ASTM_G_201_-_09.pdf

Designation:G20109Standard Practice forConducting Exposures in Outdoor Glass-Covered ExposureApparatus with Air Circulation1This standard is issued under the fixed designation G201;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 practice covers the basic principles and operatingprocedures for using outdoor glass-covered exposure apparatuswith air circulation.This practice is limited to the proceduresfor obtaining,measuring and controlling conditions of expo-sure.A number of exposure procedures are listed in AppendixX1;however,this practice does not specify the exposureconditions best suited for the material to be tested.1.2 For direct weathering exposures,refer to Practice G7.For exposures behind glass without air circulation,refer toPractice G24.1.3 Test specimens are exposed to solar radiation filteredthrough glass under partially controlled environmental testconditions.Different glass types and operating parameters aredescribed.1.4 Specimen preparation and evaluation of the results arecovered in ASTM methods or specifications for specificmaterials.More specific information for determining thechange in properties after exposure and reporting these resultsis described in Practices D5870,D2244 and Test MethodD523.1.5 The values stated in SI units are to be regarded asstandard.1.6 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:2D523 Test Method for Specular GlossD2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD5870 Practice for Calculating Property Retention Index ofPlasticsE903 Test Method for Solar Absorptance,Reflectance,andTransmittance of Materials Using Integrating SpheresE1084 Test Method for Solar Transmittance(Terrestrial)ofSheet Materials Using SunlightG7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic MaterialsG24 Practice for Conducting Exposures to Daylight FilteredThrough GlassG113 Terminology Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG141 Guide for Addressing Variability in Exposure Testingof Nonmetallic MaterialsG173 Tables for Reference Solar Spectral Irradiances:DirectNormal and Hemispherical on 37 Tilted SurfaceG177 Tables for Reference Solar Ultraviolet Spectral Distri-butions:Hemispherical on 37 Tilted SurfaceG179 Specification for Metal Black Panel and White PanelTemperature Devices for Natural Weathering TestsG183 Practice for Field Use of Pyranometers,Pyrheliom-eters and UV Radiometers2.2 Other Document:3WMO No.8 Guide to Meteorological Instruments andMethods of Observation,Fifth Edition2.3 ISO Standard:4ISO 9060 Solar energy Specification and classification ofinstruments for measuring hemispherical solar and directsolar radiation3.Terminology3.1 The definitions given in Terminology G113 are appli-cable to this practice.3.2 Other Definitions:1This practice is under the jurisdiction ofASTM Committee G03 on Weatheringand Durability and is the direct responsibility of Subcommittee G03.02 on Naturaland Environmental Exposure Tests.Current edition approved Dec.1,2009.Published May 2010.DOI:10.1520/G020109.2For 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.3Available from World Meteorological Organization(WMO),7bis,avenue de laPaix,Case postale 2300,CH-1211 Geneva 2,Switzerland,http:/www.wmo.int.4Available from International Organization for Standardization(ISO),1,ch.dela Voie-Creuse,Case postale 56,CH-1211,Geneva 20,Switzerland,http:/www.iso.ch.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.1 limit temperature,nFor enclosures operated in tem-perature control mode,the specified black panel temperature atwhich the circulating fan switches on in order to prevent orminimize black panel temperature readings above the settemperature.4.Summary of Practices4.1 Specimens are exposed to light,moisture(in the form ofhumidity)and heat in an outdoor glass-covered enclosure withair circulation.4.2 The exposure conditions may be varied by selection of:4.2.1 Glass Type:4.2.2 Operation of the circulating fan(whether constantlyon during daylight hours or only on when a specific limittemperature is reached).4.2.3 Temperature level at which the fan operates.4.2.4 Orientation of the test fixture.5.Significance and Us