1、Designation: F3253 17 An American National StandardStandard Specification forCrosslinked Polyethylene (PEX) Tubing with Oxygen Barrierfor Hot- and Cold-Water Hydronic Distribution Systems1This standard is issued under the fixed designation F3253; the number immediately following the designation indi
2、cates the 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, te
3、st methods,and marking requirements for crosslinked polyethylene (PEX)tubing with a polymeric oxygen barrier layer, made in onestandard dimension ratio (SDR 9), and distribution systemcomponents intended for hydronic heating and cooling appli-cations up to and including a maximum working temperature
4、of 200F (93C).1.1.1 Components are comprised of tubing, fittings, valves,and manifolds. Tubing made to this specification incorporatesa single outer or middle wall oxygen barrier layer intended forinhibiting the transmission or permeation of oxygen throughthe tubing wall. Requirements and test metho
5、ds are includedfor materials, workmanship, tubing dimensions and tolerances,burst pressure, sustained pressure, excessive temperature andpressure, thermo-cycling, bent tube, oxidative resistance, layeradhesion, UV resistance, oxygen permeation, and fitting pull-out strength tests. The components cov
6、ered by this specifica-tion are intended for use in residential and commercial hy-dronic heating and cooling systems. Requirements for potablewater applications are outside the scope of this specification.1.2 The text of this specification references notes, footnotes,and appendixes which provide exp
7、lanatory 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 mathematicalconversions to SI units that are pr
8、ovided 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, health, and environmental practices and deter-mi
9、ne the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations
10、 issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD1505 Test Method for Den
11、sity 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 Terminology forAbbreviated Terms Relating to Plas-ticsD21
12、22 Test Method for Determining Dimensions of Ther-moplastic Pipe and FittingsD2749 Symbols for Dimensions of Plastic Pipe FittingsD2765 Test Methods for Determination of Gel Content andSwell Ratio of Crosslinked Ethylene PlasticsD2837 Test Method for Obtaining Hydrostatic Design Basisfor Thermoplast
13、ic Pipe Materials or Pressure Design Basisfor Thermoplastic Pipe ProductsF412 Terminology Relating to Plastic Piping SystemsF876 Specification for Crosslinked Polyethylene (PEX) Tub-ingF877 Specification for Crosslinked Polyethylene (PEX) Hot-and Cold-Water Distribution SystemsF1281 Specification fo
14、r Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene (PEX-AL-PEX)Pressure PipeF1588 Test Method for Constant Tensile Load Joint Test(CTLJT)F1960 Specification for Cold Expansion Fittings with PEXReinforcing Rings for Use with Cross-linked Polyethylene(PEX) Tubing1This specification is under
15、the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.61 on Water.Current edition approved Dec. 1, 2017. Published February 2018. DOI: 10.1520/F3253172For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cu
16、stomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was dev
17、eloped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1F1961 Specificati
18、on for Metal Mechanical Cold Flare Com-pression Fittings with Disc Spring for Crosslinked Poly-ethylene (PEX) Tubing (Withdrawn 2018)3F1807 Specification for Metal Insert Fittings Utilizing aCopper Crimp Ring for SDR9 Cross-linked Polyethylene(PEX) Tubing and SDR9 Polyethylene of Raised Tem-perature
19、 (PE-RT) TubingF1865 Specification for Mechanical Cold Expansion InsertFitting With Compression Sleeve for Cross-linked Poly-ethylene (PEX) Tubing (Withdrawn 2018)3F2023 Test Method for Evaluating the Oxidative Resistanceof Crosslinked Polyethylene (PEX) Pipe, Tubing andSystems to Hot Chlorinated Wa
20、terF2080 Specification for Cold-Expansion Fittings with MetalCompression-Sleeves for Crosslinked Polyethylene (PEX)Pipe and SDR9 Polyethylene of Raised Temperature(PE-RT) PipeF2159 Specification for Plastic Insert Fittings Utilizing aCopper Crimp Ring for SDR9 Cross-linked Polyethylene(PEX) Tubing a
