1、Designation:D149422An 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-ticsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE2935 Practice for Evaluating Eq
8、uivalence of Two TestingProcesses2.2 ASTM Adjuncts:Test Cabinet for Diffuse Light Transmission Factor ofReinforced Panels33.Terminology3.1 GeneralFor definitions of terms that appear in thisspecification relating to plastics,refer to Terminology D883.For abbreviations that appear in this specificati
9、on,refer toTerminology D1600.3.2 For definitions of terms that appear in this practicerelating to quality and statistics,refer to Terminology E456.4.Significance and Use4.1 The purpose of this test method is to obtain the diffuselight transmittance factor of both flat and corrugated translu-cent bui
10、lding 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 shall consist of atransmissometer,Fig.1,comprising essentially the following:5
11、.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 PhotometerThe photometer shall consist of a pho-tocell and of a galvanometer.The
12、 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 should contain one scale graduated from 0 to 100,and1This test method is under the
13、 jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.24 on Plastic BuildingProducts.Current edition approved Nov.1,2022.Published November 2022.Originallyapproved in 1957.Last previous edition approved in 2017 as D1494 17.DOI:10.1520/D1494-22.2For refer
14、enced 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.3Detailed working drawings and a bill of materials for this equipment can be
15、obtained at a nominal charge fromASTM Headquarters,100 Barr Harbor Drive,POBox 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.Un
16、ited StatesThis international standard 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.1a circuit with sufficient variable resistance so that the sensitiv-ity of the photometer can be adjusted over the range of 50 to100 footcandles.5.1.3 Test Cabinet,constructed
