ASTM_D_4821_-_15.pdf

Designation:D482115Standard Guide forCarbon BlackValidation of Test Method Precision andBias1This standard is issued under the fixed designation D4821;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 guide covers procedures for using the ASTMStandard Reference Blacks2(SRBs)and the HT and INRIodine Number Standards to continuously monitor the preci-sion of those carbon black test methods for which referencevalues have been established.It also offers guidelines fortroubleshooting various test methods.1.2 This guide establishes procedures for the use of x-chartsto continuously monitor those tests listed in Section 2 forwithin-lab precision(repeatability)and between-lab accuracy(reproducibility).1.3 This guide provides a statistical procedure for improv-ing test reproducibility when a laboratory cannot physicallycalibrate its apparatus to obtain the reference values of theASTM reference blacks,within the ranges given in this guide.2.Referenced Documents2.1 ASTM Standards:3D1510 Test Method for Carbon BlackIodine AdsorptionNumberD1513 Test Method for Carbon Black,PelletedPour Den-sityD1765 Classification System for Carbon Blacks Used inRubber ProductsD2414 Test Method for Carbon BlackOil AbsorptionNumber(OAN)D3265 Test Method for Carbon BlackTint StrengthD3324 Practice for Carbon BlackImproving Test Repro-ducibility UsingASTM Standard Reference Blacks(With-drawn 2002)4D3493 Test Method for Carbon BlackOil AbsorptionNumber of Compressed Sample(COAN)D6556 Test Method for Carbon BlackTotal and ExternalSurface Area by Nitrogen AdsorptionE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE2282 Guide for Defining the Test Result of a Test MethodE2586 Practice for Calculating and Using Basic Statistics3.Terminology3.1 Definitions:3.1.1 accepted reference value,na value that serves as anagreed-upon reference for comparison,and which is derivedas:(1)a theoretical or established value,based on scientificprinciples,(2)an assigned or certified value,based on experi-mental work of some national or international organization,or(3)a consensus or certified value,based on collaborativeexperimental work under the auspices of a scientific orengineering group.3.1.1.1 DiscussionAnationalorinternationalorganization,referred to in(2),generally maintains measure-ment standards to which the reference values obtained aretraceable.E1773.1.2 accuracy,nthe closeness of agreement between atest result and an accepted reference value.3.1.2.1 DiscussionThe term accuracy,when applied to aset of test results,involves a combination of a randomcomponent and of a common systematic error or biascomponent.E1773.1.3 ASTM reference blacks,na set of carbon blacks thatspan the useful range of the test method for which they arereference materials.D33243.1.4 bias,nthe difference between the expectation of thetest results and an accepted reference value.1This guide is under the jurisdiction ofASTM Committee D24 on Carbon Blackand is the direct responsibility of Subcommittee D24.61 on Carbon Black Samplingand Statistical Analysis.Current edition approved Jan.1,2015.Published February 2015.Originallyapproved in 1988.Last previous edition approved in 2014 as D4821 14.DOI:10.1520/D4821-15.2Standard Reference Blacks are available from Laboratory Standards&Technologies,Inc.,227 Somerset St.,Borger,TX 79007.3For 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.4The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.4.1 DiscussionBias is the total systematic error ascontrasted to random error.There may be one or moresystematic error components contributing to the bias.A largersystematic difference from the accepted reference value isreflected by a larger bias value.E1773.1.5 characteristic,na property of items in a sample orpopulation which,when measured,counted or otherwiseobserved,helps to distinguish between the items.E22823.1.6 coeffcient of variation,CV,nfor a nonnegativecharacteristic,the ratio of the standard deviation to the meanfor a population or sample.E25863.1.7 intermediate precision,nthe closeness of agreementbetween test results obtained under specified intermediateprecision conditions.3.1.7.1 DiscussionThe specific measure and the specificconditions must be specified for each intermediate measure ofprecision;thus,“standard deviation of test results amongoperators in a laboratory,”or“day-to-day standard deviationwithin a laboratory for the same operator.”3.1.