1、Designation: D5365 12 An American National StandardStandard Test Method forLong-Term Ring-Bending Strain of “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pipe1This standard is issued under the fixed designation D5365; the number immediately following the designation indicates the year of
2、original 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 a procedure for determining thelon
3、g-term ring-bending strain (Sb) of “fiberglass” pipe. Bothglass-fiber-reinforced thermosetting-resin pipe (RTRP) andglass-fiber-reinforced polymer mortar pipe (RPMP) are “fiber-glass” pipes.1.2 The values stated in inch-pound units are to be regardedas the standard. The SI units given in parentheses
4、 are forinformation only.1.3 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 determine the applica-bility of regulatory limitations pri
5、or to use. A specific warningstatement is given in 9.5.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD3567 Practice for Determining Dimensions of “Fib
6、erglass”(Glass-Fiber-Reinforced Thermosetting Resin) Pipe andFittings3. Terminology3.1 Definitions:3.1.1 GeneralDefinitions are in accordance with Termi-nology D883 and abbreviations are in accordance with Termi-nology D1600 unless otherwise indicated.3.2 Definitions of Terms Specific to This Standa
7、rd:3.2.1 end pointthe failure of the test specimen. The failuremode may be catastrophic, characterized by a sudden fracturethrough the pipe wall in the area of greatest strain.3.2.2 fiberglass pipetubular product containing glass-fiberreinforcements embedded in or surrounded by curing thermo-setting
8、 resin. The composite structure may contain aggregate,granular or platelet fillers, thixotropic agents, pigments, ordyes; thermoplastic or thermosetting liners or coatings may beincluded.3.2.3 reinforced polymer mortar pipe (RPMP)fiberglasspipe with aggregate.3.2.4 reinforced thermosetting resin pip
9、e (RTRP)fiberglass pipe without aggregate.4. Summary of Test Method4.1 This test method consists of subjecting submerged-pipering specimens to various increasing deflections induced by aconstant load and monitoring the time to failure.Aminimum of18 samples are required. Test temperatures are obtaine
10、d bytesting in a fluid environment where the temperature iscontrolled.4.2 The long-term ring-bending strain is obtained by anextrapolation to 50 years of a log-log linear regression line forfailure strain versus time.NOTE 2It is the consensus of Subcommittee D 20.23 that the log-loglinear regression
11、 analysis of test data is a conservative approach and isrepresentative of standard industry practice. However, a task group hasbeen formed to evaluate alternative non-linear analysis methods.5. Significance and Use5.1 This test method determines the long-term ring-bendingstrain of pipe when deflecte
12、d under constant load and im-mersed in a chemical environment. It has been found thateffects of chemical environments can be accelerated by straininduced by deflection. This information is useful and necessaryfor the design and application of buried fiberglass pipe.NOTE 3Pipe of the same diameter bu
13、t of different wall thicknesseswill develop different strains with the same deflection. Also, pipes havingthe same wall thickness but different constructions making up the wallmay develop different strains with the same deflection.1This test method is under the jurisdiction ofASTM Committee D20 on P
14、lasticsand is the direct responsibility of Subcommittee D20.23 on Reinforced PlasticPiping Systems and Chemical Equipment.Current edition approved April 1, 2012. Published May 2012. Originallyapproved in 1993. Last previous edition approved in 2006 as D5365 - 06. DOI:10.1520/D5365-12.2For referenced
15、 ASTM standards, visit the ASTM website, 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.*A Summary of Changes section appears at the end of this standardCopyright A
16、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Loading DeviceThe testing apparatus shall be suitablefor maintaining a constant load on the test specimen.6.2 Load ApplicationThe load may be applied to the testspecimens using any
17、of three alternative pairs of parallelloading surfaces; flat plates, rods or bars of a length at least aslong as the pipe ring and of sufficient strength and stiffness toensure a straight loading surface throughout the test. The sametype of loading device shall be used for each specimen in a testser
18、ies. In order to achieve uniform strain along the pipe, use0.25-in. (6-mm) thick elastomeric pads between the parallelloading surfaces and the pipe ring (see Note 2).6.2.1 Flat PlatesThe plates shall have a minimum 6-in.(152-mm) width.6.2.2 BarsThe bars shall have a flat contact surface of0.75 6 0.2
