1、Designation:D723820Standard Test Method forEffect of Exposure of Unreinforced PolyolefinGeomembrane Using Fluorescent UV CondensationApparatus1This standard is issued under the fixed designation D7238;the number immediately following the designation indicates the year oforiginal adoption or,in the c
2、ase 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 standard covers the specific procedures and testconditions that are applicable for exposur
3、e of unreinforcedpolyolefin geomembranes to fluorescent UV radiation andcondensation.NOTE1Polyolefin geomembranes include high-density polyethylene(HDPE),linear low-density polyethylene(LLDPE),flexible polyproply-ene(fPP),etc.1.2 Test specimens are exposed to fluorescent UVA-340lamps under controlle
4、d environmental conditions.UVA-340lamps are standard for this method.NOTE2Other types of fluorescent UV lamps,such as UVB-313,canalso be used based upon discussion between involved parties.However,ifthe test is run with another type of fluorescent UV lamp,such asUVB-313,this should be considered as
5、a deviation from the standard andclearly stated in the test report.UVB-313 and UVA-340 fluorescent lampsgenerate different amounts of radiant power in different wavelengthranges;thus,the photochemical effects caused by these different lampsmay vary.1.3 This method covers the conditions under which t
6、heexposure is to be performed and the test methods for evaluatingthe effects of fluorescent UV,heat,and moisture in the form ofcondensation on geomembranes.General guidance is given inPractices G151 and G154.1.4 The values listed in SI units are to be regarded as thestandard.1.5 This standard does n
7、ot 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international stand
8、ard was developed in accor-dance with internationally recognized 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.Refere
9、nced Documents2.1 ASTM Standards:2D1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrusion PlastometerD5885/D5885M Test Method for Oxidative Induction Timeof Polyolefin Geosynthetics by High-Pressure DifferentialScanning CalorimetryD6693/D6693M Test Method for Determining Tensile Prop-ert
10、ies of Nonreinforced Polyethylene and NonreinforcedFlexible Polypropylene GeomembranesG113 Terminology Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG151 Practice for Exposing Nonmetallic Materials inAccel-erated Test Devices that Use Laboratory Light SourcesG154 Pract
11、ice for Operating Fluorescent Ultraviolet(UV)Lamp Apparatus for Exposure of Nonmetallic MaterialsG156 Practice for Selecting and Characterizing WeatheringReference Materials3.Terminology3.1 Definitions:(According to Terminology G113.)3.1.1 control,na material which is of similar compositionand const
12、ruction to the test material used for comparison,exposed at the same time.3.1.2 irradiance,nthe radiant power per unit area incidenton a receiver,typically reported in units of W/(m2nm)atspecified wavelength of measurement or in W/m2in a specifiedspectral range.3.1.3 reference material,na material w
13、ith known perfor-mance.3.1.4 ultraviolet regions,nthe UV region of the spectrumis divided into three regions:UVA,radiation in wavelengths1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.02 on Endur-ance Properties.
14、Current edition approved July 1,2020.Published July 2020.Originally approvedin 2006.Last previous edition approved in 2017 as D7238 06(2017).DOI:10.1520/D7238-20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of A
15、STMStandards 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 standard was developed in accordance with internationally recognized principl
16、es 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.between 315 nm and 400 nm;UVB,radiation in wavelengthsbetween 280 nm and 315 nm;and UVC,radiation in wave-lengths shorter than 280 nm(Ref.CIE Publication No.20(1972).4.Summary of Test Method4.1 Geomembrane coupons are exposed to repetitive cyclesconsisting of ultraviolet radiation