1、Designation: F876 15aStandard Specification forCrosslinked Polyethylene (PEX) Tubing1This standard is issued under the fixed designation F876; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers crosslinked polyethylene(PEX) tubing that incorporates an optional polymeric inner,middle or outer layer and that is ou
3、tside diameter controlled,made in nominal SDR9 tubing dimension ratios except wherenoted, and pressure rated for water at three temperatures (seeAppendix X1). Included are requirements and test methods formaterial, workmanship, dimensions, burst pressure, hydrostaticsustained pressure, excessive tem
4、perature pressure, environ-mental stress cracking, stabilizer functionality, bent-tube hy-drostatic pressure, oxidative stability in potable chlorinatedwater, and degree of crosslinking. Requirements for tubingmarkings are also given.1.2 The text of this specification references notes, footnotes,and
5、 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 values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconver
6、sions 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 this specification: Thisstandard does not purport to address all of the safety concerns,if any, associated with its
7、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. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD792 Test Methods for De
8、nsity 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 HydraulicPressure o
9、f 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 FittingsD2765 Test Methods for Determination of Gel Content andSwell Ratio
10、of Crosslinked Ethylene PlasticsD2837 Test Method for Obtaining Hydrostatic Design Basisfor Thermoplastic Pipe Materials or Pressure Design Basisfor Thermoplastic Pipe ProductsD3895 Test Method for Oxidative-Induction Time of Poly-olefins by Differential Scanning CalorimetryF412 Terminology Relating
11、 to Plastic Piping SystemsF1281 Specification for Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene (PEX-AL-PEX)Pressure PipeF2023 Test Method for Evaluating the Oxidative Resistanceof Crosslinked Polyethylene (PEX) Tubing and Systemsto Hot Chlorinated WaterF2657 Test Method for Outdoor Wea
12、thering Exposure ofCrosslinked Polyethylene (PEX) Tubing2.2 ANSI Standard:B36.10 Standards 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 Storage51This specification is under the jurisdi
13、ction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.26 on OlefinBased Pipe.Current edition approved Sept. 1, 2015. Published November 2015. Originallyapproved in 1984. Last previous edition approved 2015 as F876 15. DOI:10.1520/F0876-15A.2For ref
14、erenced 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.3The last approved version of this historical standard is referenced
15、onwww.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5DLA Document Services Building 4/D 700 Robbins Avenue Philadelphia, PA19111-5094 http:/quicksearch.dla.mil/*A Summary of Changes section appears at the end o
16、f this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.5 NSF Standard:NSF/ANSI 14 for Plastic Piping Components and RelatedMaterials62.6 ISO Standards:4ISO 1167 Thermoplastics pipes, fittings and assemblies forthe conveyance
17、 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 for the Transportof Fluids (Outside Diameter
18、s and Nominal Pressures) Part1, Metric Series2.7 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
19、are in accordance with Termi-nology F412, and abbreviations are in accordance with Termi-nology D1600, unless otherwise specified. The abbreviation forcrosslinked polyethylene is PEX. Plastic tubing denotes aparticular diameter schedule of plastic pipe in which outsidediameter of the tubing is equal
20、 to the nominal size plus18 in.Plastic pipe outside diameter schedule conforms to ANSIB36.10.3.2 Definitions of Terms Specific to This Standard:3.2.1 crosslinked polyethylenea polyethylene materialwhich has undergone a change in molecular structure using achemical or a physical process whereby the p
21、olymer chains arechemically linked.3.2.2 hydrostatic design stress (HDS)the estimated maxi-mum tensile stress 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 pres
22、sure is applied. The HDS is equal to thehydrostatic design basis (HDB) times the design factor (DF)for water. For this standard, the design factor is equal to 0.50.HDS 5 HDB 3DF5HDB 30.50 for this standard!3.2.3 hydrostatic design basis (HDB)one of a series ofestablished stress values (specified in
23、Test Method D2837) fora plastic compound obtained by categorizing the long-termhydrostatic strength determined in accordance with TestMethod D2837.3.2.3.1 DiscussionA listing of HDB and HDS values arecontained in PPI publication PPI TR4.3.2.4 pressure rating (PR)the estimated maximum waterpressure t
24、he tube is capable of withstanding continuously witha high degree of certainty that failure of the tube 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
25、 dimensions, hydrostatic design stress, and pressurerating:2S/P 5 DO/t! 2 1 (1)or2S/P 5 R 2 1where:S = hydrostatic 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
26、.6 standard dimension ratio (SDR)the ratio of outsidediameter to wall thickness. For PEX-tubing, it is calculated 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 i
27、sless than 0.070 in. (1.78 mm) it shall be arbitrarily increased to0.070 in. except for sizes516 in. and smaller, as specified inTable 1. The SDR values shall be rounded to the nearest 0.5.3.2.7 standard thermoplastic tubing materials designationcodeThe tubing material designation code shall consist
28、 of theabbreviation for the type of plastic (PEX) followed by fourArabic digits that describe short-term properties in accordancewith applicable ASTM standards and as shown in Table 2. SeeFig. 1.6Available from NSF International, P.O. Box 130140, 789 N. Dixboro Rd., AnnArbor, MI 48113-0140, http:/ww
29、w.nsf.org.7Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825 Irving TX, 75062.http:/www.plasticpipe.org8ISO R161-1690.TABLE 1 Wall Thickness and Tolerances for Nominal PEX SDR 9Plastic TubingANominal TubingMinimum WallThicknessTolerancein. mm in. mm in. mm18 3 0.047B1.19B+0.007 +0.1814 7 0.
