1、Designation: F2818 10 (Reapproved 2014)1Standard 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 adoption o
2、r, 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.1NOTESections 2 and 5.9 were editorially corrected in May 2015.1. Scope1.1 This specificat
3、ion covers requirements and test methodsfor material 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 andfoot
4、notes provide explanatory material. These notes and foot-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 S
5、I units that are provided for information onlyand are 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 deter
6、mine the applica-bility of regulatory limitations prior 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 Method
7、s for Density and Specific Gravity (Rela-tive Density) 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 HydraulicPr
8、essure of Plastic Pipe, Tubing, and FittingsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD1898 Practice for Sampling of Plastics (Withdrawn 1998)3D2122 Test Method for Determining Dimensions of Ther-moplastic Pipe and FittingsD2290 Test Method for Apparent Hoop Tensile Strength ofPlas
9、tic or Reinforced Plastic PipeD2513 Specification 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
10、 Pressure Design Basisfor Thermoplastic Pipe ProductsD3350 Specification for Polyethylene Plastics Pipe and Fit-tings MaterialsD4883 Test Method for Density of Polyethylene by theUltrasound TechniqueF412 Terminology Relating to Plastic Piping SystemsF1473 Test Method for Notch Tensile Test to Measur
11、e theResistance to Slow Crack Growth of Polyethylene Pipesand ResinsF1563 Specification for Tools to Squeeze-off Polyethylene(PE) Gas Pipe or TubingF1041 Guide for Squeeze-Off of Polyolefin Gas PressurePipe and Tubing2.2 Other Standards:B31.8 Gas Transmission and Distribution Piping Systems4PPI-TR3
12、Policies and Procedures for Developing Hydro-static Design Basis (HDB), Pressure Design Basis (PDB),1This specification is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.60 on Gas.Current edition approved Aug. 1, 2014. Publi
13、shed November 2014. Originallypublished in 2010. Last previous edition approved in 2010 as F281810.DOI:10.1520/F281810R14E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
14、refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM Internatio
15、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Strength Design Basis (SDB), and Minimum RequiredStrength (MRS) Ratings for Thermoplastic Piping Mate-rials or Pipe5CFR Part 192 Transportation of Natural and Other Gas byPipeline: Minimum Federal Safety Standar
16、ds63. Terminology3.1 Definitionsare in accordance with Terminology F412,and abbreviations are in accordance with Terminology 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
17、The term pipe used herein refers to both pipe and tubingunless specifically stated otherwise.3.4 Definitions of Terms Specific to This Standard:3.4.1 toe-ina small reduction of the outside diameter atthe cut end of a length of thermoplastic pipe.4. Ordering Information4.1 GeneralThe plastic used to
18、make pipe and fittingsshall have a Plastics Pipe Institute (PPI) long-term hydrostaticdesign stress and hydrostatic design 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 stron
19、g correlation between nominaldensity and results of short-term strength tests.4.2 Basic MaterialsPEX pipe shall be made from poly-ethylene compounds which have been crosslinked byperoxides, Azo compounds, or silane compounds in extrusion,or by electron beam after extrusion, or by other means suchtha
20、t the pipe meets the performance requirements of thisspecification. The materials, procedure for mixing, and theprocess for crosslinking shall result in a product with minimumrecommended long term hydrostatic design basis (HDB) equalto or greater than 1250 psi at 73.4F (23C) (PEX XX06) and800 psi at
21、 180F (82.2C) when determined in accordance withPPI-TR3 and Test Method D2837.4.3 DensityThe PEX pipe material shall 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 Spec
22、ification D3350. Code C materialshall contain 2 to 3 percent well dispersed carbon black, anddue to the absorptive properties 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 protec
23、ted against deterioration fromunprotected UV exposure for not less than 3 years.4.5 Rework MaterialPEX rework shall 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 suppl
