1、Designation:F72503(Reapproved 2013)Standard Practice forDrafting Impact Test Requirements In Thermoplastic PipeAnd Fittings Standards1This standard is issued under the fixed designation F725;the number immediately following the designation indicates the year of originaladoption or,in the case of rev
2、ision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes a procedure for setting up impacttest requirements on the basis of test data obtain
3、ed by TestMethod D2444.1.2 This practice is applicable to thermoplastic pipe andfittings.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standa
4、rd.1.4 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 Do
5、cuments2.1 ASTM Standards:2D2444 Test Method for Determination of the Impact Resis-tance of Thermoplastic Pipe and Fittings by Means of aTup(Falling Weight)3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 binomial probability equationthe equation that de-fines the chance for exa
6、ctly r specimens to pass,when n aretested,given p,the chance that a single specimen chosen atrandom will pass.It is expressed as follows:rPn5n!r!n 2 r!pr1 2 p!n2r(1)NOTE1The factorial of zero is one.3.1.2 binomial testa test that has only two possible results(for example,pass or fail,heads or tails,
7、true or false).3.1.3 mean strengththe average strength of the total popu-lation(see Note 2).3.1.4 OC curve(operating characteristic curve)a graphthat illustrates the chance of success or failure when a givenspecification format is employed,given any quality level from0 to 1(0 to 100%passing in the l
8、ot from which test specimensare selected).3.1.5 probability graph papercommercially availablegraph paper that provides straight-line plots when the distribu-tion of attributes is normal.For a discussion on the use ofproability graph paper,see Test Method D2444 Appendix X2.3.1.6 specification formatt
9、he rules set forth by the testrequirement,including the number of specimens to be testedand the minimum acceptable number of passes.3.1.7 standard deviationa statistical term that relates tothe size of the expected variation in test results.NOTE2The terms“mean,”“normal distribution,”and“standarddevi
10、ation”are dealt with in elementary statistics textbooks.4.Summary of Practice4.1 Round-robin tests of representative pipe and fittingsspecimens are performed to identify the energy levels at which90%or more of the specimens in acceptable lots will pass.Apreferred test format is listed.The B-tup and
11、the V-blockholder,and room-temperature conditioning and tests are pre-ferred choices.5.Significance and Use5.1 This practice is used for drafting impact test specifica-tion requirements,and it presupposes no special familiaritywith statistical methods.It provides for specification valuesthat will pa
12、ss acceptable lots with a high degree of certainty.The impact test requirement is intended to discriminate be-tween acceptable materials and manufacturing methods andthose which are not;it is not a simulated service test.6.Procedure6.1 Test thermoplastic pipe or fittings specimens in accor-dance wit
13、h Test Method D2444,and plot the test results onprobability graph paper.1This practice is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.40 on TestMethods.Current edition approved Aug.1,2013.Published October 2013.Originally
14、approved in 1981.Last previous edition approved in 2008 as F725 03(2008)1.DOI:10.1520/F0725-03R13.2For 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
15、Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 It will be clear,from the probability paper plot,that theenergy level where 98%or 99%of all specimens would passwill be low.On the one hand,when the test
16、format requires thatfive of five,or six of six,or nine or ten of ten tested shall pass,or the lot rejected,then the specified energy levels mustcorrespond to these levels(see Fig.1,the operating character-istic(OC)curve for the“nine or ten of ten”test format).On theother hand,five of five,six of six,and nine or ten of ten testsat low energy levels will not screen marginal or poor lotseffectively.(See Fig.1 again).6.3 A format which will accept reliably when 90%or moreof the specimens in acceptab