1、Designation: D2924 12 (Reapproved 2017) An American National StandardStandard Test Method forExternal Pressure Resistance of “Fiberglass”(Glass-Fiber-Reinforced Thermosetting-Resin) Pipe1This standard is issued under the fixed designation D2924; the number immediately following the designation indic
2、ates 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. Scope1.1 This test method covers determination of th
3、e resistanceof fiberglass pipe to external pressure. It classifies failures asbuckling, compressive, and leaking. Both glass-fiber-reinforced thermosetting-resin pipe (RTRP) and glass-fiber-reinforced polymer mortar pipe (RPMP) are fiberglass pipes.NOTE 1For the purposes of this standard, polymer do
4、es not includenatural polymers.1.2 The values stated in inch-pound units are to be regardedas standard. The SI units given in parentheses are for informa-tion only.NOTE 2There is no known ISO equivalent to this standard.1.3 This standard does not purport to address all of thesafety concerns, if any,
5、 associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationall
6、y recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C33 Specificat
7、ion for Concrete AggregatesD618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsF412 Terminology Relating to Plastic Piping Systems3. Terminology3.1 Definitions:3.1.1 Definitions are in accordance with Ter
8、minology D883or F412 and abbreviations are in accordance with TerminologyD1600, unless otherwise indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 aggregate, na siliceous sand conforming to therequirements of Specification C33, except that the require-ments for gradation shall not a
9、pply.3.2.2 buckling failure pressure the external gage pressureat which buckling occurs. Buckling is characterized by a sharpdiscontinuity in the pressure-volume change graph and subse-quent fracture in the test specimen appearing as an axiallyoriented crack. Buckling is an elastic instability type
10、of failureand is normally associated with thin-wall pipe.3.2.3 compressive failure pressurethe maximum externalgage pressure that the specimen will resist without transmis-sion of the testing fluid through the wall. Compressive failurepressure will not be associated with a sharp discontinuity in the
11、pressure-volume change graph nor lead to a fracture appearingas a sharp axially oriented crack. It will appear as a fracturewhich is the result of reaching the compressive strength limitsof the material and is normally associated with thick-wall pipe.Failure is usually identified by a sudden drop in
12、 pressure.3.2.4 fiberglass pipe, na tubular product containing glassfiber reinforcements embedded in or surrounded by curedthermosetting resin; the composite structure may containaggregate, granular, or platelet fillers, thixotropic agents,pigments, or dyes; thermoplastic or thermosetting liners orc
13、oatings may be included.3.2.5 leaking pressurethe external gage pressure at whichthe test fluid is transmitted through the pipe wall. It ischaracterized in this test by continuous volume change indica-tions with no pressure increase.3.2.6 reinforced polymer mortar pipe (RPMP), na fiber-glass pipe wi
14、th aggregate.3.2.7 reinforced thermosetting resin pipe (RTRP), nafi-berglass pipe without aggregate.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.23 on Reinforced PlasticPiping Systems and Chemical Equipment.Current
15、edition approved Sept. 1, 2017. Published September 2017. Originallyapproved in 1970. Last previous edition approved in 2012 as D2924 12. DOI:10.1520/D2924-12R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
16、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 StatesThis international st
17、andard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14.
