1、Designation: F2818 10 (Reapproved 2014) An 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 t
2、he 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. Scope1.1 This specification covers requirements and test m
3、ethodsfor 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 andfootnotes provide explanatory material
4、. 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 SI units that are provided for info
5、rmation 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 determine the applica-bility of regulat
6、ory 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 Methods for Density and Specific Gravity
7、 (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 HydraulicPressure of Plastic Pipe, Tubing, an
8、d FittingsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD1898 Practice for Sampling of Plastics (Withdrawn 1998)3D2122 Test Method for Determining Dimensions of Ther-moplastic Pipe and FittingsD2290 Test Method for Apparent Hoop Tensile Strength ofPlastic or Reinforced Plastic PipeD251
9、3 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 Pressure Design Basisfor Thermopl
10、astic 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 Measure theResistance to Slow Crack Grow
11、th of Polyethylene Pipesand ResinsF1563 Specification for Tools to Squeeze-off Polyethylene(PE) Gas Pipe or TubingF1051 Test Method for Comparing Multistrike Film Ribbons2.2 Other Standards:B31.8 Gas Transmission and Distribution Piping Systems4PPI-TR3 Policies and Procedures for Developing Hydro-st
12、atic Design Basis (HDB), Pressure Design Basis (PDB),Strength Design Basis (SDB), and Minimum RequiredStrength (MRS) Ratings for Thermoplastic Piping Mate-rials or Pipe51This specification is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Su
13、bcommittee F17.60 on Gas.Current edition approved Aug. 1, 2014. Published November 2014. Originallypublished in 2010. Last previous edition approved in 2010 as F281810.DOI:10.1520/F281810R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
14、iceastm.org. For Annual Book of ASTMStandards volume information, 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
15、, New York, NY 10036, http:/www.ansi.org.5Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,Irving, TX 75062, http:/www.plasticpipe.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1CFR Part 192 Transportatio
16、n of Natural and Other Gas byPipeline: Minimum Federal Safety Standards63. 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 accordan
17、ce 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 Specific to This Standard:3.4.1 toe-ina small reduction of the outside diameter atthe cut end of a length of ther
18、moplastic 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 design basis rating. PEX pipe areprimarily defined by means of three criteria, namely, (1)nominal density, (2) degr
19、ee 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 from poly-ethylene compounds which have been crosslinked byperoxides, Azo compounds, or silane compounds in ext
20、rusion,or by electron beam after extrusion, or by other means suchthat 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) equ
21、alto or greater than 1250 psi at 73.4F (23C) (PEX XX06) and800 psi at 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
22、 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 properties of the carbon black, isconsidered to be stabilized against deterioration from unpro-tected exposure to UV
23、 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 not be used in themanufacture of PEX pipes made in accordance to this specifi-cation.5. Requirements5.1 GeneralPipe
24、 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 crosslinking.5.2 WorkmanshipThe pipe and fittings shall be homoge-neous throughout and free of visible cracks, holes, foreign
25、inclusion, 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 properties.5.3 Pipe and Tubing Dimensions and Tolerances:5.3.1 DimensionThe dimensions shall be specified bywall thickness
26、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 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 un
27、distorted 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 end of the pipe.Undistorted outside diameter shall meet the requirements ofTable 1 or Table 2.5.3.1.3 Wall Thickness
28、The 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 minimum wall thicknessspecified in Table 2 or Table 3.6Available from Superintendent of Documents, U.S. Government P
29、rintingOffice, Washington DC 20402.TABLE 1 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 (0.12
30、7) 0.02(0.508)114 1.660 (42.1) 0.005 (0.127) 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)25.3.1.4 Wall Thickness E
31、ccentricity 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 length shall not be less than the minimumlength agre
32、ed 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 as shown in the tables.5.3.2 Degree of Crosslinkin
33、gThe 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 silane compound. The degree of c
34、rosslinkingon 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 feeding accordingly.5.3.2.2 Test
35、 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 in lieu of MethodB. Method A
36、 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 materialshall not change more than 612
37、 % 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 indication of what will happen a
38、s 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 be1320 psi (9.1 MPa), for PEX X
39、X08 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 MethodD2837.NOTE 3Many desig
40、n 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 temperature may be used in determining
41、a 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. nominal diameter, the testi
42、ng 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 Tensile Strength at YieldWhen teste
43、d 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-off in service by the pipe man
44、ufacturer.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:TABLE 2 Plastic Tubing-Diameters, Wall Thick
45、nesses, 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) 0.004 (0.10) 0.062 (1.58) +0.006 (+0.15)12 0.625
46、(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 (2.27) +0.009 (+0.23)1 1.125 (28.6) 0.005 (0.13) 0
47、.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 1.375 (34.9) 0.005 (0.13) 0.062 (1.58) +0.007 (+0.
48、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)35.9.1 Prepare six randomly selected pipe specimens inaccordance with Test Method D1598 except they shall beunf
49、illed.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 temperature water, that is 67 610F (19.4 6 5.6C), condition, a
