1、Designation: D2924 01(Reapproved 2006) D2924 12 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 designati
2、on 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 covers determinat
3、ion of the resistance of fiberglass pipe to external pressure. It classifies failures asbuckling, compressive, and leaking. Both glass-fiber-reinforced thermosetting-resin pipe (RTRP) and glass-fiber-reinforcedpolymer mortar pipe (RPMP) are fiberglass pipes.NOTE 1For the purposes of this standard, p
4、olymer does not include natural polymers.1.2 The values stated in inch-pound units are to be regarded as standard. The SI units given in parentheses are for informationonly.NOTE 2There is no similar or equivalent ISO standard.1.3 This standard does not purport to address all of the safety concerns,
5、if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C33 Specification for Concrete AggregatesD618 Pr
6、actice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1600 Terminology for Abbreviated Terms Relating to PlasticsF412 Terminology Relating to Plastic Piping Systems3. Terminology3.1 Definitions:3.1.1 Definitions are in accordance with Terminology D883 or F412 and abbrevia
7、tions 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 the requirements of Specification C33, except that the requirements forgradation shall not apply.3.2.2 buckling failure pressu
8、re the external gage pressure at which buckling occurs. Buckling is characterized by a sharpdiscontinuity in the pressure-volume change graph and subsequent fracture in the test specimen appearing as an axially orientedcrack. Buckling is an elastic instability type of failure and is normally associa
9、ted with thin-wall pipe.3.2.3 compressive failure pressurethe maximum external gage pressure that the specimen will resist without transmission ofthe testing fluid through the wall. Compressive failure pressure will not be associated with a sharp discontinuity in thepressure-volume change graph nor
10、lead to a fracture appearing as a sharp axially oriented crack. It will appear as a fracture whichis the result of reaching the compressive strength limits of the material and is normally associated with thick-wall pipe. Failureis usually identified by a sudden drop in pressure.3.2.4 fiberglass pipe
11、, na tubular product containing glass fiber reinforcements embedded in or surrounded by curedthermosetting resin; the composite structure may contain aggregate, granular, or platelet fillers, thixotropic agents, pigments, ordyes; thermoplastic or thermosetting liners or coatings may be included.3.2.
12、5 leaking pressurethe external gage pressure at which the test fluid is transmitted through the pipe wall. It is characterizedin this test by continuous volume change indications with no pressure increase.3.2.6 reinforced polymer mortar pipe (RPMP), na fiberglass pipe with aggregate.*A Summary of Ch
13、anges section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.7 reinforced thermosetting resin pipe (RTRP), na fiberglass pipe without aggregate.4. Summary of Test Method4.1 This test method cons
14、ists of loading a specimen to failure in a short time interval by means of continuouslyincrementallyincreasing external fluid pressure at a controlled constant temperature. Fluid is also maintained inside the pipe, and changes in theinside volume are monitored with a bleed hole and fluid level tube.
15、 On Cartesian coordinates, pressure versus change in volumeis plotted and the failure pressure selected as indicated by the graph. Scaling constants are presented for extending the results toother diameters.5. Significance and Use5.1 The values obtained by this test method are applicable only to con
16、ditions that specifically duplicate the procedures used.5.2 After a scaling constant is determined for one diameter, this may be used for calculating the external failure pressures ofother diameters as long as the resin and reinforcement (if used), the wall thickness-to-diameter ratio, and the reinf
17、orcement pattern(if reinforcement is used) are the same.NOTE 3Based upon tests conducted on one size of pipe, a scaling constant is calculated according to 11.110.1 or 11.210.2. The appropriate constantis used to calculate failure pressure for other pipe diameters, but it can only be applied if the
18、same resin and reinforcement are used, the wall thicknessto diameter ratios are similar, and the reinforcement pattern is constant.5.3 In the application of the following test requirements and recommendations, care must be exercised to ensure that thespecimens tested are truly representative of the
19、group being studied.6. Apparatus (see Figs. 1 and 2)1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics,Plastics and is the direct responsibility of Subcommittee D20.23 on Reinforced PlasticPiping Systems and Chemical Equipment.Current edition approved Sept. 15, 2006Oct. 1
20、, 2012. Published September 2006November 2012. Originally approved in 1970. Last previous edition approved in 20012006as D2924 01.D2924 01 (2006). DOI: 10.1520/D2924-01R06.10.1520/D2924-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serv
21、iceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.FIG. 1 Apparatus Showing Specimen Loading with Both Hoop and Axial LoadsD2924 1226.1 Test ChamberAn external chamber capable of withstanding pressures to be encountered.
