1、Designation:D149417An American National StandardStandard Test Method forDiffuse Light Transmission Factor of Reinforced PlasticsPanels1This standard is issued under the fixed designation D1494;the number immediately following the designation indicates the year oforiginal adoption or,in the case of r
2、evision,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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method
3、covers the determination of the diffuselight transmission factor of translucent reinforced plasticsbuilding panels.1.2 The values stated in SI units are to be regarded as thestandard.The values given in the parentheses are for informa-tion only.1.3 The text of this standard references notes and foot
4、noteswhich provide explanatory material.These notes and footnotes(excluding those in Tables and Figures)shall not be consideredas requirements of this standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user o
5、f this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1There is no known ISO equivalent to this standard.1.5 This international standard was developed in accor-dance with internationally recogni
6、zed principles on standard-ization established in the Decision 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:2D618 Practice for Condition
7、ing Plastics for TestingD883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsE2935 Practice for Conducting Equivalence Testing inLaboratory ApplicationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ASTM
8、 Adjuncts:Test Cabinet for Diffuse Light Transmission Factor ofReinforced Panels33.Terminology3.1 GeneralDefinitions are in accordance with Terminol-ogy D883 and abbreviations with Terminology D1600,unlessotherwise indicated.4.Significance and Use4.1 The purpose of this test method is to obtain the
9、diffuselight transmittance factor of both flat and corrugated translu-cent building panels by the use of simple apparatus and byemploying as a light source a combination of fluorescent tubeswhose energy distribution closely approximates CIE Source C.5.Apparatus5.1 The apparatus for this test method
10、shall consist of atransmissometer,Fig.1,comprising essentially the following:5.1.1 Light SourceThe illumination shall consist of twelve20-W fluorescent tubes which are assembled in three banks offour tubes each,according to the following schedule:daylight,deluxe cool white,blue,and daylight.5.1.2 Ph
11、otometerThe photometer shall consist of a pho-tocell and of a galvanometer.The photocell shall be of thebarrier-layer type and shall contain a visual correction filter.The assembly preferably should be hermetically sealed intoplastic as a protection against moisture.The indicating galva-nometer shou
12、ld contain one scale graduated from 0 to 100,anda circuit with sufficient variable resistance so that the sensitiv-ity of the photometer can be adjusted over the range of 50 to100 footcandles.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibilit
13、y of Subcommittee D20.24 on Plastic BuildingProducts.Current edition approved Dec.1,2017.Published January 2018.Originallyapproved in 1957.Last previous edition approved in 2012 as D1494 12.DOI:10.1520/D1494-17.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Custome
14、r Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Detailed working drawings and a bill of materials for this equipment can beobtained at a nominal charge fromASTM Headquarters,100 Barr Harbor Drive,POBox
15、C700,West Conshohocken,PA 194282959.Order Adjunct:ADJD1494.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with interna
16、tionally 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.1 5.1.3 Test Cabinet,constructed in accordance with thefollowing dimensions.35.1.3.1 The transmitted area of the test specimen shall be610.0 6 1.6 mm by 610.0 6 1.6 mm(24 6116in.by 24 6116in.).5.1.3.2 The distance from the bottom of the fluorescenttubes