1、Designation:F94894(Reapproved 2011)Standard Test Method forTime-to-Failure of Plastic Piping Systems and ComponentsUnder Constant Internal Pressure With Flow1This standard is issued under the fixed designation F948;the number immediately following the designation indicates the year of originaladopti
2、on or,in the case of revision,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 test method covers the determination of the time-to-failure of plastic piping
3、products under constant internalpressure and flow.1.2 This test method provides a method of characterizingplastics in the form of pipe,components,and systems underany reasonable combination of internal and external tempera-tures and environments,under the procedures described.1.3 This test method ca
4、n be used to characterize the testedplastic materials or products,or both,on the basis of pressure-,or stress-rupture data developed under the conditions pre-scribed.1.4 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to
5、 SI units that are provided for information onlyand are not considered standard.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 determ
6、ine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D543 Practices for Evaluating the Resistance of Plastics toChemical ReagentsD2122 Test Method for Determining Dimensions of Ther-moplastic Pipe and FittingsD2837 Test Method for Obtaining Hydrosta
7、tic Design Basisfor Thermoplastic Pipe Materials or Pressure Design Basisfor Thermoplastic Pipe ProductsD2992 Practice for Obtaining Hydrostatic or Pressure De-sign Basis for“Fiberglass”(Glass-Fiber-ReinforcedThermosetting-Resin)Pipe and FittingsD3567 Practice for Determining Dimensions of“Fiberglas
8、s”(Glass-Fiber-Reinforced Thermosetting Resin)Pipe andFittingsE177 Practice for Use of the Terms Precision and Bias inASTM Test Methods2.2 PPI Documents:TR-2 Policies and Procedures for the Listing of Thermoplas-tic Pipe,Fittings,and Fixture Materials When EvaluatedUnder Constant Internal Pressure W
9、ith Flow3TR-3 Policies and Procedures for Developing Recom-mended Hydrostatic Design Stresses for ThermoplasticPipe Materials33.Terminology3.1 Definitions:3.1.1 failurebursting,cracking,splitting,or weeping(seepage of test fluid through the wall of the product)duringthe test,which results in the ina
10、bility of the specimen tomaintain pressure or contain the internal test fluid,shallconstitute failure of the test specimen.Failure may sometimesoccur by ballooning,an excessive extension leading to struc-tural failure.When failure occurs by ballooning the degree ofdistension should be recorded.Assem
11、blies may also fail tojoint leakage or separation.NOTE1Overall distension,which results from creep caused bylong-term stress,is not considered to be a ballooning failure.3.1.2 hoop stressthe tensile stress in the wall of the pipingproduct in the circumferential direction due to internal pres-sure.Un
12、its will be reported as pounds per square inch(psi)ormega pascals(MPa).Hoop stress will be calculated by thefollowing ISO equation:S 5 PD 2 t!/2twhere:S=hoop stress,psi(MPa),1This test method is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of
13、 Subcommittee F17.40 on TestMethods.Current edition approved Aug.1,2011.Published August 2011.Originallyapproved in 1985.Last previous edition approved in 2006 as F948 94(2006).DOI:10.1520/F0948-94R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service
14、at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Plastics Pipe Institute(PPI),105 Decker Court,Suite 825,Irving,TX 75062,http:/www.plasticpipe.org.Copyright ASTM International,100 Barr Harbor Drive,
15、PO Box C700,West Conshohocken,PA 19428-2959.United States1 D=average outside diameter,in.(mm),P=internal pressure,psig(MPag),andt=mimimum wall thickness in.(mm).NOTE2Hoop stress should only be determined on straight hollowcylindrical specimens.Products of more complex shape may be evaluatedby Option
16、 2 of Appendix X1 based on pressure.3.1.3 make-up fluidan exchange of internal fluid withfresh fluid at a minimum rate of 10%of the total systemvolume per week.3.1.4 maximum internal surface temperaturethat tempera-ture attained when increased fluid velocity results in no furtherincrease in the outside surface temperature of the specimen(see X2.7).3.1.5 pressurethe force per unit area exerted by the testfluid in the piping product.Units will be reported as pounds persquare inch gage(psig)or mega
