ASTM_D_7856_-_15.pdf

Designation:D785615Standard Specification forColor and Appearance Retention of Solid and VariegatedColor Plastic Siding Products using CIELab Color Space1This standard is issued under the fixed designation D7856;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.Scope*1.1 This specification establishes requirements and testmethods for the color and appearance retention of solid andvariegated colored plastic siding products.1.2 Color retention testing provides a method for estimatingthe acceptability of color change in a siding product over aperiod of years of service.The exposure locations and dura-tions specified in this standard have been shown to provide agood estimation of the color change in a siding product over aperiod of years of service(see 2.2).1.3 This specification is a successor to Specifications D6864and D7251,which cover solid colors and variegated colors,respectively.This specification combines coverage for both,and has the same scope as those standards.1.4 Specifications D6864 and D7251 use Hunter Lab colorspace for measurement of colors and evaluation of colorchange.These standards require classification of colors intoregions based on the L,a,and b coordinates of the color,andevaluation of color changes is done using an ellipsoid valueequation having unique coefficients for each color region.Thisspecification uses CIE 1976 L*a*b*color space for measure-ment and evaluation of color change.Using this method,theneed for separate color regions and evaluation equations hasbeen eliminated.1.5 Provisions for sample selection and preparation,andweathering are the same in this specification as in Specifica-tions D6864 and D7251.1.6 Characterization of color and appearance for variegatedcolors is complicated by the presence of multiple colors in arandom pattern.The procedure for measuring variegated colorsin this specification is based on using a template to referencesix spots for color measurement.1.7 This standard specifies outdoor weathering in threespecific climate zones for a single 24-month exposure,and thecolor retention performance requirements under these condi-tions are established to predict acceptable performance for theexpected service life.However,nothing in this standard pre-cludes the use of different or additional climate zones,ordifferent exposure durations,so long as those conditions areclearly specified in any reports.1.8 UnitsThe values stated in inch-pound units are to beregarded as standard.The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.9 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.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D660 Test Method for Evaluating Degree of Checking ofExterior PaintsD661 Test Method for Evaluating Degree of Cracking ofExterior PaintsD662 Test Method for Evaluating Degree of Erosion ofExterior PaintsD714 Test Method for Evaluating Degree of Blistering ofPaintsD772 Test Method for Evaluating Degree of Flaking(Scal-ing)of Exterior PaintsD883 Terminology Relating to PlasticsD1435 Practice for Outdoor Weathering of PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinates1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.24 on Plastic BuildingProducts.Current edition approved April 1,2015.Published April 2015.Originallyapproved in 2014.Last previous edition approved in 2014 as D7856 14.DOI:10.1520/D7856-15.2For 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.*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 D4214 Test Methods for Evaluating the Degree of Chalkingof Exterior Paint FilmsD6864 Specification for Color and Appearance Retention ofSolid Colored Plastic Siding ProductsD7251 Specification for Color and Appearance Retention ofVariegated Color Plastic Siding ProductsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE1331 Test Method for Reflectance Factor and Color bySpectrophotometry