30、062B1.57B+0.010 +0.25516 8 0.064 1.63 +0.010 +0.2538 10 0.070B1.78B+0.010 +0.2512 13 0.070B1.78B+0.010 +0.2558 16 0.083 2.12 +0.010 +0.2534 19 0.097 2.47 +0.010 +0.251 25 0.125 3.18 +0.013 +0.33114 32 0.153 3.88 +0.015 +0.38112 38 0.181 4.59 +0.019 +0.482 51 0.236 6.00 +0.024 +0.61212 64 0.292 7.41
31、+0.030 +0.763 76 0.347 8.82 +0.033 +0.84312 89 0.403 10.23 +0.035 +0.894 102 0.458 11.64 +0.040 +1.02412 114 0.514 13.05 +0.045 +1.145 127 0.569 14.46 +0.050 +1.276 152 0.681 17.29 +0.060 +1.52AThe minimum is the lowest wall thickness of the pipe at any cross section. Themaximum permitted wall thick
32、ness, at any cross section, is the minimum wallthickness plus the stated tolerance. All tolerances are on the plus side of theminimum requirement.BFor tubing sizes of12 in. and below, wall thickness minimums are not functionsof SDR.F876 15a23.2.7.1 DiscussionThe first digit is for chlorine resistanc
33、etested in accordance with Test Method F2023.(1) A digit “0” indicates that the PEX tubing either has notbeen tested for chlorine resistance or that the PEX tubing doesnot meet the minimum requirement for chlorine resistance.(2) A digit “1” indicates the PEX tubing has been testedand meets the requi
34、rement of 6.10 for minimum chlorineresistance at the end use condition of 25% at 140F (60C) and75% at 73F (23C).(3) A digit “2” is reserved for future application.(4) A digit “3” indicates that the PEX tubing has beentested and meets the requirement of 6.10 for minimum chlorineresistance at end use
35、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 of 6.10 for minimum chlorineresistance at end use conditions of 100% of the time at 140F3.2.7.2 DiscussionThe second digit
36、is for demonstratedUV resistance of PEX material when tested in accordance withTest Method F2657. For PEX tubing with the first digit of thematerial designation code equal to 1, 3, or 5 the second digitshall be one of the classification digits listed in Table 2 for theNominal Exposure Time Period fr
37、om Table 1 in Test MethodF2657 where the decreased average failure time from 10.3 ofTest Method F2657 is less than or equal to 21%. For PEXtubing with the first digit of the material designation code equalto 0, the second digit shall be one of the classification digitsfrom Table 2 for the Nominal Ex
38、posure Time Period fromTable 1 of Test Method F2657 where the UV-exposed samplesmeet the requirement of 7.10 Stabilizer Functionality, oralternatively using the criteria for potable water piping found inthe preceding sentence of this clause.3.2.7.3 DiscussionThe 21% pass/fail criteria originatesfrom
39、 the statistical analysis of an aggregate of data setsgenerated using Test Method F2023 and represents the meanLower Predictive Limit (95% two sided) compared to theexpected failure times based on three stress levels at each ofthree temperatures. Thus, this value represents the limit forstatistical
40、differentiation in failure times using Test MethodF2023 at the 95% confidence level (2 sided). This research wasconducted for the Plastics Pipe Institute in 2005.9(1) The UV resistance shall be demonstrated on represen-tative pipe samples for the original validation of pipe madefrom a particular PEX
41、 material, that material being the com-bination of PEX resin and its additive system.(2) The last two digits are the hydrostatic design stress forwater at 73F (23C) in units of 100 psi with any decimalfigures dropped. Where the hydrostatic design stress codecontains less than two figures, a zero is
42、used before the number.Thus, a complete material designation code for PEX tubingshall consist of the three letters “PEX” and four digits.4. Tubing Classification4.1 GeneralThis specification covers one PEX tubingmaterial in one standard dimension ratio and having pressureratings for water of three t
43、emperatures. The pressure ratingsdecrease as the temperature is increased.4.2 Standard Thermoplastic Pipe Dimension Ratio (SDR)This specification covers PEX tubing in one standard dimen-sion ratio (SDR 9) for nominal diameters58 in. and larger, andwith a specified wall thickness for smaller diameter
44、s. Thepressure ratings are uniform for all nominal tubing sizes.9PPI Technical literature, Final Report Proposal for the Evaluation of theChlorine Resistance of UV Exposed PEX Pipe.For example ASTM F876 PEX tubing marked with the material designation code PEX 1106 is a PEX tubing meeting the chlorin
45、e resistance requirement for 25% of thetime at 140F and 75% of the time at 73F having a Minimum UV resistance of 1 month and having an HDS for water at 73F of 630psi (HDB of 1250 psi).FIG. 1 Standard Thermoplastic Tubing Materials Designation CodeTABLE 2 Material Designation Code CellsProperty Stand
46、ard 0 1 2 3 4 5 6 7 8 9ChlorineResistanceF2023 Not testedor rated75 %at 73Fand 25 %at 140FReserved 50 %at 73Fand 50 %at 140FReserved 100 %at 140F. . . .Minimum UVResistanceF2657 Not testedor rated1 month 3 months 6 months . . . . . .HDSfor water at73F. . . . . . . 630 . 800 .F876 15a35. Materials5.1
47、 GeneralCrosslinked polyethylene tubing, meeting therequirements of this specification, are primarily defined bymeans of 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-
48、term strength tests.NOTE 1PEX tubing intended for use in the transport of potable watershould be evaluated and certified 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 o
49、dorthat are no less restrictive than those included in NSF/ANSI 14. The sealor mark of the laboratory making the evaluation should be included on thetubing.5.2 Basic MaterialsPEX tubing 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 suchthat the tubing meets the performance requirements of Section6. For the use temperatures that the tubing will be marked for,the materials, proced
