ASTM_D_4204_-_12.pdf

Designation:D420412Standard Practice forPreparing Plastic Film Specimens for a Round-Robin Study1This standard is issued under the fixed designation D4204;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 practice covers the preparation of test sets of plasticfilm specimens for subsequent use in an interlaboratory round-robin study to evaluate the precision of a test method.1.2 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:2E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 film specimenone piece of a sample obtained bycutting across the width of the sample and to a length such thatone test specimen can subsequently be prepared.NOTE2For any sample in a laboratory,the specified number of filmspecimens in a test unit(n1)are tested to produce a single test result in ashort-time period,while replicate test results are obtained over a longertime period.Thus,there are within-laboratory components of variabilityfor both short-term and long-term testing.This practice calls thesewithin-day and between-day components of variability,inasmuch asround-robin protocols often specify that replicate test results be obtainedon different days.3.1.2 samplea quantity of film of a width appropriate tothe test method under study and of a length sufficient to yieldthe total number of film specimens needed for the plannedround-robin study.3.1.3 test resultthe value(usually,the arithmetic average)of the property derived from one test unit.3.1.4 test seta group of several film specimens,in anumber greater than that specified for a test unit.3.1.5 test specimenthe individual piece of film to betested,usually of specified dimensions,that is to be cut fromone film specimen and tested,to produce one value of theproperty,or properties,by the test method under study.3.1.6 test unita specified number of film specimens fromwhich an equal number of test specimens is to be prepared andtested in a short-time span to yield one test result for eachproperty.3.2 Abbreviations:RR=round-robin studyq=number of samples to be used in the RRr=total number of film assemblies that will be neededfor each lab to complete the necessary testingn1=specified number of film specimens in a test unitn2=number of additional film specimens in each test setp1=number of laboratories participating in the RRp2=number of additional“latent”laboratories providedfor in the specimen preparation procedureL1=film-specimen length appropriate for preparing onetest specimenL2=total length of film necessary to produce samples froparticipating plus latent laboratories;L2=(p1+p2)(L1)SD=standard deviation for a single source of variabilityfor one given sampleS1=standard deviation for within-laboratory within-dayvariability of a test valueS2=standard deviation for within-laboratory variability ofa test resultS3=standard deviation for between-laboratory variabilityof a test resultS4=standard deviation for within-sample variabilitySr=standard deviation of a within-laboratory single testresult for one given sample on any daySR=standard deviation of a between-laboratory single testresult for one given sample on any day1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.19 on Film,Sheeting,and MoldedProducts.Current edition approved Aug.1,2012.Published September 2012.Originallyapproved in 1982.Last previous edition approved in 2006 as D4204-06.DOI:10.1520/D4204-12.2For 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 4.Significance and Use4.1 This practice is intended to assist task groups participat-ing in a round-robin study with the preparation of test sets offilm specimens from film samples in the form of rolls on a core.4.2 This practice assumes that the essential features of theround-robin protocol have already been established by follow-ing the guidance of Practice E691.In particular,it is assumedthat the following are known:(1)the number of film samplesto be used,(2)the n