21、nd SDR9 Polyethylene of Raised Tem-perature (PE-RT) TubingF2434 Specification for Metal Insert Fittings Utilizing aCopper Crimp Ring for SDR9 Cross-linked Polyethylene(PEX) Tubing and SDR9 Cross-linked Polyethylene/Aluminum/Cross-linked Polyethylene (PEX-AL-PEX)TubingF2657 Test Method for Outdoor We
22、athering Exposure ofCrosslinked Polyethylene (PEX) TubingF2735 Specification for Plastic Insert Fittings For SDR9Cross-linked Polyethylene (PEX) and Polyethylene ofRaised Temperature (PE-RT) Tubing2.2 AWWA Standard:4Manual M-11, Steel Pipe Design and Installation2.3 Federal Standard:5FED-STD-123 Mar
23、king for Shipment (Civil Agencies)2.4 ISO Standards:6ISO 1167 Thermoplastics pipes, 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 - Ca
24、lculation method for cumu-lative damageISO 17455 Plastics piping systems Multilayer pipes Determination of the oxygen permeability of the barrierpipeISO R161-1690 Pipes of Plastic Materials for the Transportof Fluids (Outside Diameters and Nominal Pressures) Part1, Metric Series2.5 Military Standard
25、:5MIL-STD-129 Marking for Shipment and Storage2.6 NSF Standard:7NSF/ANSI Standard No. 14 for Plastic Piping Componentsand Related Materials2.7 PPI Standard:8PPI TR-3 Policies and Procedures for Developing Hydro-static Design Basis (HDB), Hydrostatic Design Stresses(HDS), Pressure Design Basis (PDB),
26、 Strength DesignBasis (SDB), Minimum Required Strength (MRS)Ratings, and Categorized Required Strength (CRS) forThermoplastic Piping Materials or PipePPI TR-4 PPI Listing of Hydrostatic Design Basis (HDB),Strength Design Basis (SDB), Pressure Design Basis(PDB) and Minimum Required Strength (MRS) Rat
27、ingsfor Thermoplastic Piping Materials or Pipe3. Terminology3.1 The terminology used in this specification is in accor-dance with Terminology F412, Terminology D1600, and Sym-bols D2749, unless otherwise specified. The abbreviation forcrosslinked polyethylene is PEX.3.2 Definitions of Terms Specific
28、 to This Standard:3.2.1 barrier layera very thin polymeric film within thetube wall or around the circumference of the tubing whichprovides a means for greatly reducing the transmission ofoxygen from the atmosphere and into the fluid within the tube.3.2.2 hydrostatic design basis (HDB)As defined by
29、Ter-minology F412 is one of a series of established stress values(specified in Test Method D2837) for a plastic compoundobtained by categorizing the long-term hydrostatic strengthdetermined in accordance with Test Method D2837.3.2.2.1 DiscussionA voluntary listing of HDB, and HDSvalues are contained
30、 in PPI publication PPI TR-4.3.2.3 hydrostatic design stress (HDS)As defined by Ter-minology F412 is the estimated maximum tensile stress thematerial is capable of withstanding continuously with a highdegree of certainty that failure of the tube will not occur. Thisstress is circumferential when int
31、ernal hydrostatic water pres-sure is applied. The HDS is equal to the hydrostatic designbasis (HDB) times the design factor (DF) for water; HDS5HDB3DF. For this specification, the design factor is less thanor equal to 0.50.3.2.4 hydrostatic strength equivalency (HSE)a pressuretesting evaluation meth
32、odology where hydrostatic testing isconducted on PEX tubing that is constructed with a barrierlayer or layers in the middle or outside wall of the tubing, andis constructed with PEX material that has an established HDB.HSE methodology is applied where the barrier layer or layersreduce the thickness
33、of the HDB rated PEX material in the wallsuch that the PEX wall thickness excluding the barrier layer(s)is slightly less than that required for SDR 9.0.3.2.4.1 DiscussionHSE testing is conducted to confirmthat the pressure rating of the PEX tubing having a barrier layer3The last approved version of
34、this historical standard is referenced onwww.astm.org.4Available from American Water Works Association (AWWA), 6666 W. QuincyAve., Denver, CO 80235, http:/www.awwa.org.5DLA Document Services Building 4/D 700 Robbins Avenue Philadelphia, PA19111-5094 http:/quicksearch.dla.mil/6Available from Internat
35、ional Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.7Available from NSF International, P.O. Box 130140, 789 N. Dixboro Rd., AnnArbor, MI 48113-0140, http:/www.nsf.org.8Plastics Pipe Institu
