ASTM_D_6796_-_02_2008.pdf

Designation:D679602(Reapproved 2008)Standard Practice forProduction of Coal,Coke and Coal Combustion Samples forInterlaboratory Studies1This standard is issued under the fixed designation D6796;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 describes the essential activities that arerequired to produce samples for interlaboratory studies.1.2 The suitability of a particular interlaboratory sampledeveloped using this guide will depend on the tests beingmade.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 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sampleof CoalD2492 Test Method for Forms of Sulfur in CoalD2961 Test Method for Single-Stage Total Moisture Lessthan 15%in Coal Reduced to 2.36-mm(No.8 Sieve)TopsizeD3172 Practice for Proximate Analysis of Coal and CokeD3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3302 Test Method for Total Moisture in CoalD4596 Practice for Collection of Channel Samples of Coalin a MineD5142 Test Methods for Proximate Analysis of the AnalysisSample of Coal and Coke by Instrumental Procedures(Withdrawn 2010)3D5263 Test Method for Determining the Relative Degree ofOxidation in Bituminous Coal by Alkali ExtractionE178 Practice for Dealing With Outlying ObservationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE826 Practice for Testing Homogeneity of a Metal Lot orBatch in Solid Form by Spark Atomic Emission Spec-trometry3.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,refer to Terminology D121.4.Summary of Practice4.1 Test samples of adequately defined composition andhomogeneity are required for interlaboratory studies.Thesesamples should be typical in all respects to the samples forwhich the test method is applicable.4.1.1 The sample should be of sufficient quantity to performall necessary tests and replicates.Guidelines specifying mini-mum quantities are given in Practice D2013.4.1.2 The top size must be consistent for the test being run.4.2 Differences in results due to the homogeneity oroxidation,or both,of the test sample should be minimal withrespect to other errors.5.Significance and Use5.1 The objective of this practice is to provide guidelines forthe preparation of samples for interlaboratory studies to evalu-ate new test methods or for quality control purposes.5.2 These samples prepared using these guidelines may beused for the testing of the precision and bias mandatory forASTM test methods.Such an evaluation is necessary toprovide guidance to the user as to the reliability of measure-ments that can be expected by its use.The statements are1This practice is under the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.24 on Statistics.Current edition approved Feb.1,2008.Published March 2008.Originallyapproved in 2002.Last previous edition approved in 2002 as D679602.DOI:10.1520/D6796-02R08.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 developed on the basis of user experience(ordinarily throughinterlaboratory studies)with the test method.5.3 The availability of appropriate samples is a key require-ment for interlaboratory studies.5.4 The homogeneity of the sample produced for interlabo-ratory studies must be small enough so that the variance causedby the sample is small compared to the variance of the testbeing performed.6.Sample Selection and Preparation6.1 Collect samples using Practice D2234/D2234M,Prac-tice D4596 for coal,or D346 for coke.Coal combustionproducts should be sampled in a manner to provide a repre-sentative sample free from contamination.The sample shouldbe typical of a certain class of samples(for example,EasternU.S.bituminous coal)or a certain value for a component(suchas coals with two percent sulfur),or both,so that appropriatediversity of samples can be identified for interlaboratorystudies.See Note 1.6.2 Grind samples to