1、Designation: F2818 10An American National StandardStandard Specification forSpecification for Crosslinked Polyethylene (PEX) MaterialGas Pressure Pipe and Tubing1This standard is issued under the fixed designation F2818; the number immediately following the designation indicates the year oforiginal
2、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 specification covers requirements and test methodsfor material
3、dimensions and tolerances, hydrostatic burststrength, chemical resistance, and impact resistance of PEXpipe and tubing for use in fuel gas mains and services for directburial applications.1.2 The text of this specification references notes andfootnotes provide explanatory material. These notes and f
4、oot-notes (excluding those in tables and figures) shall not beconsidered as requirements of the specification.1.3 The values 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
5、 not considered standard.1.4 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
6、or to use.2. Referenced Documents2.1 ASTM Standards:2D543 Practices for Evaluating the Resistance of Plastics toChemical ReagentsD618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD792 Test Methods for Density and Specific Gravity (Rela-tive Density
7、) of Plastics by DisplacementD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD1598 Test Method for Time-to-Failure of Plastic PipeUnder Constant Internal PressureD1599 Test Method for Resistance to Short-Time HydraulicPressure of Plastic Pipe, Tubing, and FittingsD1600 Ter
8、minology for Abbreviated Terms Relating toPlasticsD1898 Practice for Sampling of Plastics3D2122 Test Method for Determining Dimensions of Ther-moplastic Pipe and FittingsD2290 Test Method for Apparent Hoop Tensile Strength ofPlastic or Reinforced Plastic Pipe by Split Disk MethodD2513 Specification
9、for Polyethylene (PE) Gas PressurePipe, Tubing, and FittingsD2765 Test Methods for Determination of Gel Content andSwell Ratio of Crosslinked Ethylene PlasticsD2837 Test Method for Obtaining Hydrostatic Design Basisfor Thermoplastic Pipe Materials or Pressure Design Basisfor Thermoplastic Pipe Produ
10、ctsD3350 Specification for Polyethylene Plastics Pipe andFittings MaterialsD4883 Test Method for Density of Polyethylene by theUltrasound TechniqueF412 Terminology Relating to Plastic Piping SystemsF1473 Test Method for Notch Tensile Test to Measure theResistance to Slow Crack Growth of Polyethylene
11、 Pipesand ResinsF1563 Specification for Tools to Squeeze-off Polyethylene(PE) Gas Pipe or TubingF1051 Test Method for Comparing Multistrike Film Rib-bons2.2 Other Standards:B31.8 Gas Transmission and Distribution Piping Systems4PPI-TR3 Policies and Procedures for Developing Hydro-static Design Basis
12、 (HDB), Pressure Design Basis (PDB),Strength Design Basis (SDB), and Minimum RequiredStrength (MRS) Ratings for Thermoplastic Piping Mate-rials or Pipe31This specification is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.60
13、 on Gas.Current edition approved March 1, 2010. Published March 2010. DOI:10.1520/F2818.2For 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 Document Summa
14、ry page onthe ASTM website.3Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,Irving, TX 75062, http:/www.plasticpipe.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM Internation
15、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.CFR Part 192 Transportation of Natural and Other Gas byPipeline: Minimum Federal Safety Standards3. Terminology3.1 Definitionsare in accordance with Terminology F412,and abbreviations are in accordance with Termi
16、nology D1600,unless otherwise specified.3.2 The gas industry terminology used in this specificationis in accordance with ANSI B31.8 or 49 CFR Part 192, unlessotherwise indicated.3.3 The term pipe used herein refers to both pipe and tubingunless specifically stated otherwise.3.4 Definitions of Terms
17、Specific to This Standard:3.5 toe-ina small reduction of the outside diameter at thecut end of a length of thermoplastic pipe.4. Ordering Information4.1 GeneralThe plastic used to make pipe and fittingsshall have a Plastics Pipe Institute (PPI) long-term hydrostaticdesign stress and hydrostatic desi
18、gn basis rating. PEX pipe areprimarily defined by means of three criteria, namely, (1)nominal density, (2) degree of crosslinking, and (3) long-termstrength tests. There is a strong correlation between nominaldensity and results of short-term strength tests.4.2 Basic MaterialsPEX pipe shall be made
19、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 thepipe meets the performance requirements of this specification.The materials, procedure for mixing, and the proce
