ASTM_F_1473_-_13.pdf

Designation:F147313Standard Test Method forNotch Tensile Test to Measure the Resistance to Slow CrackGrowth of Polyethylene Pipes and Resins1This standard is issued under the fixed designation F1473;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 test method determines the resistance of polyeth-ylene materials to slow crack growth under conditions speci-fied within.NOTE1This test method is known as PENT(Pennsylvania NotchTest)test.1.2 The test is generally performed at 80C and at 2.4 MPa,but may also be done at temperatures below 80C and withother stresses low enough to preclude ductile failure andthereby eventually induce brittle type of failure.Generally,polyethylenes will ultimately fail in a brittle manner by slowcrack growth at 80C if the stress is below 2.4 MPa.1.3 The test method is for specimens cut from compressionmolded plaques.2See Appendix X1 for information relating tospecimens from pipe.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 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:3D1600 Terminology forAbbreviated Terms Relating to Plas-ticsD4703 Practice for Compression Molding ThermoplasticMaterials into Test Specimens,Plaques,or SheetsF412 Terminology Relating to Plastic Piping Systems3.Terminology3.1 Definitions:3.1.1 Definitions are in accordance with Terminology F412.Abbreviations are in accordance with Terminology D1600,unless otherwise indicated.3.1.2 brittle failurea pipe failure mode which exhibits novisible(to the naked eye)permanent material deformation(stretching,elongation,or necking down)in the area of thebreak(Terminology F412).3.2 Definitions of Terms Specific to This Standard:3.2.1 slow crack growththe slow extension of the crackwith time.4.Summary of Test Method4.1 Specimens are prepared from compression moldedplaques,precisely notched and then exposed to a constanttensile stress at elevated temperatures in air.Time on test isrecorded for tests conducted against a minimum time beforefailure requirement or the time to complete failure is recorded.NOTE2Minimum time before failure requirements are found inmaterial or product specifications,codes,etc.5.Significance and Use5.1 This test method is useful to measure the slow crackgrowth resistance of molded plaques of polyethylene materialsat accelerated conditions such as 80C,2.4-MPa stress,andwith a sharp notch.5.2 The testing time or time to failure depends on thefollowing test parameters:temperature;stress;notch depth;andspecimen geometry.Increasing temperature,stress,and notchdepth decrease the time to failure.Thus,in reporting the testtime or time to failure,all the conditions of the test shall bespecified.6.Apparatus6.1 Lever Loading Machine,with a lever arm ratio of about5:1.The tensile load may also be applied directly using deadweights or any other method for producing a constant load.Thepull rods on the grips shall have universal action to prevent1This test method 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 August 2013.Originallyapproved in 1997.Last previous edition approved in 2011 as F1473 11.DOI:10.1520/F1473-13.2Lu,X.,and Brown,N.,“ATest for Slow Crack Growth Failure in PolyethyleneUnder a Constant Load,”Journal of Polymer Testing,Vol 11,pp.309319,1992.3For 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.*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 bending.The grips shall be serrated to prevent slippage.Theload on the specimen shall be accurate to at least 60.5%.6.2 Furnace,heated by ordinary incandescent light bulbscovered with aluminum foil or any other suitable heatingelement.6.3 Temperature Controller,shall be able to control thetemperature within 60.5C with respect to the set point.6.4 Temperature-Measuring Device,a thermometer or athermocouple which can measure the temperature with anaccuracy better than 0.5C.6.5 Timer,shall have an accuracy of at least 1%and shallautomatically stop when the specimen fails.6.6 Alignment Jig,as shown in Fig.1,which aligns the gri