ASTM F876-2008 Standard Specification for Crosslinked Polyethylene (PEX) Tubing.pdf

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1、Designation: F 876 08An American National StandardStandard Specification forCrosslinked Polyethylene (PEX) Tubing1This standard is issued under the fixed designation F 876; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o

2、f 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 specification covers crosslinked polyethylene(PEX) tubing that is outside diameter controlled, made instandard

3、 thermoplastic tubing dimension ratios, and pressurerated for water at three temperatures (see Appendix X1).Included are requirements and test methods for material,workmanship, dimensions, sustained pressure, burst pressure,environmental stress cracking, stabilizer migration resistance,and degree of

4、 crosslinking. Methods of marking are also given.1.2 The text of this specification references notes, footnotes,and appendixes which provide explanatory material. Thesenotes and footnotes (excluding those in tables and figures) shallnot be considered as requirements of the specification.1.3 The valu

5、es stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 The following safety hazards caveat pertains only to thetest methods portion, Section 7, of t

6、his specification: Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.

7、Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD 1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD 1598 Test Method for Time-to-Fa

8、ilure of Plastic PipeUnder Constant Internal PressureD 1599 Test Method for Resistance to Short-Time Hydrau-lic Pressure of Plastic Pipe, Tubing, and FittingsD 1600 Terminology for Abbreviated Terms Relating toPlasticsD 1898 Practice for Sampling of Plastics3D 2122 Test Method for Determining Dimens

9、ions of Ther-moplastic Pipe and FittingsD 2765 Test Methods for Determination of Gel Content andSwell Ratio of Crosslinked Ethylene PlasticsD 2837 Test Method for Obtaining Hydrostatic DesignBasis for Thermoplastic Pipe Materials or Pressure DesignBasis for Thermoplastic Pipe ProductsD 3895 Test Met

10、hod for Oxidative-Induction Time of Poly-olefins by Differential Scanning CalorimetryF 412 Terminology Relating to Plastic Piping SystemsF 2023 Test Method for Evaluating the Oxidative Resis-tance of Crosslinked Polyethylene (PEX) Tubing andSystems to Hot Chlorinated Water2.2 ANSI Standard:B36.10 St

11、andards Dimensions of Steel Pipe (IPS)42.3 Federal Standard:FED-STD-123 Marking for Shipment (Civil Agencies)52.4 Military Standard:MIL-STD-129 Marking for Shipment and Storage52.5 NSF Standard:NSF 14 for Plastic Piping Components and Related Mate-rials62.6 ISO Standard:4ISO 1167 Thermoplastics pipe

12、s, fittings and assemblies forthe conveyance of fluids - Determination of the resistanceto internal pressure - Part 1: General methodISO 13760 Plastics pipes for the conveyance of fluids underpressure - Miners rule - Calculation method for cumu-lative damageISO R 161-1690 Pipes of Plastic Materials

13、for the Transportof Fluids (Outside Diameters and Nominal Pressures) Part1, Metric Series1This specification is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.26 on OlefinBased Pipe.Current edition approved Aug. 1, 2008. Pub

14、lished August 2008. Originallyapproved in 1984. Last previous edition approved 2007 as F 876 07.2For referenced 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 Docume

15、nt Summary page onthe ASTM website.3Withdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098,

16、 http:/www.dodssp.daps.mil.6Available from NSF International, P.O. Box 130140, 789 N. Dixboro Rd., AnnArbor, MI 48113-0140, http:/www.nsf.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194

17、28-2959, United States.2.7 PPI Standard:7PPI TR-4 PPI Listing of Hydrostatic Design Basis (HDB),Strength Design Basis (SDB), Pressure Design Basis(PDB) and Minimum Required Strength (MRS) Ratingsfor Thermoplastic Piping Materials or Pipe3. Terminology3.1 DefinitionsDefinitions are in accordance with

18、 Termi-nology F 412, and abbreviations are in accordance with Ter-minology D 1600, unless otherwise specified. The abbreviationfor crosslinked polyethylene is PEX. Plastic tubing denotes aparticular diameter schedule of plastic pipe in which outsidediameter of the tubing is equal to the nominal size

19、 plus18 in.Plastic pipe outside diameter schedule conforms to ANSIB36.10.3.2 Definitions of Terms Specific to This Standard:3.2.1 crosslinked polyethylene plasticsplastics preparedby crosslinking (curing) polyethylene compounds.3.2.2 hydrostatic design stress (HDS)the estimated maxi-mum tensile stre

20、ss the material is capable of withstandingcontinuously with a high degree of certainty that failure of thetube will not occur. This stress is circumferential when internalhydrostatic water pressure is applied. The HDS is equal to thehydrostatic design basis (HDB) times the design factor (DF)for wate

