ASTM_E_1477_-_98a_2013.pdf

Designation:E147798a(Reapproved 2013)Standard 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 adoption 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 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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by 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 ofColor 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 device 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 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 fromthe 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 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,tristimulus(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 reflectance factor is calculated as CIEtristimulus value Y for the CIE 1964(10)standard observerand CIE standard illuminant D65(daylight)or F2(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 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,and a1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.02 onSpectrophotometry and Colorimetry.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 1992.Last previous edition approved in 2008 as E1477 98a(2008).DOI:10.1520/E1477-98AR13.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 standard observer,for the standard hemispherical(integrating-sphere)geometry 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 non-glossy whiteor near-white finish.The types of surface cover a wide rangefrom smooth to deeply fi