1、Designation: D 2924 01(Reapproved 2006)An American National StandardStandard Test Method forExternal Pressure Resistance of “Fiberglass”(Glass-Fiber-Reinforced Thermosetting-Resin) Pipe1This standard is issued under the fixed designation D 2924; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers determination of
3、the 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
4、does 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 similar or equivalent ISO 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C33 Specification for Concrete AggregatesD 618 Practi
6、ce for Conditioning Plastics for TestingD 883 Terminology Relating to PlasticsD 1600 Terminology for Abbreviated Terms Relating toPlasticsF 412 Terminology Relating to Plastic Piping Systems3. Terminology3.1 Definitions:3.1.1 Definitions are in accordance with Terminology D 883or F 412 and abbreviat
7、ions are in accordance with TerminologyD 1600, 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 apply.3.2.2 buckling failure press
8、ure 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 of failureand is normally associa
9、ted 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 thepressure-volume change graph nor
10、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 pressure.3.2.4 fiberglass pipe,
11、na tubular product containing glassfiber reinforcements embedded in or surrounded by curedthermosetting resin; the composite structure may containaggregate, granular, or platelet fillers, thixotropic agents, pig-ments, or dyes; thermoplastic or thermosetting liners or coat-ings may be included.3.2.5
12、 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 with aggregate.3.2.7 reinforced
13、 thermosetting resin pipe (RTRP), nafiberglass pipe without aggregate.4. Summary of Test Method4.1 This test method consists of loading a specimen tofailure in a short time interval by means of continuouslyincreasing external fluid pressure at a controlled constanttemperature. Fluid is also maintain
14、ed inside the pipe, andchanges in the inside volume are monitored with a bleed holeand fluid level tube. On Cartesian coordinates, pressure versuschange in volume is plotted and the failure pressure selected as1This test method is under the jurisdiction ofASTM Committee D20 on Plastics,and is the di
15、rect responsibility of Subcommittee D20.23 on Reinforced PlasticPiping Systems and Chemical Equipment.Current edition approved Sept. 15, 2006. Published September 2006. Originallyapproved in 1970. Last previous edition approved in 2001 as D 2924 01.2For referenced ASTM standards, visit the ASTM webs
16、ite, 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor
17、 Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.indicated by the graph. Scaling constants are presented forextending the results to other diameters.5. Significance and Use5.1 The values obtained by this test method are applicableonly to conditions that specifically duplicate the
18、 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-diameter ratio, and the reinforce-ment pattern (if reinforcement is use
19、d) are the same.NOTE 3Based upon tests conducted on one size of pipe, a scalingconstant is calculated according to 11.1 or 11.2. The appropriate constantis used to calculate failure pressure for other pipe diameters, but it canonly be applied if the same resin and reinforcement are used, the wallthi
20、ckness 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 representative of the group beingstudied.6. Apparatus (see Figs. 1 and 2)6
21、.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. In eitherevent, the report shall state which type loading was used fo
22、rtest.6.2 Volume or Weight Change IndicatorThe specimenshall be instrumented to measure changes in volume or weight.One of the following two devices shall be used.6.2.1 Transparent Tubeconnected to the test specimen sothat the volume changes of the specimen result in changes inthe level of fluid in
23、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.6.2.2 ScaleA balance accurate to within 60.1 g.6.3 Pressurizing SystemA device capable of exertingexternal fluid pressure to the specimen at a specified
24、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 external
25、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 mai
26、ntain the temperature of thetesting fluid and specimen at a specified amount 62C.FIG. 1 Apparatus Showing Specimen Loading with Both Hoopand Axial LoadsFIG. 2 Apparatus Showing Specimen Loading with Hoop LoadOnlyD 2924 01 (2006)27. Test Specimens7.1 Number of SpecimensA minimum of five specimensshal
27、l be used for determining the external pressure resistance.Any specimens that are tested and fall outside the specifiedtime limits shall be discounted and replaced with equivalentspecimens, so that a minimum of five valid specimens aretested.7.2 Specimen SizeThe inside and outside diameters of thepi
28、pe specimens shall be as fabricated, with the permissibleexception of that portion of the pipe within 2 in. (50 mm) of theend closures. The minimum specimen length exposed toexternal pressure shall be the greater of:L 5 10D!or Roarks formula for long tube length:3L 5 4.90rrtwhere:L = length of test
29、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 unreinforcedliner), in. (or mm).8. Conditioning8.1 All samples shall be conditioned