19、5 in. (19 6 6 mm).6.2.3 RodsThe rod diameter shall be 2 6 0.25 in. (51 6 6mm) for pipe rings 12 in. (305 mm) and greater in diameter.For smaller pipes, the rod diameter shall be 1 6 0.25 in. (25 66 mm).6.3 Environment ContainmentA test enclosure of suffi-cient size to fully immerse the test specimen
20、s shall be used tocontain the test solution. The enclosure shall not chemicallyaffect the test solution.NOTE 4Elastomeric pads with a hardness of Shore A40 to 70 havebeen used successfully.7. Test Specimens7.1 The test specimens shall be ring sections taken fromsample(s) of pipe selected at random f
21、rom a normal productionrun. The test specimens shall have a minimum length of onenominal pipe diameter or 12 in. (305 mm) 6 5 %, whichever isless. Treat the cut edges of the specimens by the sameprocedure as production products.8. Test Conditions8.1 The standard temperature shall be 23 6 5C (73.4 69
22、F).9. Procedure9.1 Test Specimen Measurements:9.1.1 Wall ThicknessDetermine in accordance with TestMethod D3567.9.1.2 Inside DiameterDetermine in accordance with TestMethod D3567 at both ends prior to deflection and average themeasurements.NOTE 5It is recommended that the inside diameter be measured
23、 withthe axis vertical.9.2 Place the test apparatus into the test enclosure.9.3 Place the pipe ring in the test apparatus (see Fig. 1) andapply force to deflect the specimen at a rate not to exceed 10 %of its diameter per minute while keeping the top and bottomloading devices (plates, bars, or rods)
24、 of the apparatus as nearparallel as practical. When the desired deflection is obtainedcease adding load to the apparatus.NOTE 6Alignment of the specimen within the loading devices iscritical. The loading devices should not only be parallel with the loadpoints 180 opposite, but the pipe ring should
25、also be centered between theload-application guides. Additionally, the load-application guides shouldpermit complete vertical freedom of movement, so the specimen remainsunder constant load.9.4 Measure the vertical inside diameter of the deflectedpipe specimen at both ends to the nearest 0.01 in. (0
26、.25 mm).Average the measurements and determine the initial deflectionby subtracting the average vertical inside diameter after load-ing from the measurement determined in 9.1.2.NOTE 7Deflections in excess of 28 % of diameter may cause localflattening of the pipe and lead to erratic test results. For
27、 deflectionsapproaching 28 %, improved accuracy is obtained by use of strain gagesor by establishing, for each pipe product, a calibration of deflection versusmeasured strain. This calibration technique may also be useful at alldeflection levels.9.5 Introduce the test solution to completely submerge
28、 thepipe ring. The solution may be added prior to loading the pipering and should be added within 30 min of loading the pipering.Testing time commences only after both specimen loading(deflection) and the addition of solution are complete.(WarningSince the failure mode could be catastrophic, takepre
29、cautions to prevent or contain splashing or spilling of thetest solution or other damages resulting from the suddencollapse of the pipe specimen.)9.6 Periodically check and maintain the test solution within65 % of the specified strength or concentration for theduration of the test. The test specimen
30、 must remain completelysubmerged.NOTE 8As some solutions become more concentrated with theevaporation of water, care must be exercised in replenishment to preventa build-up in strength. It may be necessary, with some reagents, toperiodically clean the deflected specimen and replace the test solution
31、 witha fresh mixture. The use of plastic film, cut carefully to fit around the testapparatus and floated on the top of the test solution, has been foundhelpful in reducing evaporation.9.7 Continuously monitor the decreasing pipe-ring insidevertical diameter versus time or inspect the loaded specimen
32、 atSide View Front View1 Load-Application Guides 5 Submerged Test Specimen2 Load-Application Device 6 Test Solution3 0.25 in (6 mm) Rubber Pad 7 0.25 in. (6 mm) Rubber Pad4 Test Enclosure 8 Load-Applicatiion DeviceFIG. 1 Long-Term Ring Bending Test ApparatusD5365 122least at the frequency given belo
33、w and measure the pipespecimen inside vertical diameter:Hours Inspect at Least0 to 20 Every hour20 to 40 Every 2 h40 to 60 Every 4 h60 to 100 Every 8 h100 to 600 Every 24 h600 to 6000 Every 48 hAfter 6000 Every weekDetermine the deflection by subtracting the inside verticaldiameter from the measurem
34、ent determined in 9.1.2.NOTE 9Decreasing diameter of the pipe ring (deflection change) maybe monitored with an appropriate indicator on the apparatus above thesolution and submerged specimen.9.8 Calculate the end point (failure time and failure deflec-tion) in accordance with 10.1.9.9 Record the fol
