1、Designation: E 1477 98a (Reapproved 2008)Standard Test Method forLuminous Reflectance Factor of Acoustical Materials by Useof Integrating-Sphere Reflectometers1This standard is issued under the fixed designation E 1477; the number immediately following the designation indicates the year oforiginal a
2、doption or, in the case of revision, 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 test method covers the measurement of the lumi-nous reflectance
3、factor of acoustical materials for use inpredicting the levels of room illumination.1.2 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 practices and
4、 determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 284 Terminology of AppearanceE 308 Practice for Computing the Colors of Objects byUsing the CIE SystemE 1164 Practice for Obtaining Spectrometric Data forObject-Color EvaluationE 1264 Cl
5、assification for Acoustical Ceiling ProductsE 1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical GeometryE 1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple MeasurementsE 1347 Test Method for Color and Color-Difference
6、Mea-surement by Tristimulus Colorimetry3. Terminology3.1 DefinitionsDefinitions of appearance terms in Termi-nology E 284 are applicable to this test method.3.1.1 integrating sphere, nan optical device used either tocollect flux reflected or transmitted from a specimen into ahemisphere or to provide
7、 isotropic irradiation of a specimenfrom a complete hemisphere, consisting of an approximatelyspherical cavity with apertures (ports) for admitting anddetecting flux, and usually having additional apertures overwhich sample and reference specimens are placed and forincluding or excluding the specula
8、rly reflected components.(E 284)3.1.2 luminous, adjweighted according to the spectralluminous efficiency function V (l) of the CIE. (E 284)3.1.3 reflectance factor, R, nratio of the flux reflectedfrom the specimen to the flux reflected from the perfectreflecting diffuser under the same geometric and
9、 spectralconditions of measurement. (E 284)3.1.4 perfect reflecting diffuserideal reflecting surface thatneither absorbs nor transmits light, but reflects light in adiffused manner with the radiance of the reflecting surfacebeing the same for all reflecting angles, regardless of theangular distribut
10、ion of the incident light. (E 284)4. Summary of Test Method4.1 Test specimens are measured for (total) luminous reflec-tance factor by standard color-measurement techniques using aspectrophotometer, tristimulus (filter) colorimeter, or otherreflectometer having a hemispherical optical measuring sys-
11、tem, such as an integrating sphere. The specular component isincluded to provide the total reflectance factor condition. Theinstrument standard is referenced to the perfect reflectingdiffuser. Luminous reflectance factor is calculated as CIEtristimulus value Y for the CIE 1964 (10) standard observer
12、and CIE standard illuminant D 65 (daylight) or F 2 (cool whitefluorescent).5. Significance and Use5.1 Acoustical materials are often used as the entire ceilingof rooms and are therefore an important component of thelighting system. The luminous reflectance of all importantcomponents must be known in
13、 order to predict the level ofillumination that will be obtained.5.2 The reflecting properties of a surface are measuredrelative to those of a standard reflector, the perfect reflectingdiffuser, to provide a reflectance factor. The luminous reflec-tance factor is calculated for a standard illuminant
14、, and astandard observer, for the standard hemispherical (integrating-sphere) geometry of illumination and viewing, in which allreflected radiation from an area of the surface is collected. In1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct r
15、esponsibility of Subcommittee E12.02 onSpectrophotometry and Colorimetry.Current edition approved June 1, 2008. Published June 2008. Originallyapproved in 1992. Last previous edition approved in 2003 as E 1477 - 98a (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta
16、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.this way the reflecting
17、 properties of an acoustical material canbe represented by a single number measured and calculatedunder standard conditions.5.3 Acoustical materials generally have a non-glossy whiteor near-white finish. The types of surface cover a wide rangefrom smooth to deeply fissured. Measurement with integrat
18、ing-sphere reflectometers has been satisfactory although multiplemeasurements may be required to sample the surface ad-equately. Instruments with other types of optical measuringsystems may be used if it can be demonstrated that theyprovide equivalent results.5.4 The use of this test method for dete
19、rmining the luminousreflectance factor is required by Classification E 1264.6. Apparatus6.1 ReflectometerAny spectrophotometer, tristimulus (fil-ter) colorimeter, or other reflectometer having a hemisphericaloptical measuring system and allowing the measurement orcalculation of CIE 1964 (10) tristim
20、ulus value Y for standardilluminant D 65 or F 2 may be used. The instrument standardshall be calibrated to provide absolute reflectance factorsrelative to the perfect reflecting diffuser. For this test method,the perfect reflecting diffuser shall be assigned a reflectancefactor of 100.00.7. Procedur
21、e7.1 Standardize and operate the instrument in accordancewith Practice E 1164 and either Test Method E 1331 or TestMethod E 1347, whichever is applicable. Make the measure-ments with the specular component included.7.2 Most reflectometers compute the luminous reflectancefactor automatically; select
22、parameters to obtain CIE Y for the1964 (10) standard observer and standard illuminant D 65 orF 2. If the computation is not automatic, calculate Y inaccordance with Practice E 308.7.3 Operate the reflectometer with the largest available areaof illumination or view. Measure at least three test specim
23、ensrandomly selected from the tiles or panels constituting eachsample.7.4 Additional test specimens or multiple measurements ofeach test specimen may be required to meet the tentativetolerance of 60.1 unit of Y. Compute the number of testspecimens or of multiple measurements in accordance withPracti
24、ce E 1345.NOTE 1Drilled acoustical materials, which have large diameter holesof appreciable depth, have a high reflectance from the tile surface and alow reflectance from the hole location. Fissured tiles provide a similar butless exaggerated condition. In addition, fissured tiles and striated tiles
25、 havereflectances that depend on the angle of incidence of the light relative tothe general direction of the surface features. This test method provides asuitable average over these surface features.8. Report8.1 Report the following information:8.1.1 The material or sample identification,8.1.2 The i
26、nstrument used, and any pertinent informationconcerning its standardization and operation,8.1.3 The number of test specimens measured and thenumber of multiple measurements of each test specimen, and8.1.4 The average luminous reflectance factor for the mate-rial tested and the CIE illuminant used.9.
27、 Precision and Bias9.1 RepeatabilityMeasurement data obtained show thatrepeatability of test equipment is on the order of 0.2 unit for theY CIE function of the CIE 10 Observer and Illuminant D65.9.2 ReproducibilityThe reproducibility within a labora-tory is on the order of 0.4 unit for the Y CIE fun
28、ction of the CIE10 Observer and Illuminant D65. This value includes operatorreproducibility, test equipment repeatability, and nominalsample variation.9.3 Each user should evaluate the precision and bias of hisinstrument by routinely measuring typical specimens, and thendeciding whether the resultin
29、g uncertainties are sufficientlysmall for the purpose for which the data are being obtained.10. Keywords10.1 acoustical materials; integrating sphere; luminous re-flectance factor; reflectometerASTM International takes no position respecting the validity of any patent rights asserted in connection w
30、ith 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 rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible tec
31、hnical committee 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 considera
32、tion at a meeting 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 H
33、arbor 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 1477 98a (2008)2
