1、Designation: D1598 02 (Reapproved 2009)D1598 15Standard Test Method forTime-to-Failure of Plastic Pipe Under Constant InternalPressure1This standard is issued under the fixed designation D1598; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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 Scope*1.1 This test method covers the determination of the time-to-failure of both thermoplastic a
3、nd reinforced thermosetting/resinpipe under constant internal pressure.1.2 This test method provides a method of characterizing plastics in the form of pipe under the conditions prescribed.1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are m
4、athematicalconversions to SI units that are provided for information only and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety an
5、d health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2122 Test Method for Determining Dimensions of Thermoplastic Pipe and FittingsD2837 Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials
6、 or Pressure Design Basis forThermoplastic Pipe ProductsD2992 Practice for Obtaining Hydrostatic or Pressure Design Basis for “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pipe and FittingsD3517 Specification for “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pressure PipeD356
7、7 Practice for Determining Dimensions of “Fiberglass” (Glass-Fiber-Reinforced Thermosetting Resin) Pipe and Fittings3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 failureany continuous loss of pressure with or without the transmission of the test fluid through the body of the
8、 specimenunder test shall constitute failure. Failure may be by one or a combination of the following modes:3.1.1 ballooningfailure, nany localized expansion of a pipe specimen while under internal pressure. This is sometimesreferred to as ductile failure. occurrence of ballooning, rupture, seepage
9、or weeping.NOTE 1Overall distention which results from creep caused by long-term stress is not considered to be a ballooning failure.3.1.1.1 ballooning, nany localized expansion of a pipe while under internal pressure. This is sometimes referred to as ductilefailure.3.1.1.1.1 DiscussionOverall diste
10、ntion caused by applied stress is not considered to be a failure.3.1.1.2 rupture, na break in the pipe wall with immediate loss of test fluid and continued loss at essentially no pressure. Ifrupture is not preceded by some yielding, this may be termed a non-ductile failure.3.1.1.3 seepage or weeping
11、, ntest fluid passing through cracks in the pipe wall to an extent detectable visually orelectronically. A reduction in pressure will frequently enable the pipe to carry fluid without apparent evidence of loss of fluid.1 This test method is under the jurisdiction of ASTM Committee F17 on Plastic Pip
12、ing Systems and is the direct responsibility of Subcommittee F17.40 on Test Methods.Current edition approved Aug. 1, 2009Nov. 1, 2015. Published November 2009December 2015. Originally approved 1958. Last previous edition approved in 20082009as D1598 02(2008).(2009). DOI: 10.1520/D1598-02R09.10.1520/
13、D1598-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intende
14、d only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current
15、versionof the standard as published by ASTM is to be considered the official document.*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 States13.1.2 free (unrestrained) end closu
16、reclosure, na pipe specimen end closure (cap) closure(cap) that seals the end of the pipeagainst loss of internal fluid and pressure, and is fastened to the pipe specimen.3.1.3 restrained end closureclosure, na pipe specimen end closure (cap) that seals the end of the specimen against loss ofinterna
17、l fluid and pressure, but is not fastened to the pipe specimen. RestrainedRetained end closures rely on tie-rod(s) through thepipe specimen or on an external structure to resist internal pressure end thrust.3.1.5 rupturea break in the pipe wall with immediate loss of test fluid and continued loss at
18、 essentially no pressure. If ruptureis not preceded by some yielding, this may be termed a non-ductile failure.3.1.6 seepage or weepingwater or fluid passing through microscopic breaks in the pipe wall. A reduction in pressure willfrequently enable the pipe to carry fluid without evidence of loss of
19、 the liquid.4. Summary of Test Method4.1 This test method consists of exposing specimens of pipe to a constant internal pressure while in a controlled environment.Such a controlled environment may be accomplished by, but is not limited to, immersing the specimens in a controlled temperaturewater or