35、lowing data:9.9.1 Average pipe-wall thickness,9.9.2 Average inside pipe diameter before deflection,9.9.3 Average inside pipe diameter after deflection,9.9.4 Initial deflection,9.9.5 Type of loading device,9.9.6 Type, location and time of any distress of the pipewall,9.9.7 Failure deflection and time
36、 at the end point, and9.9.8 Type of failure.9.10 To determine the regression line and the lower confi-dence level, a minimum of 18 samples is required. Distributionof data points shall be as follows:Hours Failure Points10 to 1000 At least 41000 to 6000 At least 3After 6000 At least 3After 10 000 At
37、least 19.10.1 Those specimens that have not failed after more than10 000 h may be included as failures to establish the regressionline. Use of these data points may result in a higher or lowerextrapolated value.NOTE 10Non-failed specimens may be left under test and theregression line recalculated as
38、 failures are obtained.10. Calculation10.1 Determine the failure time and deflection:10.1.1 The failure deflection and failure time shall be thelast values noted prior to the fracture occurrence.10.2 Long-Term Ring-Bending Strain:10.2.1 Compute the failure strain for each failed specimenas given in
39、10.2.1.1 and 10.2.1.2.10.2.1.1 Crown and invert failures:f54.28e!f!D1f/2!2where:f= failure strain in inches per inch (millimetres permillimetre),e = wall thickness in inches (millimetres) in accordancewith 9.1.1 (see Note 11),D = mean diameter in inches (millimetres) (ID in accor-dance with 9.1.2 pl
40、us e in accordance with 9.1.1 or ODminus e), andf= failure deflection in accordance with 10.1.10.2.1.2 Springline failures:f52.44e!f!D1f/2!2NOTE 11The Sbcalculations assume that the neutral axis is at thepipe-wall midpoint. For pipe-wall constructions that produce an alteredneutral-axis position, it
41、 may be necessary to evaluate results by substitut-ing 2y for e.(y is the distance from the appropriate pipe surface to theneutral axis.) Neutral-axis position must be determined with strain-gagecouples.10.2.2 Use for each specimen in the series, the log of thefailure strain and the log of the failu
42、re time in hours asdescribed in A1.4.1. Calculate Sb, the strain at 50 years(438 000 h).10.2.3 If Sxy 0 (see Annex A1.4.2.2), consider the dataunsuitable.10.2.4 Calculate r in accordance with A1.4.3.1.Ifr is lessthan the applicable minimum value given in Table A1.1,consider the data unsuitable.10.2.
43、5 Prepare a graph on a log-log diagram showing timeto failure versus failure strain, with time plotted on thehorizontal (x) axis and strain on the vertical (y) axis.11. Reconfirmation of the SbRegression Line11.1 When a piping product has an existing Sbregressionline, any change in material, manufac
44、turing process, construc-tion or liner will necessitate a screening evaluation as describedin 11.2, 11.3, 11.4, 11.5, and 11.6.11.2 Obtain failure points for at least two sets of specimens.Each specimen set shall consist of three or more specimenstested at the same initial strain level, as follows:H
45、ours to Failure(Average of Set)Failure Points10 to 200 At least 3More than 1000 At least 3Total: At least 6Include as failures those specimens that have not failed after3000 h, provided they exceed the regression line.11.3 Calculate and plot the 95 % confidence limits and the95 % prediction limits o
46、f the original regression line inaccordance with A1.4.6.2 using only data obtained prior to thechange.NOTE 12Prediction limits define the bounds for single observations,whereas confidence limits define the bounds for the regression line.NOTE 13For 95 % confidence limits, there is a 2.5 % probability
47、 thatthe mean value for the regression line may fall above the UCLand a 2.5 %probability that the mean value for the regression line may fall below theLCL. For 95 % prediction limits, there is a 2.5 % probability thatindividual data points may fall above the UPLand a 2.5 % probability thatindividual
48、 data points may fall below the LPL.11.4 Consider any changes in material or manufacturingprocess minor and permissible if the results of 11.2 meet thefollowing criteria:11.4.1 The average failure point for each specimen set fallson or above the 95 % lower confidence limit of the originalregression
49、line.D5365 12311.4.2 The earliest individual failure point falls on or abovethe 95 % lower-prediction limit of the original regression line.11.4.3 The failure points are distributed about the originallydetermined regression line. No more than two-thirds of theindividual failure points may fall below the original regressionline.11.5 Alternatively to 11.4, consider changes in material ormanufacturing process permissible if the results of 11.2 meetthe following:11.5.1 All data points fall above the 95 % lower confidencelimit of the original
