Designation: G156 − 17Standard Practice forSelecting and Characterizing Weathering ReferenceMaterials 1This standard is issued under the f i xed designation G156; 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 standard describes the criteria to be used forselection of a weathering reference material (WRM) andprocedures to be used for determining within lab and betweenlab tolerances of changes in measured properties of weatheringreference materials. This standard also describes a procedurefor comparing different lots of the same type of a weatheringreference material.N OTE 1—Examples of laboratory accelerated tests in which a weather-ing reference material could be used to monitor consistency are exposuretests such as those described in Practices G152, G153, G154, andG155and other standards in which tests conducted according to thesestandards are referenced. Examples of outdoor exposures where a weath-ering reference material could be used to monitor consistency are thoseconducted according to Practices G7, G24, or G90. A reference materialcan also be used to monitor consistency of exposure or conditioning testthat do not involve exposure to light.1.2 Weathering reference materials are most often used to(1) monitor consistency (that is, repeatability, reproducibility,or both) of exposure tests, (2) to determine the time or radiantexposure at which test materials are evaluated, (3) as areference material for comparing to test materials exposed atthe same time. Weathering reference materials cannot be usedto classify or characterize the relative severity of any exposuretest because of the large variability in material responses to theeffects of light, heat, and water.1.3 This practice does not cover control materials which, bydef i nition are selected to be of similar composition andconstruction to the test materials, and are exposed at the sametime as test materials.1.4 This practice provides an outline of experiments re-quired to determine how the measured properties of thereference material change as a function of exposure to specif i edtest conditions. It includes establishment of reproducible mea-surement procedures, determination of the critical spectralregion in the light source causing the changes, and effects ofother critical exposure stresses such as temperature and mois-ture.2. Referenced Documents2.1 ASTM Standards: 2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1169 Practice for Conducting Ruggedness TestsG7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic MaterialsG24 Practice for Conducting Exposures to Daylight FilteredThrough GlassG90 Practice for Performing Accelerated Outdoor Weather-ing of Nonmetallic Materials Using Concentrated NaturalSunlightG113 Terminology Relating to Natural and Artif i cial Weath-ering Tests of Nonmetallic MaterialsG152 Practice for Operating Open Flame Carbon Arc LightApparatus for Exposure of Nonmetallic MaterialsG153 Practice for Operating Enclosed Carbon Arc LightApparatus for Exposure of Nonmetallic MaterialsG154 Practice for Operating Fluorescent Ultraviolet (UV)Lamp Apparatus for Exposure of Nonmetallic MaterialsG155 Practice for Operating Xenon Arc Light Apparatus forExposure of Non-Metallic MaterialsG178 Practice for Determining the Activation Spectrum of aMaterial (Wavelength Sensitivity to an Exposure Source)Using the Sharp Cut-On Filter or Spectrographic Tech-nique2.2 SAE Standard:SAE J2527, Accelerated Exposure of Automotive ExteriorMaterials using a Controlled Irradiance Water-CooledXenon Arc Apparatus 31 This practice is under the jurisdiction ofASTM Committee G03 on Weatheringand Durability and is the direct responsibility of Subcommittee G03.01 on JointWeathering Projects.Current edition approved Feb. 1, 2017. Published February 2017. Originallyapproved in 1997. Last previous edition approved in 2009 as G156–09. DOI:10.1520/G0156-17.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service@astm.org. For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3 Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001, http://www.sae.org.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 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.1 Copyright by ASTM Int'l (all rights reserved); Fri Oct 6 10:41:35 EDT 2017Downloaded/printed byUniversity of Edinburgh (University of Edinburgh) pursuant to License Agreement. No further reproductions authorized.