36、te (PPI), 105 Decker Court, Suite 825 Irving TX, 75062.http:/www.plasticpipe.orgF3253 172or layers as described herein is at least equal to comparableSDR 9.0 PEX tubing that does not have a barrier layer orlayers. When PEX tubing has a barrier layer(s) that does notreduce the thickness of the HDB-ra
37、ted PEX material below thatrequired for SDR 9.0, it is not necessary to conduct HSEtesting because pressure rating is determined using the ISOequation (3.2.6).3.2.5 HSE-SDR 9an identifying term for the tubing wherethe minimum PEX wall thickness falls outside the calculatedSDR 9 values yet the tubing
38、 as constructed meets the pressurerating requirements of this standard as demonstrated by HSEevaluation testing.3.2.6 ISO equation and pressure rating (PR)The relation-ship between dimensions, hydrostatic design basis, hydrostaticdesign stress, and pressure rating as defined by TerminologyF412 is il
39、lustrated as follows specific to this specification.The following is commonly referred to as the ISO equation(See ISO R161-1690.) :S 5 POD 2 t!2t For outside diameter controlled pipe! (1)where:S = hoop stress,P = pressure,OD = average outside diameter,t = minimum wall thicknessThe pressure rating (P
40、R) and HDS/HDB are related by thefollowing equation:PR 5 2HBD!DF!SDR 2 1! 5 2HDS!SDR 2 1! (2)(being specific to this specification with DF=0.50 and SDR9)PR 5 2HDB!0.50!9 2 1! 5 2HDS!8 (3)Example: PEX with HDB of 800 PSI at 180 F made ac-cording to this specification to SDR 9PR 5 2800!0.50!9 2 1! 5 1
41、00 PSI (4)3.2.7 manifoldan appurtenance that has at least one inletand multiple outlets3.2.8 standard dimension ratio (SDR)the ratio of outsidediameter to wall thickness as defined by Terminology F412except this standard uses the minimum total wall thickness,inclusive of layers, to establish SDR. Wh
42、en the total wallthickness calculated by the given formula is less than 0.070 in.(1.78 mm) then the total wall thickness is arbitrarily increasedto 0.070 in. except for NTS516 and smaller which areprescriptively assigned.3.2.9 standard thermoplastic tubing materials designationcodeThis material desi
43、gnation code consists of the abbrevia-tion for the type of plastic (PEX) followed by fourArabic digitsthat describe those properties in accordance with applicableASTM standards and as shown in Table 1. This materialdesignation code solely addresses the PEX material and doesnot address any other poly
44、meric materials which might be usedin the construction of oxygen barrier tubing.3.2.9.1 DiscussionThe first digit is for chlorine resistance.Since this standard is specific to hydronic distribution systems,chlorine resistance is not a mandatory requirement of thisapplication and the default “0” is u
45、sed if oxidative stability isevaluated only per 6.1.9.1 (stabilizer functionality). If oxida-tive stability is evaluated per 6.1.9.2 (chlorine resistance), thisdigit is defined by Specification F876 as follows:(1) A digit “0” indicates that the PEX tubing either has not been tested forchlorine resis
46、tance or that the PEX tubing does not meet the minimumrequirement for chlorine resistance.(2) A digit “1” indicates the PEX tubing has been tested and meets therequirement of 6.1.9.2 for minimum chlorine resistance at the end usecondition of 25% at 140F (60C) and 75% at 73F (23C).(3) A digit “2” is
47、reserved for future application.(4) A digit “3” indicates that the PEX tubing has been tested and meets therequirement of 6.1.9.2 for minimum chlorine resistance at end usecondition of 50% at 140F and 50% at 73F.(5) A digit “4” is reserved for future application.(6) A digit “5” indicates that the PE
48、X tubing has been tested and meets therequirement of 6.1.9.2 for minimum chlorine resistance at end useconditions of 100% of the time at 140F.3.2.9.2 DiscussionThe second digit is for demonstratedUV resistance of PEX material when tested in accordance withTest Method F2657. For this specification it
49、 is one of theclassification digits listed in Table 1 for the Nominal ExposureTime Period from Table 1 in Test Method F2657 where thedecreased average failure time from 10.3 of Test MethodF2657 is less than or equal to 21%.Alternately, the second digitmay be one of the classification digits from Table 1 for theNominal Exposure Time Period from Table 1 of Test MethodF2657 where the UV-exposed samples meet the requirement of7.2.10 Stabilizer Functionality.(1) The 21% pass/fail criteria originates from the statisticalanalysis of a