22、 It may be either the type thatapplies both hoop and axial loads as shown in Fig. 1 or the type that applies hoop load only as shown in Fig. 2. In either event,the report shall state which type loading was used for test.6.2 Volume or Weight Change IndicatorThe specimen shall be instrumented to measu
23、re changes in volume or weight. Oneof the following two devices shall be used.weight by use of a balance accurate to within 60.1 g.6.2.1 Transparent Tubeconnected to the test specimen so that the volume changes of the specimen result in changes in thelevel of fluid in the tube. A scale shall be affi
24、xed to the tube so variations in fluid level can be recorded. Absolute measurementof volume change is not required.6.2.2 ScaleA balance accurate to within 60.1 g.6.3 Pressurizing SystemA device capable of exerting external fluid pressure to the specimen at a specified constant rate. ABourdon-tube pr
25、essure gage or recording gage with an accuracy of6 1 % of full scale should be used, and the anticipated failurepressure should be in the middle two thirds of the gage range. Care should be exercised so the gage is placed where it will givea true reading of the external pressure on the test specimen
26、.6.4 Test FluidWater or hydraulic oil.6.5 TimerAny time-measuring device that can measure the duration of test with accuracy of 1 s.6.6 Temperature RegulatorWhen temperatures other than ambient are being studied, a temperature-regulating system will beemployed that will maintain the temperature of t
27、he testing fluid and specimen at a specified amount 62C.7. Test Specimens7.1 Number of SpecimensA minimum of five specimens shall be used for determining the external pressure resistance. Anyspecimens that are tested and fall outside the specified time limits shall be discounted and replaced with eq
28、uivalent specimens, sothat a minimum of five valid specimens are tested.7.2 Specimen SizeThe inside and outside diameters of the pipe specimens shall be as fabricated, with the permissibleexception of that portion of the pipe within 2 in. (50 mm) of the end closures. The minimum specimen length expo
29、sed to externalpressure shall be the greater of:FIG. 2 Apparatus Showing Specimen Loading with Hoop Load OnlyD2924 123L 510D!or Roarks formula for long tube length:3L 54.90rrtwhere:L = length of test specimen exposed to external pressure, in. (or mm),D = average outside diameter of pipe, in. (or mm)
30、,r = mean wall radius (do not include unreinforced liner), in. (or mm), andt = minimum wall thickness (do not include unreinforced liner), in. (or mm).8. Conditioning8.1 All samples shall be conditioned for a minimum of 2 h in the fluid in which they will be tested. The temperature of the fluidshall
31、 be uniform and stabilized to within 62C of the test temperature during conditioning.9. Procedure A9.1 Mount the specimen in the test chamber and fit the specimen with the volume change measuring tube with both externaland internal volumes filled with the test fluid. Take care to expel all air from
32、the inside of the specimen as any gaseous fluidescaping through the measuring tube during test will disqualify the test.9.2 Condition the system at a temperature in accordance with Section 8.9.3 Increase the pressure at a constant rate so failure occurs in not less than 1 min nor greater than 5 min.