18、Summary of Test Method4.1 This test method consists of loading a specimen tofailure in a short time interval by means of incrementallyincreasing external fluid pressure at a controlled constanttemperature. Fluid is also maintained inside the pipe, andchanges in the inside volume are monitored with a
19、 bleed holeand fluid level tube. On Cartesian coordinates, pressure versuschange in volume is plotted and the failure pressure selected asindicated by the graph. Scaling constants are presented forextending the results to other diameters.5. Significance and Use5.1 The values obtained by this test me
20、thod are applicableonly to conditions that specifically duplicate the proceduresused.5.2 After a scaling constant is determined for one diameter,this may be used for calculating the external failure pressuresof other diameters as long as the resin and reinforcement (ifused), the wall thickness-to-di
21、ameter ratio, and the reinforce-ment pattern (if reinforcement is used) are the same.NOTE 3Based upon tests conducted on one size of pipe, a scalingconstant is calculated according to 10.1 or 10.2. The appropriate constantis used to calculate failure pressure for other pipe diameters, but it canonly
22、 be applied if the same resin and reinforcement are used, the wallthickness to diameter ratios are similar, and the reinforcement pattern isconstant.5.3 In the application of the following test requirements andrecommendations, care must be exercised to ensure that thespecimens tested are truly repre
23、sentative of the group beingstudied.6. Apparatus (see Figs. 1 and 2)6.1 Test ChamberAn external chamber capable of with-standing pressures to be encountered. It may be either the typethat applies both hoop and axial loads as shown in Fig. 1 or thetype that applies hoop load only as shown in Fig. 2.
24、In eitherevent, the report shall state which type loading was used fortest.6.2 Weight Change IndicatorThe specimen shall be in-strumented to measure changes in weight by use of a balanceaccurate to within 60.1 g.6.2.1 Transparent TubeConnected to the test specimen sothat the volume changes of the sp
25、ecimen result in changes inthe level of fluid in the tube. A scale shall be affixed to the tubeso variations in fluid level can be recorded. Absolute measure-ment of volume change is not required.6.3 Pressurizing SystemA device capable of exerting ex-ternal fluid pressure to the specimen at a specif
26、ied constantrate. A Bourdon-tube pressure gage or recording gage with anaccuracy of6 1 % of full scale should be used, and theanticipated failure pressure should be in the middle two thirdsof the gage range. Care should be exercised so the gage isplaced where it will give a true reading of the exter
27、nal pressureon the test specimen.6.4 Test FluidWater or hydraulic oil.6.5 TimerAny time-measuring device that can measurethe duration of test with accuracy of 1 s.6.6 Temperature RegulatorWhen temperatures other thanambient are being studied, a temperature-regulating systemwill be employed that will
28、 maintain the temperature of thetesting fluid and specimen at a specified amount 62C.7. Test Specimens7.1 Number of SpecimensA minimum of five specimensshall be used for determining the external pressure resistance.Any specimens that are tested and fall outside the specifiedtime limits shall be disc
29、ounted and replaced with equivalentspecimens, so that a minimum of five valid specimens aretested.7.2 Specimen SizeThe inside and outside diameters of thepipe specimens shall be as fabricated, with the permissibleexception of that portion of the pipe within 2 in. (50 mm) of theend closures. The mini
30、mum specimen length exposed toexternal pressure shall be the greater of:L 5 10D!or Roarks formula for long tube length:3L 5 4.90rrt3Roark, Raymond J., Roarks Formulas for Stress and Strain, McGraw-HillBook Company, New York, NY, Sixth Edition, 1989, p. 690.FIG. 1 Apparatus Showing Specimen Loading w
31、ith Both Hoopand Axial LoadsD2924 12 (2017)2where:L = length of test specimen exposed to external pressure, in.(or mm),D = average outside diameter of pipe, in. (or mm),r = mean wall radius (do not include unreinforced liner), in.(or mm), andt = minimum wall thickness (do not include unreinforcedlin
32、er), in. (or mm).8. Conditioning8.1 All samples shall be conditioned for a minimum of 2 hin the fluid in which they will be tested. The temperature of thefluid shall be uniform and stabilized to within 62C of the testtemperature during conditioning.9. Procedure9.1 Mount the specimen in the test cham
