1、Designation: E1477 98a (Reapproved 2017)1Standard Test Method forLuminous Reflectance Factor of Acoustical Materials by Useof Integrating-Sphere Reflectometers1This standard is issued under the fixed designation E1477; the number immediately following the designation indicates the year oforiginal ad
2、option 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.1NOTEA typo in Section 6.1 was editorially corrected in April 2018.1. Scope1.1 Thi
3、s test method covers the measurement of the lumi-nous reflectance 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
4、standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decisi
5、on on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by
6、Usingthe CIE SystemE1164 Practice for Obtaining Spectrometric Data for Object-Color EvaluationE1264 Classification for Acoustical Ceiling ProductsE1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical GeometryE1345 Practice for Reducing the Effect of Variability o
7、fColor Measurement by Use of Multiple MeasurementsE1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus Colorimetry3. Terminology3.1 Definitions:3.1.1 Definitions of appearance terms in Terminology E284are applicable to this test method.3.1.2 integrating sphere, nan optical de
8、vice used either tocollect flux reflected or transmitted from a specimen into ahemisphere or to provide isotropic irradiation of a specimenfrom a complete hemisphere, consisting of an approximatelyspherical cavity with apertures (ports) for admitting anddetecting flux, and usually having additional
9、apertures overwhich sample and reference specimens are placed and forincluding or excluding the specularly reflected components.(E284)3.1.3 luminous, adjweighted according to the spectralluminous efficiency function V() of the CIE. (E284)3.1.4 reflectance factor, R, nratio of the flux reflected from
10、the specimen to the flux reflected from the perfect reflectingdiffuser under the same geometric and spectral conditions ofmeasurement. (E284)3.1.5 perfect reflecting diffuserideal reflecting surface thatneither absorbs nor transmits light, but reflects light in adiffused manner with the radiance of
11、the reflecting surfacebeing the same for all reflecting angles, regardless of theangular distribution of the incident light. (E284)4. Summary of Test Method4.1 Test specimens are measured for (total) luminous reflec-tance factor by standard color-measurement techniques using aspectrophotometer, tris
12、timulus (filter) colorimeter, or otherreflectometer having a hemispherical optical measuringsystem, such as an integrating sphere. The specular componentis included to provide the total reflectance factor condition. Theinstrument standard is referenced to the perfect reflectingdiffuser. Luminous ref
13、lectance factor is calculated as CIEtristimulus value Y for the CIE 1964 (10) standard observerand CIE standard illuminant D65 (daylight) or F2 (cool whitefluorescent).1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcomm
14、ittee E12.02 onSpectrophotometry and Colorimetry.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 1992. Last previous edition approved in 2013 as E1477 98a (2013).DOI: 10.1520/E1477-98AR17E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcon
15、tact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international stan
16、dard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15. Si
17、gnificance 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 order to predict the level ofillumination that will be obtained.5.2 The reflect
18、ing 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, and astandard observer, for the standard hemispherical (integrating-sphere) ge
19、ometry of illumination and viewing, in which allreflected radiation from an area of the surface is collected. Inthis way the reflecting properties of an acoustical material canbe represented by a single number measured and calculatedunder standard conditions.5.3 Acoustical materials generally have a
20、 non-glossy whiteor near-white finish. The types of surface cover a wide rangefrom smooth to deeply fissured. Measurement with integrating-sphere reflectometers has been satisfactory although multiplemeasurements may be required to sample the surface ad-equately. Instruments with other types of opti
21、cal measuringsystems may be used if it can be demonstrated that theyprovide equivalent results.5.4 The use of this test method for determining the luminousreflectance factor is required by Classification E1264.6. Apparatus6.1 ReflectometerAny spectrophotometer, tristimulus (fil-ter) colorimeter, or
22、other reflectometer having a hemisphericaloptical measuring system and allowing the measurement orcalculation of CIE 1964 (10) tristimulus value Y for standardilluminant D65 or F2 may be used. The instrument standardshall be calibrated to provide absolute reflectance factorsrelative to the perfect r
23、eflecting diffuser. For this test method,the perfect reflecting diffuser shall be assigned a reflectancefactor of 100.00.7. Procedure7.1 Standardize and operate the instrument in accordancewith Practice E1164 and either Test Method E1331 or TestMethod E1347, whichever is applicable. Make the measure
24、-ments with the specular component included.7.2 Most reflectometers compute the luminous reflectancefactor automatically; select parameters to obtain CIE Y for the1964 (10) standard observer and standard illuminant D65 orF2. If the computation is not automatic, calculate Y inaccordance with Practice
25、 E308.7.3 Operate the reflectometer with the largest available areaof illumination or view. Measure at least three test specimensrandomly 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
26、tentativetolerance of 60.1 unit of Y. Compute the number of testspecimens or of multiple measurements in accordance withPractice E1345.NOTE 1Drilled acoustical materials, which have large diameter holesof appreciable depth, have a high reflectance from the tile surface and alow reflectance from the
27、hole location. Fissured tiles provide a similar butless exaggerated condition. In addition, fissured tiles and striated tiles 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
28、 these surface features.8. Report8.1 Report the following information:8.1.1 The material or sample identification,8.1.2 The instrument used, and any pertinent informationconcerning its standardization and operation,8.1.3 The number of test specimens measured and thenumber of multiple measurements of
29、 each test specimen, and8.1.4 The average luminous reflectance factor for the mate-rial tested and the CIE illuminant used.9. 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
30、 and Illuminant D65.9.2 ReproducibilityThe reproducibility within a labora-tory is on the order of 0.4 unit for the Y CIE function of the CIE10 Observer and Illuminant D65. This value includes operatorreproducibility, test equipment repeatability, and nominalsample variation.9.3 Each user should eva
31、luate the precision and bias of hisinstrument by routinely measuring typical specimens, and thendeciding whether the resulting uncertainties are sufficientlysmall for the purpose for which the data are being obtained.10. Keywords10.1 acoustical materials; integrating sphere; luminous re-flectance fa
32、ctor; reflectometerE1477 98a (2017)12ASTM 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 ri
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