21、r. For this standard, the design factor is equal to 0.50.HDS 5 HDB 3 DF5 HDB 3 0.50 for this standard!3.2.3 hydrostatic design basis (HDB)one of a series ofestablished stress values (specified in Test Method D 2837) fora plastic compound obtained by categorizing the long-termhydrostatic strength det

22、ermined in accordance with TestMethod D 2837.3.2.3.1 DiscussionA listing of HDB and HDS values arecontained in PPI publication PPI TR43.2.4 pressure rating (PR)the estimated maximum waterpressure the tube is capable of withstanding continuously witha high degree of certainty that failure of the tube

23、 will not occur.3.2.5 relation between dimensions, hydrostatic designstress, and pressure ratingthe following expression, com-monly known as the ISO equation,8is used in this specificationto relate dimensions, hydrostatic design stress, and pressurerating:2S/P 5DO/t! 2 1 (1)or2S/P 5 R 2 1where:S = h

24、ydrostatic design stress, psi (or MPa),P = pressure rating, psi (or MPa),DO= average outside diameter, in. (or mm),t = minimum wall thickness, in. (or mm), andR = standard dimension ratio, SDR.3.2.6 standard dimension ratio (SDR)the ratio of outsidediameter to wall thickness. For PEX-tubing, it is c

25、alculated bydividing the average outside diameter of the tubing in inches orin millimetres by the minimum wall thickness in inches ormillimetres. If the wall thickness calculated by this formula isless than 0.070 in. (1.78 mm) it shall be arbitrarily increased to0.070 in. except for sizes18 in. and

26、smaller. The SDR valuesshall be rounded to the nearest 0.5.3.2.7 standard thermoplastic tubing materials designationcodeThe tubing material designation code shall consist ofthe abbreviation for the type of plastic (PEX) followed by fourArabic digits that describe short-term properties in accordancew

27、ith applicable ASTM standards and as shown in Table 1.3.2.7.1 DiscussionThe first digit is for chlorine resistancetested in accordance with Test Method F 2023.(1) A digit “0” indicatesthat the PEX tubing either has notbeen tested for chlorine resistance or that the PEX tubing doesnot meet the minimu

28、m requirement for chlorine resistance.(2) A digit “1” indicates the PEX tubing has been testedand meets the F 876 requirement for minimum chlorine resis-tance at the end use condition of 25% at 140F (60C) and 75%at 73F (23C).(3) A digit “2” is reserved for future application.(4) A digit “3” indicate

29、s that the PEX tubing has beentested and meets the F876 requirement for minimum chlorineresistance at end use condition of 50% at 140F and 50% at73F.(5) A digit “4” is reserved for future application.(6) A digit “5” indicates that the PEX tubing has beentested and meets the requirement for minimum c

30、hlorine resis-tance at end use conditions of 100% of the time at 140F3.2.7.2 DiscussionThe second digit is a “0”. This digit isreserved for another PEX tubing property.3.2.7.3 Discussion The last two digits are the hydrostaticdesign stress for water at 73F (23C) in units of 100 psi withany decimal f

31、igures dropped. Where the hydrostatic designstress code contains less than two figures, a zero is used before7Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825 Irving TX, 75062.http:/www.plasticpipe.org8ISO R161-1690.TABLE 1 Material Designation Code CellsProperty Standard 0 1 2 3 4 5 6789C

32、hlorineResistanceF 2023 Not testedor rated75 %at 73Fand 25 %at 140FReserved 50 %at 73Fand 50 %at 140FReserved 100 %at 140F. . . .Reserved . . . . . . . . . . .HDSfor water at73F. . . . . . . 630 . 800 .F876082the number. Thus, a complete material designation code forPEX tubing shall consist of the t

33、hree letters “PEX” and fourdigits.4. Tubing Classification4.1 GeneralThis specification covers one PEX tubingmaterial in one standard dimension ratio and having pressureratings for water of three temperatures. The pressure ratingsdecrease as the temperature is increased.4.2 Standard Thermoplastic Pi

34、pe Dimension Ratio (SDR)This specification covers PEX tubing in one standard dimen-sion ratio (SDR 9). The pressure ratings are uniform for allnominal tubing sizes.5. Materials5.1 GeneralCrosslinked polyethylene tubing, meeting therequirements of this specification, are primarily defined bymeans of

35、three criteria, namely, (1) nominal density, (2) degreeof crosslinking, and (3) long-term strength tests. There is astrong correlation between nominal density and results ofshort-term strength tests.NOTE 1PEX tubing intended for use in the transport of potable watershould be evaluated and certified

36、as safe for this purpose by a testingagency acceptable to the local health authority. The evaluation should bein accordance with requirements for chemical extraction, taste, and odorthat are no less restrictive than those included in NSF 14. The seal or markof the laboratory making the evaluation sh