33、ber and fill bothinternal and external volumes with the test fluid. Take care toexpel all air from the inside of the specimen as any gaseousfluid escaping through the measuring tube during the test willdisqualify the test. Fit the specimen with a tube to direct thefluid into a suitable basin for col
34、lecting and weighing. Condi-tion the system at a temperature in accordance with Section 8.9.2 Increase the pressure at an incremental rate. The incre-ment shall be chosen to allow at least 10 readings beforefailure. After the fluid has stopped flowing from the tube,record the pressure and weight of
35、the fluid displaced. Rapidlyincreasing weight of displaced fluid with a small increase inpressure indicates failure. Record the time to failure.9.3 After the specimen has failed, remove it from theexternal pressure chamber and observe and record appearance.9.4 Make a graph showing external pressure
36、versus weightof fluid displaced. A sharp change in slope indicates either abuckling pressure or a pressure at which the pipe walltransmitted fluid. Either condition is classified as failure.10. Calculation10.1 For specimens that failed by buckling, calculate abuckling scaling constant as follows:K 5
37、 PEr t!3where:K = buckling scaling constant,P = external collapse pressure, psi (or MPa),E = circumferential modulus of elasticity,r = mean wall radius (do not include unreinforced liner inreinforced wall), in. (or mm), andt = minimum wall thickness (do not include unreinforcedliner in reinforced wa
38、ll), in. (or mm).10.2 For specimens that failed by collapse, calculate acompressive failure scaling constant as follows:C 5 PcD 2 t!/2twhere:C = compressive failure scaling constant,Pc= pressure at failure, psi (or MPa),D = the average outside diameter of the specimen, in. (ormm), andt = minimum pip
39、e wall thickness (do not include liner infilament reinforced wall), in. (or mm).10.3 Calculate the average failure pressure for all fivespecimens tested.10.4 Calculate the average scaling constant for all fivespecimens tested.11. Report11.1 Report the following information:11.1.1 Complete identifica
40、tion of the specimens, includingmaterial type, source, manufacturers name, pipe trade name,and previous history,11.1.2 Pipe DimensionsRecord dimensions of each speci-men including nominal size, length exposed to externalpressure, minimum wall thickness, and average outside diam-eter. The wall thickn
41、ess and outside diameter shall be rein-forced dimensions only. Unreinforced thickness shall also berecorded.11.1.3 Test temperature and test fluid, (water or oil),11.1.4 Type of loading used (hoop only or both hoop andaxial),11.1.5 Failure pressures for each specimen tested and theaverage,11.1.6 Typ
42、e of failure (buckling, compressive, or leaking),11.1.7 Time to failure of each specimen tested,FIG. 2 Apparatus Showing Specimen Loading with Hoop LoadOnlyD2924 12 (2017)311.1.8 Scaling constant (see 10.1 for buckling failures, 10.2for compressive failures, no scaling permitted for leakingfailures)
43、, and11.1.9 Date of test.12. Precision and Bias12.1 The precision of this test method was determined fromthe results of one laboratory performing one set of tests by eachloading method on each of six pipe sizes and conditions.12.2 The following values of precision have been calculatedfrom the above
44、test program.NOTE 4These values were developed using ProcedureA. The sampleswere conditioned at 23 6 2 (73.4 6 3.6F) and 50 6 5 % relativehumidity for not less than 40 h prior to test in accordance with ProcedureA of Practice D618.The critical differences indicate the maximum deviation ofresults bey
45、ond which measured values should be consideredsuspect at a probability level of 0.95. They are expressed aspercentages of the mean value.12.2.1 Hoop Load MethodFor individual values within aset of five, the precision is 68.4 %. Between averages of fivedeterminations, the precision is 64.9 %.12.2.2 A
46、xial and Hoop Load MethodFor individual valueswithin a set of five, the precision is 613.1 %. Betweenaverages of five determinations, the precision is 67.6 %.12.3 There are presently no definite means of establishing atrue value, so no bias statement can be made.13. Keywords13.1 external pressure re
47、sistance; fiberglass pipe; pipe; re-inforced polymer mortar pipe (RPMP); reinforcedthermosetting-resin pipe (RTRP)ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly adv
48、ised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either
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