1、Designation:D149412An 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 Department of Defense.1.Scope*1.1 This test method cove
3、rs 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 footnote
4、swhich 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 of th
5、is standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1There is no know ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminolog
6、y Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ASTM Adjuncts:Test Cabinet for Diffuse Light Transmission Factor ofReinforced Panels33.Terminology3.1 Definitions:Gene
7、ralDefinitions are in accordance withTerminology D883 and abbreviations with TerminologyD1600,unless otherwise indicated.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 building panels by the use of
8、 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:5.1.1 Light SourceThe illum
9、ination 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 photocell shall be of the
10、barrier-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,anda circuit with sufficient variable resistance so that th
11、e sensitiv-ity of the photometer can be adjusted over the range of 50 to100 footcandles.5.1.3 Test Cabinet,constructed in accordance with thefollowing dimensions.31This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.24 on P
12、lastic BuildingProducts.Current edition approved Oct.1,2012.Published November 2012.Originallyapproved in 1957.Last previous edition approved in 2008 as D1494 97(2008)1.DOI:10.1520/D1494-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at servicea
13、stm.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 C700,West Conshohocke
14、n,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 States1 5.1.3.1 The transmitted area of the test specimen shall be610.0 6 1.6 mm by 610.0 6 1.6
15、 mm(24 6116in.by 24 6116in.).5.1.3.2 The distance from the bottom of the fluorescenttubes to the bottom of the test specimen shall be 203.0 6 0.8mm(8 6132in.).5.1.3.3 A 4.8-mm(316-in.)thick,white,standard outdoor,translucent diffusing plate shall be placed between the lightsource and the test specim
16、en so that the distance from thebottom of the diffusing plate to the bottom of the test specimenis 31.8 6 0.8 mm(1146132in.).5.1.3.4 The photocell shall be positioned below the centeraxis of the test specimen so that the distance from the bottomof the specimen to the top of the cell is 283.0 6 0.8 mm(11186132in.).5.1.3.5 A masking plate containing a 31.8-mm(114-in.)diameter hole in its center shall be placed between the testspecimen and the photocell so that the distance from thebottom of the te
