ASTM_G_179_-_04_2011.pdf

Designation:G17904(Reapproved 2011)Standard Specification forMetal Black Panel and White Panel Temperature Devices forNatural Weathering Tests1This standard is issued under the fixed designation G179;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 specification provides specific information for themanufacturing and use of metal black and white panel tem-perature devices to measure temperatures that estimate highestmaximum(black)and lowest maximum(white)temperaturesof coated metal specimens during natural weathering tests.1.1.1 The construction of a black or white panel has asignificant effect on the indicated temperature.This standarddescribes a robust construction from the panels investigated,which has been shown to provide the highest,most consistenttemperatures when compared side-by-side with other blackpanel constructions.1.2 This specification includes details on design require-ments and quantitative measurement techniques,which willlead to the proper selection of materials and use for black andwhite panel temperature sensors.1.3 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 requirements prior to use.NOTE1There is no equivalent ISO standard describing the selectionand use of black panel sensors for natural weathering tests.2.Referenced Documents2.1 ASTM Standards:2D523 Test Method for Specular GlossE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE430 Test Methods for Measurement of Gloss of High-GlossSurfaces by Abridged GoniophotometryE772 Terminology of Solar Energy ConversionE881 Practice for Exposure of Solar Collector Cover Mate-rials to Natural Weathering Under Conditions SimulatingStagnation ModeE903 Test Method for Solar Absorptance,Reflectance,andTransmittance of Materials Using Integrating Spheres(Withdrawn 2005)3G7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic MaterialsG113 Terminology Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG147 Practice for Conditioning and Handling of Nonmetal-lic Materials for Natural and Artificial Weathering TestsG151 Practice for Exposing Nonmetallic Materials inAccel-erated Test Devices that Use Laboratory Light Sources2.2 ISO Standard:ISO 4892-1 Plastics:Exposure to Laboratory LightSourcesGeneral Guidance43.Terminology3.1 The definitions given in Terminologies G113 and E772are applicable to this practice.4.Significance and Use4.1 The measurement of the primary elements of weather;solar radiation,temperature,and moisture is necessary toquantify the weather conditions during exposure in naturalweathering(outdoor)tests.This practice is applicable toweathering tests described in Practices G7,G24,or D4141(Method A)and other standards in which these standards arereferenced.4.2 The surface temperature of exposed materials dependsprimarily on the amount of radiation absorbed,the emissivityof the specimen,the thermal conduction within the specimen,and the heat transfer between the specimen and the air incontact with the specimen surface and specimen holder.Sinceit is often not practical to measure the surface temperature ofindividual test specimens,a specified black or white panel1This specification is under the jurisdiction of ASTM Committee G03 onWeathering and Durability and is the direct responsibility of Subcommittee G03.02on Natural and Environmental Exposure Tests.Current edition approved July 1,2011.Published August 2011.Originallyapproved in 2004.Last previous edition approved in 2010 as G179 04(2010).DOI:10.1520/G0179-04R11.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 temperature sensor is used to measure a reference temperature.This reference temperature provides an indication of thetemperature of a black or white specimen of similar construc-tion to the panel sensor.It is important to locate the black orwhite panel sensor in proximity to the specimens,using thesame support,so that it receives the same radiation and coolingconditions as the test specimen.For sites where multipleexposure racks are used,a single black or white