24、ied in coils must meet the samerequirements before and after coiling. The requirements applyto pipe after crosslinking.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 a
25、nd fittings shall be as uniform as commercially practi-cable in color, opacity, density, and other physical properties.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
26、 therequirements given in Table 1 or Table 2 when measured inaccordance with 6.5.5.3.1.2 Toe-InWhen measured in accordance 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 dia
27、meter shall be madeno closer than 1.5 pipe diameters or 11.8 in. (300 mm),whichever distance is less, from the cut end 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 me
28、asured in accordancewith 6.5.1.2. The minimum wall thickness at any point of5Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,Irving, TX 75062, http:/www.plasticpipe.org.6Available from Superintendent of Documents, U.S. Government PrintingOffice, Washington DC 20402.TABLE 1
29、Outside Diameters and Tolerances for Plastic Pipe, in. (mm)Iron Pipe Size(IPS)Outside Diameter ToleranceMaximum Out of RoundnessSDR 17SDR 13.5SDR 1112 0.840 (21.3) 0.004 (0.102) 0.016(0.406)34 1.050 (26.7) 0.004 (0.102) 0.02(0.508)1 1.315 (33.4) 0.005 (0.127) 0.02(0.508)114 1.660 (42.1) 0.005 (0.127
30、) 0.024(0.61)112 1.900 (48.3) 0.006 (0.152) 0.024(0.61)2 2.375 (60.3) 0.006 (0.152) 0.024(0.61)3 3.500 (88.9) 0.008 (0.203) 0.03(0.762)4 4.500 (114.3) 0.009 (0.229) 0.03(0.762)6 6.625 (168.3) 0.011 (0.279) 0.07(1.778)F2818 10 (2014)12measurement shall be not less than the minimum wall thicknessspeci
31、fied 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 manufacturer andthe purchaser. The l
32、ength 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,use same tolerance of next smaller size; for wall thickness, usesame tolerance percentage
33、 as shown in the tables.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 electr
34、onbeam, or 65 % by silane 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
35、 setting the lathe feeding 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 D27
36、65, MethodAmay be used 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 pi
37、pe ring, the materialshall 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 pi
38、pe test is only an indication 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 materia
39、l, the stress shall be1320 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 i
40、n accordance with Test 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
41、 of a higher temperature 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. Fo
42、r pipesizes above 4-in. 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 MP
43、a).5.8 Apparent Tensile 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 deemed
44、suitable for squeeze-off in service by the pipe manufacturer.Squeeze-off shall be performed per Guide F1041 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 asf
45、ollows:TABLE 2 Plastic Tubing-Diameters, Wall Thicknesses, and Tolerances, in. (mm)Copper TubingSize(CTS)OutsideDiameterTolerance MinimumWall ThicknessWall ThicknessTolerance14 0.375 (9.52) 0.004 (0.10) 0.062 (1.58) +0.006 (+0.15)38 0.500 (12.7) 0.004 (0.10) 0.062 (1.58) +0.006 (+0.15)12 0.625 (15.9
46、) 0.004 (0.10) 0.062 (1.58) +0.006 (+0.15)12 0.625 (15.9) 0.004 (0.10) 0.090 (2.27) +0.009 (+0.23)12 0.625 (15.9) 0.004 (0.10) 0.104 (2.64) +0.010 (+0.25)34 0.875 (22.2) 0.004 (0.10) 0.062 (1.58) +0.006 (+0.15)34 0.875 (22.2) 0.004 (0.10) 0.077 (1.95) +0.008 (+0.20)34 0.875 (22.2) 0.004 (0.10) 0.090
47、 (2.27) +0.009 (+0.23)1 1.125 (28.6) 0.005 (0.13) 0.062 (1.58) +0.007 (+0.18)1 1.125 (28.6) 0.005 (0.13) 0.090 (2.27) +0.011 (+0.28)1 1.125 (28.6) 0.005 (0.13) 0.099 (2.51) +0.012 (+0.31)1 1.125 (28.6) 0.005 (0.13) 0.101 (2.56) +0.012 (+0.31)1 1.125 (28.6) 0.005 (0.13) 0.121 (3.07) +0.015 (+0.38)114
48、 1.375 (34.9) 0.005 (0.13) 0.062 (1.58) +0.007 (+0.18)114 1.375 (34.9) 0.005 (0.13) 0.090 (2.27) +0.011 (+0.28)114 1.375 (34.9) 0.005 (0.13) 0.121 (3.07) +0.015 (+0.38)134 1.875 (47.6) 0.006 (0.15) 0.062 (1.58) +0.007 (+0.18)F2818 10 (2014)135.9.1 Prepare six randomly selected pipe specimens inaccor
49、dance 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 hold in constraint for 4 h. Removesqueeze bar and reround pipe by closing squeeze bars at a point90 from the squeeze area.5.9.3 Immediately upon removal of the squeeze-off tool, fillthe specimens with ambient tempera