20、ss forcrosslinking shall result in a product with minimum recom-mended long term hydrostatic design basis (HDB) equal to orgreater than 1250 psi at 73.4F (23C) (PEX XX06) and 800psi at 180F (82.2C) when determined in accordance withPPI-TR3 and Test Method D2837.4.3 DensityThe PEX pipe material shall
21、 have a minimumdensity of 0.926 g/cc when determined in accordance with TestMethods D1505, D792,orD4883.4.4 Outdoor Storage StabilityPE materials shall be CodeC or E as defined in Specification D3350. Code C materialshall contain 2 to 3 percent well dispersed carbon black, anddue to the absorptive p
22、roperties of the carbon black, isconsidered to be stabilized against deterioration from unpro-tected exposure to UV for at least 10 years. Code E materialshall be stabilized and protected against deterioration fromunprotected UV exposure for not less than 3 years.4.5 Rework MaterialPEX rework shall
23、not be used in themanufacture of PEX pipes made in accordance to this specifi-cation.5. Requirements5.1 GeneralPipe shall be supplied in either coils orstraight lengths. Any pipe supplied in coils must meet the samerequirements before and after coiling. The requirements applyto pipe after crosslinki
24、ng.5.2 WorkmanshipThe pipe and fittings shall be homoge-neous throughout and free of visible cracks, holes, foreigninclusion, blisters, and dents, or other injurious defects. Thepipe and fittings shall be as uniform as commercially practi-cable in color, opacity, density, and other physical properti
25、es.5.3 Pipe and Tubing Dimensions and Tolerances:5.3.1 DimensionThe dimensions shall be specified bywall thickness and outside diameter.5.3.1.1 DiametersThe outside diameter shall meet therequirements given in Table 1 or Table 2 when measured inaccordance with 6.5.5.3.1.2 Toe-InWhen measured in acco
26、rdance with 6.5.1.1,the outside diameter at the cut end of the pipe shall not be morethan 1.5 % smaller than the undistorted outside diameter.Measurement of the undistorted outside diameter shall be madeno closer than 1.5 pipe diameters or 11.8 in. (300 mm),whichever distance is less, from the cut e
27、nd of the pipe.Undistorted outside diameter shall meet the requirements ofTable 1 or Table 2.5.3.1.3 Wall ThicknessThe wall thickness shall be asspecified in Table 2 or Table 3 when measured in accordancewith 6.5.1.2. The minimum wall thickness at any point ofmeasurement shall be not less than the m
28、inimum wall thicknessspecified in Table 2 or Table 3.5.3.1.4 Wall Thickness Eccentricity RangeThe wall thick-ness eccentricity range shall be within 12 % when measured inaccordance with 6.5.1.3.5.3.1.5 LengthThe pipe shall be supplied in straightlengths or coils as agreed upon between the manufactur
29、er andthe purchaser. The length shall not be less than the minimumlength agreed upon when corrected to 73F (23C).5.3.1.6 When sizes other than those listed in Table 1, Table2,orTable 3 are used, tolerances shall be: for outside diameter,TABLE 1 Outside Diameters and Tolerances for Plastic Pipe, in.
30、(mm)Iron Pipe Size(IPS)Outside Diameter ToleranceMaximum Out of RoundnessSDR 17SDR 13.5SDR 1112 0.840 (21.3) 60.004 (60.102) 0.016(0.406)34 1.050 (26.7) 60.004 (60.102) 0.02(0.508)1 1.315 (33.4) 60.005 (60.127) 0.02(0.508)114 1.660 (42.1) 60.005 (60.127) 0.024(0.61)112 1.900 (48.3) 60.006 (60.152) 0
31、.024(0.61)2 2.375 (60.3) 60.006 (60.152) 0.024(0.61)3 3.500 (88.9) 60.008 (60.203) 0.03(0.762)4 4.500 (114.3) 60.009 (60.229) 0.03(0.762)6 6.625 (168.3) 60.011 (60.279) 0.07(1.778)F2818 102use same tolerance of next smaller size; for wall thickness, usesame tolerance percentage as shown in the table
32、s.5.3.2 Degree of CrosslinkingThe degree of crosslinkingfor PEX pipe shall be within the range from 65 to 89 %inclusive. Depending on the process used, the followingminimum percentage crosslinking values shall be achieved: 70% by peroxides, 65 % by Azo compounds, 65 % by electronbeam, or 65 % by sil
33、ane compound. The degree of crosslinkingon a pipe sample is obtained as follows:5.3.2.1 Place a pipe sample in a lathe with automaticfeeding. Shave a strip that consists of the full wall thickness.The strip thickness shall be approximately 0.004 in. (0.1 mm)which is obtained by setting the lathe fee
34、ding accordingly.5.3.2.2 Test the specimens in accordance with Test MethodD2765, Method B, with the only deviation: test specimenpreparation. For the purpose of this specification, degree ofcrosslinking (V) is defined as 100 % minus extract percentequals V.NOTE 1Test Method D2765, MethodAmay be used