33、 As the pressure isbeing increased, take readings of the pressure and associated volume change so a buckling pressure, if present, can be ascertained.Rapidly increasing volume change indications with a reduction in the pressurizing rates constitutes failure. Continue the test untilthe specimen fract
34、ures, if possible.9.4 After the specimen has failed, remove it from the external pressure chamber and observe and record appearance.9.5 Make a graph showing external pressure versus volume change. A sharp change in slope indicates either a buckling pressureor a pressure at which the pipe wall transm
35、itted fluid. Either condition is classified as failure.9. Procedure B9.1 Mount the specimen in the test chamber and fill both internal and external volumes with the test fluid. Take care to expelall air from the inside of the specimen as any gaseous fluid escaping through the measuring tube during t
36、he test will disqualifythe test. Fit the specimen with a tube to direct the fluid into a suitable basin for collecting and weighing. Condition the system ata temperature in accordance with Section 8.9.2 Increase the pressure at an incremental rate. The increment shall be chosen to allow at least 10
37、readings before failure. Afterthe fluid has stopped flowing from the tube, record the pressure and weight of the fluid displaced. Rapidly increasing weight ofdisplaced fluid with a small increase in pressure indicates failure. Continue the test until the specimen fractures, if possible. Recordthe ti
38、me to failure.9.3 After the specimen has failed, remove it from the external pressure chamber and observe and record appearance.9.4 Make a graph showing external pressure versus weight of fluid displaced. A sharp change in slope indicates either a bucklingpressure or a pressure at which the pipe wal
39、l transmitted fluid. Either condition is classified as failure.10. Calculation10.1 For specimens that failed by buckling, calculate a buckling scaling constant as follows:K = P/E (r/t)3where:K = buckling scaling constant,P = external collapse pressure, psi (or MPa),E = circumferential modulus of ela
40、sticity,r = mean wall radius (do not include unreinforced liner in reinforced wall), in. (or mm), andt = minimum wall thickness (do not include unreinforced liner in reinforced wall), in. (or mm).10.2 For specimens that failed by collapse, calculate a compressive failure scaling constant as follows:
41、3 Roark, Raymond J., Roarks Formulas for Stress and Strain, McGraw-Hill Book Company, New York, NY, Sixth Edition, 1989, p. 690.D2924 124C 5 P cD 2 t!/2twhere:C = compressive failure scaling constant,Pc = pressure at failure, psi (or MPa),D = the average outside diameter of the specimen, in. (or mm)
42、, andt = minimum pipe wall thickness (do not include liner in filament reinforced wall), in. (or mm).10.3 Calculate the average failure pressure for all five specimens tested.10.4 Calculate the average scaling constant for all five specimens tested.11. Report11.1 Report the following information:11.
43、1.1 Complete identification of the specimens, including material type, source, manufacturers name, pipe trade name, andprevious history,11.1.2 Pipe DimensionsRecord dimensions of each specimen including nominal size, length exposed to external pressure,minimum wall thickness, and average outside dia
44、meter. The wall thickness and outside diameter shall be reinforced dimensionsonly. Unreinforced thickness shall also be recorded.11.1.3 Test temperature and test fluid, (water or oil),11.1.4 Type of loading used (hoop only or both hoop and axial), and procedure used (A or B),11.1.5 Failure pressures
45、 for each specimen tested and the average,11.1.6 Type of failure (buckling, compressive, or leaking),11.1.7 Time to failure of each specimen tested,11.1.8 Scaling constant (see 11.110.1 for buckling failures, 11.210.2 for compressive failures, no scaling permitted for leakingfailures), and11.1.9 Dat
46、e of test.12. Precision and Bias12.1 The precision of this test method was determined from the 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 calculated from the above test program.
47、NOTE 4These values were developed using Procedure A. The samples were conditioned at 23 6 2 (73.4 6 3.6F) and 50 6 5 % relative humidityfor not less than 40 h prior to test in accordance with Procedure A of Practice D618.The critical differences indicate the maximum deviation of results beyond which
48、 measured values should be considered suspectat a probability level of 0.95. They are expressed as percentages of the mean value.12.2.1 Hoop Load MethodFor individual values within a set of five, the precision is 68.4 %. Between averages of fivedeterminations, the precision is 64.9 %.12.2.2 Axial an
49、d Hoop Load MethodFor individual values within a set of five, the precision is 613.1 %. Between averagesof five determinations, the precision is 67.6 %.12.3 There are presently no definite means of establishing a true value, so no bias statement can be made.13. Keywords13.1 external pressure resistance; fiberglass pipe; pipe; reinforced polymer mortar pipe (RPMP); reinforced thermosetting-resinpipe (RTRP)D2924 125SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue, issue(D292