20、air bath. The time-to-failure is measured.NOTE 1Dimensional changes should be measured on specimens undergoing long-term strength tests. Measurements using circumferential tapes,strain gages, or mechanical extensometers provide useful information.5. Significance and Use5.1 The data obtained by this
21、test method are useful for establishing stress versus failure time relationships in a controlledenvironment from which the hydrostatic design basis for plastic pipe materials can be computed. (Refer to Test Method D2837 andPractice D2992.)5.2 In order to determine how plastics will perform as pipe,
22、it is necessary to establish the stress-failure time relationships forpipe over 2 or more logarithmic decades of time (hours) in a controlled environment. Because of the nature of the test andspecimens employed, no single line can adequately represent the data, and therefore the confidence limits sh
23、ould be established.NOTE 2Some materials may exhibit a nonlinear relationship between log-stress and log-failure time, usually at short failure times. In such cases, the105-hour stress value computed on the basis of short-term test data may be significantly different than the value obtained when a d
24、istribution of data pointsin accordance with Test Method D2837 is evaluated. However, these data may still be useful for quality control or other applications, provided correlationwith long-term data has been established.5.3 The factors that affect creep and long-term strength behavior of plastic pi
25、pe are not completely known at this time. Thisprocedure takes into account those factors that are known to have important influences and provides a tool for investigating others.5.4 Creep, or nonrecoverable deformation for pipe made of some plastics, is as important as actual leakage in deciding whe
26、theror not a pipe has failed. Specimens that exhibit localized ballooning, however, may lead to erroneous interpretation of the creepresults unless a method of determining creep is established that precludes such a possibility. Circumferential measurements at twoor three selected positions on a spec
27、imen may not be adequate.5.5 Great care must be used to ensure that specimens are representative of the pipe under evaluation. Departure from thisassumption may introduce discrepancies as great as, if not greater than, those due to departure from details of procedure outlinedin this test method.6. A
28、pparatus6.1 Constant-Temperature SystemA water bath or other fluid bath equipped so that uniform temperature is maintainedthroughout the bath. This may require agitation. If an air or other gaseous environment is used, provision shall be made foradequate circulation. The test may be conducted at 23C
29、 (73F) or other selected temperatures as required and the temperaturetolerance requirements shall be 62C (63.6F).6.2 Pressurizing SystemAny device that is capable of continuously applying constant internal pressure on the specimen maybe used. The device shall be capable of reaching the test pressure
30、 without exceeding it and of holding the pressure within thetolerance shown in 6.6 for the duration of the test.6.3 Pressure GageA pressure gage having an accuracy sufficient to meet the pressure tolerance requirements of 6.6 isrequired.6.4 Timing DeviceA time meter connected to the pressurized flui
31、d side of the system through a pressure or flow switch, orboth. The timing device and pressure or flow switch, or both, together shall be capable of measuring the time when the specimenis at 98 % or more of test pressure with sufficient accuracy to meet the tolerance requirements of 6.6.6.5 Specimen
32、 End ClosuresEither free-end or restrained-end closures that will withstand the maximum test pressures may beused. Closures shall be designed so that they do not cause failure of the specimen. Free-end closures shall be used for referee testsfor thermoplastic pipe.NOTE 3Free-end closures fasten to t
33、he specimen so that internal pressure produces longitudinal tensile stress in addition to hoop. Compared to freeD1598 152end closure specimens, stresses in the wall of restrained-end closure specimens act in the hoop and radial directions only. Because of this difference inloading, the equivalent ho
34、op stress in free-end closure specimens of solid wall thermoplastic pipe are approximately 11 % lower than in restrained-endclosure specimens tested at the same pressure. The test results for each specimen and the LTHS will reflect this difference in test method.6.6 Time and Pressure ToleranceWhen a