35、 in lieu of MethodB. Method A gives more accurate and reproducible values but require aspecial grinder for sample preparation.5.4 Chemical ResistanceThe pipe and fittings shall notincrease in weight more than 0.5 % (1.0 % for toluene inmethanol). Where the test specimen is a pipe ring, the materials
36、hall not change more than 612 % in apparent tensile yieldstrength when measured in accordance with 6.9. Where the testspecimen is a plaque, the material shall not change more than612 % in tensile strength at yield when measured in accor-dance with Test Method D638.NOTE 2This pipe test is only an ind
37、ication of what will happen as aresult of short term exposure to these chemicals. For longterm results,additional testing is required.5.5 Sustained Pressure 73F (23C)The pipe shall not failin less than 1000 h when tested in accordance with TestMethod D1598. For PEX XX06 material, the stress shall be
38、1320 psi (9.1 MPa), for PEX XX08 material, the stress shall be1600 psi (11.03 MPa).5.6 Elevated Temperature 203F (95C)PEX piping ma-terials intended for use at temperatures above 100F (38C)shall have the PPI hydrostatic design basis (HDB) determinedat the specific temperature in accordance with Test
39、 MethodD2837.NOTE 3Many design factors for elevated temperature service cannotbe covered in this specification. Users should consult applicable codes forlimitations on pertinent maximum temperatures.NOTE 4In the absence of an HDB established at the specifiedtemperature, the HDB of a higher temperatu
40、re may be used in determininga design pressure rating at the specified temperature by arithmeticinterpolation.5.7 Minimum Hydrostatic Burst Pressure/Apparent TensileStrength (Quick Burst)The pipe shall fail in a ductile mannerwhen tested in accordance with Test Method D1599. For pipesizes above 4-in
41、. nominal diameter, the testing lab shall beallowed to replace the quick burst test (Test Method D1599)bythe apparent ring tensile strength test (Test Method D2290).The minimum apparent tensile strength at yield when deter-mined in accordance with 6.7 shall be 2520 psi (17.4 MPa).5.8 Apparent Tensil
42、e Strength at YieldWhen tested inaccordance to 6.8, the PEX pipe shall demonstrate a minimumof 2600 psi for PEX XX06 materials and 3000 psi for PEXXX08 materials.5.9 Squeeze-OffThis requirement is limited to pipe sizes,wall thicknesses, squeeze procedures, and conditions deemedsuitable for squeeze-o
43、ff in service by the pipe manufacturer.Squeeze-off shall be performed per Guide F1051 using toolsthat meet Specification F1563. There shall be no leakage orvisual evidence of splitting, cracking, breaking or reduction in1000-h sustained pressure category when pipe is tested asfollows:5.9.1 Prepare s
44、ix randomly selected pipe specimens inaccordance with Test Method D1598 except they shall beunfilled.5.9.2 The squeeze-off shall be effected at the mid-point ofthe test specimen, 90 to the point of the measured minimumwall thickness. Close the squeeze bars to the gap stop inSpecification F1563 and h
45、old in constraint for 4 h. Removesqueeze bar and reround pipe by closing squeeze bars at a point90 from the squeeze area.TABLE 2 Plastic Tubing-Diameters, Wall Thicknesses, and Tolerances, in. (mm)Copper TubingSize(CTS)OutsideDiameterTolerance MinimumWall ThicknessWall ThicknessTolerance14 0.375 (9.
46、52) 60.004 (60.10) 0.062 (1.58) +0.006 (+0.15)38 0.500 (12.7) 60.004 (60.10) 0.062 (1.58) +0.006 (+0.15)12 0.625 (15.9) 60.004 (60.10) 0.062 (1.58) +0.006 (+0.15)12 0.625 (15.9) 60.004 (60.10) 0.090 (2.27) +0.009 (+0.23)12 0.625 (15.9) 60.004 (60.10) 0.104 (2.64) +0.010 (+0.25)34 0.875 (22.2) 60.004
47、 (60.10) 0.062 (1.58) +0.006 (+0.15)34 0.875 (22.2) 60.004 (60.10) 0.077 (1.95) +0.008 (+0.20)34 0.875 (22.2) 60.004 (60.10) 0.090 (2.27) +0.009 (+0.23)1 1.125 (28.6) 60.005 (60.13) 0.062 (1.58) +0.007 (+0.18)1 1.125 (28.6) 60.005 (60.13) 0.090 (2.27) +0.011 (+0.28)1 1.125 (28.6) 60.005 (60.13) 0.09
48、9 (2.51) +0.012 (+0.31)1 1.125 (28.6) 60.005 (60.13) 0.101 (2.56) +0.012 (+0.31)1 1.125 (28.6) 60.005 (60.13) 0.121 (3.07) +0.015 (+0.38)114 1.375 (34.9) 60.005 (60.13) 0.062 (1.58) +0.007 (+0.18)114 1.375 (34.9) 60.005 (60.13) 0.090 (2.27) +0.011 (+0.28)114 1.375 (34.9) 60.005 (60.13) 0.121 (3.07)
49、+0.015 (+0.38)134 1.875 (47.6) 60.006 (60.15) 0.062 (1.58) +0.007 (+0.18)F2818 1035.9.3 Immediately upon removal of the squeeze-off tool, fillthe specimens with ambient temperature water, that is 67 610F (19.4 6 5.6C), condition, and test in accordance with6.6.5.10 Thermal StabilitySpecimens of the pipe inside wallsurface not more than 0.005 in. (0.13 mm) thick shall demon-strate a minimum induction temperature of 428F (220C)when tested in accordance with the Test Method for ThermalStability in Specification D3350.5.11 S