37、ould be included on the tubing.5.2 Basic MaterialsPEX tubing shall be made from poly-ethylene compounds which have been crosslinked by perox-ides, Azo compounds, or silane compounds in extrusion, or byelectron beam after extrusion, or by other means such that thetubing meets the performance requirem

38、ents of Section 6. Forthe use temperatures that the tubing will be marked for, thematerials, procedure for mixing, and the process for crosslink-ing shall result in a product with long term hydrostatic stressratings equal to or better than those shown in Table 2, whendetermined in accordance with pr

39、ocedures no less restrictivethan those of PPI TR-3/92.9See Appendix X1 for additionalinformation on PPI hydrostatic stress ratings.NOTE 2Tubing produced by crosslinking by peroxides, Azo com-pounds, or silane compounds in extrusion, or by electron beam afterextrusion have met the requirements of Sec

40、tion 6. There are several otherprocesses for producing crosslinked polyethylene tubing. However, eachprocess must be established as meeting the requirements of this specifi-cation.5.3 Tubing Material DesignationThe tubing meeting therequirements of this specification shall be designated PEX.6. Requi

41、rements6.1 WorkmanshipThe tubing shall be homogeneousthroughout and free of visible cracks, holes, foreign inclusions,or other defects. The pipe shall be as uniform as commerciallypracticable in color, opacity, density, and other physical prop-erties.6.2 Dimensions and Tolerances:6.2.1 Outside Diame

42、tersThe outside diameters and toler-ances shall be as shown in Table 3, when measured inaccordance with 7.4 and 7.4.1.6.2.2 Wall ThicknessThe wall thickness and tolerancesshall be as shown in Table 4, when measured in accordancewith 7.4 and 7.4.2.9PPI Technical Report TR-3/92, Policies and Procedure

43、s for DevelopingRecommended Hydrostatic Design Stresses for Thermoplastic Pipe Materials.TABLE 3 Outside Diameters and Tolerances for PEX TubingNominal Tubing SizeAverage OutsideDiameterTolerances for Average Diameter Out-of-RoundnessAin. mm in. mm in. mm in. mm18 3 0.250 6.35 60.003 60.08 0.008 0.2

44、014 7 0.375 9.52 60.003 60.08 0.008 0.20516 8 0.430 10.92 60.003 60.08 0.008 0.2038 10 0.500 12.70 60.003 60.08 0.012 0.3212 13 0.625 15.88 60.004 60.10 0.016 0.4058 16 0.750 19.05 60.004 60.10 0.016 0.4034 19 0.875 22.22 60.004 60.10 0.016 0.401 25 1.125 28.58 60.005 60.12 0.020 0.48114 32 1.375 34

45、.92 60.005 60.12 0.020 0.48112 38 1.625 41.28 60.006 60.16 0.024 0.602 51 2.125 53.98 60.006 60.16 0.030 0.76212 64 2.625 66.68 60.007 60.18 0.038 0.953 76 3.125 79.38 60.008 60.20 0.045 1.14312 89 3.625 92.08 60.008 60.20 0.046 1.164 102 4.125 104.78 60.009 60.23 0.052 1.32412 114 4.625 117.48 60.0

46、09 60.23 0.059 1.495 127 5.125 130.18 60.010 60.25 0.065 1.656 152 6.125 155.58 60.011 60.28 0.072 1.83AThe Out-of-Roundness specification applies only to tubing prior to coiling.TABLE 2 Hydrostatic Design Stresses and Pressure Ratings forPEX SDR 9 Plastic Tubing for Water at Different TemperaturesR

47、ated TemperatureHydrostatic DesignStressPressure Rating forWaterF C psi (MPa) psi (MPa)73.4 23 630 (4.34) 160 (1.10)180 82.2 400 (2.76) 100 (0.69)200 93.3 315 (2.17) 80 (0.55)F8760836.3 DensityWhen determined in accordance with 7.5, thecrosslinked polyethylene tubing material shall have a minimumden

48、sity of 0.926 Mg/m3.6.4 Sustained PressureThe tubing shall not fail, balloon,burst, or weep as defined in Test Method D 1598, at the testpressures given in Table 5 when tested in accordance with 7.6.6.5 Burst PressureThe minimum burst pressure for PEXplastic tubing shall be as given in Table 6, when

49、 determined inaccordance with 7.7.6.6 Environmental Stress Cracking There shall be no lossof pressure in the tubing, when tested in accordance with 7.8.6.7 Degree of CrosslinkingWhen tested in accordancewith 7.9, the degree of crosslinking for PEX tubing materialshall be within the range from 65 to 89 % inclusive. Dependingon the process used, the following minimum percentagecrosslinking values shall be achieved: 70 % by peroxides, 65 %by Azo compounds, 65 % by electron beam, or 65 % by silanecompounds.NOTE 3Tech