35、dded together, the tolerance for the timing device and the tolerance for the pressuregage shall not exceed 62 %.7. Test Specimens7.1 Pipe Specimen LengthFor pipe sizes of 6 in. (150 mm) or less, the specimen length between end closures shall be not lessthan five times the nominal outside diameter of
36、 the pipe, but in no case less than 12 in. (300 mm). The 12 in. (300 mm) minimumspecimen length requirement shall not apply to molded specimens. For larger sizes of pipe, the minimum length between endclosures shall be not less than three times the nominal outside diameter but in no case less than 3
37、0 in. (760 mm).7.2 MeasurementsDimensions shall be determined in accordance with Test Method D2122 or Practice D3567.8. Conditioning8.1 Specimens to be tested at 23C shall be conditioned at test temperatures in a liquid bath for a minimum of 1 h or in a gaseousmedium for a minimum of 16 h before pre
38、ssurizing.8.2 When specimens are to be tested at higher temperatures, condition them in the elevated temperature environment until theyhave reached test temperature.NOTE 4Conditioning time is a function of pipe size wall thickness, temperature differential, the film heat transfer coefficient and whe
39、ther the elevatedtemperature environment is applied to one or both sides of the specimen. One-hour conditioning of 1-in. and smaller pipe at 82C (180F) in a waterenvironment has been found to be sufficient.8.3 Unless otherwise agreed upon, the test temperature shall be 23 6 2C (73 6 3.6F) for thermo
40、plastics. For thermosets testat 23 6 2C (73 6 3.6F) or at maximum rated temperature depending on intended service. While every effort should be madeto meet the temperature tolerances listed, temporarily exceeding the (+) temperature tolerance does not necessarily require that allsamples under test b
41、e abandoned. Data points from such samples may still be acceptable. Refer also to Test Method D2837 orPractice D2992 to determine the suitability of these data points.9. Procedure9.1 Attach end closures to the pipe test sections and fill each specimen completely with the test fluid conditioned to th
42、e testtemperature. Attach the specimens to the pressuring device, making certain no gas is entrapped when using liquids. Completelyimmerse the test specimens in the conditioning medium.9.2 Support specimens in such a way as to prevent bending or deflection by the weight of the pipe while under test.
43、 This supportshall not constrain the specimen circumferentially or longitudinally.9.3 After conditioning the specimens as specified in Section 8, adjust the pressure to produce the desired loading. Apply thepressure to the specimens and make sure the timing devices have started.9.4 Record the time-t
44、o-failure of each specimen.The time-to-failure shall not include periods of time during which the specimenwas under depleted pressure or under no pressure.9.4.1 Any failure occurring within one pipe diameter of the end closure shall be examined carefully. If there is any reason tobelieve that the fa
45、ilure is attributable to the end closure, the value shall be discarded in computing averages or in plotting the data.9.4.2 The failure value of a specimen that fails due to column buckling shall be discarded in computing averages or in plottingthe data.NOTE 5For certain materials creep measurements
46、should be made in accordance with Test Method D2837. It describes the procedure for determiningwhen “circumferential expansion” must be used as a criterion for establishing the hydrostatic design stress.9.5 Pressure ConnectionsEach specimen may be pressured individually or through a manifold system.
47、 If a manifold systemis utilized, each pressure connection should include a check valve to prevent pressure depletion of the system when one specimenfails. Where the system is designed to prevent one specimen failure from depressurizing the manifold, each specimen shall haveits own timing device.9.6
48、 Test FluidsWhile water is normally used inside the test specimens, any fluid may be used. However, if a gas is used specialcare must be taken because of the potential energy stored in any compressed gas.NOTE 6Test ApparatusAll the above components with some additional features can be acquired as as
49、sembled stress rupture testers. Some unitsutilize a liquid bath environment that can be adjusted from 20 to +150C. Other units offer a single pressure source with as many as 40 manifolds thatcan each be set for a different pressure and 240 specimen positions. A list of manufacturers of stress rupture test equipment can be obtained from theASTM Information Center.D1598 15310. Calculation10.1 Hoop stress in the pipe specimens is calculated using equations (approximation) for the hoop stress, as follows:S 5PD2t!/2t (1)orS 5PDR21!2 (2)wh