30、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. Procedure A9.1 Mount the specimen in the test chamber and fit thespecimen with the volume change measuring tube with
31、bothexternal and internal volumes filled with the test fluid. Takecare to expel all air from the inside of the specimen as anygaseous fluid escaping through the measuring tube during testwill disqualify the test.9.2 Condition the system at a temperature in accordancewith Section 8.9.3 Increase the p
32、ressure at a constant rate so failure occursin not less than 1 min nor greater than 5 min. As the pressureis being increased, take readings of the pressure and associatedvolume change so a buckling pressure, if present, can beascertained. Rapidly increasing volume change indicationswith a reduction
33、in the pressurizing rates constitutes failure.Continue the test until the specimen fractures, if possible.9.4 After the specimen has failed, remove it from theexternal pressure chamber and observe and record appearance.9.5 Make a graph showing external pressure versus volumechange. A sharp change in
34、 slope indicates either a bucklingpressure or a pressure at which the pipe wall transmitted fluid.Either condition is classified as failure.10. Procedure B10.1 Mount the specimen in the test chamber and fill bothinternal and external volumes with the test fluid. Take care toexpel all air from the in
35、side 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 collecting and weighing. Condi-tion the system at a temperature in accordance with Section 8.10.2 Increase t
36、he pressure at an incremental rate. Theincrement 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 the fluid displaced. Rapidlyincreasing weight of displaced fluid with a small increase inpressure indicate
37、s failure. Continue the test until the specimenfractures, if possible. Record the time to failure.10.3 After the specimen has failed, remove it from theexternal pressure chamber and observe and record appearance.10.4 Make a graph showing external pressure versus weightof fluid displaced. A sharp cha
38、nge in slope indicates either abuckling pressure or a pressure at which the pipe walltransmitted fluid. Either condition is classified as failure.11. Calculation11.1 For specimens that failed by buckling, calculate abuckling scaling constant as follows:K = P/E (r/t)3where:K = buckling scaling consta
39、nt,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 wall), in. (or mm).11.2 For specimens that
40、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 pipe wall thickness (do not include liner in
41、filament reinforced wall), in. (or mm).11.3 Calculate the average failure pressure for all fivespecimens tested.11.4 Calculate the average scaling constant for all fivespecimens tested.12. Report12.1 Report the following information:3Roark, Raymond J., Roarks Formulas for Stress and Strain, McGraw-H
42、illBook Company, New York, NY, Sixth Edition, 1989, p. 690.D 2924 01 (2006)312.1.1 Complete identification of the specimens, includingmaterial type, source, manufacturers name, pipe trade name,and previous history,12.1.2 Pipe DimensionsRecord dimensions of each speci-men including nominal size, leng
43、th exposed to external pres-sure, minimum wall thickness, and average outside diameter.The wall thickness and outside diameter shall be reinforceddimensions only. Unreinforced thickness shall also be re-corded.12.1.3 Test temperature and test fluid, (water or oil),12.1.4 Type of loading used (hoop o
44、nly or both hoop andaxial), and procedure used (A or B),12.1.5 Failure pressures for each specimen tested and theaverage,12.1.6 Type of failure (buckling, compressive, or leaking),12.1.7 Time to failure of each specimen tested,12.1.8 Scaling constant (see 11.1 for buckling failures, 11.2for compress
45、ive failures, no scaling permitted for leakingfailures), and12.1.9 Date of test.13. Precision and Bias13.1 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.13.2 The following
46、values of precision have been calculatedfrom the above 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 D 618.The critical
47、differences indicate the maximum deviation ofresults beyond which measured values should be consideredsuspect at a probability level of 0.95. They are expressed aspercentages of the mean value.13.2.1 Hoop Load MethodFor individual values within aset of five, the precision is 68.4 %. Between averages
48、 of fivedeterminations, the precision is 64.9 %.13.2.2 Axial and Hoop Load MethodFor individual val-ues within a set of five, the precision is 613.1 %. Betweenaverages of five determinations, the precision is 67.6 %.13.3 There are presently no definite means of establishing atrue value, so no bias s
49、tatement can be made.14. Keywords14.1 external pressure resistance; fiberglass pipe; pipe; re-inforced polymer mortar pipe (RPMP); reinforcedthermosetting-resin pipe (RTRP)SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue, D 292499,that may impact the use of this standard.(1) Changed acronym, RPMP, definition form reinforced plas-tic mortar pipe to reinforced polymer mortar pipe.ASTM International takes no position respecting the validity of any patent rights asserted in connection
