 0.4259 0.4450 0.4642 0.4836510 0.503 0.
38、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 0.9661 0.9713 0.9760 0.9803 0.9840 0.9873 0.9902 0.9928550 0.995 0.9969 0.9983
39、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 0.8388 0.8277 0.8163 0.8046 0.7928 0.7809 0.7690590 0.757 0.7449 0.7327 0.7202 0.707
40、6 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 0.3210 0.3092 0.2977 0.2864 0.2755630 0.265 0.2548 0.2450 0.2354 0.2261 0.2170 0.2
41、082 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 0.0391 0.0366 0.0343670 0.032 0.0299 0.0280 0.0263 0.0247 0.0232 0.0219 0.0206 0
42、.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 0.00291 0.00273 0.00256 0.00241 0.00225710 0.0021 0.001954 0.001821 0.001699 0.001
43、587 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 0.000291 0.000270740 0.00025 0.000231 0.000214 0.000198 0.000185 0.000172 0.000160 0.
44、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 Handbook, 1981 Reference Volume, Illuminating Engineering Society of North Ame
45、rica, 345 East 47th Street, New York, NY 10017, Figs. 37, pp. 35,is the source for this table.E 971 88 (2003)3ASTM 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
46、 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 committee and must be reviewed every five years andif not revised, either rea
47、pproved 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 meeting of theresponsible technical committee, which you may attend. If yo
48、u 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 (e-mail); or through the ASTM website(www.astm.org).E 971 88 (2003)4
